# Hall effect woes!



## creast

Hi,
I have finally managed to get my Kerzel H&M running but am now plagued with Hall effect failures.
I have used a few circuits but the latest was posted in an earlier thread here which I cannot track back to. The circuit is attached.
This circuit works fine but I have yet to run more than a few minutes before the Hall effect goes T*ts up and dies. I have put protection diode and capacitor as recommended elsewhere but no luck. Any ideas?


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## Noitoen

There is no supply to the hall device. You should put a 5v zener diode in parallel with the hall ic to protect it from voltage spikes


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## jgedde

If I understand correctly, you're saying you've tried multiple driver circuits and the hall keeps dying?

Is this the circuit you were referring to?

http://www.homemodelenginemachinist.com/f31/new-ignition-circuit-20415/index2.html#post214570



John


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## stevehuckss396

I have found that a poor ground to the engine block causes most hall failures in my garage.


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## canadianhorsepower

You should be sending you Hall circuit connected to this one
this would allow us to see your source voltage and if you had a current limiter somewhere


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## creast

Although the circuit shows no direct supply on the diagram, I am supplying 12v to the Hall device which the spec says it should be ok with. The supply however is the same as that to the coil so maybe thats a problem?



Noitoen said:


> There is no supply to the hall device. You should put a 5v zener diode in parallel with the hall ic to protect it from voltage spikes


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## creast

Thanks Steve,
I found that too when I forgot to connect the -ve rail to the engine and it arced from the Hall to the block. However, I have ensured a good connection to the -ve rail now and still I get Hall failures.
A friend has suggested a true earth, ie earth to ground or on appliance, as high static charges can build up and at one stage I was getting mild electric shocks as I spun the flywheel.
I can't think that I would have to have to ground to earth since we don't do that to our cars do we.



stevehuckss396 said:


> I have found that a poor ground to the engine block causes most hall failures in my garage.


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## creast

Hi John,
I have not tried that particular circuit.
The one I attached is somewhere on this site but I am having problems finding it again.
I had tried Jan Ridders Blokker circuit modified with a hall effect but had similar problems with the Hall effect dying.



jgedde said:


> If I understand correctly, you're saying you've tried multiple driver circuits and the hall keeps dying?
> 
> Is this the circuit you were referring to?
> 
> http://www.homemodelenginemachinist.com/f31/new-ignition-circuit-20415/
> 
> 
> John


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## jgedde

OK.  Try this.  Power the hall with a 100 ohm resistor in series with its power lead.  Put a 0.1 uF capacitor between the power lead and the ground pin.  Put a 12V or 15V zener diode in parallel with the cap between the power and ground pins on the hall.  

Using a zener will protect the hall from both positive _and_ negative transients.  For positive transients, it'll avalanche at 12V, for negative transients it'll conduct like a regular forward biased diode and clamp the transient to about -0.6V.

If the Halls _still_ blow, then it's the output transistor in the hall that's popping.  That transistor is comparatively large in scale, but on the Honeywell die (who make the guts for many manufacturers) the collector lead to the transistor burns up (I was present for a Hall sensor failure analysis and that's what we saw when the part was delidded).

If the resistor, cap and zener diode don't help, put a 100 ohm series resistor between the hall output pin and the drive circuit to prevent excessive currents.  If it's this solution that works, we have to dig into this some more.  If it does, I would suspect the large value of capacitance in the circuit (4.7 uF) is providing enough surge current to pop the Hall output transistor's collector trace.


In addition, it's IMPERATIVE that the engine block be well grounded.  If there's aluminum around, you'd be surprized about how hard it it to get a solid electrical connection through the oxide layer and hardware.
John


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## canadianhorsepower

jgedde; 
                instead of blasting any sugestion"like we are all phone post" are stupid and relating your circuit to close to perfection
do me a favour and everybody else a favour
put your knowledge were your mouth is and draw a circuit that we can all use
NOT ONE THAT YOU CAN ***** ABOUT

cheers


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## jgedde

canadianhorsepower said:


> jgedde;
> instead of blasting any sugestion"like we are all phone post" are stupid and relating your circuit to close to perfection
> do me a favour and everybody else a favour
> put your knowledge were your mouth is and draw a circuit that we can all use
> NOT ONE THAT YOU CAN ***** ABOUT
> 
> cheers


 

What???  You've got the wrong idea friend...  My circuit is irrelevant.  He's having problems and I have some ideas on how to fix it.  

The parts for my circuit will be here on Monday.  If it doesn't work, I'm humble enough to say so, revise it accordingly, and share my results.  But, I really have little doubt it will work with no more changes than resistor values. 

John


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## canadianhorsepower

jgedde said:


> What??? You've got the wrong idea friend...


ok then prove it, or put it on the table


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## jgedde

canadianhorsepower said:


> ok then prove it, or put it on the table


 

Like I said, the parts for my circuit will be here Monday.  Apart from my circuit, if my suggestions on how to cure the hall sensors from dying works, then everyone is happy right?

John


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## GailInNM

Play nice Luc.
Everyone here is just trying to help.  No need to fight.
Gail in NM


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## creast

jgedde,
Thanks for the suggestions. I will give them a try and keep fingers crossed.
Not sure why Canadianhorsepower gave that outburst when you are being helpful.
Thanks anyway
Rich




jgedde said:


> OK.  Try this.  Power the hall with a 100 ohm resistor in series with its power lead.  Put a 0.1 uF capacitor between the power lead and the ground pin.  Put a 12V or 15V zener diode in parallel with the cap between the power and ground pins on the hall.
> 
> Using a zener will protect the hall from both positive _and_ negative transients.  For positive transients, it'll avalanche at 12V, for negative transients it'll conduct like a regular forward biased diode and clamp the transient to about -0.6V.
> 
> If the Halls _still_ blow, then it's the output transistor in the hall that's popping.  That transistor is comparatively large in scale, but on the Honeywell die (who make the guts for many manufacturers) the collector lead to the transistor burns up (I was present for a Hall sensor failure analysis and that's what we saw when the part was delidded).
> 
> If the resistor, cap and zener diode don't help, put a 100 ohm series resistor between the hall output pin and the drive circuit to prevent excessive currents.  If it's this solution that works, we have to dig into this some more.  If it does, I would suspect the large value of capacitance in the circuit (4.7 uF) is providing enough surge current to pop the Hall output transistor's collector trace.
> 
> 
> In addition, it's IMPERATIVE that the engine block be well grounded.  If there's aluminum around, you'd be surprized about how hard it it to get a solid electrical connection through the oxide layer and hardware.
> John


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## jerrybilt

The first thing I would do with this circuit is place a diode ( 1N4004 ) across the primary winding of the ignition transformer. The anode of the diode is connected to pin 2 and the cathode is connected to pin 1 ( + 12V). The other thing that I would do is to redesign the final drive to the ignition transformer. Notice that the transformer is left floating when the final transistor (IGBT) is turned off so an emitter follower, where transformer will be earthed, will be more suitable.

Jerry.


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## jgedde

jerrybilt said:


> The first thing I would do with this circuit is place a diode ( 1N4004 ) across the primary winding of the ignition transformer. The anode of the diode is connected to pin 2 and the cathode is connected to pin 1 ( + 12V). The other thing that I would do is to redesign the final drive to the ignition transformer. Notice that the transformer is left floating when the final transistor (IGBT) is turned off so an emitter follower, where transformer will be earthed, will be more suitable.
> 
> Jerry.


 
Jerry, I believe you are mostly correct.  However, a diode across the primary clamps the kickback voltage (since it spikes positive by a few hundred volts at the collector of the transistor when it turns off).  While this would give a path for the current as you state, but it also affects the output voltage...  Instead of transforming 300V or so by a ratio of 100, you'd only be transforming the diode drop by a factor of 100.

That's why I maintain the age old method of putting a "condenser" across the breaker points (or output transistor) is necessary.  Not only do you give the oscillating current somewhere to go without clamping the kickback, but you get a LC resonant circuit which, if used with the right value cap, will give you even more voltage...

John


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## jerrybilt

Only one problem John, when the drive transistor turns off the transformer is effectively removed from the circuit as the common connection is left floating and the only thing completing the circuit is some parasitic capacitance that helps complete the circuit. The capacitor across the points will stop the arching due to the high current being interrupted. This arching causes the current to decay more slowly hence the induced voltage is much lower in a system with points. But using a transistor, as opposed to points, as a switch there is no arching and the rate of change of current is limited by the primary inductance and the circuit resistance.


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## jgedde

jerrybilt said:


> Only one problem John, when the drive transistor turns off the transformer is effectively removed from the circuit as the common connection is left floating and the only thing completing the circuit is some parasitic capacitance that helps complete the circuit. The capacitor across the points will stop the arching due to the high current being interrupted. This arching causes the current to decay more slowly hence the induced voltage is much lower in a system with points. But using a transistor, as opposed to points, as a switch there is no arching and the rate of change of current is limited by the primary inductance and the circuit resistance.


 
Again, the capacitor does more than prevent arcing.  It provides a bidirection path for the flyback current, thus the circuit is not open...  In any case, even if there is no capacitor, the circuit is not floating when the transistor turns off.  An ignition coil is an autotransformer and secondary current flows through the spark plug thus completing the circuit.


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## canadianhorsepower

GailInNM said:


> Play nice Luc.
> Everyone here is just trying to help.  No need to fight.
> Gail in NM


 
I don't have problem with playing nice  and I understand that we are all trying to help. 
What pinches  me is when your giving wrong information to someone just to look smart.
Not having the circuit diagram or parts number any parts replacement 
suggestion can  make things worst . 
And nobody on earth can guess what circuit he's using


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## jgedde

canadianhorsepower said:


> I don't have problem with playing nice  and I understand that we are all trying to help.
> What pinches  me is when your giving wrong information to someone just to look smart.
> Not having the circuit diagram or parts number any parts replacement
> suggestion can make things worst .
> And nobody on earth can guess what circuit he's using


 
Luc, He _did_ give his circuit diagram. It's in his original post... And, bipolar, non-latching, hall sensors are "you've seen one, you've seen them all". My suggestions were for general filtering, bypassing, and transient protection. If you'd draw out my recommendations, you'd see that it is not wrong... A series resistor, and a bypass capacitor along with a zener in parallel with the hall sensor to clamp transients that still get through. 

I use hall sensors here at work on a daily basis. After 15 years of working with them, I know that they're generally robust, but do fail under certain conditions and I'm well versed in what they are. Want to see the inside of a failed sensor? Look here...

Let's see what he comes back with. I think there's a good chance my sugegstions will work.

John


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## jgedde

creast said:


> Hi,
> I have finally managed to get my Kerzel H&M running but am now plagued with Hall effect failures.
> I have used a few circuits but the latest was posted in an earlier thread here which I cannot track back to. The circuit is attached.
> This circuit works fine but I have yet to run more than a few minutes before the Hall effect goes T*ts up and dies. I have put protection diode and capacitor as recommended elsewhere but no luck. Any ideas?


 

By the way Creast, what hall sensor are you using?  Can you give us the part number?   If not, verify you have the correct pin out.  Generally they are as follows:
pin 1: Power
pin 2: Ground
pin 3: Out

I can't help but wonder if you have output and power pins reversed...  The hall will actually sort of work that way, but it shorts out the power supply through itself every time it turns on...

John


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## canadianhorsepower

jgedde said:


> Luc, He _did_ give his circuit diagram. It's in his original post... And, bipolar, non-latching, hall sensors are "you've seen one, you've seen them all". My suggestions were for general filtering, bypassing, and transient protection. If you'd draw out my recommendations, you'd see that it is not wrong... A series resistor, and a bypass capacitor along with a zener in parallel with the hall sensor to clamp transients that still get through.
> 
> I use hall sensors here at work on a daily basis. After 15 years of working with them, I know that they're generally robust, but do fail under certain conditions and I'm well versed in what they are. Want to see the inside of a failed sensor? Look here...
> 
> Let's see what he comes back with. I think there's a good chance my sugegstions will work.
> 
> John


 
I've been working with hall sensor  for many year. It's the most common sensor we put in Robots. Designing robot is a part of my hobby, I teach robotic engineering as a job.
As far as the diagram is concern their is a partial one, no voltage applied to the sensor is specified or what kind of sensor he's using check the picture I've attached . After you've seen one sensor you've seen them all as far as operation is concern yes, but not as far as specs.


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## Noitoen

That's what I meant in post #2. There is no supply to the hall device but then again, maybe the drawing was incorrectly posted with a mistake.


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## canadianhorsepower

Noitoen said:


> That's what I meant in post #2. There is no supply to the hall device but then again, maybe the drawing was incorrectly posted with a mistake.


 
I saw that to that's why I ask for the drawing if this is it a simple fixe
but if something is missing we just can't guess what it is


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## jgedde

creast said:


> Although the circuit shows no direct supply on the diagram, I am supplying 12v to the Hall device which the spec says it should be ok with. The supply however is the same as that to the coil so maybe thats a problem?


 
Luc,

Remember he said this? (see above) His hall is running from 12V despite what the schematic shows...

John


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## canadianhorsepower

jgedde said:


> Luc,
> 
> Remember he said this? (see above) His hall is running from 12V despite what the schematic shows...
> 
> John


back to square one 
no specs nobody knows the value and
numbers assume are useless


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## creast

Hi Guys,
The circuit was published here on another thread and I have yet to find the original thread again so I can quote who published it.
Although the device shows no supply to the hall I thought it obvious to connect the supply to + and - rails the device is connected to.
The device I am using is Allegro A1102 and running at 12V from a battery.
I have implemented the mods suggested by John and so far its holding out but I have added extra safety by earthing to my PSU unit.
As I need to do some work on the engine I will make a test rig for long term testing the circuit and then without a real earth since I want to run battery only.
I will keep you posted.
Many thanks
Rich




canadianhorsepower said:


> back to square one
> no specs nobody knows the value and
> numbers assume are useless


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## steam58

i would like to build a circuit for my upshur that uses a hall effect. can you post the circuit that you got that will work
thanks 
jay


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## creast

Hi again,
I located where I saw the circuit.
http://www.homemodelenginemachinist.com/f26/ignition-circuit-help-19673/index2.html
John, I am surprised you didn't remember since you did comment on it to member DSage.
You said not to connect the common HT to the collector. So should it go to the +ve ??
Cheers
Rich


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## jgedde

Creast,  No need to rewire the coil it should be OK the way it is.  dsage's circuit is just fine.

My circuit is well on it's way to being completed and I expect to have test results on Monday along with any circuit revisions that were necessary to:
1) Ensure robust operation despite component tolerances.
2) Safety of the hall sensor.
3) A good strong spark whikle maintaining a long battery life.

John


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## creast

Hi John
I did all the safety measures you suggested including the 100 ohm to the capacitor and the circuit seems to behave ok.
I am rigging it to a motor to keep triggering for some hours whilst I do work on the engine.
Look forward to the results of your circuit.
Cheers
Rich





jgedde said:


> Creast,  No need to rewire the coil it should be OK the way it is.  dsage's circuit is just fine except for guarding the hall from the discharge of the 4.7uF cap.
> 
> I would just add a resistor in series with the output lead to protect the hall from the discharge current when the hall turns on if you haven't already done so.  That sucker can hold enough energy to fry the hall if you don't limit the current.  100 to 400 ohms should be fine.
> 
> My circuit is well on it's way to being completed and I expect to have test results on Monday along with any circuit revisions that were necessary to:
> 1) Ensure robust operation despite component tolerances.
> 2) Safety of the hall sensor.
> 3) A good strong spark whikle maintaining a long battery life.
> 
> John


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## jgedde

creast said:


> Hi John
> I did all the safety measures you suggested including the 100 ohm to the capacitor and the circuit seems to behave ok.
> I am rigging it to a motor to keep triggering for some hours whilst I do work on the engine.
> Look forward to the results of your circuit.
> Cheers
> Rich


 
Rich,  I'm glad to hear it all worked out so far.  Keep us posted on your life test.  

Cheers,
John


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## dsage

Sorry I wasn't aware of this thread or I would have chimed in earlier to defend (as it were) my circuit. But it seems John (jgedde) has done a good job since his circuit is almost the same. Albeit he chose to add a bit more protection ( no harm done with a few extra parts). I haven't found any of it necessary. Read on...

The only thing I wish is that people would link to the original post and not take things like the schematic out of context and paste it without the original comments on it.  I think it was properly linked a couple of posts back but if not here it is (I hope I have it right myself)
http://www.homemodelenginemachinist.com/f26/ignition-circuit-help-19673/index2.html

POST #17

You will note that #6 in the list states that the hall sensor CAN but need not be supplied from the same supply as the coil. 

LUC there IS a supply stated for the Hall sensor and you in fact circled it a few posts back it's +VE just like the rest of the stuff connected to the same point on the left side. 
 I guess to be more clear (and conventional) there COULD have been another line marked +VE up at the top shown feeding the whole left side but it would be somewhat redundant since the hall sensor is connected there already and it's marked clearly +VE which is somewhat standard notation for a logic power supply (well, for me anyway).

As for the Hall sensor, I suppose a part number would have been useful but most of the ones folks use are pretty much the same. There is very little current requirement for the sensor so I can't imagine one that wouldn't work. Read on....

The coil supply is marked separately as +12v ignition supply. On purpose to show that it need not be the same as +VE.

The circuit was designed so you can drive it from any logic circuit not just a hall sensor. You could substitute any 5v logic device even a microprocessor output to the driver input. Of course +Ve would be the supply used for that circuit. In the case of a micro +Ve would be 5v.
*** I did state  in the original post that the only important thing is to be sure the grounds (negatives) of the two supplies are connected together.

I also have a version with the front end driven by a 555 timer to create a "buzz" coil" multi-spark ignition. I have the ignition coil and the 555 running from the same 12v battery as well READ ON...

I find in a lot of cases problems are self-inflicted. A lot of folks don't follow proper grounding procedures interconnecting the various pieces so it's not a problem with the circuit per se but an interconnecting wiring issue.
I think Steve touched on it when he said when he grounded something properly he had no more problems.
This is just something you learn after 38 years experience (like me). You can't really put it in a schematic.

Addition of extra components to cure whatever problems one experiences in their particular situation are certainly allowed but don't be afraid to look at the wiring to see if the problems are being caused by other issues. I admit finding these things is a bit of a black art. One that I don't even understand most times. But attention to grounding detail is important.

The suggestion of resistor and capacitor on the +VE  to the Hall sensor (a filter of you wish) if you are going to use a common supply for the logic and ignition is a good suggestion. Although you have the biggest filter in the world right there in front of you connected to exactly the same place. It's called the battery. Having said that the battery does have some impedance so it may not pass spikes well. So go ahead and use the resistor/capacitor filter or what ever makes you happy.
Sorry if you blow a Hall sensor figuring out that you may need that. I never did.

More important is that you have a good short heavy ground lead from the battery negative to the engine block and ground everything to the same point. No long wires.

Re the high voltage circuit:
Coils only have three leads so the negative of the coil is connected to one side of the HV side of the "transformer". As shown the connection is  inside the coil.
Someone stated that with the circuit drawn the way I have it that HV current path is made through parasitic capacitance or some such crap. To that I say draw the WHOLE circuit including the battery. You will see that the HV current comes from the HV lead, jumps the spark plug gap to ground. The HV current flows through the (very low resistance) battery back to +12v where it is connected to the primary side of the ignition coil. It then it flows through the low resistance primary winding to the junction I've shown inside the coil to the HV side to complete the HV path. (just the way it's done for as long as the kettering ignition has been around). The various low resistances along the way have no effect. In fact they can enhance the spark.

So, this brings up another point. If you have a CRAPPY battery with high resistance, and not a nice Gel Cell made with proper connections (mentioned briefly above)  spikes created by the HV current through the battery are more likely to develop across it causing problems with other things connected to the battery i.e. the driver circuit. So go ahead and add the filter.

Like I said I can't allow for everyone's self-inflicted problems. Add whatever components you need to to make it work for you.

I have no intention of sounding "snippy" here. Upon re-reading it comes across that way. Sorry for that. Just trying to clarify a few things

Sorry for such a long post.

Now let the arguments begin. :fan:

Sage


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## dsage

Based on what I've already posted maybe the drawing below will make things more clear with regards to the +VE connection. As mentioned in my previous post +VE can be, but does not need to be, the same 12V connected to the ignition coil side of the circuit. Just be sure the grounds (negatives) of both supplies are connected together (to the same point with short stout leads). if you choose to use separate supplies.

Any other components you find necessary to add to correct your local particular issues are optional and up to the individual builder. I find the circuit works fine like it is. Maybe I'm lucky. I'd be happy to analyze at any concerns others can identify.


Sage


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## canadianhorsepower

> LUC there IS a supply stated for the Hall sensor and you in fact circled it a few posts back it's +VE just like the rest of the stuff connected to the same point on the left side.
> I guess to be more clear (and conventional) there COULD have been another line marked +VE up at the top shown feeding the whole left side but it would be somewhat redundant since the hall sensor is connected there already and it's marked clearly +VE which is somewhat standard notation for a logic power supply (well, for me anyway).


 
SAGE it's funny how you can explain thing. In the first quote your giving a lecture about VE was well indicated and that We should all have known this




> The circuit was designed so you can drive it from any logic circuit not just a hall sensor. You could substitute any 5v logic device even a microprocessor output to the driver input. Of course +Ve would be the supply used for that circuit. In the case of a micro +Ve would be 5v


 
then a few line after the next quote, your explaining that VE+ could have been different then the 12 volts  so this only shows that I was wright in asking what he had as VE+.

 If someone is asking for help we must assume that he's lacking knowledge or experience to fully succeed. There for asking precise question about the circuit only makes more precise diagnosing suggestion


*

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## Mosey

I am lacking in knowledge and following along in the hopes of learning how these systems work. I would appreciate it if you would refrain from sarcasm and less than polite personal criticism of those who offer their knowledge for the rest of us. I admire and respect those folks who share their knowledge, and don't need to make themselves look wise by criticizing others.
Thank you.
Mosey


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## dsage

LUC:
Yeah - except that all of what you have written gets back to my very first point right a the top. Which I guess you didn't read. 

People need to RTFM which was left behind when the circuit was clipped from the other thread. (RTFM for those that don't know means Read the F'n manual)
 It was all explained in the other thread linked to and if people would not extract a schematic without all of the attached information AND READ IT !!! they would have seen the notes about it being able to be driven by any sort of circuit not just a hall sensor. That other circuit would include the +VE of that circuit.
I even pointed that out AGAIN in my post here so in my my mind I've explained it now 3 or 4 times. If people don't care to read and absorb the info and ask questions if they don't understand (back where the circuit was - not here) there isn't much I can do.

If I were to simply draw the circuit with +12v on the left side then the whole uniqueness of the circuit would be lost. I purposely used a logic level version of the IGBT so it could be driven this way. That little tid-bit of information was left behind as well but was explained back where the circuit came from. People have even substituted a regular bi-polar darlington transistor in it's place which defeats my purpose. But I didn't say anything.

I know I write too much and people don't like to read so I guess it's all on my head. I spend a lot of time trying to explain things so people can understand but they have to read. Certainly it's difficult to explain things to people with no background in electronics but I do my best.

I'll go away now and keep my circuits to myself.

Sorry Mosey. Your post got  in before mine since I spent so much time editing this (like I usually do to get it right). I agree with you but sometimes....

Sage


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## canadianhorsepower

[QUOTELUC:
 Yeah - except that all of what you have written gets back to my very first point right a the top. Which I guess you didn't read. 
]
Well your guess is wrong cause I read it. Btw I'm not the one needing help here I teach that stuff. But being a teacher in that field
I know that all questions should ask to diagnose something. I can't assume what someone else did with a circuit if I'm not asking.
Now if your mad at someone because they use or modify your circuit don't jump on MY head for it. I was simply trying to help


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## jixxerbill

So will there ever be a circuit posted on this site that will work AND everyone will agree upon ?? I'm seriously just asking.. Everytime this type of thread gets started it just turns into a "that wont work do it this way" thread.. I can appreciate everyone's take on doing things and I know there are several ways to skin a cat.. But with the electronic knowledge on here it seems everyone could agree on a circuit.. Maybe everyone post thier version of the PERFECT circuit and then put them together and come up with the holy grail of ic circuits.. Thanks..Bill


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## jgedde

jixxerbill said:


> So will there ever be a circuit posted on this site that will work AND everyone will agree upon ?? I'm seriously just asking.. Everytime this type of thread gets started it just turns into a "that wont work do it this way" thread.. I can appreciate everyone's take on doing things and I know there are several ways to skin a cat.. But with the electronic knowledge on here it seems everyone could agree on a circuit.. Maybe everyone post thier version of the PERFECT circuit and then put them together and come up with the holy grail of ic circuits.. Thanks..Bill


 

Bill,

I think Sage's circuit is just that.  It's very simple, yet it works and works well.  While mine has more protections against power transients and such and lower "standby" power consumption, it is more complicated as a result.   

All that said, it holds no advantage over Sage's with regard to its primary purpose...  Driving a coil to make a spark and preventing the coil from being stuck on.

So, where are we at?  Here's my _OPINION_ FWIW:
If you like soldering up components, or are concerned about power consumption, or want a "Cadillac" circuit, build mine.  If you want a good circuit to generate a spark, with "no muss or fuss", build Sage's.  You can't go wrong either way.

Bear in mind, though that in Sage's circuit, the LED should not be omitted without fully understanding that the LED and resistor are also being used cleverly as a pullup for the hall sensor - a necessary thing. 

Also, either circuit will accept input from a oscillator circuit (or a micro) to make a true multiple spark ignition circuit or to implement your own advance/retard.  That's cool stuff on a model engine to be sure!

Now, if you search around the net for model engine ignition circuits, you'll find a few.  Some of them are exceedingly bad...  I'll hold my tongue about which ones in particular...  

John


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## dsage

Thanks John:

And, I can give a vote of confidence for John's circuit.
I suggest everyone build his circuit.
There is nothing wrong with adding any of the extra components he has added. Certainly, adding the resistor and capacitor on the Hall power lead adds some protection against spikes on the power line if you're using the same 12v as the coil especially if you have have wiring issues. I haven't had any problem without them. But better safe than sorry though (apparently).

BTW.  If you want to be really safe, run the front end on 5v and make +VE 5vdc. Then you'd need to add a regulator etc. but you'd be sure there are no spikes coming from the 12V supply. That's why I designed with the logic level IGBT instead of a darlington transistor. I intended to make another micro driven ignition but decided it wasn't worth the effort for the engine I was putting it on. 
http://davesage.ca/engine14.html
Although as I mentioned I did make a multi-spark ignition with a 555 timer because this engine is pretty sketchy about running at all since it's made from plumbing fittings and has nothing for a carb except a big drip oiler. (yup it'' for gas, not oil just like Henry designed it). You can watch it running with the button there on the page somewhere. Wait a bit it takes some time to load the movie.


The Atkinson engine on my site also has a multi-spark ignition of my design but it does use a microprocessor with hall sensor. The micro also also takes care of charging the NiMh battery when you plug in a wall wart. All of the circuitry is flat and hidden under the base plate in less that 1/2" height. You can see the switch, LED and charging socket sticking out the side underneath. 

http://davesage.ca/engine3.html


Have fun.

Sage


----------



## creast

Hi Sage,
Firstly, apologies for not linking to the other thread, I am a bit new to this forum thingy.
I did eventually post a link to it since I knew it was on here somewhere but tricky to find again.
Having run your circuit with Johns mods for two hours @750 rpm via a dc motor, all is fine. I am using common 12V and an auto coil.
I agree that maybe I had done something wrong to cause my initial failures, 3 halls down, but I couldn't figure what was going wrong.
Johns mods seem to work so far, or maybe I am being a bit more careful now? It is true that earth points are critical, I once forgot to add one and saw arcing from the Hall legs to the block! Luckily, that didn't result in death of the semiconductor! 
This is my first foray into IC engines and it has taken me an age to get the thing running.
[ame]http://www.youtube.com/watch?v=iuXz7O1Ul8g[/ame]
Ultimately, I would like a very small ignition module to build into the base, but I guess this may need a custom coil or higher drive voltage to a ferrite ignitor type coil.
Anyway, thanks to all involved in this thread. It has been very useful to me.
Rich


----------



## canadianhorsepower

creast said:


> Hi Sage,
> Firstly, apologies for not linking to the other thread, I am a bit new to this forum thingy.
> I did eventually post a link to it since I knew it was on here somewhere but tricky to find again.
> Having run your circuit with Johns mods for two hours @750 rpm via a dc motor, all is fine. I am using common 12V and an auto coil.
> I agree that maybe I had done something wrong to cause my initial failures, 3 halls down, but I couldn't figure what was going wrong.
> Johns mods seem to work so far, or maybe I am being a bit more careful now? It is true that earth points are critical, I once forgot to add one and saw arcing from the Hall legs to the block! Luckily, that didn't result in death of the semiconductor!
> This is my first foray into IC engines and it has taken me an age to get the thing running.
> http://www.youtube.com/watch?v=iuXz7O1Ul8g
> Ultimately, I would like a very small ignition module to build into the base, but I guess this may need a custom coil or higher drive voltage to a ferrite ignitor type coil.
> Anyway, thanks to all involved in this thread. It has been very useful to me.
> Rich


 

Nice work on the motor.   If your interested in electronic I did put a book in the download section that can be download to PDF that book will answer almost all your needs are in electronic

enjoy


----------



## creast

Thanks Luc,
I will go check it

Rich 





canadianhorsepower said:


> Nice work on the motor.   If your interested in electronic I did put a book in the download section that can be download to PDF that book will answer almost all your needs are in electronic
> 
> enjoy


----------



## jgedde

creast said:


> Hi Sage,
> Firstly, apologies for not linking to the other thread, I am a bit new to this forum thingy.
> I did eventually post a link to it since I knew it was on here somewhere but tricky to find again.
> Having run your circuit with Johns mods for two hours @750 rpm via a dc motor, all is fine. I am using common 12V and an auto coil.
> I agree that maybe I had done something wrong to cause my initial failures, 3 halls down, but I couldn't figure what was going wrong.
> Johns mods seem to work so far, or maybe I am being a bit more careful now? It is true that earth points are critical, I once forgot to add one and saw arcing from the Hall legs to the block! Luckily, that didn't result in death of the semiconductor!
> This is my first foray into IC engines and it has taken me an age to get the thing running.
> http://www.youtube.com/watch?v=iuXz7O1Ul8g
> Ultimately, I would like a very small ignition module to build into the base, but I guess this may need a custom coil or higher drive voltage to a ferrite ignitor type coil.
> Anyway, thanks to all involved in this thread. It has been very useful to me.
> Rich


 

Rich, she looks great!  

John


----------



## dsage

creast said:


> Having run your circuit with Johns mods for two hours @750 rpm via a dc motor, all is fine. I am using common 12V and an auto coil.
> Rich



Hi Rich:

Glad to see you got it going. Are you saying you had the engine and therefore the ignition operating by turning the engine over with a motor? Or was it running on it's own? (i.e. fuel, ignition etc.). Sounds like it was firing so I assume the latter.

Is that the coil I see in the background connected by long lengths of wire and what looks like regular wire on the HV lead tangled amongst them?
 And perhaps the long Hall sensor leads in the foreground?
If so then I'm not surprised you've had problems (and that they were solved by filtering the supply). Frankly I'm surprised you still don't have issues.
Hopefully I'm wrong on that observation.


BTW nice machine work. It looks familiar,  what is it a model of?

Sage


----------



## jixxerbill

Sweet runner rich.. very nice build. congrats on getting it running.. There is so much smart on here its crazy, I knew they would get you running... Hmmmm if i could get a thimble full of smart from everyone on here, I could be a genius... And learn to spell correctly lol...Bill


----------



## dsage

jgedde said:


> Rich, she looks great!
> 
> John




John: et. al.

I get a real chuckle sometimes at the advertising that gets inserted into posts here. I assume they are different every time one has a look at the site and they are probably tailored to something in the message content.
In any case you replied to the picture of the engine

"She looks great" 

When I looked at your response right below it was an ad for a dating service with a pretty nice looking girl. I thought that perhaps you were making a comment and a joke at the same time. Now, I don't see that ad anymore attached to your response. Then the light went on as to what was going on.
 I'm sure nobody else saw the two together like I did but now I have to LOL big time.

Too funny.


Sage


----------



## jgedde

dsage said:


> John: et. al.
> 
> I get a real chuckle sometimes at the advertising that gets inserted into posts here. I assume they are different every time one has a look at the site and they are probably tailored to something in the message content.
> In any case you replied to the picture of the engine
> 
> "She looks great"
> 
> When I looked at your response right below it was an ad for a dating service with a pretty nice looking girl. I thought that perhaps you were making a comment and a joke at the same time. Now, I don't see that ad anymore attached to your response. Then the light went on as to what was going on.
> I'm sure nobody else saw the two together like I did but now I have to LOL big time.
> 
> Too funny.
> 
> 
> Sage


 
Now that is funny!  I was, however, commenting on the engine.  The girl never popped up on my screen, so I can't comment  Rof}

The weird thing is I used to see ads on this site, but now I never see any.  The one that annoyed me was a bogus "You've been unfriended by 3 people."

John


----------



## dsage

Yes.
I'm not sure what triggers them. At the moment I don't see any, anywhere. But occasionally they seem to get attached to numerous posts per page. Sometimes they are little semi-transparent rectangles with a message - no picture and they always seem to land at the bottom and obscure a picture. Sometimes I have to "X" them off to get them out of the way.
The price we pay I guess.

Sage.
http://davesage.ca


----------



## jerrybilt

For your consideration:

Here is an ignition transformer drive circuit based on a commonly available HEX FET. The input is a standard TTL input and the pulse width is set by a monostable multi-vibrator (how ever one cares to implement it!). This is a "circuit fragment" where I have not calculated the component values as I wish to show what the circuit looks like.


----------



## creast

Hi Sage,
I tested the circuit using a DC motor on its own whilst working on the engine.
The youtube clip is running without the regulator mechanism but it sounds like a hit and miss even then. LOL! I guess its down to valve bounce or something. Still have work to do to get it running correct and some polishing up.
Yes, I am guilty of using the long leads etc and not proper HT lead yet so slapped wrists for me being impatient . I duly take note of your comments and will improve the setup accordingly.
The engine is a David Kerzel design
_www.floridaame.org/GalleryPages/g1h0106.htm_

_Cheers_
_Rich_



dsage said:


> Hi Rich:
> 
> Glad to see you got it going. Are you saying you had the engine and therefore the ignition operating by turning the engine over with a motor? Or was it running on it's own? (i.e. fuel, ignition etc.). Sounds like it was firing so I assume the latter.
> 
> Is that the coil I see in the background connected by long lengths of wire and what looks like regular wire on the HV lead tangled amongst them?
> And perhaps the long Hall sensor leads in the foreground?
> If so then I'm not surprised you've had problems (and that they were solved by filtering the supply). Frankly I'm surprised you still don't have issues.
> Hopefully I'm wrong on that observation.
> 
> 
> BTW nice machine work. It looks familiar,  what is it a model of?
> 
> Sage


----------



## dsage

jerrybilt said:


> For your consideration:
> 
> Here is an ignition transformer drive circuit based on a commonly available HEX FET. The input is a standard TTL input and the pulse width is set by a monostable multi-vibrator (how ever one cares to implement it!). This is a "circuit fragment" where I have not calculated the component values as I wish to show what the circuit looks like.




Jerrybilt:

Your circuit is not unlike the ones John and I have presented. I like the idea of the HEXFET  since it has a lower voltage drop when on (Vce).  BUT
 I haven't looked up the HEXFET specs. One of the reasons for using the IGBT, which was designed for ignition systems, is it has a very high reverse breakdown voltage (400+v). This has a big effect on the operation of the coil. A regular transistor (and maybe the HEXFET) breaks down under the kickback voltage to the primary of the coil (several hundred volts). Suppressing that voltage limits the secondary output as well.
I suspect that diode you show on the HEXFET is going to also suppress that voltage. Not a good thing.

I'm also confused by the placement of the inductor and capacitor (which by the way is a good addition as a filter). If one were going to run the circuit on a single 12v supply I would have thought the inductor and capacitor  would be placed in the power line where you have the wire between the fuse and the small driver transistor. Basically isolating the left (logic) side of the circuit from the right (high power) side of the circuit.
Also, I find the power supply labeling confusing. You have the two sides connected together (through the inductor) yet you label the right side as being changeable (5-12v) and the left side as 12v.

I would have eliminated the wire between the left and right sides (between the fuse and small driver) and put the 5-12v on the left (since it can be anything in that range) and label the right side as 12v or even variable as well if you wish. The user could join the two together at the battery if they want them the same. The inductor would still be a good addition to the left side supply.
 I know I got &*@#%$ for purposely showing the two sides of my circuit with separate supplies but it was intentional to show that they need not be the same. I assume you have the same intent. 

WOW that was long winded. 
Sorry. A picture would have been appropriate but I don't have a quick drawing program. Hopefully you got the point and you can make changes or ignore me.

A few values may garner more comments. Maybe you can build it and let us know what you find.


Ok guys - have at it :hDe:

Sage
http:\\davesage.ca


----------



## dsage

Creast:

Your haste in using the long leads and bad grounds was what led to all the problems you were having blowing Hall sensors. 
Glad it's working for you. When you get some pressure in the cylinder it may be a different story.

On the positive side you've spurred on a whole discussion on improvements to the circuit that will help everyone.

Thanks

Sage
http://davesage.ca


----------



## creast

I can confirm that the IGBT is much better. I tried a power darlington first and the difference in spark with the IGBT was very marked.




dsage said:


> Jerrybilt:
> 
> Your circuit is not unlike the ones John and I have presented. I like the idea of the HEXFET  since it has a lower voltage drop when on (Vce).  BUT
> I haven't looked up the HEXFET specs. One of the reasons for using the IGBT, which was designed for ignition systems, is it has a very high reverse breakdown voltage (400+v). This has a big effect on the operation of the coil. A regular transistor (and maybe the HEXFET) breaks down under the kickback voltage to the primary of the coil (several hundred volts). Suppressing that voltage limits the secondary output as well.
> I suspect that diode you show on the HEXFET is going to also suppress that voltage. Not a good thing.
> 
> I'm also confused by the placement of the inductor and capacitor (which by the way is a good addition as a filter). If one were going to run the circuit on a single 12v supply I would have thought the inductor and capacitor  would be placed in the power line where you have the wire between the fuse and the small driver transistor. Basically isolating the left (logic) side of the circuit from the right (high power) side of the circuit.
> Also, I find the power supply labeling confusing. You have the two sides connected together (through the inductor) yet you label the right side as being changeable (5-12v) and the left side as 12v.
> 
> I would have eliminated the wire between the left and right sides (between the fuse and small driver) and put the 5-12v on the left (since it can be anything in that range) and label the right side as 12v or even variable as well if you wish. The user could join the two together at the battery if they want them the same. The inductor would still be a good addition to the left side supply.
> I know I got &*@#%$ for purposely showing the two sides of my circuit with separate supplies but it was intentional to show that they need not be the same. I assume you have the same intent.
> 
> WOW that was long winded.
> Sorry. A picture would have been appropriate but I don't have a quick drawing program. Hopefully you got the point and you can make changes or ignore me.
> 
> A few values may garner more comments. Maybe you can build it and let us know what you find.
> 
> 
> Ok guys - have at it :hDe:
> 
> Sage


----------



## dsage

Jerrybilt:

I had to rush away before, but I just had time to look up the specs on the HEXFET you proposed in your circuit. Unless I'm missing something I don't think it's going to cut it. The drain source breakdown voltage is only 30V. (BVDss). I'd have to think about it but perhaps you'd be saved by the use of it as high side driver - not sure.
  I usually avoid using the high side driver arrangement. The gate drive voltage will always need to be higher than the voltage at the top of the coil. So if you want the top of the coil to be at 12v with the transistor on then you'll have to have something higher on the gate of the HEXFET. But I might be missing something there as well.
With a low side driver (like simulating points) you'll always have available an excess of drive capability.

Sorry, one last thing. The resistor from gate to ground (across the coil primary) is going to see several hundred volts when the coil kicks back. Not sure what the gate of the HEXFET and for that matter the rest of the driving circuit is going to think about that.

Ok guys let me have it   :hDe:


Sage
httP://davesage.ca


----------



## jerrybilt

dsage said:


> Jerrybilt:
> 
> I had to rush away before, but I just had time to look up the specs on the HEXFET you proposed in your circuit. Unless I'm missing something I don't think it's going to cut it. The drain source breakdown voltage is only 30V. (BVDss). I'd have to think about it but perhaps you'd be saved by the use of it as high side driver - not sure.
> I usually avoid using the high side driver arrangement. The gate drive voltage will always need to be higher than the voltage at the top of the coil. So if you want the top of the coil to be at 12v with the transistor on then you'll have to have something higher on the gate of the HEXFET. But I might be missing something there as well.
> With a low side driver (like simulating points) you'll always have available an excess of drive capability.
> 
> Sorry, one last thing. The resistor from gate to ground (across the coil primary) is going to see several hundred volts when the coil kicks back. Not sure what the gate of the HEXFET and for that matter the rest of the driving circuit is going to think about that.
> 
> Ok guys let me have it   :hDe:
> 
> Sage
> httP://davesage.ca



Thanks for the response chaps ... Much appreciated. 

Last things first. The resistor from the gate to ground is essential and will help protect the fet. The resistor will have no effect on the circuit operation as what is important is the time constant of this part. We can can calculate this time constant from the parallel equivalent of the two resistors connected to the gate and Cgs.  The time constant of the primary inductor circuit will also have an effect.  The time overall constant can  be designed to be of the order of 1ms.

The 30V breakdown voltage will not be reached as the back EMF is clamped by the built in diode.

When examining the operation of the circuit ( it is a non linear circuit).  it would be best to think about the primary current and the way it rises and falls. ( Remember the voltage across is -L.(di/ dt). )  The max voltage appears on the output when the fet is turned off ...

Yes,  there will always be " excess drive " capability but the drive is controlled by the width of this pulse ( it only need be about 5ms).  The drive is a standard TTL drive so it is either on or off. This is a standard digital input and is obtained from the previous signal conditioning circuit.  When the i/p is high current exists in the primary cct and when low the current is off ( very fast) and the output voltage rises to a very high value.

The filter in the 12V line feed the following circuits ... In my case for the controller that adjusts the advance and " dwell " etc.

Jerry


----------



## creast

Sage,
Tonight I ran the circuit on the engine proper, even with longish leads, LOL.. did shorten them a bit anyway.
The engine ran well for two sessions of 30 minutes so I am well chuffed.
Especially as I haven't even fitted the piston rings yet!
It has taken an age to get her running and to be honest, it was the valve timing which was the real problem. But the ignition failing held me back too.
I am much a wiser man and thank everybody for their contribution on this. Now I know where to look when problems arise!th_wav
Rich



dsage said:


> Creast:
> 
> Your haste in using the long leads and bad grounds was what led to all the problems you were having blowing Hall sensors.
> Glad it's working for you. When you get some pressure in the cylinder it may be a different story.
> 
> On the positive side you've spurred on a whole discussion on improvements to the circuit that will help everyone.
> 
> Thanks
> 
> Sage
> http://davesage.ca


----------



## canadianhorsepower

> I am much a wiser man and thank everybody for their contribution on this. Now I know where to look when problems arise


 
Good news  How do you like the book I posted

cheers


----------



## creast

Hi Luc,
Yes, very interesting and explains very well.
The early bits a little basic but that's a great way to intro anyway. The latter half I find very interesting and have it on my tablet now so can peruse at leisure.
I have done some electronics in the past but am only a dabbler so any education to this 57yr brain is  welcome.
Many thanks.Thm:
Rich



canadianhorsepower said:


> Good news  How do you like the book I posted
> 
> cheers


----------



## dsage

jerrybilt:

You are correct about the resistor on the gate of the FET. I was looking right through the FET as if the resistor were connected to the coil. Sort of "not seeing the forest for the trees" as it were. Not sure What I was thinking.

Most important:
  In your most recent post you have eluded to some conditioning on the input signal that will always reduce it to a single pulse per trigger input and no possible steady state high DC level. Is that correct ??

Again, no suggestion of that was given originally (or I missed it), so my analysis of the circuit was only based on the circuit driven by points or a hall sensor.

No consideration was given (or suggested) originally that it was intended to operate in more of a switching power supply type of mode. I certainly didn't recognize it.
That requires a whole different consideration. In that light the inductor placement and a lot of my previous comments go out the window.

Sorry I was jaded by the previous "simple" designs (including my own). I can see now that your circuit is quite a bit more sophisticated.

As for your other comments on timing etc., you have the benefit of having some values in mind for the components and can therefore predict timing etc. You supplied none for our benefit. So I can't add anything in that respect.
I was looking at the whole thing as a linear circuit like the other circuits here.

So I guess I'm looking the fool here for making some of my comments on that basis 
Oh well.

Have you modeled it in SPICE or any such program?

So, go ahead and build it and report back. 
We're all looking for the "ultimate" circuit.

Sage


----------



## jgedde

jerrybilt said:


> For your consideration:
> 
> Here is an ignition transformer drive circuit based on a commonly available HEX FET. The input is a standard TTL input and the pulse width is set by a monostable multi-vibrator (how ever one cares to implement it!). This is a "circuit fragment" where I have not calculated the component values as I wish to show what the circuit looks like.


 

Jerry,

I've been scratching my head for the last few days.  In thinking about your circuit, when the MOSFET turns on, the source pin will go to roughly 12V (12V-I Rds(on)).  That said, I can't see how you will maintain enough Vgs to keep the FET on.  It is an N-channel FET right?

What am I missing here?  I can see your circuit having some possibilities if some kind of high side gate driver IC were used (say the IR2113) to create a charge pump generated gate supply referenced to the source...

John

Am I missing something here


----------



## dsage

John:

That was one of my comments as well back a bit. But he assured us that it will have an excess of drive. Maybe I don't see it.
As you say. The gate voltage is always going to be some fraction of the supply due to the resistor divider. If the source is supposed to go as high as the supply to fully energize the coil then the gate is going to have to be above the supply rail. Being that the FET is apparently a logic level device I guess the gate would need to go at least 2.5v above the supply rail.
Sorry to repeat what you just said.
Can't see see it. No values to do any math. Maybe I'm looking at the static circuit and missing some sort of effects due to switching and the inductor or who knows what.




Sage


----------



## jerrybilt

Hi John,

The source voltage will be lower than the gate voltage. Explaining common source configurations is similar to explaining common collector or emitter follower configurations - they should never work! And yes the IR 2113 is a good choice.

Yes this is an n channel enhancement mode fet ... And for old timers it is biased more like a valve then a bipolar transistor, voltage driven as opposed to current driven.

Hi Sage,

Not to worry ...we all have our moments!!

Re: Spice. I do not have anything like that on my home computer though, many moons ago, I used it to test various circuit designs ... mainly front end very low noise amplifiers and a few broad band distributed amplifiers.

Drive? Oh wow! Lots was not said as I wished only to present a circuit form. I would not refer to this as the " ultimate circuit" because this appears to be what " falls out " nothing more nothing less.

If one holds the input high then the fuse blows. 

The hall effect sensor will produce a pulse when the magnet passes the sensor. This is where the original pulse comes from ... Every thing is pulses from here on and it makes life so much easier. The Hall device is an analog device so one would amplify this signal suitably and clean up this pulse with a Schmitt trigger. This arrangement provides a timing edge and a pulse with a suitable level ... TTL levels. We now have a timing edge and the pulse width will be determined by the width of the magnet, sensor size and engine RPM.  This pulse would be suitable to drive the coil but if it is too broad the spark energy may be higher than required and the battery drain will be higher. What we can do now is control the pulse width ( mono- stable multivibrator) and use a second one to produce a variable delay to adjust the timing advance ( a single, dual, edge triggered mono will do the job) . With this arrangement one would place the magnet in advance of TDC and fine tune the timing electronically - so much easier.

My apologies for not providing component values as I only wished to present an alternative ( among many arrangements). OK I will do some calcs and get back to the discussion. Perhaps I'll have a working prototype for your consideration. This will be my evening job!

Jerry.


----------



## dsage

Thanks for that Jerry:

So it's not some sort of mysterious switching supply sort of mode relying on the inductor??
I'll take your word on the FET driving.

But maybe you can go back to my original comments about the power supply confusion. The left and right sides elude to different supplies yet they are joined together with the connection between the fuse and the signal transistor. The right side apparently variable and the left fixed to 12v.
Sorry if I missed the explanation of that.

Sage


----------



## canadianhorsepower

Gentlemen do a favour to all the  persons following post a favour 

Before posting a circuit that you're not 100% positive about the good

 operation , build it      assemble it    simulate it  and then post it only if it works other wise go back to the drawing table:fan: 

If your posting one and you know it is 100% functional in YOUR 

APPLICATION  then the readers should read all the line's before commenting

about it

cheers


----------



## jgedde

Jerry, I just simulated it in spice.  It works, sort of.  What happens is this:
1) The gate goes high and turns the FET on.
2) The coil starts to charge a bit, then the fact that the source (the side connected to the coil) goes high, there is insufficient Vgs to keep the FET on.
3) This cycle repeats until the hall untriggers.
4) The frequency is dictated by several things like total gate charge and the time constant of the coil.  

The neat thing that happens is you'd get multiple sparks!

The bad thing that happens is sure to blow the FET.  The voltage at the top of coil (at the source pin) spikes negative (as would be expected).  But, the gate is high.  I'm seeing negaive Vgs spikes of 50-60 volts with a 1mH coil.  This is absolutely positively going to cause gate rupture in the FET.

If this were a P-channel FET, the story would be different, although your input circuit would have to change a bit.

You can simulate it for yourself using LTSpice.  It's a free spice tool put out by Linear Technology and can be downloaded from here:  http://www.linear.com/designtools/software/#LTspice

BTW, I handed the schematic to one of my EE coworkers (a super smart dude) and asked him simply if he thought this would work.  He didn't do a spice simulation but predicted a result that matched the simulation I ran!

_I really think your idea has merit but needs some tweaks.  The MOSFET approach has some distinct advantages and I would love to see it pursued_.  

I think it needs either a P-channel for the MOSFET and a zener clamp for the gate, or a floating high side gate driver.  Another thought would be a small gate drive transformer like the switching power supply guys use.  The cool thing with the transformer or floating gate driver is that, inherently, the coil would never be able to get stuck on.

John


----------



## jgedde

canadianhorsepower said:


> Gentlemen do a favour to all the  persons following post a favour
> 
> Before posting a circuit that you're not 100% positive about the good
> 
> operation , build it      assemble it    simulate it  and then post it only if it works other wise go back to the drawing table:fan:
> 
> If your posting one and you know it is 100% functional in YOUR
> 
> APPLICATION  then the readers should read all the line's before commenting
> 
> about it
> 
> cheers


 
Luc,

What wrong with posting our ideas to subject them for criticism?  That way _we all_ learn, and don't end up making potentially disasterous or safety mistakes that cost us a project, money, or an eye.  But, most importantly, there is a fine line between constructive and informative criticism and just plain being arrogant and/or condescending.  I'll admit I cross that line more than I'd like, but those who know me either ignore it or tell me John, you're doing it again...

This holds true for our engine designs, machining techniques, as well as electronics.  It's a forum for those who have a common interest.  There are those who know more about certain things, those who know a lot about everything, and newbies alike.  That's life.  But we wouldn't be here unless we either knew the stuff or want to learn more.  Right?

I followed this process with my circuit and got a lot of good feedback. (BTW, my circuit works in real life.  I'm working with Dsage on the side to come up with a super reliable, yet simple, high performance coil driver).

All in all, Jerry may be right and the circuit will work.  In that event we all learn something.  I don't think he ever posted with the intent of forcing his idea down our throats and saying this is the right way.  My impression is that he had an idea and wanted to share it with us all and get our comments?  What's wrong with that?  

I'm guessing we just have some basic philosophical differences.  Either that, or nobody on earth knows electronics better than you do...  I think it's all philosophy...

Cheers,
John


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## canadianhorsepower

> Either that, or nobody on earth knows electronics better than you do.


 
maybe your right on this one but a **** happen to bad if you feel this way 
just realize you di Hi jack someone else's post that started wit a regular Hall sensor problem
and now we are at the 4th diagram, that came from another post and you're arguing about a new one.
It would be simpler start a new post and call it ignition circuit this way everyone would know what to expect


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