You don't need "power", as no current flows into the gate, just something to ensure higher voltage on the gate. That may not be the problem, just something to consider. Actually a pull-up resistor on the gate might be all you need to address the issue.

Alright, I think that I may have found my issue. All my problems started today after my coil finally came in. When I got home from work this evening, I connected my coil again and noticed smoke again coming from the board. I had fried my fly-back diode, so I removed it and connected another new one and almost immediately fried that one. So I believe this is what was causing my MOSFET to get really hot. At this point I am thinking that I may need a fly-back circuit to rectify this issue instead of a fly-back diode. So now I have to do some research on a compatible fly-back circuit. Thank you again for your help Wayne and any insight will be greatly appreciated.

 

No offense but did you install the diode reverse biased? If forward biased, it would act as a short.

 

No offense but did you install the diode reverse biased? If forward biased, it would act as a short.

No offense taken, I am human and I do know that I do make mistakes. I believe that I did, with the line facing Vcc out to coil. The TVS that I am using is a Vishay SA6.0A/23 rated at 500w, but that was the only spec that I was able to get out of it. I have been having a hard time finding any data sheet on it. I am thinking one of two things either, yes I did not install it reverse bias (bad on me if I did) or the TVS will not handle the voltage spike that is going through it. Because of spacing, I would rather keep a good TVS in place over a fly-back circuit. I have been trying to do a lot of research so that I can find a suitable replacement. Thank you again for your help Wayne. I would not have been able to get this far without you and Bill's help. Take care.

Donny

Update:
I just read accross both the blown TVS diodes and they are now both reading in both directions (I know not good). I also read my coil and it reads 20.5 ohms, so it looks like that is quite a power spike that this will put out. At this point I am thinking that I need a higher rated TVS, any ideas for a coil of this resistance? Thank you and take care.

 

Who said anything about a TVS? The diode should be a normal rectifier diode that can handle the same current that is going through your coil. A TVS will not conduct until some high voltage is exceeded. You want it to conduct immediately when the coil is turned off in order to stop a high voltage from developing.

Bob

 

Who said anything about a TVS? The diode should be a normal rectifier diode that can handle the same current that is going through your coil. A TVS will not conduct until some high voltage is exceeded. You want it to conduct immediately when the coil is turned off in order to stop a high voltage from developing.

Bob

Bob, thank you for the insight. I used a TVS because that is what I am use to using at my job, but then again as you stated, they are used for power spikes. I guess that this is what I deserve for assuming. So essentially I am looking for a diode that will handle upward of 100 volts and above 60amps to be in a safe area? Thank you for your help.

 

6 Amps, I hope you meant?

 

6 Amps, I hope you meant?

Hi Wayne, sorry that is what I ment. I got carried away with the zeros. Six amps would be double the maximum operation rang and should be safe to use. Thank you again.