Hi everyone!
I'm working on a project for home for learning and fun. I am using peltiers for cooling a water reservoir, I have most everything finished up, but realized that my control circuit could use a bit of help!
The attached schematic is incorrect in that I realized the IRFZ44N was not a Logic level FET and swapped Vcc of the driver to 12v. There is where my troubles started...
[IMG=1000,1000]http://i.imgur.com/HJlD4MQ.jpg/width[/IMG]
When the FET switches there is a 40-50v ringing on the load side and a 20v ringing on the source side, the ringing popped my both my FET and my driver, oops!
A quick correction that I am making is getting a logic level N-MOSFET and removing the 12v from the driver. I will move Vcc of the driver (back) to the 5v line of the power supply to hopefully protect it a bit more!
My question is, could someone help me reduce the voltage spikes on the ringing? It will be next week sometime before the new FET's show up (with more drivers....), but I was hoping to have a plan instead of just throwing them in and hoping for the best, I am not sure where to go from here to reduce the spikes, especially with such a large load rating.
The Schottky is a 45v 20a.
PWM is 31Khz
The load should be just under 20 amps peak current at 100% duty cycle.
I appreciate any help!
Edit: And if anyone can point out how to reduce the size of the monstrous image I posted so it's not so.... BIG, that would be great too
I'm working on a project for home for learning and fun. I am using peltiers for cooling a water reservoir, I have most everything finished up, but realized that my control circuit could use a bit of help!
The attached schematic is incorrect in that I realized the IRFZ44N was not a Logic level FET and swapped Vcc of the driver to 12v. There is where my troubles started...
[IMG=1000,1000]http://i.imgur.com/HJlD4MQ.jpg/width[/IMG]
When the FET switches there is a 40-50v ringing on the load side and a 20v ringing on the source side, the ringing popped my both my FET and my driver, oops!
A quick correction that I am making is getting a logic level N-MOSFET and removing the 12v from the driver. I will move Vcc of the driver (back) to the 5v line of the power supply to hopefully protect it a bit more!
My question is, could someone help me reduce the voltage spikes on the ringing? It will be next week sometime before the new FET's show up (with more drivers....), but I was hoping to have a plan instead of just throwing them in and hoping for the best, I am not sure where to go from here to reduce the spikes, especially with such a large load rating.
The Schottky is a 45v 20a.
PWM is 31Khz
The load should be just under 20 amps peak current at 100% duty cycle.
I appreciate any help!
Edit: And if anyone can point out how to reduce the size of the monstrous image I posted so it's not so.... BIG, that would be great too
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