Hello My mosfets are misteriously short circuiting. I had the circuit working up to yesterday using Microchip=B4s TC4427 mosfet gate driver then when it overheated (due to me failing to account for increased switching losses under pwm and insufficient heat sink) it took my last TC4427 chip with it. However manual switching was OK many repeated times so I know up to then the circuit worked. Now while I wait for more TC4427s to arrive in a couple of days I wanted to continue working so I copied the discrete driver circuit from here: http://users.tkk.fi/~jwagner/tesla/tv-driver/flyback-mosfets-large.gif However using that circuit caused the mosfet to immediately short-circuit when power is applied (with 0 gate voltage). Using a 1u cap between gate and source cured this first problem and when I turn on the transistor it works ok (gate voltage is mantained) until the point I turn it off when I can hear a small bang and the mosfet short-circuits. The load is inductive, using 15 A 120VDC, I have the necessary anti-parallel diode and also experimented with 100n and 50u polyester capacitors in parallel to attempt to control the kick back voltage, to no avail. The transistor is a IRPF460 20A, 500V. However the fact it switched on and off repeatedly with Microchips mosfet gate driver leads me to believe the problem is not in kick back voltage but rather in the gate control circuit I built. Would anyone have any idea why the switch off failure occurs? Thanks. -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist