ChocoHolic said:
I mean. NO. Not across drain gate.
And take care to run your smps from an isolation transformer !
Last but not least: Take care & survive! You are playing with a lethal weapon.
SMPS
Hi,
I will post the voltages, but I need is an explanation why the mosfets die quickly.
do I need to put Zener diodes at each secondary output?
Running the supply at 170VAC , will make it survive.
But at 220VAC , problems starts.
And please note that I know exactly what I am doing.
Hi,
I will post the voltages, but I need is an explanation why the mosfets die quickly.
do I need to put Zener diodes at each secondary output?
Running the supply at 170VAC , will make it survive.
But at 220VAC , problems starts.
And please note that I know exactly what I am doing.
I see two immediate problems with the K6 supply:
No DC blocking cap.
Gate resistors are probably too large (for turnoff) and IRFP450 have huuge Csrss, probably causing shoot-through. You should probably add a diode (or even better a suitable transistor circuit) in parallell with the gate resistors to help discharge the gate and keep the transistors off. Turn-on probably needs to be pretty slow though.
No DC blocking cap.
Gate resistors are probably too large (for turnoff) and IRFP450 have huuge Csrss, probably causing shoot-through. You should probably add a diode (or even better a suitable transistor circuit) in parallell with the gate resistors to help discharge the gate and keep the transistors off. Turn-on probably needs to be pretty slow though.
Diode
megajocke
Can you advice the place of the DC blocking capacitor?
and the direction of the diodes in parallel with the resistors? and the value of the resistor?
megajocke
Can you advice the place of the DC blocking capacitor?
and the direction of the diodes in parallel with the resistors? and the value of the resistor?
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