I am using the following circuit for high side driving of an IGBT. Details of the circuit are as follows:
+ HV is 110 V DC
IGBT = CT60AM18F (60Amps/900V Mitsubishi)
Rg = 39 Ohms / 0.25W
Rs = 0.1 Ohm / 2W NIWW
Instead of 100K (between HVRTN and pin-1 of 555 IC), I am using 56K/2W and instead of 11DF6 and 1N4148 diodes, I am using MUR160 diodes. My load is inductive and is a contactor coil of approximately 200 Ohms resistance
My problem is that, when I am applying short circuit, with system on load (fault under load) condition, my IGBT is sustaining the short-circuit and is protected. But if the load is short circuited first and then the supply is switched ON, there is no protection coming into picture and my IGBT is getting punctured (Gate – Emitter – Collector – ALL SHORTED).
already have a 4.7KOhm / 0.25W resistor connected
to Ground from IN pin. So is is guarenteed that the
IN pin is pulled to LOW during start-up.
I have sepearte power for 110 V DC at +HV and +8V at the
IN input. The exact circuit I am using is attached herewith
for your reference. My inductive load (Contactor coil) is
connected between O6 and SGND i.e, in parallel with the
100k/0.25W resitor in the circuit attached.
I am repeating my problem again:
When 110V DC is applied and when the input is applied, the
IGBT gets the gate pulses and the load is switched ON.
In this condition, When I short-circuit the load, the Gate
pulses to the IGBT are switched OFF and ERR pin goes HIGH.
Thus the IGBT gets protected from short-circuit.
If I switch OFF the 110V DC and the voltage at the IN pin,
and then short-circuit the load and if I now switch ON the
110V DC, followed by switching ON the IN voltage. My IGBT
is not protected. In this case, all Gate-Emitter_Collector
of the IGBT are shorted.
Again I have 16 such channels working in parallel on the
same 110V DC supply i.e., identical 16 circuits for 16 different
loads
+ HV is 110 V DC
IGBT = CT60AM18F (60Amps/900V Mitsubishi)
Rg = 39 Ohms / 0.25W
Rs = 0.1 Ohm / 2W NIWW
Instead of 100K (between HVRTN and pin-1 of 555 IC), I am using 56K/2W and instead of 11DF6 and 1N4148 diodes, I am using MUR160 diodes. My load is inductive and is a contactor coil of approximately 200 Ohms resistance
My problem is that, when I am applying short circuit, with system on load (fault under load) condition, my IGBT is sustaining the short-circuit and is protected. But if the load is short circuited first and then the supply is switched ON, there is no protection coming into picture and my IGBT is getting punctured (Gate – Emitter – Collector – ALL SHORTED).
already have a 4.7KOhm / 0.25W resistor connected
to Ground from IN pin. So is is guarenteed that the
IN pin is pulled to LOW during start-up.
I have sepearte power for 110 V DC at +HV and +8V at the
IN input. The exact circuit I am using is attached herewith
for your reference. My inductive load (Contactor coil) is
connected between O6 and SGND i.e, in parallel with the
100k/0.25W resitor in the circuit attached.
I am repeating my problem again:
When 110V DC is applied and when the input is applied, the
IGBT gets the gate pulses and the load is switched ON.
In this condition, When I short-circuit the load, the Gate
pulses to the IGBT are switched OFF and ERR pin goes HIGH.
Thus the IGBT gets protected from short-circuit.
If I switch OFF the 110V DC and the voltage at the IN pin,
and then short-circuit the load and if I now switch ON the
110V DC, followed by switching ON the IN voltage. My IGBT
is not protected. In this case, all Gate-Emitter_Collector
of the IGBT are shorted.
Again I have 16 such channels working in parallel on the
same 110V DC supply i.e., identical 16 circuits for 16 different
loads