MOSFET KILLER
New Member
I have got a rail of 10 IGBT transistors and I am wondering if I could drive the gates in parallel with one powerful gate driver IC or drive them individually with many gate drive ICs.
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IGBT's are paralleled all the time in industrial applications and driven by single driver IC's as well. You do need to know the current limits of the driver IC and the combined capacitance of the IGBT gates though. From there you can calculate what Resistance to put in series with each gate and what your peak working frequency can be based on that.
Many inverter welder, plasma cutter power supplies, and VFD's will often have H-bridge switching systems that have as many as 12 IGBT's per leg being driven off of a single gate driver IC and still be running at 25 - 40 KHZ.
However now that IGBT's are being made that can carry 1000 amps 2400 volts into the 10"s of KHZ switching frequencies there is less paralleling being done but still the gate capacitance of one large IGBT can be as much or more than what several smaller IGBT's combined are.
if those are low voltage welders, and they should be since it is a basically a short circuit load, then the miller effect would not be much of an issue. of course, why they would use IGBT's at low voltages is beyond me.
The welders just step down the power to a lower voltage at a higher amperage. Most inverter welders have around 70 volts open circuit on constant current mode and up to around 45 - 50 volts on constant voltage mode. But both modes can run up to several hundred amps output currents.
I have found an IGBT driver IC on Digikey that supplies 30 amps. How would I calculate if this would be enough to turn on a rail of lets say 10 IGBTs?