SLLIMM 2nd series low voltage input signal injection
Hello experts!
I’m developing a three-phase motor control application based on the STGIF5CH60TS-L. As suggested by the datasheet I have RC-filters at all low voltage inputs with the required 100ns time constant, in my case it’s 1kOhm and 100pF due to the driving limitation of the MCU’s PWM outputs of 4mA at 3,3V VDD. When I measure the input signals at the IPM, I can see a negative voltage spike for about 100ns which is clamped by an internal diode of the input structure. Naturally, this clamping voltage is around -0,7V and therefore lower than -0,3V given in the absolute maximum ratings. My question is now:
Which current magnitude of negative injection can be tolerated by IPM?
I could reduce the voltage spike by decrease the resistance in the RC-filter and increase the capacitance simultaneously. That will however require me to use a line driver between the MCU and the IPM, which is no nice solution in my opinion.
Best regards!
CHEG
