ISO7760: OCP issue with IPM

Part Number: ISO7760

Customer found that FAULT OUTPUT pin of the FUJI IPM is activated afterpower-on the motor driver with 10mS. In which there is a voltage spike on the

gate driver that could possibly lead to the over current on the IPM and PWM would be shutdown by IPM’s fault signal.

However, it cannot be duplicated with Mitsubishi IPM (PSS35S92F6-CG). It means

The motor driver works well with Mitsubishi IPM.

***Customer had tried two boards and the behavior are the same.


Fuji: 6MBP35XSD060-50

Mitsubishi: PSS35S92F6-CG

ISO7760 Issue with IPM.pdf

1 Reply

  • Hi Brian,

    Thank you for your post. I have gone through the PDF file that you have shared and I see the voltage spike on HS / LS gate driver output. I am not very sure if that particular voltage spike on gate drive signal can cause over-current, I am not very familiar with the IPM modules I highly doubt the voltage spike is causing any problem.

    I also see that many of the waveform are noisy, probably due to oscilloscope probes connection. It is also possible the spike observed is due to probing the signal on oscilloscope.

    I do not think ISO7760 is playing any role even in the spike and the actually issue could be associated with the setting related to IPM or PCB layout. Let me go through the datasheets of both IPM modules and see if I can find something.

    Is it possible to email me the schematic showing ISO7760 and IPM and their connection?

    Koteshwar Rao