# IGBT Driver NFAM5065L4BT SimpleFOC board

**URL:** <https://community.simplefoc.com/t/igbt-driver-nfam5065l4bt-simplefoc-board/1087>\
**Category:** hardware support\
**Created:** [August 7, 2021, 5:01pm UTC](https://community.simplefoc.com/t/igbt-driver-nfam5065l4bt-simplefoc-board/1087 "2021-08-07T17:01:56Z")\
**Posts on this page:** 1\
**Showing post:** 1

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**Author:** ![Valentine](https://community.simplefoc.com/user_avatar/community.simplefoc.com/valentine/32/1024_2.png) [@Valentine](https://community.simplefoc.com/u/Valentine)\
**Post date:** [August 7, 2021, 5:01pm UTC](https://community.simplefoc.com/t/igbt-driver-nfam5065l4bt-simplefoc-board/1087/1 "2021-08-07T17:01:56Z")

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I am opening a new thread for that one, since the old one was for my TI driver.

@Franz_Schmidt

I was finally able to get a clean PWM low voltage signal out of the driver.

I found a few small errors that prevented me originally from getting results, due to me cutting too many corners when designing the board. Eventually I was able to contact an on-semi engineer who pointed out the biggest problem, which was really easy to solve, I had to connect the over-current sense to ground via 100R to bring it to 0.4V because I didn’t use a current sense shunt for proper sensing. RTFM. Apparently the board MUST use a current sense resistor as an integral component, else the logic cuts off the low power side to prevent an apparent overload. Originally I left that open which apparently brought the CIN high and shut it down. I also had a few incorrect values of the zenner diodes, but that was pure fat-finger when I picked the components.

Anyway I will try to post later more results when I load the driver with high current. The driver works just fine with low voltage, and the on-semi engineer confirmed low voltage for that board is perfectly fine, so my plan is to use a power-dissipation resistor to test 10A current at 15 volts before we graduate the board to driving a low amps low voltage servo motor which will be the ultimate test because as @runger pointed out at low power and static PWM the circuit may not charge the high side capacitors to trigger.

🤞 🤞 🤞

Edit: The power resistor is working fine, the driver maintains output, will move to driving a motor.

Edit2: The motor works. I am using a 1kw motor at 1kHz PWM. The driver gets really hot, I am running without a heatsink and the mode of operation is really inefficient so a lot of heat is generated. Also the trigger capacitors are too large for lower PWM and the 1kHz noise is a bit too much.

Conclusion: The driver works fine. Next steps are to prepare a real board with smaller high side capacitors suitable for 10 to 15kHz PWM and shunts and a heatsink and everything. And re-read the datasheet in case I missed anything 🥵

Here is a pic of the setup. Notice I am using the same supply for the logic and power, a really bad idea.

 ![image](https://community.simplefoc.com/uploads/default/original/2X/9/9245ff57262ab3dfda63f1ae9251ea643b7c3692.jpeg)

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