DRV8432EVW - one question about GVDD

Hi,

The out A/B/C/D are not square wave when the outs are disconnected with any other things.they have big fluctuations when on and off? Why?

Thanks!

Hi, I have merged your two threads into one. This will allow both issues to be discussed here.

Would you please confirm you are using the DRV8432EVM?

It seems like the first problem is the GVDD. The EVM seems to be damaged.

GVDD is used to power the DRV8432 and two regulators (VR1 and VR2) on the board. Any of these could have suffered damage.

Has the board worked in the past?

Thank you so much, Rick.

Yes, I am using the DRV8432EVM. It is a new board. I was testing it this afternoon. And the board has worked for 1-2 hours today in the past. And when it can work, I found: the out A/B/C/D are not square wave when the outs are disconnected with any other things. They have big fluctuations when on and off.

If the EVM has been damaged, how can I repair it?

Thanks!

Best,
Xinjing

Hi,

I am using the DRV8432EVM. It is a new board. I was testing it this afternoon. And the board has worked for 1-2 hours. I found: the out A/B/C/D are not square wave when the outs are disconnected with any other things. Output have big fluctuations when PWM is high/low level. Why the turning on and stabilazing time is not so short as the datasheet says?

Then I turned off and stopped the testing for a while. When I went back and turned on the power, to find that the board cannot work and the 3.3v light is not bright. When I connect 12v power to GVDD, the power can be reduced to 0. and then everything cannot work. I measured the resistance between GVDD and GND, and it is about only 12Ω.Why? My board is bad? But it is a new borad.

I do not know what to do now.

Many thanks!

Best,
Xinjing

Hi Xinjing,

Sorry for the delay. The board may have experienced an overvoltage event. The DRV8432 has an absolute maximum voltage on GVDD of 13.2V. Anything above that could damage the device. If the power supply spiked too high when powering up this could have damaged the device.

What voltage was PVDD when you were originally testing? How much current was the load consuming?

I suggest that you isolate what part of the board suffered damage and replace it. Lifting pin 1 of VR1 and VR2 removes two of the three loads on GVDD. If the short is still there, the DRV8432 has probably been damaged and should be replaced.

Once repaired, I suggest you check the power supply for a stable voltage prior to powering the EVM.

Thank you so much, Rick.

The board may be damaged. I tested another board and it can work. But I still can see big fluctuations of the outputs:

When I disconnect its outputs with anything , I can see many fluctuations. Please see Figure1.

When I connect its outputs with a coil (resistance=11Ω)， I can see many fluctuations.  Please see Figure1.

When I connect its outputs with a 200Ω resistor, the number of fluctuations can be reduced to one.   Please see Figure2.

When I connect its outputs with a 100Ω resistor, the fluctuations disappear.  Please see Figure3

 Why the turning on and stabilazing time is not so short as the datasheet says?

figure1

.

figure2

figure3

Thanks!

Best,

Xinjing