DRV8428: DRV8428EPWPR

Daniel Grant

Prodigy 20 points

Part Number: DRV8428

We are evaluating the DRV8428EPWPR for a consumer product, using the attached schematic.

The issue is when pulsing Step, OUT1 stays at 12V (VM) regardless of DIR/Step.

BOUT pulses as expected.

Any suggestions?

Thank you,

Grant

over 2 years ago

0 Wang5577 over 2 years ago

TI__Guru 56650 points

Hello, Daniel,

Please measure AOUT load resistance. If you can post the AOUT and BOUT current waveform, it can speed up the debugging process.

Regards,

Wang

0 Daniel Grant over 2 years ago

Prodigy 20 points

Wang,

both Aout and Bout are 31 ohms

Daniel

0 Wang5577 over 2 years ago in reply to Daniel Grant

TI__Guru 56650 points

Daniel,

What is the AOUT and BOUT current when pulsing Step? I would think the load may not be connected to the output.

Regards,

Wang

0 Daniel Grant over 2 years ago in reply to Wang5577

Prodigy 20 points

Wang,

the load is connected for sure. To measure the current I am using 10 ohm shunt resistors since that is all I had available. The flat line is Aout, the other one is Bout. Aout shows 240mA, Bout is 30 mA. Also noticed that when VM is not on, turning the motor shows current on both A and B.

0 Ryan Kehr over 2 years ago in reply to Daniel Grant

TI__Guru 54665 points

Daniel,

I am a little bit confused as you mention DRV8428EPWPR which does NOT have the STEP input. DRV8428....no "E".

Can you confirm exactly what part and marking is on the board?

Regards,

Ryan

0 Daniel Grant over 2 years ago in reply to Ryan Kehr

Prodigy 20 points

Ryan, you are a genius!!!

That is exactly what is going on, I am using DRV8428EPWPR and not the DRV8428PWPR. Thank you!!!

Now, since the DRV8428PWPR is not available, is there is another device that is similar to the DRV8428PWPR and available?

Daniel

0 Wang5577 over 2 years ago in reply to Daniel Grant

TI__Guru 56650 points

Daniel,

DRV8426PWPR is the function device as DRV8428PWPR. But, it has four extra pins for the output.

As a workaround, DRV8428EPWPR can drive a stepper motor (see the EVM example). But, the host controller has to change the VREF setting every step.

Regards,

Wang

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DRV8428: DRV8428EPWPR