DRV8231: DRV8231ADSGR OCP tripping 50% below design threshold...... RSENSE of 90mΩ

Cole Radoja

Part Number: DRV8231

I am using the DRV8231DSGR in my design to drive an actuator which contains a drive motor inside it.....

As soon as my actuator draws more than 1.8A in current, the DRV8231 internal over current protection gets tripped and I have no idea why.

My RSENSE resistor value is 90mΩ which according to your own datasheet should allow VREF = 3.3V / (10X0.09) = 3.6A. I specifically picked this value as I wasn't sure if the device would protect itself under extreme situations.

In anycase - why is the OCP tripping almost 50% below its rated threshold?

Can somebody please respond!!

Thanks,

Cole

over 1 year ago

0 Pablo Armet over 1 year ago

TI__Mastermind 37683 points

Hi Cole,

Can you provide a waveform of the output current and output voltage if possible? It may be possible that the inrush current or a sudden spike in current is going above the OCP threshold for longer than the OCP deglitch time and triggering the OCP protection.

Regards,

Pablo Armet

0 Cole Radoja over 1 year ago

Prodigy 10 points

Pablo,

I will provide you the WFs , however I can almost guarantee you this is not what is happening, as it is making it past the initial inrush. If is only when I apply force to the actuator and it creeps above 1.6-1.8 A that it starts turning on and off rapidly. ( Which as far as I can tell is what happens when the OCP gets tripped)

I will get wfs today for you.

Thanks for the early reply!

0 Pablo Armet over 1 year ago in reply to Cole Radoja

TI__Mastermind 37683 points

Hi Cole,

Another question: are you using an evaluation board from TI or your own board? Is the problem seen in multiple devices and board?

Regards,

Pablo Armet

0 Cole Radoja over 1 year ago in reply to Pablo Armet

Prodigy 10 points

Hey Pablo,

The problem exists on multiple boards - it is my own board however I followed the layout recommendations. The only difference is the rsense resistor is connected through a via path which goes underneath the board.

0 Pablo Armet over 1 year ago in reply to Cole Radoja

TI__Mastermind 37683 points

Hi Cole,

Thanks for the information.

Can you send a screenshot of the Rsense layout?

Can you send waveform of output current, or sense voltage, when the output starts to turn on and off. Measuring the TOFF will indicate if it is truly an OCP fault.

Regards,

Pablo armet

0 Pablo Armet over 1 year ago in reply to Pablo Armet

TI__Mastermind 37683 points

Hi Cole,

Any update from your side? Has your issue been resolved?

Regards,

Pablo Armet

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DRV8231: DRV8231ADSGR OCP tripping 50% below design threshold...... RSENSE of 90mΩ