DRV8301: no waveform output

Cherry Zhou

Part Number: DRV8301

Hi team,

Here's an issue from the customer may need your help:

No fault shows and AVDD, GVDD, PVDD and BST are all working properly, while there is now waveform. A brushed DC motor is connected and the input is as follows:

The output is as follows:

The customer would like to know what's the possible reason for that. Could you help check this case? Thanks.

Best Regards,

Cherry

over 3 years ago

0 Aaron Barrera over 3 years ago

TI__Mastermind 26046 points

Hi Cherry,

Is EN_GATE set high? Can the customer share schematic?

Thanks,
Aaron

0 Cherry Zhou over 3 years ago in reply to Aaron Barrera

TI__Mastermind 22235 points

Hi Aaron,

Thanks for your help.

Aaron Barrera said:
Is EN_GATE set high?

Yes, but it takes a while to set high after power up. Will the pulse width be too long?

Please see the schematic below:

Thanks and regards,

Cherry

0 Aaron Barrera over 3 years ago in reply to Cherry Zhou

TI__Mastermind 26046 points

Hi Cherry,

Today is a holiday in the US, we will get back to you tomorrow.

Thanks,
Aaron

0 Andrew Liu over 3 years ago in reply to Cherry Zhou

TI__Mastermind 18981 points

Hi Cherry,

For the EN_GATE functionality, please refer to datasheet section below:

you'll have to toggle this pin high and give the device adequate time to wake up and power-up all the necessary regulators before they start toggling
- can you try delaying the device operation (input PWMs, SPI commands, etc...) for at least 10ms after EN_GATE=H rising edge?
also, saw a mention that you're using a Brushed-DC motor?
- did you mean Brushless-DC?

Even the SPI commands need to wait over 10ms before the device is ready to use:

Best Regards,
Andrew

0 Cherry Zhou over 3 years ago in reply to Andrew Liu

TI__Mastermind 22235 points

Hi Andrew ,

Thanks for your help.

Andrew Liu said:

can you try delaying the device operation (input PWMs, SPI commands, etc...) for at least 10ms after EN_GATE=H rising edge?

Allow enough time to power up for 3 seconds before pulling EN_GATA high(including SPI etc.).

Andrew Liu said:
did you mean Brushless-DC?

No, it's a brushed-DC, that is only two outputs. Does this have an impact?

Thanks and regards,

Cherry

0 Andrew Liu over 3 years ago in reply to Cherry Zhou

TI__Mastermind 18981 points

Hi Cherry,

EN_GATE=H has to happen first, and then add time delay (at least 10ms) before starting to use SPI or gate-driver INHx/INLx inputs.
1. is your '3 seconds' of delay after EN_GATE=H? The charge pump and other regulators will not start powering on until EN_GATE=H.
From motor schematic, it looks like there's still 3 half-bridge phases.
1. I'm a bit unsure about their implementation - how are they connecting the motor? to phases B and C only?

Best Regards,
Andrew

0 Andrew Liu over 3 years ago in reply to Cherry Zhou

TI__Mastermind 18981 points

Hi Cherry,

Closing the thread for now - please let us know if further assistance is needed. Thanks

Best Regards,
Andrew

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DRV8301: no waveform output