DRV8316: Regarding cycle by cycle current limited by internal PWM

Daisuke Higa

Genius 3475 points

Part Number: DRV8316

Hi support team.

My customer has asked me regarding cycle by cycle current limited by internal PWM.

They are considering to use in 6xPWM MODE.

When we use on PWM MODE bit =00b and with 100% duty cycle input, is the current flow controlled by internal PWM clock?

Best Regards,

Higa

over 1 year ago

0 Aaron Barrera over 1 year ago

TI__Mastermind 26046 points

Hi Higa-san,

To use cycle-by-cycle current limit mode, you must use Mode 2 or Mode 4.

When 100% PWM duty cycle is used, cycle-by-cycle current limit is monitored by an internal PWM clock, which can be set to 20kHz/40kHz in the SPI variant using the PWM_100_DUTY_SEL bit. It is defaulted to 20kHz in the hardware variant.

Thanks,
Aaron

0 Daisuke Higa over 1 year ago in reply to Aaron Barrera

Genius 3475 points

Hi Aron-san

Thank you for answering.

My Customer would like to use with not controlled by internal PWM clock.

Therefore, they are considering setting 6xPWM.

Is their considering correct?

Best regards,

Higa

0 Aaron Barrera over 1 year ago in reply to Daisuke Higa

TI__Mastermind 26046 points

Hi Higa-san,

If current limiting needs to occur, I would recommend using 6x PWM mode (Mode 1) and using SOA/SOB/SOC to detect overcurrent by the external MCU. This way the inputs from the MCU can be reduced in duty cycle to implement the cycle-by-cycle overcurrent limiting at 100% duty cycle.

Out of curiosity, is there any reason why the customer does not wish to use the current limit function in DRV8316?

Thanks,
Aaron

0 Daisuke Higa over 1 year ago in reply to Aaron Barrera

Genius 3475 points

Hi Aron-san

Thank you for your support.

My customer is considering that current regulation and limiting with external MCU.

Best Regards,

Higa

0 Daisuke Higa over 1 year ago in reply to Daisuke Higa

Genius 3475 points

Hi Aaron-san

I had one more question before closing the post.

Does OCP function work on 6xPWM(MODE1)?

Best Regards,

Higa

0 Aaron Barrera over 1 year ago in reply to Daisuke Higa

TI__Mastermind 26046 points

Hello Higa-san,

Yes, OCP works in all modes. This is set by the OCP bits in Ctrl Reg 4 for DRV8316R, or the OCP/SR mode in DRV8316T.

Thanks,
Aaron

0 Daisuke Higa over 1 year ago in reply to Aaron Barrera

Genius 3475 points

Hi Aaron-san

Thank you for your answering.

I understand.

Best Regards,

Higa

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DRV8316: Regarding cycle by cycle current limited by internal PWM