DRV8353: SHx pins can not be HiZ in 1xPWM mode

Ticola Nesla

Part Number: DRV8353

We designed a motor drive circuit with drv8353s.

1xPWM mode is used for motor driving.

When DRV is disable(sleep mode), motor can be spined easy by hand.

However when DRV is enable(active) and the referance PWM signal is not be implemented to DRV, motor is aligned and spinning the motor is more difficult.

We checked SHx pins. SHx pins are connected to GND. According to datasheet SHx pins must be HiZ or Not Connected.

How can we get SHx pins as NOT CONNECTED?

over 3 years ago

0 Anthony Lodi over 3 years ago

TI__Mastermind 26416 points

Hi Serdar,

Thank you for your question! Can you check to ensure the INLC pin is pulled high when the DRV is enabled? For 1xPWM mode the INLC pin is used to brake the motor by turning on all the low side MOSFETs. If INLC is low, then the output will be in brake mode and the SHx pins will be pulled to ground through the low side MOSFETs.

Regards,

Anthony Lodi

0 Ticola Nesla over 3 years ago in reply to Anthony Lodi

Prodigy 40 points

Hello

We checked the INLC pin (nBrake). It is always logic high.

+1 Anthony Lodi over 3 years ago in reply to Ticola Nesla

TI__Mastermind 26416 points

Hi Serdar,

The default mode for the DRV8323S device is 6xPWM mode, so you will need to write to the PWM_MODE bits to set it to 1xPWM mode after every power on and after coming out of sleep mode. Can you read the PWM_MODE bits to confirm that it is in 1xPWM mode while you are performing the test? Are you directly using hall sensors as inputs to the INLA, INHB, INLB pins? If not, and the signals are coming from the MCU, you can put INLA, INHB, an INLB pins logic low to put the outputs in Hi-Z state while in 1xPWM mode.

Regards,

Anthony Lodi

0 Ticola Nesla over 3 years ago in reply to Anthony Lodi

Prodigy 40 points

Thank you sir. It's done. We are grateful to you.

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DRV8353: SHx pins can not be HiZ in 1xPWM mode