DRV8601: Haptic Voltage Supply Dips

Chris Turner29

Part Number: DRV8601

Hi,

I am using the DRV8601 to power a 3.3V ERM, at the moment we are powering the motor from a 3.3V 3A bench top supply. So there is no issue with regard to the amount of power but everytime we enable the motor and send a PWM waveform to the motor the voltage drops on the supply rail by 0.1V ~ 0.5V. The voltage dip is for the duration that the motor is on not just when the motor starts up. I was hoping that the DRV8601 would manage the inductive nature of the load and prevent voltage dips on the voltage rail? Does anyone have any suggestions on what I might have done wrong?

Thanks
Chris

over 4 years ago

0 Chris Turner29 over 4 years ago

Prodigy 40 points

0 Luis Fernando Rodriguez S. over 4 years ago in reply to Chris Turner29

TI__Guru* 84915 points

Hi, Chris,

The schematic seems to be all in order. Do you have details about the supply current that your circuit demands? Is there another device connected to the power supply? Do you have additional DRV8601 and motor samples that you could use to compare the results? This is just to discard that there's a problem in the circuit or the load.

Thank you.

Best regards,
Luis Fernando Rodríguez S.

0 Chris Turner29 over 4 years ago in reply to Luis Fernando Rodriguez S.

Prodigy 40 points

Hi,

Thank you for getting back to me, the haptic motor has a current requirement of 85ma, yes there is another device connected to the power supply. We have a SAMD20 processor that is procssing sensor readings from capactive sensors this processor is also controling the PWM singal that is sent to the DRV8601. This is the main issue as everytime the hapitc motor starts the voltage reduces and this causes the capacitive touch electroincs to report a touch delta.

Would you expect the voltage to dip at all in this scenario?

Thanks

Chris

0 Luis Fernando Rodriguez S. over 4 years ago in reply to Chris Turner29

TI__Guru* 84915 points

Hi, Chris,

Do you have the same results if you just connect the DRV8601 to the power supply? In the meantime, I will get an EVM to verify this behavior.

Best regards,
Luis Fernando Rodríguez S.

0 Luis Fernando Rodriguez S. over 4 years ago in reply to Luis Fernando Rodriguez S.

TI__Guru* 84915 points

Hi, Chris,

I'm getting a similar result than yours in the EVM. It seems that once the load is connected, there's a small drop of voltage in the power supply. This seems to be a normal behavior in the device.

Best regards,
Luis Fernando Rodríguez S.

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DRV8601: Haptic Voltage Supply Dips