DRV8884: Current adjust using a PWM signal

NAOKI AOYAMA

Part Number: DRV8884

Hello,

Our customer try to control the full scale current using a PWM signal with the circuit of the Figure 16 on the datasheet.

They want to control the full scale current from 0.05A to 1A.

They calculate the maximum current as follows.

I_max : ARREF / (RREF+ (R1//R2) ) at 0% duty

How should the customer calculate the minimum current at 100% duty?

Best Regards,

Naoki Aoyama

0 Rick Duncan over 7 years ago

Hi Aoyama-san,

Once a duty cycle is applied to the PWM, the voltage appear in at the RC filter acts like a DAC in Figure 15. Equation 2 can be used.

0 NAOKI AOYAMA over 7 years ago in reply to Rick Duncan

Guru 11215 points

Hi Rick-san,

Thank you for your reply.
It may be necessary to consider the impedance of GPIO and R1//R2.

Thanks,
Naoki Aoyama

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