LP5861: PWM duty setting when paralleling 2 channels in 100mA application

David Huang

Part Number: LP5861

Hi Team

For application paralleling 2 channels to get a 100mA output current, how do I setup PWM duty?

I assume since I would need to make both 2 channels sink the same current, the PWM setting for both channels should be the same.

Could you confirm if my understanding here is correct? Is there any other recommended way to setup the PWM duty?

Regards

over 2 years ago

0 Aaron Bing over 2 years ago

TI__Expert 4160 points

Hi David,

For full-scale current output, you need modify registers 004h(IOUT_MAX), 00Ch~00Fh(CC), 100h~111h(DC) values.

Best Regards,

Aaron

0 David Huang over 2 years ago in reply to Aaron Bing

TI__Intellectual 2285 points

Hi Aaron

Thx for the response.

Just checked the datasheet, the (IOUT_MAX) register setting was 3h which means it's 15mA by default.

Does the user need to configure the register to 7h to get 50mA upon every startup?

I also spot that MC, CC and DC setting specifications are only mentioned in the analog dimming part, does PWM dimming require such setting as well?

Regards

0 Aaron Bing over 2 years ago in reply to David Huang

TI__Expert 4160 points

Hi David,

David Huang said:
Does the user need to configure the register to 7h to get 50mA upon every startup?

Yes, it requires re-configuration after startup, but I don't think LP5861 needs repeated startup. For PWM dimming, we have similar registers like below.

Best Regards,

Aaron

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LP5861: PWM duty setting when paralleling 2 channels in 100mA application