LP8860-Q1: Use PWM to control output

Amelie Zheng

Genius 10865 points

Part Number: LP8860-Q1

Hi Team,

My customer now use LP8860-Q1 and want to use PWM to control output.

The output voltage is 21V, but OUT 1-4 don't have current because the FET is off.

May I ask how to turn on the FET in OUT1-4?

Thanks!

over 4 years ago

0 Charles-Chen over 4 years ago

TI__Genius 11836 points

Hi Amelie,

In PWM dimming mode, the on and off of FET of sink is related to the mode listed in Table 4.

What's the PWM mode do you need? Please refer to Table 4 of datasheet. You can refer to Figure 17 of datasheet for PWM data flow and the configuration of registers.

0 Amelie Zheng over 4 years ago in reply to Charles-Chen

TI__Genius 10865 points

Hi Charles,

Do you mean when configure BRT_MODE[1:0], the internal FET which I noted in the above picture will be on automatically?

Could it be configure by hardware or EEPROM software?

0 Charles-Chen over 4 years ago in reply to Amelie Zheng

TI__Genius 11836 points

Hi Amelie,

The BRT_MODE[1:0] is used for configure the PWM dimming mode. You need to configure other registers as well according to different PWM dimming mode. Hence, what's the mode do you use?

I think you need some onsite support and our AE frank qiu is in Shenzhen site now and you can turn him for more direct onsite support.

0 Charles-Chen over 4 years ago in reply to Charles-Chen

TI__Genius 11836 points

Hi Amelie,

Since you have no reply for a long time and I will close this thread. You can ask in this thread again if you get any feedback.

Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

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LP8860-Q1: Use PWM to control output