LP8862-Q1: Output power parallel with FET to control two different LED Strings in which only one get's ON at a time

Vishnu G

Part Number: LP8862-Q1

Tool/software:

Hi,

I would like to know whether Output Voltage of driver can be paralleled with FET control to operate 2 different LED strings in which only one turns ON at a time.

5 LED's used in one String. Two strings has cool white & other two strings has warm white LED's.

Either of one color is illuminated at a time. Instead of using 2 separate drivers for 2 set of strings I am looking for cost effective solution.

Attached a snap of schematic to understand in detail. This is a idea popped up if it works I will add diode to LED string for Reverse stand off protection.

4 months ago

0 Zhiqian Wu 4 months ago

TI__Mastermind 31695 points

Hi, Vishnu

May I kindly know if the string switching will be changed when LED is worked.

If you setup before the device startup, it will work.

0 Vishnu G 4 months ago in reply to Zhiqian Wu

Prodigy 20 points

Hi,

Thanks for the feedback.

Yes String switching will be changed based on user input.

Working Scenario - LED Driver is turned on ready with VIN and VDDIO/EN external 5V supply.

When user presses the button (White / Warm white) respective color string is turned ON via Mosfet switch and PWM input.

Let me know if this logic works for the circuit made.

0 Zhiqian Wu 4 months ago in reply to Vishnu G

TI__Mastermind 31695 points

Hi, Vishnu

It is related with your switching speed. If it has a time that two switch is both off with some time. Device may report the open fault. If not it can work normally.

Power management

Power management forum

LP8862-Q1: Output power parallel with FET to control two different LED Strings in which only one get's ON at a time