TPS92612-Q1: Driving a string with 6 LEDs

Michael Gilge

Part Number: TPS92612-Q1

Hello,

I was wondering if you have a reference schematic for driving a string with 6 LEDs. The LEDs have a forward voltage of 1.9V and the supply voltage is 12V. This would leave 0.6V headroom.

Thanks.

Michael

over 5 years ago

0 Frank Qiu over 5 years ago

TI__Genius 15776 points

Hi Michael,

Could you tell me the LED's forward current.

0 Michael Gilge over 5 years ago in reply to Frank Qiu

Expert 1710 points

Hi Frank,

we want to use 4-6 pieces of the Osram SFH4050 at 100-150mA. Our supply is 12V.

The forward voltage at 100mA is 1.5V, so the string needs 9V.

I am concerned about the power loss.

Also, the IR illumination will be for camera night vision.

Will the PWM input switch the LEDs ON/OFF so there might be visible flickering or is the current regulated?

Michael

0 Frank Qiu over 5 years ago in reply to Michael Gilge

TI__Genius 15776 points

Hi Michael,

1）if the condition is as you say(if=0.1A Vf=1.5V Vsup=12V num of LED=6) the ambient temperture is about 50 ℃，

the loss of device is about 0.3W and the thermal of junction maybe 110℃

2）The PWM input functions as an enable for the output current.

Power management

Power management forum

TPS92612-Q1: Driving a string with 6 LEDs