AL5873Q

Document number: DS42780 Rev. 2 - 2

13 of 16

www.diodes.com

February 2021

© Diodes Incorporated

AL5873Q

Application and Implementation

For many automobiles, the same set of LEDs function as both tail lights and stop lights. Thus, the LEDs must operate at two different brightness

levels. The AL5873Q can be used in stop/tail applications where the LED current is switched between a high current (indicating stop or brake) and

a low current (for normal tail light operation). Figure 7 illustrates the recommended way to configure the AL5873Q for stop/tail applications, and the

RPWM and RFULL with 10kΩ or larger one are recommended to reduce the influence of power supply variation.

PWM

GND

LED1

LED2

VIN

CIN

Tail

AL5873Q

FULL

RREF1

REF1

LED3

FAULTB

ADIM

RREF2

REF2

Stop

RFULL

RPWM

Battery

BCM

Figure 7. Stop/Tail Light Application Circuit through FULL pin

The stop light LED current per channel is set by RREF2, and the tail light LED current is set by RREF1. When the LED lamps work as stop light, the

FULL is pulled high and higher LED current is set by RREF2. When the LED lamps work as tail light, the FULL is pulled low and lower LED current

is set by RREF1.