20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
20
40
60
80
100
120
140
160
I
O
U
T
(
m
A
)
R
ISET
(k
)
C012
LED Current Sinks
Figure 8. Output Current vs R
ISET
8.3
Brightness Control
The LP8862-Q1 controls the brightness of the display with conventional PWM. Output PWM will directly
follow the input PWM. Input PWM frequency can be in the range of 100 Hz to 20 kHz.
An external digital PWM signal can be connected to connector J18. For test purposes the PWM input of
LP8862-Q1 can be connected to ground to turn off LEDs or connected to VDDIO/EN to set up 100%
brightness using jumper J2.
9
Fault Detection
9.1
Fault Indicator
The LP8862-Q1 has fault detection for LED open and short, V
IN
input overvoltage, V
IN
undervoltage
lockout, power-line overcurrent, boost overcurrent, and thermal shutdown. An open-drain FAULT pin
indicates faults. The FAULT pin can be connected to LED D2 for indication (jumper J10).
11
SNVU478A – July 2015 – Revised October 2015
LP8862-Q1EVM Evaluation Module
Copyright © 2015, Texas Instruments Incorporated