A8516 Datasheet, PDF (1/17 Pages) Allegro MicroSystems – The A8516 is a multi-output WLED/RGB driver for backlighting LCD monitors and televisions.

A8516
LED Backlight Driver for LCD Monitors and Televisions
Features and Benefits
▪ Six integrated high current sinks
▪ Fixed frequency current mode control with integrated gate driver
▪ 300 kHz to 1 MHz adjustable Boost switching frequency
▪ Controlled startup using options of Enable, PWM signal, or
battery voltage ramp
▪ Active current sharing between LED strings for ±0.6% accuracy
and matching
▪ No audible MLCC noise during PWM dimming
▪ Adjustable overvoltage protection (OVP)
▪ Open or shorted LED string protection
▪ Overtemperature, cycle-by-cycle current limit, and
undervoltage protection
▪ SOIC 24-pin package for easy single-side PCB manufacturing,
or TSSOP 24-pin package with exposed thermal pad for better
thermal performance
Packages:
24-pin SOICW
with internally fused pins
(LB package)
Not to scale
Description
The A8516 is a multi-output WLED/RGB driver for
backlighting LCD monitors and televisions. It integrates a boost
controller to drive external MOSFET, and six internal current-
sinks. The boost converter operates in constant frequency
(programmable) current mode control.
The LED sink current is set by an external R_ISET resistor
(see chart below). More than one LED sinks can be combined
together to achieve even higher current per LED string.
TheA8516 operates from a single supply of 8 to24V. It provides
protection against overvoltage, open or shorted LED string,
and overtemperature. A dual level cycle-by-cycle current limit
function provides soft start and protects against overloads.
The device is provided in a 24-pin SOICW package (LB), with
internally fused pins for enhanced thermal dissipation, and a
24-pin TSSOP package (LP), with an exposed thermal pad
for enhanced thermal dissipation. All packages are lead (Pb)
free, with 100% matte tin leadframe plating.
24-pin TSSOP
with exposed thermal pad
(LP package)
Typical Application Circuit
V_OUT 18 LEDs per string
V_BAT
8 to 24 V
C1 C2
L1
D1
Q1
R_SC R_OVP
C3 C4
P
P
P
R1
C5
R2
R3
R_FSET
R_ISET
Rz1
DRIVER SENSE1 SENSE2 OVP
VIN
VBIAS
FAULT
EN
PWM
COMP
FSET
ISET
VREG7V
A8516
LED1
LED2
LED3
LED4
LED5
C6
Cz1
LED6
AGND AGND LGND LGND PGND
130
120
110
100
90
80
70
60
50
40
30
20
6
LED Current versus ISET Resistor Value
V_REF = 1.24 V, Gain = 640
8 10 12 14 16 18 20 22 24 26 28 30
R_ISET (kΩ)
R2, R3 optional (A8516 has
internal pull-down resistors)
A8516, Rev. 1
P
Figure 1. Typical application circuit; VIN pin tied to V_BAT .