A8515 Datasheet, PDF (1/34 Pages) Allegro MicroSystems – The A8515 is a multi-output white LED (WLED) driver for LCD backlighting in consumer and industrial displays.

A8515
Wide Input Voltage Range, High Efficiency
Fault Tolerant LED Driver
Features and Benefits
• Wide input voltage range: 5 to 40 V
• Maximum LED current of 120 mA
• TSSOP-16 (LP) package; exposed pad offers best-in-class
thermal performance
• Typical LED accuracy of 0.5%, and 0.5% for
LED-to-LED matching
• Internal bias supply for single-supply operation (typically
between V_IN = 8 to 24 V)
• Integrated boost converter with 60 V DMOS switch with
overvoltage protection (OVP)
• Drives up to 12 series LEDs in 2 parallel strings
• Single EN/PWM pin interface for both PWM dimming
and enable function
• Sync function to synchronize boost converter switching
frequencies up to 2.3 MHz, this gives the designer the
ability minimize component size
• Provides driver for external PMOS input disconnect switch
• Protection features:
▫ Open or shorted V_LED pin protection
▫ Open Schottky protection
▫ Cycle-by-cycle current limit
▫ Overtemperature protection (OTP)
▫ Output short circuit protection
Package: 16-pin TSSOP with exposed
thermal pad (suffix LP)
Description
TheA8515 is a multi-output white LED (WLED) driver for LCD
backlighting in consumer and industrial displays. It integrates
a current-mode boost converter with an internal power DMOS
switch and two current sinks. The boost converter can drive
up to 24 LEDs: 12 LEDs per string at 120 mA. The LED sinks
can be paralleled together to achieve higher LED currents,
up to 240 mA. The A8515 can operate from a single power
supply, from 5 to 40 V.
PWM dimming is implemented with an external PWM input
signal. The EN/PWM dimming pin is used to control the LED
intensity by using pulse width modulation.
The low, 720 mV regulation voltage on the LED current
sources reduces power loss and improves efficiency.
The A8515 is provided in a 16-pin TSSOP package (suffix LP)
with an exposed thermal pad. It is lead (Pb) free, with 100%
matte tin leadframe plating.
Applications
• Desktop LCD flat panel displays (FPD)
• Flat panel video displays
• LCD TVs and monitors
Not to scale
Typical Application Diagram
V_IN 10 to 14 V
L1
10 μH
D1
2 A / 60 V
V_OUT
C_IN
4.7 μF/ 50 V
V_C
100 kΩ
C_VDD
0.1 μF
NC GATE
VSENSE
VIN
VDD
SW
A8515
PAD
OVP
R_ISET
8.25 kΩ
R_FSET
10 kΩ
FAULT
EN/PWM
APWM
ISET
FSET
LED1
LED2
COMP
AGND PGND
R_OVP
158 kΩ
C_OUT
4.7 μF
50 V
10 LEDs
each string
C_P
120 pF
R_Z
150 Ω
C_Z
0.47 μF
Figure 1. Typical Application Circuit;
12 V input, output to 20 LEDs
(10 series LEDs in each of two
strings) at 120 mA each.
A8515-DS, Rev. 2