A8510 Datasheet, PDF (1/33 Pages) Allegro MicroSystems – Wide Input Voltage Range, High Efficiency

A8510
Wide Input Voltage Range, High Efficiency
Fault Tolerant LED Driver
Features and Benefits
• Integrated 2 MHz capable boost converter with 60 V DMOS
switch with OVP protection
• Sync function to synchronize boost converter switching
frequencies up to 2.3 MHz
• LED current up to 40 mA per LED channel into 8 channels
• Drives up to 12 series LEDs in 8 parallel strings
(V_f = 3.5 V, I_f = 40 mA), V_IN = 8 V, switching frequency
of 1 MHz
• Single EN/PWM pin interface for PWM dimming and
enable functions
• APWM pin for fine-tuning color adjustment and/or
maximizing contrast ratio
• Integrated driver for optional external PMOS input
disconnect switch
• Typical LED accuracy of 0.7% and 0.8% for
LED-to-LED matching
• Internal bias supply for single-supply operation
from 5 to 40 V
• Extensive protection features
Package: 26-pin QFN (suffix EC)
Description
The A8510 is a multi-output white LED driver for LCD
backlighting. It integrates a current-mode boost converter with
internal power switch and 8 current sinks. The boost converter
can drive up to 96 LEDs with 12 LEDs at 40 mA per string.
The LED sinks can also be paralleled together to achieve even
higher LED currents, up to 320 mA. The A8510 can operate
from a single power supply, from 5 to 40 V.
If required, the A8510 can drive an external P-FET to
disconnect the input supply from the system in the event of a
fault. The A8510 provides protection against output short and
overvoltage, open or shorted diode, open or shorted LED pin,
and overtemperature. A dual level cycle-by-cycle current limit
function provides soft start and protects the internal current
switch against high current overloads.
The A8510 has a synchronization pin that allows PWM
switching frequencies to be synchronized in the range of
580 kHz to 2.3 MHz.
The device package is a 26-contact, 4 mm × 4 mm, 0.75 mm
nominal overall height QFN, with exposed pad for enhanced
thermal dissipation. It is lead (Pb) free, with 100% matte tin
leadframe plating.
Approximate scale 1:1
Applications
• Industrial LCD displays
• Backlighting LCD displays
• Infotainment displays
Typical Application Diagram
V_IN
R_SC
0.056 Ω
Q1
L1
22 μH
D1
2 A / 60 V
C_IN
4.7 μF/ 50 V
V_C
100 kΩ
R_ADJ
590 Ω
R_ISET
8.25 kΩ
C_VDD
0.1 μF
R_FSET
25.5 kΩ
VGATE
VSENSE
VIN
VDD
SW SW
A8510
OVP
LED1
LED2
LED3
PAD LED4
FAULT
EN/PWM
APWM
ISET
FSET/SYNC
LED5
LED6
LED7
LED8
COMP
AGND PGND PGND
R_OVP
169 kΩ
C_P
120 pF
V_OUT
C_OUT
4.7 μF
50 V
R_Z
120 Ω
C_Z
0.47 μF
Figure 1. Typical Application Circuit showing VIN to GND
short protection using P-MOSFET sensing
A8510-DS, Rev. 2