A8518 and A8518-1
Wide Input Voltage Range, High-Efficiency,
Fault-Tolerant LED Driver
FEATURES AND BENEFITS
DESCRIPTION
• Automotive AEC-100 qualified
The A8518 is a multi-output LED driver for small-size LCD
backlighting. It integrates a current-mode boost converter
with internal power switch and two current sinks. The boost
convertercandriveupto22whiteLEDs, 11LEDsperstring, at
200 mA. The LED sinks can be paralleled together to achieve
higher LED currents up to 400 mA. The A8518 operates from
a single power supply from 4.5 to 40 V, which allows the part
to withstand load dump conditions encountered in automotive
systems.
• Fully integrated 42 V MOSFET for boost converter
• Fully integrated LED current sinks
• Withstands surge input to 40 VIN for load dump
• Operates down to 3.9 VIN (max) for idle stop
• Drives two strings of LEDs
• Maximum output voltage 40 V
□ Up to 11 white LEDs in series
• Drive current for each string is 200 mA
• Fixed 2.15 MHz boost switching frequency
• Dithering of boost switching frequency to reduce EMI
(A8518 only)
• Extremely high LED contrast ratio
□ 10,000:1 using PWM dimming alone
□ 100,000:1 when combining PWM and analog dimming
• Excellent input voltage transient response at lowest
PWM duty cycle
• Gate driver for optional P-channel MOSFET input
disconnect switch
• LED current accuracy 0.7%
The A8518 can control LED brightness through a digital
(PWM) signal. An LED brightness contrast ratio of 10,000:1
can be achieved using PWM dimming at 100 Hz; a higher ratio
of 100,000:1 is possible when using a combination of PWM
and analog dimming.
Ifrequired,theA8518candriveanexternalP-channelMOSFET
to disconnect input supply from the system in the event of a
fault. The A8518 provides protection against output short,
overvoltage, open or shorted diode, open or shorted LED pin,
and overtemperature. A cycle-by-cycle current limit protects
the internal boost switch against high-current overloads.
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Package: 16-Pin TSSOP with Exposed Thermal
Pad (suffix LP)
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APPLICATIONS:
• Automotive infotainment backlighting
• Automotive cluster
• Automotive center stack
Not to scale
*optional
VIN
L1
D1
VOUT > VIN
RSC
Q1
ROVP
RADJ
CIN
COUT1
COUT2
GATE
SW
VOUT
OVP
VSENSE
VIN
VDD
VC
CVDD
A8518
LED1
RPU
FAULT
PWM
LED2
APWM
COMP
ISET
AGND PGND
RZ
CZ
CP
RISET
GND
Typical Application Circuit Showing VOUT-to-Ground Short Protection Using Optional P-Channel MOSFET
A8518-DS, Rev. 4
October 24, 2016