The A8519 is a multi-output LED driver for small-size LCD
backlighting. It integrates a current-mode boost converter
with internal power switch and four current sinks. The boost
converter can drive up to 44 white LEDs, 11 LED per string, at
100 mA. The LED sinks can be paralleled together to achieve
higher LED currents up to 400 mA. The A8519 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.
The A8519 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.
If required, the A8519 can drive an external P-channel MOSFET
to disconnect input supply from the system in the event of a
fault. The A8519 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.
The A8519 has a synchronization pin that allows boost switching
frequencies to be synchronized in the range of 260 kHz to 2.3 MHz.
The high switching frequency allows the converter to operate above
the AM radio band. The IC contains a clock output pin that allows
other converters to be synchronized to the A8519’s boost switching
frequency.
The A8519 employs hysteresis control to help regulate the LED
current at extremely short PWM on-time. The A8519-1 is identical
to the A8519, except that it uses a smaller hysteresis window to
reduce output voltage ripple during PWM dimming.
Applications
- Automotive infotainment backlighting
- Automotive cluster
- Automotive center stack
