A8519and A8519-1: Wide Input Voltage Range, High-Efficiency, Fault-Tolerant LED Driver

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.

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• Automotive infotainment backlighting
• Automotive cluster
• Automotive center stack

• Automotive AEC-Q100 qualified
• Fully integrated 42 V MOSFET for boost converter
• Fully integrated LED current sinks
• Withstands surge input up to 40 V_INfor load dump
• Operates down to 3.9 V_IN(max) for idle stop
• Drives four strings of LEDs
• 最大输出电压40 V
  • Up to 11 white LEDs in series
• Drive current for each string is 100 mA
• Programmable boost switching frequency (200 kHz to 2.15 MHz)
• Synchronized boost switching frequency option (260 kHz to 2.3 MHz)
• Dithering of boost switching frequency to reduce EMI
• 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%
• LED string current matching accuracy 0.8%
• Protection against:
  • ƒƒShorted boost switch, inductor or output capacitor
  • Shorted FSET or ISET resistor
  • Open or shorted LED pins and LED strings
  • Open boost diode
  • Overtemperature