A8518KLPTR-T

• Product introduction

A8518is a multi-output for small LCD backlightingLED drivers。 It integrates a current-mode boost converter with an internal power switch and two current sinks. The boost converter can drive up to 22 white LEDs with 11 LEDs per string at 200 mA per string. LED current sinks can be paralleled to achieve higher LED currents up to 400 mA. The A8518 can operate from a single supply from 4.5 V to 40 V, allowing the part to withstand load dump conditions in automotive systems.

The A8518 controls the brightness of LEDs through digital (PWM) signals. With PWM dimming at 100 Hz, a 10,000:1 contrast ratio of LED brightness can be achieved. If PWM is combined with analog dimming, it is possible to achieve a higher ratio of 100,000:1.

If needed, the A8518 can drive an external P-channel MOSFETP-FET to disconnect the system's input power in the event of a fault. Protection provided by the A8518 includes output short-circuit and overvoltage protection, open- or short-circuit protection of diodes, open- or short-circuit protection of LED pins, and overtemperature protection. Cycle-by-cycle current limiting prevents high current overload in the internal boost switch.

The A8518 has a fixed boost switching frequency of 2.15 MHz. The high switching frequency allows the converter to operate above the AM radio band.

• Automotive AEC-Q100 compliant
• Fully integrated 42 V MOSFETs for boost converters
• Fully integrated LED current sink
• Withstands a surge input of 40 VIN to handle load dumps
• Can operate down to 3.9 VIN (max) for start-stop
• Drives two strings of LEDs
• The maximum output voltage is 40 V
  • Up to 11 white LEDs are connected in series
• The drive current per string is 200 mA
• Fixed 2.15 MHz boost switching frequency
• Jitter boost switching frequency to reduce EMI
• Very high contrast ratio of LED brightness
  • 10,000:1 with PWM dimming only
  • 100,000:1 when PWM and analog dimming are combined
• Excellent input voltage transient response with the lowest PWM duty cycle
• Gate driver for optional P-channel MOSFET input disconnect switch
• LED current accuracy of 0.7%
• LED string current matching accuracy of 0.8%
• Provides the following protections:
  • Boost switch, inductor, or output capacitor short-circuit protection
  • ISET resistor short-circuit protection
  • LED pins and LEDs are protected against open or short circuits
  • Boost diode open circuit protection
  • Overtemperature protection