LED Driver with Pre-Emptive Boost for Ultra-High Dimming Ratio and Low Output Ripple


A80603 Package Image


Top Features


The A80603 and A80603-1 are multi-output LED drivers that integrate a current-mode boost converter with an internal power switch and four current sinks. The boost converter can drive four strings of LEDs at up to 120 mA, or LED sinks can be paralleled together to achieve higher currents up to 480 mA total.

The devices operate from single power supply from 4.5 to 40 V; once started, they can continue to operate down to 3.9 V. This allows the parts to withstand stop/start, cold crank, and load dump conditions encountered in automotive systems. By using patented Pre-Emptive Boost control, an LED brightness contrast ratio of 15,000:1 can be achieved using PWM-only dimming at 200 Hz. Higher ratios are possible when using a combination of PWM and analog dimming.

Switching frequency can be either above or below the AM band, set by either a resistor or the synchronization pin to between 200 kHz and 2.3 MHz. A programmable dithering feature further reduces EMI. The Clock-Out pin allows other converters to be fed the clock frequency, including programmed dithering—even when the LED output is turned off.

The A80603 provides protection against application faults and external component open/short. Current sense/gate drive functions allow optional use of an input supply disconnect FET in case of output to ground short fault in boost configuration. The A80603-1 is identical to the A80603 except for soft start timer and FAULT pin behavior.

  • Automotive AEC-Q100 qualified
  • Enhanced fault handling for ASIL B system compliance
  • Wide input voltage range of 4.5 to 40 V for start/stop, cold crank, and load dump requirements
  • Fully integrated LED current sinks and boost converter with internal power MOSFET
  • Operate in Boost or SEPIC mode for flexible output
  • Drives up to 11 series white LED in 4 parallel strings, at up to 120 mA per string (VF = 3.3 V max).
  • Boost switching frequency synced externally or programmed from 200 kHz to 2.3 MHz
  • Clock-Out feature for internal switching frequency
  • Adjustable boost frequency dithering to reduce EMI
  • Advanced control allows minimum PWM on-time down to 0.3 μs, and avoids MLCC audible noises
  • LED contrast ratio: 15,000:1 at 200 Hz using PWM dimming alone, 150,000:1 when combining PWM and analog dimming
  • Excellent input voltage transient response even at lowest PWM duty cycle
  • Gate driver for optional PMOS input disconnect switch
  • Extensive protection against:
    • Shorted boost switch, inductor or output capacitor
    • Shorted FSET or ISET resistor
    • Open or shorted LED pins and LED strings
    • Open boost Schottky diode
    • Overtemperature

Typical Applications


Part Number Specifications and Availability

Documentation and Resources


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Pre-Emptive Boost Control Improves LED Driver Performance