STMicroelectronics – Integrated voltage regulator and LED driver for LCD backlighting in cars

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The ALED7707 from STMicroelectronics integrates in a single chip the power- conversion and current-sinking functions required to drive up to six strings of LEDs in automotive LCD backlights.

Its AEC-Q100 qualified monolithic boost converter supplies an output voltage of up to 36V, sufficient for 10 white LEDs per channel, from a battery input-voltage range of 4.5V to 36V.

The ALED7707’s LED driver consists of six controlled-current generators supplying the LED arrays used in LCD backlights. These generators may be externally programmed to sink up to 85mA, and may be dimmed via a PWM signal to a 1% duty cycle at 1kHz.

The device detects and manages open and short LED faults. It offers output over-voltage, internal MOSFET over-current and thermal shut-down protection.

FEATURES

  • Constant-frequency peak current-mode control
  • Adjustable switching-frequency range: 250kHz to 1MHz
  • Pulse-skip power-saving mode at light load
  • Programmable soft-start
  • ±3% current matching between rows

APPLICATIONS

  • LCD backlighting for infotainment systems
  • Daytime running lights
  • Interior and exterior lights in cars
  • Dashboard backlighting

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This evaluation board provides an application example of a six-channel, medium-current LED driver using the ALED7707 chip. It demonstrates a compact reference solution for automotive applications involving several LEDs arranged in multiple strings, such as interior lighting or infotainment LCD backlighting.

Orderable Part Number: STEVAL-ILL067V1

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