AllegromicroA8514 Multi-Output White LED Driver Solution

/a>LED” title=”LED”>LED” title=”LED”>LED driver, integrated current mode boost converter with power switch and four current sinks. The boost converter can drive up to 80mA 48 LEDs, 12 LEDs per string. LEDs can be connected in parallel to provide higher current, up to 320mA. The device operating voltage is 5V-40V, the switching frequency is up to 2.3MHz, the matching current accuracy of each LED string is 0.7% – 0.8%, PWM and Analog dimming input, mainly used in car infotainment system, car dashboard and car center control area. This article introduces the main features and advantages of A8514, block diagram, and various application circuits.

The A8514 is a multi-output white 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 48 LEDs, 12 LEDs per string, at 80 mA. The LED sinks can be paralleled together to achieve even higher LED currents, up to 320 mA. The A8514 can operate with a single power supply, from 5 to 40 V, which allows the part to withstand load dump conditions encountered in automotive systems.

The A8514 can drive an external P-FET to disconnect the input supply from the system in the event of a fault. The A8514 provides protection against output short and overvoltage, open or shorted diode, open or shorted LED pin, shorted boost switch or Inductor , shorted FSET or ISET resistor, and IC overtemperature. A dual level cycle-by-cycle current limit function provides soft start and protects the internal current switch against high current overloads.

The A8514 has a synchronization pin that allows PWM switching frequencies to be synchronized in the range of 580 kHz to 2.3 MHz. The high switching frequency allows the A8514 to operate above the AM radio band.

A8514 main features and advantages:

• Wide input voltage range of 5 to 40 V for start/stop, cold crank and load dump requirements

• Fully integrated LED current sinks and boost converter with 60 V DMOS

• Sync function to synchronize boost converter switching frequency up to 2.3 MHz, allowing operation above the AM band

• Excellent input voltage transient response

• Single resistor primary OVP minimizes VOUT leakage

• Internal secondary OVP for redundant protection

• LED current of 80 mA per channel

• Drives up to 12 series LEDs in 4 parallel strings

• 0.7% to 0.8% LED to LED matching accuracy

• PWM and analog dimming inputs

• Provides driver for external PMOS input disconnect switch

• Extensive protection against:

▫ Shorted boost switch or inductor

▫ Shorted FSET or ISET resistor

▫ Shorted output

▫ Open or shorted LED pin

▫ Open boost Schottky

▫ Overtemperature (OTP)

A8514 Application:

LCD backlighting or LED lighting for:

▫ Automotive infotainment

▫ Automotive cluster

▫ Automotive center stack

Figure 1. A8514 block diagram

Figure 2. Application circuit diagram of A8514 with P-MOSFET detection and VIN short-to-ground protection

Figure 3. A8514 Design Case Circuit Diagram

Figure 4. A8514 Application Circuit Diagram in SEPIC Configuration with Precision Input Current Sensing and VSENSE Ground Protection
For details, see:

The Links:   G150XTN069 AT070TN07-V1