Multi-output boost converter LED driver ICs are fault-tolerant

October 22, 2014 // By Graham Prophet
Designed for industrial backlighting and lighting applications as well as automotive infotainment, A8518 and A8519 from Allegro MicroSystems are multi-output boost converter devices with built-in fault-tolerant protection.

Each device integrates a current-mode boost converter with an internal power switch with either two current sinks (dual string) in the A8518 or four current sinks (quad string) in the A8519. Both devices are targeted at the automotive and industrial markets.

In the automotive sector, end applications include high-efficiency, high-dimming-ratio, low EMI automotive infotainment and instrument cluster LCD backlighting, head-up displays, interior lighting and accent lighting. The devices are also suited to robust commercial and industrial backlighting and lighting applications.

In the A8518, the boost converter can drive up to 22 white LEDs, eleven per string, at 200 mA. The LED sinks can be paralleled together to achieve higher LED currents of up to 400 mA. In the A8519, the boost converter can drive up to 44 white LEDs, eleven per string, at 100 mA each. The LED sinks can be paralleled together to achieve higher LED currents of up to 400 mA.

Both devices contain industry-leading features such as high dimming ratio, string current matching, frequency dithering and fault detection. They also include input current sensing and gate drive to control an optional input disconnect MOSFET.

The A8518 and the A8519 are AEC-Q100 qualified and operate from a single power supply with a 4.5-40 V range. This allows each part to withstand load dump and start-stop conditions encountered in automotive systems.

The A8518KLPTR-T is available in a 16-contact eTSSOP package (suffix LP) and the A8519KETTR-T is available in a 5 × 5 mm, 28-contact QFN (suffix ET) and a 20-contact eTSSOP package (suffix LP). All packages have an exposed pad for enhanced thermal performance.

Allegro; www.allegromicro.com