Charge-pump IC drives up to six white LEDs

26th March 2007

ES Admin

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The A8434 from Allegro MicroSystems Europe is a high-efficiency charge pump IC that offers a simple, low-cost method of driving up to six white LEDs in various application configurations. Using a proprietary adaptive control scheme (1x, 1.5x and 2x), the A8434 can deliver well-matched (within 0.5%) LED currents of up to 30 mA per LED channel while maintaining very high efficiency and low levels of electromagnetic interference. The LED current is regulated over the entire range of lithium-ion battery voltage to provide uniform intensity.

The A8434 offers a high level of configuration flexibility. All six LEDs could be backlighting a single display, for example. Alternatively, multiple display configurations could include four LEDs for a main display and the other two backlighting a sub-display or a low-current flash/torch. LED brightness and on/off status can be controlled for the six channels, either all together or independently as main display and sub-display/torch, through two single-wire serial interface pins.

The device features soft start circuitry to limit the inrush current, and has built-in short-circuit, overvoltage and thermal shutdown protection.

Applications include backlighting for LCD displays in portable electronic equipment such as mobile telephones, cameras, recorders and audio devices, as well as automotive systems.

The new white LED driver is available in a 16-lead QFN space-conserving (3 x 3 mm footprint and 0.75 mm profile) ES package.