White LED Drivers: Inductive & Charge Pump Types

July 11, 2006
PHOENIX, Ariz. – June 28, 2006 – A leading global supplier of advanced power management control solutions, ON Semiconductor (Nasdaq: ONNN) today introduced three new white LED drivers designed to drive high brightness LEDs in backlighting applications for cellular phones, digital cameras, MP3 players, and other portable consumer electronics devices. With up to 90 percent efficiency and an ultra-thin 0.6 mm package profile, the devices help designers meet the stringent power and board space budgets of today’s battery-powered portable electronics. “As a rule, driving an LED in a display for a portable application can be accomplished by either an inductive solution or a charge pump solution, but our customers have very clear preferences,” said Marie Capron, ON Semiconductor’s business director for Low Voltage Products. “The inductive solution typically places LEDs in series, using a boost-type architecture. The charge pump solution has LEDs in parallel to eliminate the need for an inductor. To address the needs and preferences of all our portable product customers, we have expanded our LED driver portfolio to offer both, and provide key value-added features for circuit protection and to save valuable board space.” Inductive Solution The NCP5010 supplies up to 22 volts (V) typical to power a series of two to five white LEDs for LCD backlighting applications. Delivering up to 84 percent efficiency and 1 microamp (µA) shutdown current, the NCP5010 operates on input voltages from 2.7 V to 5.5 V. It features true cut-off, short-circuit and overvoltage protection, and offers undervoltage lock-out. This space-saving device is offered in a flip-chip package – which utilizes less than 3 mm2 of board space and requires only 0.6 mm of profile room. Its compact size makes it ideal for use in the thinnest of portable products. The 1 megahertz (MHz) frequency of the device’s integral pulse width modulation (PWM) boost converter and the integration of a Schottky rectifier, enables board designs to be optimized for small inductors and capacitors – saving additional board space. Charge Pump Solution The NCP5604A and NCP5604B drive either 3 LEDs or 4 LEDs, respectively at up to 25 milliamps (mA) of current per LED. Current matching tolerances of 0.5 percent ensure excellent uniform LED brightness. Delivering up to 90 percent efficiency and less than 1 µA quiescent current, these devices operate on input voltages from 2.7 V to 5.5 V and feature unique short-circuit and overvoltage protection. Both the NCP5604A and NCP5604B are offered in a thin profile QFN package (WQFN) that requires only 0.8 mm of profile room - making it ideal for ultra-slim phone form factor where space is at a premium Packaging and Price The NCP5010 is offered in a Pb-free, 8-pin, 1.7 mm x 1.7 mm x 0.6 mm flip-chip package. It is priced at $0.67 per unit in 3,000 unit quantities. The NCP5604A is offered in a Pb-free WQFN-16 package and priced at $0.69 per unit in 3,000 unit quantities. The NCP5604B is offered in a Pb-free WQFN-16 package and priced at $0.66 per unit in 3,000 unit quantities. * 2.7 to 5.5 V Input Voltage Range * Efficiency: 84% for 5 LED (VF= 3.5 V by LED) at 30mA and 4.2 V VIN * Low Noise 1 MHz PWM DC/DC Converter * Open LED Protection and Short Circuit Protection * 1 µA Shutdown Current Facility with True-Cutoff * Very Small 8-Pin Flip-Chip 1.7 X 1.7 mm Package