LED driver enhances efficiency of battery-operated devices

ZMD AG introduces the second wave of its ZLED family of LED control solutions with two new low-voltage ICs designed for battery-powered handheld devices. The ZLED7012 and ZLED7022 incorporate low noise, constant frequency charge pump dc/dc converters that can efficiently drive up to four (ZLED7012) or six (ZLED7022) strings of LEDs. The devices come in the ultra-small UTQFN package (2 x 2 mm) and require only three external components for operation, thus enabling a very low bill of material.

Capable of operating efficiently with dc voltage supplies ranging from 2.8 to 5.5 V, the devices are suitable for small, battery-powered LED backlighting applications such as mobile phones, PDAs, GPS, and navigation systems. The devices can also be used for illumination of digital photo frames and low voltage LED lighting fixtures as well as all kinds of general-purpose low-voltage industrial and consumer applications.

With the pulse count control (PCC) serial digi­tal input, designers can enable and disable the LEDs and set the current level. The programmable current levels range from 1.8 to 20 mA per LED channel. This simple, high-speed interface allows efficient real-time manage­ment of LEDs via microcontrollers or control systems.

Additional device features include integrated soft-start circuitry to protect against excessive in-rush current dur­ing power-on and a low-current shutdown mode that reduces quiescent current consumption to approximately 1 μA. The ZLED7012 and ZLED7022 operate over a temperature of range of -40°to 85° C.

For more information, contact ZMD America Inc., 201 Old Country Rd., Suite 204, Melville, NY 11747. Phone: (631) 549-2666.