Miniature LED driver can drive up to 16 high power LEDs

28th May 2007

ES Admin

0 0

Operating from a 6V to 60V input supply and achieving up to 95% efficiency, the ZXLD1362 from Zetex Semiconductors can drive up to 16 high power LEDs with an adjustable output current of up to 1A. Provided in the tiny TSOT23-5 package, this LED driver is the smallest of its kind in its current rating, with a maximum footprint of 2.8mm x 2.9mm and off-board height of 1mm.

Simple to use and requiring just four external components, this highly integrated chip supports a range of flexible LED brightness and thermal management schemes. Output current can be adjusted by applying either PWM or DC voltage control signals to the adjust pin. Application of a low voltage signal turns the output off and puts the device into a low current standby mode.

Supporting an operating frequency of up to 1MHz, the ZXLD1362 is able to offer highly sensitive and accurate LED brightness control, with a typical dimming ratio of 1000:1 cited at 300Hz. A soft-start feature can also be achieved by the addition of an external capacitor.

Integrating a 60V MOS switch and a high-side output current sensing circuit, which uses an external resistor to set the nominal output current, the chip enables high power LEDs to benefit from ground referenced return paths, of particular importance in architectural lighting applications.

To simplify thermal control, the input resistance of the chip’s adjust pin has been set at 50kΩ in order to be compatible with common thermistor values. The chip’s compact design and ability to comfortably withstand high-voltage transients, means it will also appeal to space-starved automotive and industrial applications.

A drop-in upgrade for many lower power solutions, including Zetex Semiconductor’s own ZXLD1350 (30V, 350mA) and ZXLD1360 (30V, 1A), the ZXLD1362 high power LED driver is priced at $1.78 in 1K quantities.