White LED Drivers Deliver 90 % Efficiency

Introduced as 1.25-MHz current-mode boost converters optimized for white LED applications, the SiP12510 and SiP12511 specify an input voltage range of 2.5V to 6.0V and output voltages of up to 17V for the SiP12510 and 28V for the SiP12511. Their typical efficiency of 90 % is reportedly the highest ever achieved for this device type. Integrated protection features include over voltage, a cycle-by-cycle current limit of 0.55A supporting up to three parallel LED strings consuming 20 mA each, and a thermal shutdown block that shuts down the device once the internal temperature exceeds 165°C. The devices support both linear and PWM techniques for regulating LED string current. Other shared features include a 3-phase soft-start function, feedback voltage of 0.1V, and an operating temperature range from -40°C to +85°C degrees. Price for either device is $1.08 each/1,000. VISHAY INTERTECHNOLOGY, INC., Malvern, PA. (619) 336-0860.