LED Driver Exploits Closed-Loop System

Promoting high current accuracy and consistent brightness, the HV9963 LED driver employs a closed-loop system with PWM dimming capability to optimize performance and efficiency as well as extend LED life. The closed-loop system controls the current going to the LED string. It is an active, real-time system that continuously monitors the LED current via sense resistors. The device includes a 1-MHz transconductance amplifier with a tri-state output that closes feedback loops in the sensing process and provides accurate current control. It can be synchronized in applications requiring multiple LED drivers to prevent the system sub-harmonic oscillations that are often associated with driving multiple driver schemes. Other features include hiccup mode protection for short- and open-circuit conditions, a high PWM dimming ratio, and operation in a constant-frequency mode. Available in a 16-lead SOIC package, pricing is $0.85 each/1,000. SUPERTEX INC., Sunnyvale, CA. (800) 222-9883.