Constant-Current Controller Targets Retrofit LED Bulbs

Integrated Silicon Solution’s (ISSI) IS31LT3932 LED controller offers a universal input voltage range from 85 to 265 V ac, power factor correction greater than 0.97, and typical output current accuracy of ±3%. As a result, it will suit  offline LED retrofit lamp solutions such as E26, GU10, PAR, and T8. The true constant-current controller supports LED lighting solutions up to 30 W with a minimal number of external components. Its current-mode-control scheme maintains inductor current regulation regardless input/output voltage variation. Pulse frequency modulation operates without an optocoupler and secondary-side control or loop-compensation circuitry. Non-isolated buck or buck-boost mode, or isolated flyback mode configurations are possible. Input power-line sensing and output-voltage sensing circuits operate in primary feedback mode to deliver accurate current regulation to the LED load. Other features include soft-start and V_CC undervoltage lockout with hysteresis. The device is protected against output overvoltage, output open and short circuit, primary-side overcurrent, and thermal shutdown with hysteresis. A high-voltage gate drive supports a range of low-cost power MOSFETs.

INTEGRATED SILICON SOLUTIONS INC. (ISSI)