Off-line constant current LEDs driver using the HVLED primary controller

The article introduces an off-line constant current LEDs driver controller, using the HVLED, an innovative all-primary controller, by STMicroelectronics. Using the proprietary patented technique, the IC is able of providing a constant output current using primary sensing feedback, thus eliminating the need for the optocoupler, secondary voltage reference and current sensor, still maintaining quite accurate current regulation. The power supply is able to drive up to 4 LEDs in the European range, i.e. 185-265VAC, even if the same configuration can be also used in U.S. range and for a different numbers of LEDs, only limited from the maximum IC power capability. The proposed driver can be suitably used in all the applications where the tight regulation tolerance, efficiency performances and low component count are decisive to meet the LED's market requirements.