Low-Flicker Lighting From High-Voltage LEDs Driven by a Single Converter-Free Driver

This letter reports the design and characterization of high-power flip-chip high-voltage light-emitting diodes (HVLEDs), driven by a single converter-free LED driver for a compact and low-flicker lighting system. The HVLED chips show small forward voltage variation, uniform light emission, good optical output linearity, and stable thermal performance. All these characteristics well satisfy the demanding requirements of the novel quasi-constant power control scheme adopted in the converter-free LED driver. After bonding 12 HVLED chips (60 LED cells in total) and a single driver onto a silicon carrier through metal bonding, a low lighting flicker of 15.2%~17% was demonstrated, showing great potential for high-quality illumination applications that require low flicker, high light output, and good thermal stability.