A VO -Hopping Reconfigurable RGB LED Driver With Automatic Δ VO Detection and Predictive Peak Current Control

A cost-effective single-converter reconfigurable CMOS LED driver is proposed to accurately and adaptively bias RGB color LEDs. An automatic ΔVOdetection technique is developed to precisely detect the voltage difference between the red and green/blue LEDs regardless of the PVT variations. The fast VO-hopping technique is also implemented to instantaneously adjust the output voltage level, achieving 198 ns/V VO-hopping speed on 0.35 μm CMOS. This is at least one order faster than the state-of-the-arts. Predictive peak current control and burst-mode operation are employed for fast inductor current modulation and robust operation. The switching frequency is stabilized around 1 MHz by an adaptive off-timer for switching noise spectrum control. The proposed driver consumes 8.6 times less headroom power than its fixed-output counterparts. The performance has been verified by measurement results of a 0.35 μm CMOS prototype.