An Integrated Multilevel Converter With Sigma–Delta Control for LED Lighting

LEDs have finally emerged as the dominant lighting technology. As such, the lighting industry values power converters that have high efficiency, unity power factor, minimal flicker, dimming, low cost, and a small form factor. This paper presents an integrated circuit (IC) LED driver that is designed to achieve these goals. It introduces multilevel converters with sigma-delta modulation to the power IC space. The driver features a pair of sigma-delta-controlled multilevel converters. The first is a multilevel rectifier responsible for power factor correction and dimming. The second is a bidirectional multilevel inverter used to cancel ac power ripple from the dc bus. The system also contains an output stage that powers the LEDs with dc and provides for galvanic isolation. The IC LED driver has been simulated and prototyped on a silicon fabrication process. Its functional performance indicates that integrated multilevel converters are a viable topology for lighting or other similar applications.