A Negative Single-Input/Multi-Output LED Driver and Its Analysis Method

Abstract

A negative single-input/multi-output (SIMO) LED driver is proposed in this paper. Unlike the conventional LED driver using SIMO boost converters, the proposed LED driver using an SIMO buck-boost converter offers a negative stepped-down voltage to drive LED’s cathodes. By turning on output switches in rotation during a transferring process, the proposed driver can suppress the imbalance among output currents. This paper also presents a novel analysis method to estimate properties of the SIMO LED driver using a buck-boost converter. By assuming a five-terminal equivalent circuit, the proposed analysis method can derive the power efficiency and output voltages without complex matrix calculations. The theoretical analysis and experiments show the effectiveness of the proposed SIMO LED driver. 