A Single-Inductor Bipolar-Output DC/DC Converter with High Efficiency Over Wide Load Range for Active Matrix OLED

摘要

This paper proposes a single-inductor bipolar-output (SIBO) switching converter with high efficiency over a wide load range for active matrix organic light-emitting diode (AMOLED) display. The SIBO converter provides a pair of positive and negative output voltages with only one external inductor. The proposed burst mode function can enhance the light load efficiency with low output ripples, 25mV and 10mV for positive and negative voltages, respectively. With the smooth start-up function, the inductor current can rise smoothly and have low peak value, reducing the current stress on inductor and power MOSFETs. The efficiency can be maintained higher than 80% with the load current from 20mA to 140mA. At light loads, the efficiency is higher than 60% when the load current is above 5mA. The maximum efficiency is 88% when the input voltage is 3.7V and the load current is 60mA.