P‐56: A Single‐Inductor Bipolar‐Output DC/DC Converter with High Efficiency Over Wide Load Range for Active Matrix OLED

Abstract

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.

Embedded Single-Inductor Bipolar-Output DC–DC Converter in Class-D Amplifier for Low Common Noise

“…Finally, the derived equation in (9) can be established at the source voltage of M P6 to stand for actual and accurate power request in the inductor current [22].…”

A Hybrid Single-Inductor Bipolar Triple-Output DC–DC Converter With High-Quality Positive Outputs for AMOLED Displays

“…In addition, the OPDC scheme charges V OP every cycle, resulting in a smaller ripple compared with the one with TMC scheme. Therefore, the single-inductor bipolar-output (SIBO) converters designed in [15], [16], [17], [18], [19], and [20] used this solution. However, a small voltage ripple is difficult to achieve in those OPDC converters due to the pulsing charging current for V OP , causing an unavoidable voltage ripple on the output capacitor, especially when taking the equivalent series resistor (ESR) of the capacitor into consideration.…”

“…So far, all the prior reported SIBO converters [15], [16], [17], [18], [19], [20], [21], [22] for AMOLED displays did not provide AV DD for the source driver. A conventional solution to provide all the supply rails employs the utilization of low-dropout regulators for both V OP and AV DD , and an inverting charge pump in cascade with a linear regulator for V ON obviously degrading the system efficiency.…”