A Single-Inductor Step-Up DC-DC Switching Converter With Bipolar Outputs for Active Matrix OLED Mobile Display Panels

• Published in: IEEE journal of solid-state circuits Vol. 44; no. 2; pp. 509 - 524
• Main Authors: CHAE, Chang-Seok, LE, Hanh-Phuc, LEE, Kwang-Chan, CHO, Gyu-Ha, CHO, Gyu-Hyeong
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.02.2009; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Active matrix technology; AMOLED; Applied sciences; BiCMOS integrated circuits; bipolar output; body switching; charge pump; Charge pumps; Circuit properties; comparator control; Comparators; Converters; current sense; DC-DC converter; Display; Electric potential; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Flat panel displays; Magnetic devices; Matrix converters; Optoelectronic devices; Organic light emitting diodes; Panels; Pi control; Proportional control; Pulse duration modulation; Ripples; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Signal convertors; single-inductor multiple-output (SIMO); Switching; Switching converters; Voltage; Voltage control; Performance evaluation; Output power; Inductor; Adaptive method; Implementation; BiCMOS technology; Current mode; Active matrix; Output voltage; Optoelectronic device; Comparator circuit; Charge pumping; current sense; Organic electronics; single-inductor multiple-output (SIMO); body switching; Transient response; bipolar output; AMOLED; Direct current convertor; LED displays; Matrix display; Switching; DC-DC converter; Organic light emitting diodes; charge pump; Pulse duration modulation; comparator control
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2008.2010986

A single-inductor step-up DC-DC switching converter with bipolar outputs is implemented for active-matrix OLED mobile display panels. The positive output voltage is regulated by a boost operation with a modified comparator control (MCC), and the negative output voltage is regulated by a charge-pump operation with a proportional-integral (PI) control. The proposed adaptive current-sensing technique successfully supports the implementation of the proposed converter topology and enables the converter to work in both discontinuous-conduction mode (DCM) and continuous-conduction mode (CCM). In addition, with the MCC method, the converter can guarantee a positive output voltage that has both a fast transient response of the comparator control and a small output voltage ripple of the PWM control. A 4.1 mm 2 converter IC fabricated in a 0.5 mum power BiCMOS process operates at a switching frequency of 1 MHz with a maximum efficiency of 82.3% at an output power of 330 mW.