To cope with monolithic controller replicas and the current unbalance situation in multiphase converters, a pseudoramp current balance technique is proposed to achieve timemultiplexing current balance in voltage-mode multiphase DC-DC buck converter. With only one modulation controller, silicon area and power consumption caused by the replicas of controller can be reduced significantly. Current balance accuracy can be further enhanced since the mismatches between different controllers caused by process, voltage, and temperature variations are removed. Moreover, the offset cancellation control embedded in the current matching unit is used to eliminate intrinsic offset voltage existing at the operational transconductance amplifier for improved current balance. An explicit model, which contains both voltage and current balance loops with non-ideal effects, is derived for analyzing system stability. Experimental results show that current difference between each phase can be decreased by over 83% under both heavy and light load conditions. Index Terms-Offset cancellation control (OCC), pseudoramp current balance (PRCB), pulse frequency modulator (PFM), pulse width modulator (PWM), skipping modulator, time-multiplexing (TM) current balance.

Cholesteric liquid-crystal display (Ch-LCD) has the bi-stable characteristic to achieve the energy-saving for the green technology. Backlight is even unnecessary in the Ch-LCD system. The single-inductor bipolar-output (SIBO) converter is one of best candidate to supply the power management function for the Ch-LCD with dual positive and negative output voltages by using a single inductor for a compact solution. The energy control methodology with the current-mode control and the power conservation mechanism (PCM) can strengthen the voltage quality to get high display quality. The test chip fabricated by 0.25 μm CMOS technology demonstrates the non-noticeable crossregulation at dual outputs with 90 % peak power conversion efficiency.

Electronic paper display (EPD) shows the trend of state-of-the-art display technique. It not only holds image/text without consuming energy but also presents thin and flexibility like ordinary paper. Single-inductor multi-output (SIMO) converter, with innovative multi-vector current-control methodology, precisely tracks and quantifies the actual demanded-energy and addresses excessive-energy for power-efficient and space-minimized requirements of EPDs. The testing chip occupies 0.45 mm 2 in 0.25 μm CMOS technology and achieves the power conversion efficiency larger than 85 % at the order of 0.5 mW output power.

This paper proposes a design methodology for implementing a high efficiency and/or a low cost RGB backlight module in color sequential notebook computers' display. A RGB LED driver composed of an asynchronous 1.5MHz DC/DC boost converter with dual loop control is fabricated by TSMC 0.25 μm BCD 40V to generate 17V or 21V output voltage to turn on more than 6 series‐red, 6 series‐green, or series‐blue LEDs at the same time for the notebooks' backlight. Besides, charge‐recycling technique is used to restore extra energy at the output node when switching to different forwarding light emitting diodes (LEDs) and release the energy next time. The total power consumption of a 15.4′ LCD panel of a notebook computer can be reduced from 5W to about 2–3W.

This paper presents a high integrated dual-side dual-output (DSDO) switched-capacitor (SC) regulator with only two flying capacitors. Generally, a dual-phase voltage doubler and an inverter are used to supply positive and negative voltage for TFT-LCD gate drivers, respectively. Four flying capacitors, eight pinouts, and sixteen power switches are necessary for their operations in the driver integrated chip (IC). The proposed DSDO SC regulator combines both dual-phase voltage doubler and inverter converter into one channel through the use of time multiplexing technique at the cost of little performance degradation. As a result, it not only diminishes the number of flying capacitor from four to two but also removes four IC pinouts for low cost and compact size. Beside, sixteen necessary power switches are reduced to twelve for decreasing about 27% silicon area.