Browsing by Author "Ma, Gin-Kou"

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Dithering skip modulator with a width controller for ultra-wride-load high-efficiency DC-DC converters
(2006-01-01)
Huang, Hong-Wei
;
Ho, Hsin-Hsin
;
Chien, Chieh-Ching
;
Chen, Ke-Horng
;
Ma, Gin-Kou
This paper proposes a temperature-independent load sensor to decide the optimum power MOSFET width for power saving of DC-DC converters. Besides, it also can decide the optimum modulation technique in tri-mode operation, which is composed of pulse-width modulation (PWM), pulse-frequency modulation (PFM), and a new proposed dithering sldp modulation (DSM). An efficiency-improving DSM operation is introduced to raise the efficiency drop because of transition from PWM to PFM. Importantly, DSM mode can dynamically sldp the number of gate driving pulses, which is inverse proportional to load current. Simplistically and qualitatively stated, the novel load sensor can automatically select the optimum modulation method and optimum power MOSFET width to achieve high efficiency over a wide load range. Experimental results show the tri-mode operation can have high efficiency about 89 % over a wide load current range from 3mA to 500mA. Owing to the effective mitigation of the switching loss contributed by large power MOSFET, the novel width controller not only achieves high efficiency about 95 % but also extends this high efficiency to a lower load current range about 0.1mA.
Fast transient DC-DC converter with on-chip compensated error amplifier
(2006)
Huang, Hong-Wei
;
Ho, Hsin-Hsin
;
Chien, Chieh-Ching
;
Chen, Ke-Horng
;
Ma, Gin-Kou
A novel fast transient DC-DC converter with on-chip compensated error amplifier is presented in this paper. The error amplifier uses on-chip current-mode Miller capacitor to replace a large off-chip capacitor. Only three transistors and one voltage follower are used to implement this novel architecture. Not only on-chip compensated error amplifier is implemented without off-chip components and I/O pins, but also it can have fast transient response. Furthermore, we accurately decrease the transient response time without suffering from the oscillation issue. Experimental results demonstrate the stability and the fast transient response of the DC-DC converters.
High Efficiency Buck-Boost Converter with Reduced Average Inductor Current (RAIC) Technique
(2009)
Huang, Ping-Ching
;
Wu, Wei-Quan
;
Ho, Hsin-Hsin
;
Chen, Ke-Horng
;
Ma, Gin-Kou
This paper presents a buck-boost converter with high-efficiency and smooth-transition to extend the battery life of portable devices. The new control topology minimizes the switching and conduction losses at the same time even four switches are used. Therefore, over a wide input voltage range, the proposed buck-boost converter with minimum switching loss like the buck or boost converter can reduce the conduction loss through the use of the reduced average inductor current (RAIC) level. Especially, the converter offers good line/load regulation and thus provides a smooth and stable output voltage without being affected by the decreasing battery voltage. Experimental results show that the output voltage is regulated for the whole battery life time and the output transition is very smooth during mode transition. Besides, the output voltage ripple and the average inductor current are effectively minimized by the proposed control scheme. The peak efficiency is 97% and output voltage ripple is reduced from 100mV to within 10mV.
Sub-1V Input Single-Inductor Dual-Output (SIDO) DC-DC Converter with Adaptive Load-Tracking Control (ALTC) for Single-Cell-Powered System
(2009)
Huang, Ming-Hsin
;
Tsai, Yu-Nong
;
Lee, Yu-Huei
;
Wang, Shih-Jung
;
Chen, Ke-Horng
In this paper, a sub-1V input single-inductor dual-output (SIDO) DC-DC converter with an adaptive load-tracking control (ALTC) technique is proposed for single-cell-powered portable devices. The ALTC technique adaptively and accurately adjusts storage charge in form of the inductor current according to actual load condition without wasting surplus charge and increasing cross-regulation through the use of minimized the number of switch and optimum current sequence. A current-mode ring oscillator with a self-bias current source (SBCS) circuit is proposed to replace conventional startup oscillator to produce a nearly constant system clock. The test chip was fabricated by TSMC 0.25 mu m 2.5 V/5 V BCD process and experimental results show a high efficiency of 92 % and a cross- regulation smaller than 10 mV.