Browsing by Author "Chien, Chieh-Ching"

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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.
Highly efficient tri-mode control of buck converters with load sensing technique
(2006)
Huang, Hong-Wei
;
Chien, Chieh-Ching
;
Chen, Ke-Horng
;
Kuo, Sy-Yen
;
電控工程研究所
A highly efficient tri-mode buck converter with a novel load sensor circuit is proposed in this paper. The combination of pulse-width modulation (PWM), pulse-frequency modulation (PFM) and pulse-skipping circuit makes it efficient to operate in wide loading region. By using the novel load sensor, the buck converter can achieve high efficiency for the load range from 3mA to 400mA. This load sensor can automatically switch the modes according to the different load conditions. It changes the modulation methods from PWM mode to pulse-skipping modulation mode or to PFM mode. This tri-mode buck converter is fabricated by TSMC 0.35um. The efficiency above 90% is achieved for the load range about 90-400mA in PWM operation, and above 78 % attained for the load range about 3-50m.A in PFM mode. The insertion of the pulse skipping mode operation extends the high efficiency 90% of PWM operation for the load range from 90mA down to 50mA.
Optimum power-saving method for power MOSFET width of one-cycle control DGDC converters
(2006)
Chen, Ke-Horng
;
Chien, Chieh-Ching
;
Ho, Hsin-Hsin
;
Huang, Li-Ren
;
電控工程研究所
An optimum power MOSFET width technique is proposed in this paper for enhancing the efficiency characteristics of switching DC-DC converters. By implementing a one-cycle buck DC-DC converter, we demonstrate that the dynamic power MOSFET width controlling technique has much improvement in power reduction when the load current is light or heavy. The maximum efficiency of the buck converter is about 92% with 3% efficiency improvement for the heavy load condition. Besides, the efficiency can be enormously improved about 16% for light load condition as a result of the power reduction from the large power MOSFET transistors. Meanwhile, we also propose a new error correction loop circuit (ECL) to get a better load regulation than that of the previous designs. Furthermore, as compared to the adaptive gate driver voltage technique, the optimum power MOSFET width can achieve a great improvement on power saving. It is a better power-saving technique than the low-voltage-swing MOSFET gate drive technique for switching DC-DC converters.