Browsing by Author "Hsieh, Wei-Lun"

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Fast Mode-Switching Technique in Hrbrid-Mode Operation
(2008)
Chen, Chi-Lin
;
Hsieh, Wei-Lun
;
Huang, Han-Hsiang
;
Chen, Ke-Horng
;
電控工程研究所
A fast mode-switching technique between pulse width modulation (PWM) and pulse frequency modulation (PFM) modes Is proposed to keep high efficiency over wide load range. Load dependent zero-current detector (ZCD) can effectively speed up the transition from PWM to PFM mode. Especially, the overshoot voltage can be minimized by using the reversed current provided by the ZCD circuit. Furthermore, the undershoot voltage of the transition from PFM to PWM mode can be reduced because the recovery time can be reduced by restoring the output voltage of the error amplifier. Thus, the efficiency of current mode DC-DC buck converter is higher than 88% at light loads and the recovery time is smaller than 35 mu s when load current changes from 500mA to 10mA suddenly.
Programmable voltage-to-current converter with linear voltage control resistor
(2008)
Huang, Hong-Wei
;
Hsieh, Wei-Lun
;
Chen, Ke-Horng
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A programmable voltage-to-current converter with linear voltage control resistor (VCR) is presented in this paper. It uses a cascoded flipped voltage follower (CASFVF) to be the input stage in order to enhance the response time and accuracy. Programmability is achieved by using the control signal V-ctrl to adjust the equivalent resistance of VCR. Simulation results in 0.25-mu m CMOS technology demonstrate the high linearity of the proposed voltage-to-current converter and VCR circuit.