Voltage Regulated Charge Pump
Date Issued
2006
Date
2006
Author(s)
Chen, Chung-Chieh
DOI
zh-TW
Abstract
Nowadays, many electronic products are battery powered devices. However, most batteries are unable to maintain a steady voltage. In order to provide a steady voltage source, the charge pump and regulator are significant. With bandgap reference, to regulate the output voltage is easy. Nevertheless, the bandgap reference increases the manufacture complexity. In order to solve this problem, the charge pump regulated without bandgap reference is proposed in the thesis.
The charge pump structure is cross-coupled type, and the clock is provided with a relaxation oscillator. In order to regulate the charge pump by pulse-skip mode, the current operated in the relaxation oscillator should be adjusted. The bandgap reference voltage was replaced by threshold voltage, and the output voltage is sensed with a PMOS transistor. If the output exceeds the default voltage, the PMOS transistor turns on, and the relaxation oscillator turns off. Meanwhile, the charge pump stops boosting.
The circuit needs to be normally operated in a wide voltage range due to the gradually decreased voltage supply from the battery. To overcome this problem is also an important issue in this thesis.
The circuit system is checked and verified with the simulation software “HSPICE”, and the result shows that the output voltage provided from the charge pump is weakly dependent on power supply and load current.
Subjects
電荷幫浦
脈衝跨越模式
帶差參考電壓
charge pump
pulse-skip mode
bandgap reference
Type
thesis
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