| Summary: | 碩士 === 國立中興大學 === 電機工程學系 === 87 === The charge pumping circuits are very useful and crucial for applications in Flash EEPROM memories circuits. Those are also widely used in switch capacitor systems, such as A/D, D/A, filter systems.
The recent development of portable mixed-mode communication systems has driven to the circuits tolow voltage and low power consumption. Therefore, this thesis proposed the novel charge pumping circuits for low supply voltages utilizing N-MOSFET’s or P-MOSFET’s with capacitors to generate positive and negative boosted voltages. The two major factors limiting the pumping gain and efficiency are the body effect and the threshold voltage. Two techniques were proposed to minimize the influence of them. One is the new substrate connected technique to eliminate the body effect. The other one is the small pumping circuit providing higher gate voltages of the major pumping circuit to enhance the pumping gain. With these two new techniques, the new pumping circuits have high positive or negative boosted voltages at low supply voltages. In addition, a new “gate-drain bias” auxiliary transistor technique which overcomes charge reverse sharing problem when the circuit output node has load current, can keep the high pumping gain and generate more stable output voltage waveform.
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