Patent ID: 7099224

Claim:
A voltage generator for generating a substantially stable voltage, the voltage generator comprising: a voltage dividing circuit for generating a first input voltage and a second input voltage according to a high reference voltage and a generator output voltage, wherein the high reference voltage is higher than the first input voltage, the first input voltage is higher than the second input voltage, and the second input voltage is higher than the generator output voltage; a first differential amplifier for generating a first output voltage signal in response to a reference input voltage and the first input voltage; a second differential amplifier for generating a second output voltage signal in response to the reference input voltage and the second input voltage; a first switch for providing a high voltage source to the generator output voltage when the first output voltage signal is at high state; and a second switch for providing a low voltage source to the generator output voltage when the second output voltage signal is at high state: wherein when the first input voltage is lower than the reference input voltage, the first output voltage signal is at high state so that the generator output voltage increases; and when the second input voltage is higher than the reference input voltage, the second output voltage signal is at high state so that the generator output voltage decreases.