Patent ID: 7005912
Filing Date: 2006-02-28
Classification: H02M

Abstract:
1. A step-up apparatus comprising: a first level shift circuit for receiving a first clock signal to generate two phase-opposite second clock signals; a second level shift circuit for receiving said first clock signal to generate two phase-opposite third clock signals; a charge pump circuit, connected to said first level shift circuit, for stepping up a power supply voltage at a power supply voltage terminal using said second clock signals to generate a positive voltage; and a polarity inverting circuit, connected to said charge pump circuit and said second level shift circuit, for inverting said positive voltage using said third clock signals to generate a negative voltage whose absolute value is the same as said positive voltage, a high level of said second clock signals being not higher than said positive voltage, a low level of said second clock signals being not lower than a voltage at a ground terminal, a high level of said third clock signals being not higher than said power supply voltage, a low level of said third clock signals being not lower than said negative voltage.