Patent ID: 7589583
Filing Date: 2009-09-15
Classification: G11C,H02M,H03K

Abstract:
1. A charge pump circuit comprising: a plurality of charge transfer devices connected in serial between an input terminal and an output terminal; a plurality of capacitor elements, a terminal of each of the capacitor elements being connected to a corresponding connecting node of the charge transfer devices; and an oscillator circuit connected to another terminal of said each of the capacitor elements and supplying a clock signal to the capacitor elements, the oscillator circuit comprising a ring oscillator circuit comprising a plurality of inverters and outputting the clock signal, and a current generation circuit controlling a current flowing through the inverters so as to reduce a frequency of the clock signal according to an increase of a power supply voltage, wherein the ring oscillator circuit comprises first transistors controlling a current flowing from a power terminal to the inverters, the current generation circuit comprises a second transistor forming a first current mirror circuit with the first transistors, a constant current generation circuit connected in serial with the second transistor and a resistor connected to the second transistor in parallel with the constant current generation circuit, and the resistor has such a resistance value that a frequency of the clock signal is inversely proportional to an increase of a power supply voltage.