Charge pump circuit
First Claim
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, andthe resistor has such a resistance value that a frequency of the clock signal is inversely proportional to an increase of a power supply voltage.
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Accused Products
Abstract
The invention is mainly directed to providing a charge pump circuit which realizes low power consumption. A first clock signal is supplied from an oscillator circuit to capacitor elements forming a charge pump circuit. A current generation circuit controls a current flowing through each of inverters by controlling operation of PMOS and NMOS, and as a result controls the frequency of the first clock signal. A gate and a drain of PMOS are short-circuited, and between the node thereof and a ground terminal a constant current generation circuit and a resistor are connected in parallel. The constant current generation circuit serves to keep the current flowing through the inverters constant against a change of a power supply voltage. Therefore, the frequency of the clock signal is reduced according to the increase of the power supply voltage.
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Citations
2 Claims
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1. A charge pump circuit comprising:
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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. - View Dependent Claims (2)
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Specification