US 5,179,296 AGranted

Charge pump substrate bias circuit

AssigneeSharp Kabushiki Kaisha

InventorNobuhiko Ito

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Abstract

A charge pump circuit having a pumping capacitor is provided. A first terminal of the pumping capacitor is connected to a V.sub.CC power source through a P-MOS transistor, and grounded via an N-MOS transistor. The gates of these transistors receive a signal in which the HIGH level and the LOW level are alternately repeated. A second terminal of the pumping capacitor is grounded via an N-MOS transistor. The gate of the N-MOS transistor is connected to a terminal through a capacitor, and also to the second terminal of the pumping capacitor via an N-MOS transistor the gate of which is grounded. The second terminal is connected to an external circuit through an N-MOS transistor. The gate of the N-MOS transistor is connected to a terminal through a capacitor, and also to the output terminal through an N-MOS transistor the gate of which is connected to the node.

Claims3

Dependent claims

A charge pump circuit comprising:

an output terminal for being connected to an external circuit;
a capacitor having first and second terminals, said second terminal being connected to said output terminal;
a voltage supplying means for supplying a first voltage and a second voltage alternately to said first terminal of said capacitor, said first voltage being higher than said second voltage;
a first switching means for grounding said second terminal of said capacitor when said first switching means is turned on, said first switching means connected between said second terminal of said capacitor and the ground;
a first driving means for turning on said first switching means when said voltage supplying means supplies said first voltage to said first terminal of said capacitor;
a second switching means for electrically connecting said second terminal of said capacitor to said output terminal when said second switching means is turned on, said second switching means connected between said second terminal of said capacitor and said output terminal;
and
a second driving means for turning on said second switching means when said voltage supplying means supplies said second voltage to said first terminal of said capacitor.

5 more elements

Dependencies are inferred from the claim text.