Patent ID: 7605638
Filing Date: 2009-10-20
Classification: H02M

Abstract:
1. A semiconductor integrated circuit comprising: a charge pump circuit that is connected to a first capacitor and a second capacitor, charges the first capacitor with an input voltage, transfers a charge accumulated in the first capacitor to the second capacitor, outouts, as an output voltage, a voltage of the second capacitor, and is capable of changing over a capability of charging the first or second capacitor; a first circuit block that receives a positive voltage and a grounding potential, as a power source; and a second circuit block that receives the positive voltage and the output voltage of the charge pump, as a power source, wherein the charge pump circuit includes: a first switching transistor that connects one end of the first capacitor with the input voltage; a second switching transistor that connects the one end of the first capacitor with the grounding potential; a third switching transistor that connects the other end of the first capacitor with the grounding potential; a fourth switching transistor that connects the other end of the first capacitor with the second capacitor; a fifth transistor having a drain and a gate connected to any one gate of the first to fourth switching transistors, and having a source connected to any one source of the first to fourth switching transistors; a current source that supplies a current to the drain of the fifth transistor; and a changeover circuit that changes over a period during which the current of the current source flows in the drain of the fifth transistor.