Patent ID: 6838927

Claim:
A semiconductor integrated circuit with stabilizing capacity having a plurality of function blocks, comprising: a voltage drop circuit that drops a power supply voltage supplied from the outside to produce a first voltage and supplies the first voltage to the plurality of function blocks; a stabilizing capacity that stabilizes the first voltage; and a plurality of voltage switching circuits each of which is provided in each function block, selectively switches between the first voltage and a base voltage to produce a second voltage, and supplies the second voltage to each corresponding function block, wherein parasitic capacity of a transistor caused by difference of voltage between the first voltage and the base voltage functions as capacity to complement said stabilizing capacity when said voltage switching circuit supplies said first voltage, and parasitic capacity of the transistor caused by difference of voltage between the first voltage and the second voltage functions as capacity to complement said stabilizing capacity, wherein in a semiconductor structure of each function block, the second voltage is supplied to a P well and a source of a P type transistor and the first voltage is supplied to a device isolation gate in a P type transistor region.