Patent ID: 7200054

Claim:
The semiconductor integrated circuit device comprising: an external terminal; a first step-down circuit that receives supply voltage supplied through the external terminal, stationarily forms internal voltage lower than the supply voltage, and outputs the internal voltage through a first output terminal; a second step-down circuit whose mode is switched according to state control signals between first mode in which the supply voltage supplied through the external terminal is received and the internal voltage is formed and outputted through a second output terminal, and second mode in which the operating current for a control system that forms the internal voltage is interrupted and the second output terminal is brought into high-impedance state; and internal circuits, wherein the internal voltage is supplied to the internal circuits through an output terminal formed by connecting the first output terminal and the second output terminal in common, wherein the internal circuits include a first internal circuit and a second internal circuit, wherein the first step-down circuit and the second step-down circuit respectively comprise a plurality of circuit blocks, wherein first internal voltage supplied to the first internal circuit is formed through a first step-down power supply circuit comprising the first step-down circuit and the second step-down circuit, wherein second internal voltage supplied to the second internal circuit is formed through a second step-down power supply circuit comprising the first step-down circuit and the second step-down circuit, wherein the first step-down power supply circuit is provided, at an output terminal, with an external terminal for connection with stabilizing capacitance, and wherein the second step-down power supply circuit is so constructed that built-in stabilizing capacitance is connected with an output terminal thereof.