Semiconductor integrated circuit device

Abstract

A semiconductor integrated circuit device with reduced consumption current is provided. A first step-down circuit stationarily forms internal voltage lower than supply voltage supplied through an external terminal. A second step-down circuit is switched between first mode and second mode according to control signals. In first mode, the internal voltage is formed from the supply voltage supplied through the external terminal and is outputted through a second output terminal. In second mode, operating current for a control system that forms the internal voltage is interrupted and an output high impedance state is established. The first output terminal of the first step-down circuit and the second output terminal of the second step-down circuit are connected in common, and the internal voltage is supplied to internal circuits.

What is claimed is: 
     
       1. A semiconductor integrated circuit device having a first operating mode and a second operating mode comprising:
 an external terminal;   a first step down circuit to receive a supply voltage through the external terminal, to generate a first internal voltage lower than the supply voltage, and to output the first internal voltage through a first output terminal during the first and second operating modes;   a second step down circuit to receive the supply voltage through the external terminal, to generate a second internal voltage lower than the supply voltage, and to output the second internal voltage through a second output terminal during the first operating mode, and to bring the second output terminal to a ground level during the second operating mode;   a first internal circuit to receive the first internal voltage through the first output terminal;   a second internal circuit to receive the second internal voltage through the second output terminal;   a state control circuit to bring the semiconductor integrated circuit device into the first operating mode or the second operating mode;   wherein the operating current of the second step down circuit is interrupted during the second operating mode.   
     
     
       2. The semiconductor integrated circuit device according to  claim 1  further comprising:
 a third step down circuit to receive the supply voltage through the external terminal, to generate the first internal voltage, and to output the first internal voltage through a third output terminal during the first operating mode, and to bring the third output terminal into high-impedance state during the second operating mode; 
 wherein the first and third output terminals are connected in common. 
 
     
     
       3. The semiconductor integrated circuit device according to  claim 1  further comprising:
 a switch connected between the first output terminal and the second output terminal; 
 wherein the first and second internal voltages are substantially equal, and 
 wherein the switch is turned on during the first operating mode, and turned off during the second operating mode. 
 
     
     
       4. The semiconductor integrated circuit device according to  claim 1 ,
 wherein the first internal circuit includes a RAM.   
     
     
       5. The semiconductor integrated circuit device according to  claim 1   wherein the second internal circuit includes a ROM.   
     
     
       6. The semiconductor integrated circuit device according to  claim 2  further comprising:
 a fourth step down circuit to receives the supply voltage through the external terminal, to generate the second internal voltage, and to output the second internal voltage through a fourth output terminal during the first operating mode, and to bring the second output terminal to a ground level during the second operating mode; 
 wherein the second and fourth output terminals are connected in common. 
 
     
     
       7. A semiconductor integrated circuit device having a first operating mode and a second operating mode comprising;
 an external terminal receiving a supply voltage;   a first step down circuit to generate a first internal voltage lower than the supply voltage, and to output the first internal voltage to a first output terminal in the first and the second operating modes;   a second step down circuit to receive the supply voltage through the external terminal, to generate a second internal voltage, and to output the second internal voltage through a second output terminal in the first operating mode, and not to supply the second internal voltage to the second output terminal in the second operating mode;   a third step down circuit to generate a third internal voltage lower than the supply voltage, and to output the third internal voltage to a third output terminal in the first and the second operating modes;   a first volatile memory and a second volatile memory;   a non-volatile memory; and   an analog circuit;   wherein the first internal voltage is supplied to the first volatile memory through the first output terminal, and the second internal voltage is supplied to the non-volatile memory and the second volatile memory through the second output terminal, the third internal voltage is supplied to the analog circuit through the third output terminal,   wherein a consumption current of the semiconductor integrated circuit device in the second operating mode is lower than a consumption current of the semiconductor integrated circuit device in the first operating mode.   
     
     
       8. The semiconductor integrated circuit device according to claim 7 further comprising;
 a logic circuit;   wherein the second internal voltage is supplied to the logic circuit through the second output terminal.   
     
     
       9. The semiconductor integrated circuit device according to claim 8,
 wherein the logic circuit includes a CPU.   
     
     
       10. The semiconductor integrated circuit device according to claim 8,
 wherein the first volatile memory is a register that stores operational data of the logic circuit.