Power-saving voltage supply

Claim 2

A semiconductor device comprising: an external power supply terminal to which an external power supply voltage is supplied; an internal power supply line; first voltage dropping means, connected between said external power supply terminal and said internal power supply line, operative in at least a standby interval, for generating a first voltage having a smaller value than that of the external power supply voltage to supply the first voltage to said internal power supply line; and second voltage dropping means, connected between said external power supply terminal and said internal power supply line, operative in an interval other than the standby interval for generating a second voltage having a smaller value than that of the external power supply voltage to supply the second voltage to said internal power supply line.

Claim 3

A semiconductor device comprising: an external power supply terminal to which an external power supply voltage is supplied; an internal power supply line; an internal circuit, connected to said internal power supply line, having a standby interval for reducing power consumption and being operated using a voltage of said internal power supply line as a power supply voltage; first voltage dropping means, connected between said external power supply terminal and said internal power supply line, operative in the standby interval, for generating a first voltage having a lower value than that of the external power supply voltage to supply the first voltage to said internal power supply line; and second voltage dropping means, connected between said external power supply terminal and said internal power supply line, operative in an interval other than the standby interval, for generating a second voltage having a lower value than that of said external power supply voltage to supply the second voltage to said internal power supply line.

Claim 4

A semiconductor device comprising: an external power supply terminal to which an external power supply voltage is supplied; an internal power supply line; an internal circuit, connected to said internal power supply line, having a standby interval for reducing power consumption and being operated using a voltage of said internal power supply line as a power supply voltage; first voltage dropping means, connected between said external power supply terminal and said internal power supply line, operative in the standby interval, for generating a first voltage having a lower value than that of the external power supply voltage to supply the first voltage to said internal power supply line; and second voltage dropping means, connected between said external power supply terminal and said internal power supply line, operative in an interval other than the standby interval, for generating a second voltage having a lower value than that of said external power supply voltage to supply the second voltage to said internal power supply line.

Claim 5

A semiconductor device according to claim 2, wherein said first voltage dropping means is operated at all times.

Claim 6

A semiconductor device according to claim 2, wherein a first current consumption when said first voltage dropping means is in an operative mode is lower than a second current consumption of said second voltage dropping means.

Claim 7

A semiconductor device according to claim 2, wherein said first voltage dropping means includes a plurality of impedance elements each having an impedance of at least more than several mega ohms which are respectively inserted in direct current paths.

Claim 8

A semiconductor device according to claim 2, wherein said first voltage dropping means includes voltage dividing means for dividing the voltage of said internal power supply line; voltage amplifying means, to which a voltage of said external terminal is supplied as an operating voltage, for amplifying a voltage which is divided by said voltage dividing means; and variable impedance means, inserted between said external terminal and said internal power supply line, and an impedance controlled in accordance with an output from said voltage amplifying means.

Claim 9

A semiconductor device according to claim 2, wherein said second voltage dropping means includes reference voltage generating means, operative only in an interval other than the standby interval, for generating a predetermined reference voltage; voltage comparing means, operative only in an interval other than the standby interval, for comparing a voltage of said internal power supply line with the reference voltage; and variable impedance means, inserted between said external terminal and said internal power supply line and an impedance controlled in accordance with output from said voltage comparing means.

Claim 10

A semiconductor device according to claim 6, wherein said voltage dividing means includes a plurality of impedance elements each having a resistance of several mega ohms and being connected in series with each other.

Claim 11

A semiconductor device according to claim 6, wherein said voltage amplifying means includes an inverting circuit including a load element having a resistance of several mega ohms and a metal oxide semiconductor transistor as a driver.

Claim 12

A semiconductor device according to claim 6, wherein said variable impedance means includes a metal oxide semiconductor transistor having a gate to which an output from said voltage amplifying means is supplied.

Claim 13

A semiconductor device according to claim 8, wherein said plurality of impedance elements are resistors.

Claim 14

A semiconductor device according to claim 8, wherein said plurality of impedance elements are metal oxide semiconductor transistors.

Claim 15

A semiconductor device according to claim 9, wherein said load element is a resistor.

Claim 16

A semiconductor device according to claim 9, wherein said load element is a metal oxide semiconductor transistor.

Claim 17

A semiconductor device according to claim 7, wherein said reference voltage generating means includes switching means, being controlled to switch in accordance with a control signal, for controlling the standby interval; and a plurality of metal oxide semiconductor transistors, being connected in series, and generating a constant voltage when a current is supplied through said switching means.

Claim 18

A semiconductor device according to claim 7, wherein said voltage comparing means includes a differential amplifier including first and second current paths, and a switching means, being controlled to switch in accordance with a control signal, for controlling the standby interval, said differential amplifier and said switching means being respectively inserted in said first and second current paths.

Claim 19

A semiconductor device according to claim 7, wherein said variable impedance means includes a metal oxide semiconductor transistor having a gate to which an output from said voltage comparing means is supplied.