US 7,023,757 B2 · Semiconductor device

Abstract

When a leakage current of a circuit block under a non-use state is reduced by means of a power switch, frequent ON/OFF operations of the switch within a short time invite an increase of consumed power, on the contrary. Because a pre-heating time is necessary from turn-on of the switch till the circuit block becomes usable, control of the switch during an operation deteriorates a processing time of a semiconductor device. The switch is ON/OFF-controlled with a task duration time of a CPU core for controlling logic circuits and memory cores as a unit. After the switch is turned off, the switch is again turned on before termination of the task in consideration of the pre-heating time.

Claims11

Dependent claims

A semiconductor device comprising:

a power source line;
a plurality of circuit blocks containing at least one first circuit block;
at least one switch so arranged as to respectively correspond to said at least one first circuit block, for controlling the supply of a power source from said power source line to said first circuit block;
and
a processor for executing a task by keeping at least one of said plurality of circuit blocks under a use state;
wherein said first circuit block receives a state signal instructing a shift thereof to a non-use state and turns off said switch corresponding thereto and, in case of execution of said task by said processor, said switch is turned on before said first circuit block receives a state signal instructing a shift thereof to a use state.

3 more elements

Dependencies are inferred from the claim text.

Semiconductor device

Life of this patent

Semiconductor device

Life of this patent

Abstract

Claims11