US 8,008,659 B2 · Semiconductor integrated circuit device

Abstract

A substrate bias is controlled such that a leakage current is minimum. A semiconductor integrated circuit device comprises a leakage detecting circuit which detects a leakage current by using leakage detecting MOSFETs, a control circuit which generates a control signal depending on an output from the leakage detecting circuit, a substrate bias generating circuit which changes a substrate bias depending on the control signal, and a controlled circuit including a MOSFET having the same characteristics as that of each of the leakage detecting MOSFETs. The leakage detecting circuit detects a substrate leakage current which includes as the substrate bias becomes deep and a subthreshold leakage current which decreases as the substrate bias becomes deep. A control signal is transmitted to the substrate bias generating circuit such that the substrate bias is made deep when the substrate leakage current is smaller than the subthreshold leakage current and such that the substrate bias is made shallow when the substrate leakage current is larger than the subthreshold leakage current.

Claims26

Dependent claims

A semiconductor integrated circuit device comprising:

a leakage detecting circuit which includes a plurality of leakage detecting MOSFETs and which detects components of leakage current of the plurality of MOSFETs;
a control circuit which outputs a control signal depending on a detection result from the leakage detecting circuit;
and
a substrate bias generating circuit which changes a substrate bias of a semiconductor substrate depending on the control signal,
wherein the substrate bias is controlled such that a ratio of a subthreshold leakage current component including a subthreshold leakage current of a first one of the plurality of leakage detecting MOSFETs to a substrate leakage current component including a substrate leakage current of a second one of the plurality of the leakage detecting MOSFETs is a predetermined value, and
wherein the first and second ones of the plurality of leakage detecting MOSFETs detect different leakage current components.

3 more elements

A semiconductor integrated circuit device comprising:

a leakage detecting circuit which detects a leakage current of a semiconductor substrate;
a control circuit which outputs a control signal;
and
a substrate bias generating circuit which changes a substrate bias,
wherein the leakage detecting circuit detects a substrate leakage current and a subthreshold leakage current,
wherein the substrate leakage current exceeds n times the subthreshold leakage current as a magnitude of the substrate bias increases past a point where the substrate leakage current and n times the subthreshold leakage current are equal, and n times the subthreshold leakage current exceeds the substrate leakage current as the magnitude of the substrate bias decreases past a point where the substrate leakage current and n times the subthreshold leakage current are equal,
wherein the control circuit transmits a control signal to the substrate bias generating circuit such that the magnitude of the substrate bias increases when the substrate leakage current is smaller than a current which is n times the subthreshold leakage current and such that the magnitude of the substrate bias decreases when the substrate leakage current is larger than the current, and
wherein n is a predetermined number.

5 more elements

Dependencies are inferred from the claim text.

Semiconductor integrated circuit device

Life of this patent

Semiconductor integrated circuit device

Life of this patent

Abstract

Claims26