Patent ID: 7737720

Claim:
An integrated circuit comprising: a switch block coupled to a virtual power rail to couple said virtual power rail to a power supply having a source voltage level; a switch controller coupled to said switch block to control conduction through said switch block and thereby selectively to connect said virtual power rail to said power source having said source voltage level; and logic circuitry coupled to said virtual power rail to draw power therefrom, wherein said switch controller modulates conduction through said switch block to maintain said virtual power rail at an intermediate voltage level, wherein said logic circuitry statically retains one or more state signal values when said logic circuitry is not active and said intermediate voltage results in greater than a minimum retention voltage across said logic circuitry, and said switch controller modulates conduction through said switch block such that said intermediate voltage results in greater than said minimum retention voltage across said logic circuitry and said one or more state signal values are retained in said logic circuitry with an average leakage current in said logic circuitry less than when said virtual power rail is continuously at said source voltage level.