Digital power gating with global voltage shift

摘要

A system which may be implemented on an integrated circuit including a global supply bus, a gated supply bus, a functional circuit receiving voltage from the gated supply bus, and a digital power gating system. The digital power gating system includes gating devices, a power gating control system, and a global control adjuster. The gating devices are coupled between the global and gated supply buses and are controlled by a digital control value. The power gating control system performs power gating by successively adjusting the digital control value to reduce a voltage of the gated supply bus to a state retention voltage level. The global control adjuster performs a global adjustment of the digital control value to increase the voltage of the gated supply bus to prevent it from falling below the state retention voltage level in response to an impending change of a voltage of the global supply bus.

主权项

1. An integrated circuit, comprising:
a global supply bus and a gated supply bus; a functional circuit having a voltage supply input coupled to said gated supply bus; and a digital power gating system with global voltage shift, comprising:
a plurality of gating devices, each said gating device having a pair of current terminals coupled between said global supply bus and said gated supply bus and each having a control terminal;a power gating control system that controls a digital control value, wherein said digital control value comprises a plurality of bits in which each bit of said digital control value is provided to control at least one control terminal of said plurality of gating devices to control activation of a corresponding subset of said plurality of gating devices, wherein said power gating control system is configured to perform power gating by successively adjusting said digital control value to reduce a voltage of said gated supply bus to a state retention voltage level that reduces leakage current while retaining a digital state of said functional circuit; anda global control adjuster that performs a global adjustment of said digital control value to increase said voltage of said gated supply bus during said power gating to prevent said voltage of said gated supply bus from falling below said state retention voltage level in response to an impending change of a voltage of said global supply bus.