DIGITAL POWER GATING WITH STATE RETENTION

摘要

A digital power gating system for performing power gating to reduce a voltage of a gated supply bus to a state retention voltage level that reduces leakage current while retaining a digital state of a functional circuit. The power gating system includes gating devices and a power gating control system. Each gating device has current terminals coupled between a global supply bus and the gated supply bus, and a control terminal controlled by a bit of a digital control value. The power gating control system successively adjusts the digital control value to reduce a voltage of the gated supply bus to the state retention voltage level. Adjustment gain and/or adjustment periods may be changed, such as when the digital control value reaches certain values or when the gated supply reaches certain voltage levels. Various parameters are programmable to adjust for particular configurations or to achieve desired operation.

主权项

1. A digital power gating system for controlling a voltage of a gated supply bus coupled to a supply voltage input of a functional circuit relative to a voltage of a global supply bus, said digital power gating system comprising:
a plurality of gating devices, each said gating device having a pair of current terminals for coupling between the global supply bus and the 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; and wherein said power gating control system is configured to perform power gating by successively adjusting said digital control value to reduce a voltage of the gated supply bus to a state retention voltage level that reduces leakage current while retaining a digital state of the functional circuit.