US 2013/0293282 A1 · CHARGE-SAVING POWER-GATE APPARATUS AND METHOD

Abstract

A power-gate circuit includes a power-gate transistor operable to switch to decouple a first supply voltage from a second supply voltage during an idle mode, and to couple the first supply voltage to the second supply voltage during a full operational mode. Part of the charge stored at a gate terminal of the power-gate transistor, would have been otherwise flushed to ground while turning on the power-gate transistor, is routed to the rail of the second supply voltage of the logic block. Part of the charge on the rail of the second supply voltage is used to charge the gate terminal of the power-gate transistor to de-activate the power-gate transistor if the logic block goes to the idle mode. Energy is saved both ways because of the charge recycling and the ability to use the power gate circuit even in cases where the duration of the idle mode may be short.

Claims19

Dependent claims

An apparatus, comprising:

a power-gate transistor configured to transition to a first state to decouple a first supply voltage from a second supply voltage, and configured to transition to a second state to couple the first supply voltage to the second supply voltage;
and
a switch coupled to a control terminal of the power-gate transistor and to the second supply voltage;
wherein for the first state, the switch is responsive to a signal to close and then responsive to the signal to open;
and
wherein for the second state, the switch is responsive to the signal to close to enable charge to flow from the control terminal of the power-gate transistor to the second supply voltage and then responsive to the signal to open.

3 more elements

A method, comprising:

transitioning a power-gate transistor of a power-gate circuit to a first state to decouple a first supply voltage from a second supply voltage;
transitioning the power-gate transistor to a second state to couple the first supply voltage to the second supply voltage;
and
operating a switch coupled between a control terminal of the power-gate transistor and the second supply voltage;
wherein said operating, for the first state and for the second state, includes the switch being responsive to a signal to close to enable charge to flow between the second supply voltage and the control terminal of the power-gate transistor and then responsive to the signal to open.

2 more elements

Dependencies are inferred from the claim text.

Charge-saving power-gate apparatus and method

Life of this patent

Charge-saving power-gate apparatus and method

Life of this patent

Abstract

Claims19