Power Gating Headswitch Leakage Reduction via Dynamic Control Voltage
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Solution Overview
Problem
Conventional power gating circuits experience leakage current due to non-ideal switches, particularly P-channel Metal Oxide Semiconductor (PMOS) headswitches, which reduce battery life despite being turned off, necessitating a need for circuits and techniques to reduce leakage.
Innovation Solution
Implementing a system with a voltage generator that adjusts the control voltage to maintain a super-cut off state or zero gate-source voltage in power gating switches, using a comparator and operational amplifier to dynamically adjust the control voltage based on the source voltage level, thereby reducing gate-induced drain leakage (GIDL).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a transistor is turned off to power collapse a part of the processing core, then power consumption is reduced, but leakage current still flows through the transistor
Solution Approach 1:
The patent changes the voltage parameter of the gate terminal from conventional levels (0V or Vdd) to an elevated voltage level (Vdd + Voverdrive). This parameter change creates a super-cutoff state in the transistor where the gate-source voltage exceeds the threshold voltage by a significant margin, thereby dramatically reducing leakage current while maintaining the power collapse function
Solution Approach 2:
The patent applies preliminary anti-action by proactively elevating the gate voltage above the source voltage before leakage current can significantly impact power consumption. The voltage generator continuously maintains this elevated gate voltage level to preemptively counteract the harmful leakage effect that would otherwise occur in conventional off-state transistors
Data Source
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AI summary
A system includes: a first power supply; a second power supply; a headswitch disposed between the first power supply and logic circuitry; an enable driver coupling the second power supply to a control terminal of the headswitch; and a voltage generator operable to adjust a control voltage from the second power supply to the control terminal of the headswitch in response to a first voltage level of the first power supply exceeding a reference voltage level.