Power Switch Gate Bias Control for Low Off-State Leakage
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Solution Overview
Problem
Integrated circuits face challenges in reducing leakage current through power switches when they are in an off state, which contributes to overall power consumption and reduces battery life in mobile computing applications.
Innovation Solution
A power management system that includes a sensor circuit to determine leakage current and resistance of the power switch, and a switch control circuit to adjust the voltage level of the power switch control signal, transitioning it from an initial voltage to a target voltage greater than the power supply voltage when opening the switch and to a target voltage less than ground voltage when closing the switch, thereby minimizing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the power switch is turned off to decouple the circuit block from the power supply, then power consumption is reduced, but leakage current still flows through the switch
Solution Approach 1:
The patent applies parameter changes by adjusting the control signal voltage beyond the standard supply voltage levels. Specifically, it uses a first control signal with voltage greater than the power supply voltage to turn off the power switch, and a second control signal with voltage less than ground voltage to turn on the power switch. This extended voltage range optimization reduces leakage current in the off-state while maintaining reliable switching operation.
2Object-generated harmful factors
If the control signal voltage is increased above the power supply voltage to reduce leakage, then leakage current is reduced, but the complexity of the control circuit increases
Solution Approach 1:
The patent introduces a control circuit as an intermediary component that generates the extended voltage control signals. This control circuit receives a control input and produces the first control signal (greater than supply voltage) and second control signal (less than ground voltage), thereby mediating between the simple control input and the complex requirement of extended voltage operation, reducing leakage current while managing circuit complexity.
3Speed
If the power switch control signal transitions quickly between voltage levels, then switching speed is improved, but voltage spikes and oscillations may occur
Solution Approach 1:
The patent applies dynamics by implementing controlled transition of the control signal voltage levels. The control circuit dynamically adjusts the voltage from the initial level to the target level (greater than supply voltage or less than ground voltage) in a controlled manner, balancing the need for fast switching with the need to avoid voltage spikes and oscillations, thereby maintaining signal stability during transitions.
Data Source
AI summary
A power switch control circuit is disclosed. A sensor circuit may determine a leakage current of a power switch coupled to a power supply signal and a power terminal of a circuit block. The power switch may be configured to selectively couple or decouple the circuit block from the power supply signal using a switch control signal. The switch control circuit may, in response to receiving a request to open the power switch, determine a target voltage level that is greater than a voltage level of the power supply signal for the switch control signal using the leakage current, and transition the switch control signal from an initial voltage to the target voltage level.