Power Gating Circuit Using Dual-Threshold MOSFETs for Wide Voltage Range
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Solution Overview
Problem
Existing power gating circuits in integrated circuits face challenges in maintaining performance across a wide range of supply voltage levels, with some transistors failing to adequately block leakage current at low voltages and others not performing well at blocking leakage when power is disabled.
Innovation Solution
A power gating circuit design that incorporates a first plurality of p-channel MOSFETs with a first threshold voltage and a second plurality of p-channel MOSFETs with a second threshold voltage, where the second threshold voltage is greater, along with varying channel lengths and numbers of these devices to balance leakage and resistance across different voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single type of transistor is used in the power gating circuit, then the circuit design is simple, but the circuit cannot maintain adequate performance across a wide range of supply voltage levels
Solution Approach 1:
The power gating circuit is segmented into multiple transistor groups (first plurality and second plurality of transistors) with different threshold voltages. Each group is optimized for specific voltage ranges, allowing the circuit to maintain adequate performance across a wide voltage spectrum by activating appropriate segments based on operating conditions.
Solution Approach 2:
Different regions of the power gating circuit use transistors with locally optimized properties - specifically, transistors with different threshold voltages are placed in different groups. This local quality differentiation enables each transistor group to perform optimally in its designated voltage range, with lower-threshold transistors handling low-voltage operation and higher-threshold transistors handling high-voltage operation.
2Power
If transistors with low threshold voltage are used, then power delivery is improved at low voltage levels, but leakage current increases when power is disabled
Solution Approach 1:
The power gating circuit dynamically switches between different transistor groups based on the supply voltage level. At low voltage levels, transistors with lower threshold voltages are activated to ensure adequate power delivery. At higher voltage levels, transistors with higher threshold voltages are used to minimize leakage current when power is disabled. This dynamic adaptation allows the circuit to optimize both power delivery and leakage prevention according to operating conditions.
Solution Approach 2:
The circuit changes the effective threshold voltage parameter by selecting different transistor groups based on operating voltage. This parameter change enables the circuit to adapt its electrical characteristics - using lower threshold voltage transistors when high current delivery is needed and higher threshold voltage transistors when leakage prevention is prioritized.
3Object-generated harmful factors
If transistors with high threshold voltage are used, then leakage current is reduced when power is disabled, but power delivery is insufficient at low voltage levels
Solution Approach 1:
The circuit dynamically selects which transistor group to activate based on the supply voltage level. When operating at low voltage levels, the circuit dynamically switches to use transistors with lower threshold voltages to ensure sufficient power delivery capability. When operating at higher voltage levels, it dynamically switches to transistors with higher threshold voltages to maximize leakage current blocking. This dynamic selection resolves the contradiction between leakage prevention and low-voltage power delivery.
Solution Approach 2:
The effective threshold voltage parameter is changed by selecting different transistor groups appropriate to the operating voltage range. This parameter adaptation allows the circuit to have high threshold voltage (for leakage blocking) when needed and low threshold voltage (for power delivery) when needed, eliminating the need to choose one fixed characteristic.
4Reliability
If the power gating circuit uses multiple types of transistors with different threshold voltages, then performance across voltage levels is improved, but the circuit control complexity increases
Solution Approach 1:
The isolation signal that controls the power gating circuit is generated based on feedback from the supply voltage level. This feedback mechanism automatically determines which transistor group should be active, simplifying control logic. The control circuit monitors the voltage level and automatically selects the appropriate transistor group, reducing the complexity of manual control while maintaining reliable performance across different voltage levels.
Data Source
AI summary
A device is disclosed that includes a circuit block coupled to a local power node, and a power gating circuit coupled between the local power node and a global power supply. In one embodiment, the power gating circuit includes a first plurality of first switching devices with a first threshold voltage, and a second plurality of second switching devices with a second threshold voltage that is different from the first voltage threshold. The power gating circuit may isolate the local power node from the global power supply based on an isolation signal.