Chip Power Gating With Phased PMOS Switching to Cut Leakage
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Solution Overview
Problem
Microprocessor design faces challenges in reducing power consumption, particularly due to static power leakage through transistors even when they are turned off, which accounts for a significant portion of the chip's power budget and hinders efficiency improvements in semiconductor chips, especially in smaller sizes.
Innovation Solution
A semiconductor device with a controller that gates power supply to hardware components using PMOS transistors, gradually turning them on or off by controlling the enabling signal, thereby reducing electric current dissipation during transition periods, and employing multiple gating elements to manage power distribution in phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power supply is gated to hardware components using transistor switching, then power consumption is reduced, but electric current dissipation increases during transition periods
Solution Approach 1:
The transistor is divided into multiple gating elements (first subset and second subset) that can be controlled independently. The controller enables these subsets in phases during the transition period, allowing gradual power supply adjustment rather than abrupt switching. This segmentation enables finer control over the transition process, reducing current dissipation by distributing the switching action across multiple smaller steps.
Solution Approach 2:
The controller dynamically adjusts the enabling signal magnitude applied to the transistor during the transition period. Instead of using a fixed switching approach, the system varies the signal strength progressively, creating a smooth transition that adapts to the hardware component's power requirements. This dynamic control minimizes current dissipation by avoiding abrupt state changes.
2Ease of operation
If transistor switching is used to gate power supply, then hardware components can be turned on/off, but power leakage occurs during state transitions
Solution Approach 1:
The power gating transistor is segmented into multiple controllable gating elements that can be activated in sequence. This allows the hardware component to be transitioned through intermediate states rather than jumping directly between fully on and fully off states, reducing power leakage during the transition process while maintaining operational control.
Solution Approach 2:
The controller prepares for state transitions by gradually adjusting the enabling signal before the hardware component fully switches states. This preliminary action involves progressively modifying the power supply level, allowing the component to adapt and minimizing sudden current draws that would cause power leakage.
3Speed
If abrupt transistor switching is applied, then switching speed is fast, but current dissipation and power leakage increase
Solution Approach 1:
The switching operation is divided into multiple phases by controlling different subsets of gating elements sequentially. This segmented approach maintains relatively fast switching by using parallel control of multiple elements while reducing peak current dissipation through the phased activation strategy.
Solution Approach 2:
The controller employs periodic or phased activation of gating elements during the transition. By cycling through the enabling of different subsets in a structured sequence, the system achieves efficient switching that balances speed requirements with energy dissipation constraints, avoiding continuous high-current states.
Data Source
AI summary
According to at least one example embodiment, a semiconductor device is configured to gate power supply to a hardware component through a transistor coupled to the hardware component. The transistor is operated by a controller in a manner to limit electric current dissipated to the hardware component during a transition period. The controller is configured to gradually turn on, or off, the hardware component during a transition period by controlling at least one input signal to the transistor. Gradual turning on, or off, of the hardware component reduces electric current leakage through the hardware component and diminishes any potential disturbance to a ground reference coupled to the hardware component.