Power-Gated Semiconductor Circuit for Rush Current Recovery Timing
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Solution Overview
Problem
In semiconductor integrated circuits employing power gating, the restoration of power after a cutoff state often results in a large rush current, increasing the likelihood of malfunction and prolonging the required time for power restoration, which existing methods attempt to mitigate by delaying power restoration but at the cost of extending the overall restoration time.
Innovation Solution
The implementation of a circuit block configuration with first and second power switches, where a control input signal is propagated through separate paths to control the switches, and a restoration determination circuit adjusts the restoration timing based on the delays in these paths, allowing for synchronized power restoration that aligns with the size of the circuit block, thereby reducing rush current influences and shortening the restoration time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If power gating switches are turned on simultaneously after power cutoff, then power restoration is fast, but large rush current is generated causing voltage drops and malfunctions
Solution Approach 1:
The patent segments the power restoration process by dividing circuit blocks into groups and restoring power to each group sequentially rather than simultaneously. The control signal propagation paths have different lengths, causing control signals to reach different circuit blocks at different times, thereby segmenting the rush current generation in time and reducing the peak current magnitude.
2Object-generated harmful factors
If power gating switches are turned on sequentially to reduce rush current, then rush current is reduced, but power restoration time is increased
Solution Approach 1:
The patent applies local quality by creating different propagation path lengths for control signals to different circuit blocks. The control signal paths are designed with different delays, so that circuit blocks closer to the control signal source are restored faster, while those farther away are restored later. This local differentiation in restoration timing reduces rush current without requiring uniform sequential restoration of all blocks, thus minimizing overall restoration time.
Data Source
AI summary
In a semiconductor integrated circuit employing power gating, a control input signal is propagated to one or more first power switches through a first propagation path and to one or more second power switches through a second propagation path. A restoration determination circuit receives a first signal of the first propagation path and a second signal of the second propagation path and generates a control output signal. When the control signal performs restoration transition, the restoration determination circuit causes the control output signal to perform the restoration transition in accordance with a later timing of timings of restoration transitions of the first and second signals.