Power Gating Circuit Parallel Series Topology for Noise Reduction
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Solution Overview
Problem
Power control circuits face issues with rapid current changes during the transition from sleep mode to active mode, leading to unnecessary noise that can cause system malfunction due to the sequential turning on of power gating cells, which prolongs the mode transition time.
Innovation Solution
A power control circuit design where power gating cells receive mode change signals in parallel, with additional cells connected in series and parallel configurations, including buffers and a test logic to manage signal delays and output operations, ensuring simultaneous power supply and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If power gating cells are connected in series to control power supply, then power consumption is reduced in sleep mode, but mode transition time increases and noise is generated due to sequential switching
Solution Approach 1:
The power gating cells are divided into multiple groups (first group connected in parallel to logic circuit, second group connected in series to first group, third group connected in parallel to third power gating cell). This segmentation allows different groups to serve different functions: the first group provides immediate power for fast transition, while the second and third groups maintain power reduction in sleep mode and control switching sequences.
2Use of energy by stationary object
If power gating cells are connected in series to control power supply, then power consumption is reduced in sleep mode, but noise is generated due to rapid current changes during switching
Solution Approach 1:
The buffer is inserted between the second power gating cell and the third power gating cells to delay the transmission of the mode change signal. This preliminary action ensures that power gating cells switch on in a controlled sequence rather than simultaneously, preventing rapid current changes and reducing noise generation during mode transition.
3Manufacturing precision
If multiple power gating cells are added to control power supply, then power control precision is improved, but device complexity increases
Solution Approach 1:
The test logic unit serves multiple functions: it receives output signals from the fourth power gating cells, performs logical operations (such as XOR operations) on these signals, and generates test results. This multi-functionality improves power control precision through comprehensive monitoring while minimizing the addition of separate test components, thus controlling device complexity.
Data Source
AI summary
A power control circuit is connected between a power supply voltage and a logic circuit to switch power supplied to the logic circuit. The power control circuit includes a plurality of first power gating cells (PGCs) receiving an external mode change signal in parallel, at least one second PGC connected with one first PGC, at least one third PGC connected with the at least one second PGC, and at least one fourth PGC connected with the at least one third PGC. The second power gating cell, the third PGC, and/or the fourth PGC may include a plurality of gating cells. At least one of the second, third, and fourth pluralities has power gating cells connected in series. Each of the first through fourth PGCs switches power supplied in response to the mode change signal.