Dynamic Power Gating Sequencing for Switch Block Stress Distribution
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Solution Overview
Problem
In power control circuitry, switch blocks turned on early in a turn-on sequence experience greater stress due to initial supply current pulses, leading to premature failure from heating effects and increased current density, causing uneven degradation and failure among switch blocks.
Innovation Solution
A switch controller employs a time-varying generation operation to produce varying enable signal patterns for each sequence stage, ensuring that the stress of being the first switch block turned on is shared among all switch blocks by altering the selection of switch blocks each time the turn-on sequence is repeated, using a time-varying mapping operation controlled by a counter or pseudo-random values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If switch blocks are turned on simultaneously, then power delivery is fast and efficient, but a significant supply current pulse results causing state disruption or damage
Solution Approach 1:
The patent segments the simultaneous turn-on event into multiple sequential stages. Instead of enabling all switch blocks at once, the controller divides them into groups that are activated in sequence across multiple clock cycles. This segmentation reduces the peak current pulse while maintaining complete power delivery, resolving the contradiction between fast power delivery and circuit stability.
Solution Approach 2:
The patent employs periodic action by distributing the turn-on events across multiple clock cycles. Each switch block is activated at a different periodic interval rather than simultaneously. This periodic distribution spreads the current demand over time, preventing supply current pulses that would disrupt circuit state while ensuring all switches eventually receive power.
2Device complexity
If a fixed turn-on sequence is used, then control is simple and predictable, but uneven stress distribution causes premature failure of early switches
Solution Approach 1:
The patent introduces dynamics into the control system by implementing a variable turn-on sequence generator. Rather than a fixed hardwired sequence, the controller uses dynamic logic that can reorder switch activation based on varying patterns. This dynamic approach maintains relatively simple control architecture while significantly improving switch block durability through even stress distribution.
Solution Approach 2:
The patent changes the sequence ordering parameter dynamically. The controller modifies which switch blocks are activated at each stage based on a varying pattern that changes across power-up events. This parameter change approach maintains control simplicity while ensuring that no single switch block consistently bears the brunt of early activation stress, thereby extending durability.
Data Source
AI summary
Power control circuitry for controlling connection of a voltage source to a switched power rail powering an associated circuit is provided. A plurality of switch blocks are connected in parallel between the switched power rail and the voltage source, each switch block being controlled by an enable signal provided by a switch controller. The switch controller performs a turn-on sequence providing a series of enable signal patterns to the switch blocks. The switch controller applies a time varying generation operation to at least one sequence stage of a predetermined turn-on sequence to produce a corresponding enable signal pattern for that sequence stage. When the turn-on sequence is later repeated, the enable signal pattern produced for at least one of the sequence stages differs from the enable signal pattern previously produced for that sequence stage.