Shared Footer Circuit for Multi-Domain Power Rail Simplification

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Solution Overview

Problem

Existing electronic devices with multiple power domains face complexity in power routing and a weaker power network due to the need for multiple power rails and virtual power rails, which complicates power management and increases area requirements.

Innovation Solution

A shared footer circuit is introduced to control the connection between virtual VSS terminals and ground terminals across different power domains, allowing for independent power control and simplifying the power network by disconnecting virtual VSS from ground during sleep or shut-down modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple power rails and virtual power rails are used to support multiple power domains, then power management flexibility is improved, but device complexity and area requirements increase

Engineering Contradiction:

Improvepower management flexibilityVSAvoidpower routing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple virtual power rails into a shared virtual power rail that serves multiple power domains. Instead of having separate virtual power rails for each power domain, a single shared virtual power rail is used, reducing the number of power routing paths and simplifying the overall power network while maintaining the ability to support multiple power domains through a single footer circuit.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The shared footer circuit is designed to universally control the connection to ground for multiple power domains through a single virtual power rail. This multi-functional approach allows one footer circuit to manage power connections across different power domains, eliminating the need for separate footer circuits for each domain and reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple power rails and virtual power rails are used to support multiple power domains, then power management flexibility is improved, but area requirements increase

Engineering Contradiction:

Improvepower management flexibilityVSAvoidpower network area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If virtual VSS is continuously connected to ground, then power network robustness is improved, but power consumption increases during sleep or shut-down modes

Engineering Contradiction:

Improvepower network robustnessVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements a dynamic connection between the virtual VSS terminal and ground through a footer circuit that can change its state based on operational mode. During active modes, the footer circuit maintains a low-impedance connection for robust power networking. During sleep or shut-down modes, the footer circuit transitions to a high-impedance state, disconnecting the virtual VSS from ground to eliminate leakage current paths and reduce power consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The footer circuit changes its electrical parameters (impedance state) based on operational conditions. In active mode, it presents a low-impedance path to ground for robust power delivery. In sleep or shut-down mode, it transitions to a high-impedance state, effectively disconnecting the virtual VSS from ground, thereby reducing power consumption while maintaining the ability to quickly restore robustness when needed.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11961554B2Shared power footer circuit

Publication Date: 2024.04.16 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A device includes a first power rail for a first power domain and a second power rail for a second power domain. A first circuit block is connected to the first power rail and a second circuit block is connected to the second power rail. The first and second circuit blocks are both connected to a virtual VSS terminal. A footer circuit is connected between the virtual VSS terminal and a ground terminal, and the footer circuit is configured to selectively control a connection between the virtual VSS terminal and the ground terminal.