Virtual Power Rail Gating With Retention Flip-Flop Control

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Solution Overview

Problem

Conventional integrated circuits face increased wire length due to mode control signals used to manage power gating, leading to inefficiencies in power consumption and leakage current.

Innovation Solution

The implementation of a power gating circuit that utilizes a virtual power rail as a mode control signal, allowing the logic circuit to switch between active and standby modes by coupling and decoupling the virtual power rail with a second power rail, thereby reducing wire length and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If mode control signals are transmitted to control the power gating circuit, then the power gating circuit can switch between active and standby modes, but the overall wire length increases

Engineering Contradiction:

Improvepower gating control capabilityVSAvoidwire length

Core Design Contradiction:

Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The patent merges the mode control signal function with the existing power supply network by using the virtual power rail voltage to simultaneously provide power and control logic circuit operation state. This eliminates separate control signal wires and reduces overall wire length while maintaining power gating control capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The virtual power rail is designed to serve multiple functions: it provides power supply voltage to the logic circuit and simultaneously acts as a mode control signal source. The retention flip-flop uses the virtual power rail voltage level to determine whether to perform flip-flop or data retention operations, eliminating the need for dedicated control signal pathways.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If mode control signals are transmitted to control the power gating circuit, then the power gating circuit can switch between active and standby modes, but power consumption increases

Engineering Contradiction:

Improvepower gating control capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent combines power delivery and control signaling into a single pathway through the virtual power rail. By using the voltage presence or absence on the virtual power rail to control logic circuit operation, the system eliminates the power consumption associated with transmitting separate control signals while maintaining full power gating functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The virtual power rail automatically serves as both the power source and the control signal source for the logic circuit. The retention flip-flop autonomously responds to the virtual power rail voltage level to determine its operation mode, eliminating the need for external control signal generation and transmission that would consume additional power.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If mode control signals are transmitted to control the power gating circuit, then the power gating circuit can switch between active and standby modes, but leakage current increases

Engineering Contradiction:

Improvepower gating control capabilityVSAvoidleakage current

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent merges control functionality into the power supply structure itself. By using the virtual power rail voltage to directly control the logic circuit and retention flip-flop operation, the system eliminates separate control signal pathways that would carry additional leakage current, thereby reducing overall leakage while maintaining power gating control capability.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS7948263B2Power gating circuit and integrated circuit including same

Publication Date: 2011.05.24 SAMSUNG ELECTRONICS CO LTD

AI summary

A power gating circuit includes a logic circuit, a switching element and a retention flip-flop. The logic circuit is coupled between a first power rail and a virtual power rail. The switching element selectively couples the virtual power rail to a second power rail in response to a mode control signal indicating an active mode or a standby mode. The retention flip-flop selectively performs a flip-flop operation or a data retention operation in response to a voltage of the virtual power rail.