SCRC Gate Charge Transfer for Lower Switching Power

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Solution Overview

Problem

Sub-threshold current reduction circuit (SCRC) switches with oversized transistors consume excessive power and chip area due to high switching currents and leakage currents, which undermines the reduction of leakage current and increases power supply current.

Innovation Solution

Implementing a charge transfer circuit between the gate terminals of pull-up and pull-down SCRC transistors to reduce the power supply current by utilizing unused charge for switching, thereby minimizing the need for power from supply lines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If oversized transistors are used for SCRC switches, then leakage current reduction capability is improved, but power consumption increases due to high switching currents

Engineering Contradiction:

Improveleakage current reduction capabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the voltage parameter by applying a voltage greater than the threshold voltage to the control terminal during the charge transfer phase. This enables the third transistor to actively transfer charge between gate terminals, reducing the switching current requirement and thereby reducing power consumption while maintaining leakage current reduction capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces a third transistor as an intermediary charge transfer device between the first and second transistors. This intermediary transfers charge between the gate terminals, reducing the direct switching current burden and power consumption while maintaining the ability to reduce leakage current in the electronic circuit

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If oversized transistors are used for SCRC switches, then leakage current reduction capability is improved, but chip area increases

Engineering Contradiction:

Improveleakage current reduction capabilityVSAvoidchip area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent segments the SCRC switch into multiple transistors (first transistor, second transistor, and third transistor) with distributed functions. The first transistor handles the main switching function, the second transistor manages charge storage, and the third transistor performs charge transfer. This segmentation allows each transistor to be smaller than a single oversized transistor would need to be, reducing total chip area while maintaining leakage current reduction capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The third transistor acts as an intermediary that enables efficient charge transfer between gate terminals with smaller capacitance. This intermediary mechanism allows the use of smaller transistors overall, reducing the chip area required while maintaining the ability to reduce leakage current effectively

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If SCRC switches are activated to reduce leakage current, then power supply current increases due to charging and discharging of gate terminals

Engineering Contradiction:

Improveleakage current reductionVSAvoidpower supply current

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the control voltage parameter to greater than the threshold voltage during charge transfer, enabling the third transistor to actively pump charge between gate terminals. This active charge transfer reduces the net charge that must be supplied from power supply lines, reducing power supply current while maintaining leakage current reduction

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The third transistor serves as an intermediary charge transfer device that recycles charge between the gate terminals of the first and second transistors. This intermediary charge transfer reduces the amount of charge that must be continuously supplied from power supply lines, reducing power supply current and energy loss while maintaining SCRC functionality

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach results in a 20% reduction in power supply current during SCRC transistor switching and optimizes chip area usage by reducing transistor sizes without compromising leakage current reduction.

Implementation Method 1

Implementing a charge transfer circuit between the gate terminals of pull-up and pull-down SCRC transistors to reduce the power supply current by utilizing unused charge for switching

Methodology Applied

Scientific EffectElectrostatic charge storage and transfer: Capacitance

Data Source

PatentUS11777488B2Charge transfer between gate terminals of sub-threshold current reduction circuit transistors and related apparatuses and methods

Publication Date: 2023.10.03 MICRON TECHNOLOGY INC

AI summary

Charge transfer between gate terminals of sub-threshold current reduction circuit (SCRC) transistors and related apparatuses and methods are disclosed. An apparatus includes a first output terminal electrically connected to a pull-up gate terminal of at least one pull-up SCRC transistor and a second output terminal electrically connected to a pull-down gate terminal of at least one pull-down SCRC transistor. The apparatus also includes a first resistive path between a first input terminal and the first output terminal and a second resistive path between the second input terminal and the second output terminal. The apparatus further includes a charge transfer gate electrically connected between the first resistive path and the second resistive path.