Electromechanical Power Switch for IC Leakage Reduction

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Solution Overview

Problem

The increasing demand for small, portable electronic devices with reduced power consumption is hindered by the high OFF-state leakage current in MOS-based power gates, which approaches ON-state levels, leading to significant power consumption even when devices are in a non-operation mode, and voltage drop degrades device performance.

Innovation Solution

The integration of electromechanical power switches, such as MEMS or NEMS-based switches, monolithically with IC devices on a semiconductor substrate, which provide near-infinite OFF-state resistance and low ON-state resistance by actuating a cantilever to close an air gap between metal electrodes, minimizing parasitic voltage drop and completely turning off power supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If MOS transistors are used for power gating, then power control capability is provided, but OFF-state leakage current increases significantly

Engineering Contradiction:

Improvepower consumptionVSAvoidOFF-state leakage current

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent replaces the electrical field-based MOS transistor switching mechanism with a mechanical relay-based switching system. The relay uses a coil to generate magnetic field that mechanically moves contacts to open/close the power path, eliminating the inherent leakage current of MOS transistors while maintaining power gating functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a relay as an intermediary device between the control circuit and the power path. The relay's mechanical contacts act as a mediator that completely disconnects the power path when open, providing near-zero leakage current while still allowing MOS transistors to control the relay's switching action.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Power

If MOS transistors are used for power gating, then power switching function is achieved, but voltage drop degrades device performance

Engineering Contradiction:

Improvepower switching capabilityVSAvoidvoltage drop

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the MOS transistor's electrical resistance-based switching with a mechanical relay's contact-based switching. When the relay contacts are closed, they provide a low-resistance path that minimizes voltage drop, unlike MOS transistors which exhibit significant voltage drop due to their on-resistance, especially in scaled technologies.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If minimum feature size of MOS devices is decreased, then device performance and processing capability improve, but OFF-state leakage current increases

Engineering Contradiction:

Improveprocessing capabilityVSAvoidOFF-state leakage current

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces scaled MOS transistors with mechanical relays for power gating functions. This substitution eliminates the fundamental limitation where smaller feature sizes lead to higher leakage currents, as the relay's mechanical contact mechanism provides near-zero leakage regardless of the control circuit's scaling.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution significantly reduces standby/OFF-state consumed power to nearly zero, improving device performance by minimizing power consumption during non-operation modes and reducing parasitic voltage drops, thus enhancing the efficiency of power management in electronic devices.

Implementation Method 1

by actuating a cantilever to close an air gap between metal electrodes

Methodology Applied

Scientific EffectCantilever actuation:

Data Source

PatentUS8786130B1Method of forming an electromechanical power switch for controlling power to integrated circuit devices and related devices

Publication Date: 2014.07.22 INOSO LLC

AI summary

A method of forming an electromechanical power switch for controlling power to integrated circuit (IC) devices and related devices. At least some of the illustrative embodiments are methods comprising forming at least one IC device on a front surface of a semiconductor substrate. The at least one IC device includes at least one circuit block and at least one power switch circuit. A dielectric layer is deposited on the IC device, and first and second electromechanical power switches are formed on the dielectric layer. The first power switch gates a voltage to the circuit block and the second power switch gates the voltage to the IC device. The first power switch is actuated by the power switch circuit, and the voltage to the circuit block is switched off. Alternatively, the second power switch is actuated by the power switch circuit, and the voltage to the IC device is switched off.