MEMS Rectifier Switching for Low-Loss Ideal Diode Conversion

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Solution Overview

Problem

Conventional AC-to-DC converters using diodes suffer from power loss due to a forward voltage drop, leading to heat generation and potential damage to circuit components, while MOSFET-based solutions are expensive and performance degrades at high temperatures.

Innovation Solution

Employing MEMS switches with a circuit topology and control strategy that includes current diverting and voltage clamp switches to achieve Zero-Voltage-Zero-Current turn-on and Zero-Current-Zero-Voltage turn-off, reducing power loss and stress during state transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional diodes are used for AC-to-DC conversion, then rectification function is achieved, but power loss occurs due to forward voltage drop

Engineering Contradiction:

Improvepower lossVSAvoidcomponent simplicity

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent changes the electrical parameters of the switching component by using MEMS switches with extremely low on-resistance (Rds) values, transforming the traditional diode's fixed forward voltage drop characteristic into a variable resistance characteristic that can be optimized for minimal power loss

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the semiconductor-based diode with a micro-electro-mechanical system (MEMS) switch, substituting solid-state physics with mechanical switching action. The MEMS switch uses a movable contact that opens and closes mechanically, eliminating the forward voltage drop inherent in semiconductor diodes

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Loss of energy

If MEMS switches are used to reduce power loss, then efficiency is improved, but hard switching capability is limited

Engineering Contradiction:

Improvepower lossVSAvoidswitching durability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent applies preliminary action by using auxiliary circuits to pre-condition the MEMS switch before main switching operations. The auxiliary switches prepare the voltage and current states to ensure soft switching conditions are met before the MEMS switch transitions, preventing hard switching damage

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces auxiliary switches as intermediary components that mediate between the power source and the MEMS switch. These auxiliary switches handle the stressful switching transitions, protecting the main MEMS switch from hard switching conditions while maintaining the low power loss benefit

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If diodes are used for rectification, then AC-to-DC conversion is achieved, but heat generation occurs

Engineering Contradiction:

Improveconversion efficiencyVSAvoidheat generation

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent converts the harmful effect of resistance into a beneficial characteristic by using the MEMS switch's extremely low on-resistance to minimize power dissipation. The mechanical switching action, which could generate heat through friction, is designed to occur when voltage and current are minimal, transforming potential heat generation into efficient power conversion

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Speed

If MOSFET-based solutions are used, then switching performance is improved, but cost increases and high temperature performance degrades

Engineering Contradiction:

Improveswitching speedVSAvoidcomponent cost

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The patent uses inexpensive MEMS switch components that can be manufactured at lower cost than MOSFETs. While individual MEMS switches have limited lifetime under hard switching conditions, the use of auxiliary protection circuits extends their operational life, making them a cost-effective replacement for expensive MOSFETs

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS20260074613A1System and methods for using a MEMS switch as an ideal diode

Publication Date: 2026.03.12 DIGIQ POWER LTD

AI summary

A system and method for converting an input AC voltage of a voltage source into an output DC voltage is proposed. The proposed system and method include at least two MEMS switches coupled in parallel with a corresponding voltage clamp switch within a MEMS rectifier. The MEMS switches achieve Zero-Voltage-Zero-Current (ZVZC) Turn on and Zero-Current-Zero-Voltage (ZCZV) Turn off through the inclusion of at least one high frequency switch and a current diverting circuit which ensure that when the at least two MEMS switches transition between an on-state and off-state there is no voltage or current present in the at least two MEMS switches.