WPT Receiver Gate-Drive Power Reduction via Buck Regulator

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Solution Overview

Problem

Wireless power transfer (WPT) systems face inefficiencies in power consumption due to high power dissipation in the rectification circuit of WPT receivers, particularly in the gate-drive power management, which affects the overall efficiency of energy transfer.

Innovation Solution

The implementation of a buck switching regulator instead of a linear regulator in the rectification circuit, along with efficient gate-drive voltage management and FET scaling, reduces power losses by minimizing resistive and capacitive losses in the FET switches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a linear regulator is used in the rectification circuit, then the circuit is simple to implement, but power dissipation is high reducing overall efficiency

Engineering Contradiction:

Improvecircuit implementation simplicityVSAvoidpower dissipation

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent changes the operating parameters of the rectification circuit by replacing the linear regulator with a buck switching regulator. This switching regulator operates at high frequency with controlled duty cycle, fundamentally changing how voltage regulation is achieved from resistive dropout to inductive switching, thereby reducing power dissipation while maintaining regulation functionality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the linear regulator mechanism with a switching regulator mechanism that uses electromagnetic induction through an inductor and controlled switching of FETs. This replacement transforms the power regulation approach from direct resistive control to indirect switching control, significantly improving efficiency

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If high gate-drive voltage is applied to FET switches, then the switches operate with low on-resistance, but power consumption in the gate-drive circuit increases

Engineering Contradiction:

ImproveFET on-state power handling capabilityVSAvoidgate-drive power consumption

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic gate-drive voltage adjustment where the gate voltage is varied based on operating conditions. During switching transitions, high voltage is applied to ensure fast switching and low on-resistance. During steady-state operation, the gate voltage is reduced to minimize capacitive power consumption, achieving optimal balance between power handling and energy efficiency

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent uses periodic switching of FETs with controlled duty cycles in the buck regulator. The gate-drive circuit applies voltage periodically rather than continuously, allowing the FETs to switch between on and off states. This periodic operation reduces average gate-drive power consumption while maintaining effective power transfer during the on-state

Inventive Principle:

Principle #19Periodic action

3Power

If FET switches with large size are used, then current handling capability is high, but capacitive losses in the gate-drive circuit increase

Engineering Contradiction:

Improvecurrent handling capabilityVSAvoidcapacitive losses

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent segments the FET gate-drive circuit into multiple independent drive circuits, each controlling a subset of FET switches. This segmentation allows each drive circuit to manage fewer switches with reduced total gate capacitance, thereby reducing capacitive losses while maintaining overall current handling capability through the parallel arrangement of segmented FET groups

Inventive Principle:

Principle #1Segmentation

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 significantly improves power efficiency by reducing power consumption in the rectification circuit, achieving higher efficiency in wireless power transfer, especially at high output power levels, and extends the application to various WPT coupling methods.

Implementation Method 1

The magnetic resonance and electromagnetic induction solutions are used for short distances

Methodology Applied

Scientific EffectMagnetic coupling: Electromagnetic Induction

Implementation Method 2

In the electromagnetic induction technique an inductive coupling between coils of the power transmitter and the power receiver devices is used for wireless power transmission

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS10218225B2Wireless power transfer gate-drive power reduction

Publication Date: 2019.02.26 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

A device and circuits are provided for wireless power transfer (WPT) gate-drive power reduction. A WPT receiver circuit includes a receive coil to couple to a transmit coil of a WPT transmitter circuit. A rectification circuit is coupled to the receive coil to generate a rectified voltage. The rectification circuit is a bridge rectifier circuit including a first set of field-effect transistors (FETs). One or more gate-drive control circuits improve power dissipation of the rectification circuit by controlling drive voltages of gate terminals of the first set of FET switches after start-up of the WPT receiver circuit.