LDO-Free Wireless Power Receiver Rectifier

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Solution Overview

Problem

Existing wireless power transmission systems for portable electronic devices require additional area for voltage regulation, which is not efficient in portable devices and can be cumbersome due to the need for wired charging, and they lack space for charging ports, especially in smaller devices like earbuds and smartwatches.

Innovation Solution

A bridge rectifier and associated control circuitry that performs both rectification and regulation functions using both voltage and current feedback, allowing for in-phase and anti-phase regulation to manage excess power without an additional voltage regulation circuit, thereby reducing the need for separate components and enhancing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate voltage regulation circuit is used in wireless power transmission systems, then voltage regulation function is achieved, but integrated circuit area is substantially consumed

Engineering Contradiction:
Improvevoltage regulation functionVSAvoidintegrated circuit area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent combines the voltage regulation function with the bridge rectifier by enabling the rectifier transistors to operate in linear mode for power dissipation. The same transistor components perform both rectification and voltage regulation, eliminating the need for a separate regulator circuit and its associated power MOS device, thereby substantially reducing integrated circuit area consumption.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bridge rectifier transistors are designed to perform multiple functions: they operate as switches for rectification during normal operation and as linear regulators for voltage regulation when excess power needs to be dissipated. This multi-functionality allows a single component to replace what would traditionally require separate dedicated components for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If wireless power transmission is implemented to eliminate charging ports, then water resistance is enhanced and device space is freed, but power management complexity increases

Engineering Contradiction:
Improvewireless charging capabilityVSAvoidpower management complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the voltage regulation function into the existing bridge rectifier circuitry of the wireless power receiver. By making the rectifier transistors capable of linear operation for power dissipation, the system achieves voltage regulation without adding separate control circuits or components, thereby minimizing the increase in power management complexity while enabling wireless charging.

Inventive Principle:
Principle #5Merging (Combining)

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 enables efficient power management within a smaller form factor, reducing area consumption and improving efficiency by integrating rectification and regulation functions, allowing for cleaner data communication and stable power delivery in portable devices.

Implementation Method 1

a receiver 15 including a receiver coil Ls and a serial capacitance Cs forming a similar serial resonant L,C network in which the time-varying electric field induces an AC current

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4213341A1LDO free wireless power receiver having rectifier
Publication Date: 2023.07.19 STMICROELECTRONICS ASIA PACIFIC PTE
  • EP4213341A1 patent drawingFigure 1~3
  • EP4213341A1 patent drawingFigure 4~6
  • EP4213341A1 patent drawingFigure 7~8

AI summary

A bridge rectifier and associated control circuitry collectively form a "regtifier" which rectifies an input time varying voltage and regulates the rectified output voltage produced without the use of a traditional voltage regulator. To accomplish this, the gate voltages of transistors of the bridge rectifier that are on during a given phase may be modulated via analog control (to increase the on-resistance of those transistors) or via pulse width modulation (to turn off those transistors prior to the end of the phase). The transistors of the bridge rectifier that would otherwise be off during a given phase may be turned on to help dissipate excess power and thereby regulate the output voltage. This modulation is based upon both a voltage feedback signal and a current feedback signal.