H-Bridge Rectifier Circuit for Wireless Power
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Solution Overview
Problem
Conventional wireless power receiving apparatuses suffer from high power loss due to the use of diode-bridge circuits, leading to reduced efficiency in charging secondary batteries.
Innovation Solution
The implementation of an H-bridge circuit using N-channel MOSFETs as a rectifier, which reduces power loss by employing a capacitor to generate the required gate voltage, eliminating the need for a bootstrap circuit and minimizing circuit elements and area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a diode-bridge circuit is used for rectification, then the circuit structure is simple, but power loss increases and efficiency decreases
Solution Approach 1:
The patent changes the fundamental operating parameters of the rectification circuit by replacing diodes with MOSFETs operated in linear region. This parameter change allows for continuous current flow and reduced voltage drop, thereby reducing power loss while maintaining circuit functionality. The MOSFETs are controlled to operate in their linear region where they act as variable resistors, enabling efficient power transfer.
Solution Approach 2:
The patent substitutes the traditional diode-based mechanical rectification mechanism with an electronically controlled MOSFET-based system. Instead of relying on the inherent unidirectional conductivity of diodes, the system uses electronically controlled switches that can be precisely timed and regulated, replacing the passive mechanical-like operation of diodes with active electronic control.
2Loss of energy
If an H-bridge circuit with N-channel MOSFETs is used, then power loss is reduced and efficiency is improved, but the circuit complexity increases
Solution Approach 1:
The H-bridge circuit configuration provides multiple functions: rectification, voltage regulation, and efficient power transfer. The same MOSFETs that reduce power loss also enable controlled current flow and voltage regulation. This multi-functionality reduces the need for separate dedicated components, thereby managing circuit complexity while achieving multiple objectives simultaneously.
Solution Approach 2:
The capacitor in the circuit automatically generates the required gate voltage for the MOSFETs during the rectification process. This self-charging mechanism eliminates the need for external bootstrap circuits or additional power supply components, allowing the circuit to service itself and reducing overall complexity despite the H-bridge configuration.
3Ease of operation
If a bootstrap circuit is added to generate gate voltage, then the H-bridge circuit can operate, but the number of circuit elements and area increases
Solution Approach 1:
The capacitor connected to the rectification line charges automatically during the rectification process and provides the necessary gate voltage for the MOSFETs. This self-charging mechanism eliminates the need for external bootstrap circuits, auxiliary power supplies, or additional voltage generation components. The circuit uses its own operational energy to generate the control voltages it needs, thereby reducing the number of circuit elements and overall circuit area.
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 configuration enhances the efficiency of wireless power reception by minimizing power loss and supporting various secondary batteries without requiring circuit modifications, even with changes in battery cell count.
Implementation Method 1
When the driving current flows through the transmission coil 202, electromagnetic induction occurs, thereby supplying a coil current ICOIL that flows through the reception coil 302.
Implementation Method 2
The implementation of an H-bridge circuit using N-channel MOSFETs as a rectifier, which reduces power loss by employing a capacitor to generate the required gate voltage
Implementation Method 3
employing a capacitor to generate the required gate voltage
Data Source
AI summary
A wireless power receiver circuit forms a wireless power receiving apparatus together with a reception coil. An internal power supply line is connected to a capacitor C. An output line is connected to a secondary battery. An H-bridge circuit includes N-channel MOSFETs MH1, MH2, ML1, and ML2. A first switch is arranged between a rectification line and the internal power supply line. A second switch is arranged between the rectification line and the output line. A voltage VDD of the internal power supply line is supplied to a power supply terminal of a controller.