Bidirectional Current Sense Apparatus for Wireless Power Transfer
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Solution Overview
Problem
Current sense resistors in wireless power transfer systems experience significant power loss as current increases, making accurate current monitoring and efficient power transfer challenging, especially in high-power applications.
Innovation Solution
A high-efficiency current sense apparatus is introduced, featuring a power regulator configured as a linear regulator with bidirectional current sensing capabilities, and a current sense apparatus with two inputs coupled to the power regulator's input and output, allowing for accurate current sensing with reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current sense resistors are used to monitor current in wireless power transfer systems, then accurate current measurement is achieved, but power loss increases significantly at high currents
Solution Approach 1:
The patent introduces a current sense apparatus as an intermediary device that measures current through voltage detection across sense resistors connected in series with power switches, rather than using high-power current sense resistors in the main current path. This mediator approach allows accurate current measurement without significant power loss in the sensing elements themselves.
Solution Approach 2:
The patent replaces the traditional mechanical/electrical current sensing method (using current sense resistors that directly carry and measure current) with an electronic measurement approach using voltage detection and signal processing circuits. This substitution eliminates the need for high-power dissipating resistors while maintaining measurement accuracy.
2Ease of operation
If current sense resistors are used for current monitoring, then current sensing capability is provided, but device complexity and power consumption increase
Solution Approach 1:
The current sense apparatus is designed to handle bidirectional current flow and multiple operating modes (wireless power transfer and wired power transfer) through a unified circuit architecture. The same sense resistors and detection circuits serve both charging and discharging operations, eliminating the need for separate sensing circuits for each direction or mode.
Solution Approach 2:
The patent combines the current sensing function with the existing power management circuitry by integrating sense resistors into the power switch configurations. The voltage detection circuits are merged with the existing control architecture, reducing overall system complexity compared to adding separate dedicated current sensing subsystems.
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
The solution provides highly accurate current sensing with low power consumption, enhancing the efficiency and reliability of wireless power transfer systems, particularly in high-power applications.
Implementation Method 1
The primary side transmitter is magnetically coupled to the secondary side receiver through a magnetic coupling. The magnetic coupling may be implemented as a loosely coupled transformer having a primary side coil formed in the primary side transmitter and a secondary side coil formed in the secondary side receiver.
Implementation Method 2
a current sense apparatus having two inputs coupled to an input and an output of the power regulator, respectively, wherein the current sense apparatus is configured to sense a bidirectional current flowing through the power regulator
Data Source
AI summary
A system includes a power regulator coupled between a coil and a battery, wherein the power regulator is configured as a linear regulator when power is provided from the coil to the battery, and a current sense apparatus having two inputs coupled to an input and an output of the power regulator, respectively, wherein the current sense apparatus is configured to sense a bidirectional current flowing through the power regulator.