Current Sense Apparatus for Wireless Power Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current sense devices in wireless power transfer systems face challenges with high power loss and inaccurate current sensing, particularly at higher current levels, which affects efficiency and reliability.
Innovation Solution
A current sense apparatus with positive and negative current sense amplifiers connected to the drain and source of power switches, utilizing current sense switches and processing apparatus to accurately sense current flow and minimize power consumption, enabling bi-directional current sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current sense resistors are connected in series with power switches to achieve accurate current measurement, then measurement precision is improved, but power loss increases significantly at higher current levels
Solution Approach 1:
The patent introduces current sense switches as intermediary components between the power switches and current sense amplifiers. These switches act as mediators that enable accurate current measurement through selective connection to sense amplifiers, while the switches themselves have minimal impact on the main power path, thereby reducing power loss compared to direct resistor sensing.
Solution Approach 2:
The patent replaces the traditional passive current sense resistor approach with an active switching-based sensing system. Instead of relying on resistive voltage drops that cause continuous power loss, the system uses electronically controlled switches to selectively connect current paths to sense amplifiers, substituting a mechanical/resistive sensing method with an electronic switching method that reduces energy dissipation.
2Reliability
If current sense resistors are used for current monitoring, then current measurement information is obtained, but power consumption increases and efficiency decreases
Solution Approach 1:
The current sense switches are controlled to operate periodically or selectively rather than continuously. The switches connect to different current sense amplifiers at different times based on the operating phase, enabling current monitoring only when necessary for reliability checks, thereby reducing continuous power consumption while maintaining system reliability.
Solution Approach 2:
The patent changes the operational parameters of the sensing system by using controlled switching to activate sensing paths only during specific operating conditions. This dynamic parameter control allows the system to maintain reliability through accurate current monitoring when needed, while minimizing power consumption by keeping sensing circuits inactive during other phases.
3Measurement precision
If traditional current sense devices are used in high power applications, then current sensing is achieved, but power loss becomes significant and challenges design requirements
Solution Approach 1:
The patent segments the current sensing function into multiple parallel paths, each with its own current sense switch and amplifier. This segmentation allows the system to handle high current applications by dividing the sensing task across multiple lower-current paths, reducing power loss in each segment while maintaining overall sensing accuracy through coordinated operation of the segmented paths.
Data Source
AI summary
A device includes a positive current sense amplifier having two inputs connected to a drain and a source of a power switch respectively through a plurality of positive current sense switches, and a negative current sense amplifier having two inputs connected to the drain and the source of the power switch respectively through a plurality of negative current sense switches.