Rectifier Power Dissipation Measurement via Voltage Drop Sensing
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Solution Overview
Problem
Existing wireless power transfer systems face challenges in accurately measuring power dissipation in rectifier circuits due to limitations in coil resistance and transistor on-resistance measurements, leading to estimation inaccuracies.
Innovation Solution
A circuit and method that measures power dissipation in a voltage rectifier by sensing current and voltage drops across MOSFET transistors during rectification, using a current sensing circuit and voltage measurement circuit to calculate power dissipation accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coil resistance and transistor on-resistance measurements are used to estimate power dissipation, then the measurement method is simple, but the measurement precision is insufficient
Solution Approach 1:
The power dissipation measurement is segmented into two separate measurement components: voltage drop measurement across the transistor and current measurement through the transistor. By measuring these two parameters separately and calculating power dissipation as their product, the system achieves higher measurement precision compared to direct estimation methods while managing circuit complexity through modular measurement approaches.
2Measurement precision
If direct sensing of current and voltage drops is implemented, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent introduces intermediary measurement circuits that facilitate the detection of voltage drops and current. These intermediary circuits act as mediators between the power transistor and the measurement system, making the direct sensing process more manageable and less difficult while maintaining high measurement precision for power dissipation calculation.
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 provides precise measurement of power dissipation in rectifier circuits, improving accuracy beyond the limitations of existing methods by directly sensing current and voltage drops during operation.
Implementation Method 1
a current sensing circuit configured to sense current delivered from the first output terminal of the rectifier towards a load
Implementation Method 2
a voltage measurement circuit configured to sense a voltage drop across each transistor in the bridge synchronous with actuation of the transistor
Implementation Method 3
A voltage rectifier includes four MOSFET transistors arranged in a bridge... during a rectification mode operation for the voltage rectifier
Data Source
AI summary
A receiver circuit includes a rectifier operable in full-, half-synchronous and asynchronous modes. A measurement circuit, with method, provides for real-time power measurement within the rectifier. The measurements are made based on the average output current from the rectifier delivered to the load and measurements sampled over time of the instantaneous voltage at each input/output node of the rectifier. Equivalent resistance in the rectifier is determined from the measurements and power dissipation calculated from the determined equivalent resistance and the average output current. The instantaneous voltages are synchronously captured through high-voltage AC coupling in order to detect the voltage drop across each element of the rectifier. The sensed voltages are amplified in the low voltage domain and converted by a high-speed analog-to-digital converter in order to produce data useful in computing equivalent resistance values. From these values, power dissipation within the rectifier is calculated and real-time equivalent resistance is available.