Diode Conduction Sensor for Class E Amplifier Efficiency
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Solution Overview
Problem
Class E amplifiers face body diode conduction loss when operating at higher frequencies and driving inductive load impedances, and conventional feedback mechanisms for adjusting duty cycle do not effectively regulate power dissipation and efficiency.
Innovation Solution
A wireless power transfer system with a body diode conduction sensor that provides feedback to a controller to adjust the duty cycle of the switching element, minimizing body diode conduction time and promoting efficient operation by coupling voltage divider networks and a diode to the switching element, allowing for dynamic impedance matching and zero voltage switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the duty cycle is adjusted based on input power monitoring, then the power delivered to the amplifier can be increased or decreased, but the power dissipation and efficiency cannot be directly controlled because there is no perfect output power regulation
Solution Approach 1:
The patent implements a feedback mechanism that monitors output power rather than input power, and uses this feedback to adjust the duty cycle. This closed-loop control ensures that duty cycle adjustments directly affect output power and efficiency, eliminating the disconnect present in conventional input-power-based monitoring systems.
Solution Approach 2:
The system automatically adjusts its own operating parameters (duty cycle) based on real-time performance measurements (output power), enabling self-optimization of efficiency without external intervention. The amplifier monitors its own output and autonomously corrects for inefficiencies.
2Productivity
If the switching element operates at higher frequencies with inductive load impedances, then the power transfer capability is improved, but body diode conduction loss increases causing efficiency degradation
Solution Approach 1:
The patent dynamically adjusts the duty cycle in real-time based on measured output power and efficiency characteristics. This dynamic adaptation allows the system to optimize the trade-off between power transfer capability and body diode conduction losses by continuously tuning operating parameters rather than using fixed duty cycles.
Solution Approach 2:
The system changes the duty cycle parameter based on operating conditions to minimize body diode conduction losses. By varying this key timing parameter, the amplifier can maintain high-frequency operation for good power transfer while reducing the duration and impact of body diode conduction events.
Data Source
Figure 1
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Figure 4A
AI summary
Methods and apparatus for a body diode conduction sensor configured for coupling to a switching element. In embodiments, the sensor comprises first and second voltage divider networks coupled to a voltage source and a diode coupled to the switching element and to the first voltage divider network, wherein the diode is conductive at times corresponding to body diode conduction of the switching element decreasing the DC average voltage at the output node of the first voltage divider network. A differential output voltage can be coupled to the first and second voltage divider networks with an output signal corresponding to a time of the body diode conduction of the switching element.