DVCS Amplifier Common-Mode Control for Wireless Power Sensing
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Solution Overview
Problem
Conventional wireless power systems face challenges in accurately measuring differential-mode voltage across capacitors due to large common-mode voltage swings, which overwhelm amplifier input ranges and distort signal integrity.
Innovation Solution
Implementing a Differential Voltage Capacitor Sensing (DVCS) amplifier with a common-mode control loop and feedback resistors to maintain common-mode voltage within operational ranges, using a degenerated push-pull current mirror structure to stabilize input signals and a low-pass filter to manage high-frequency harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional amplifiers are used to measure voltage across capacitors in wireless power systems, then the amplifier can amplify the differential-mode signal, but the large common-mode voltage swings will overwhelm the amplifier input range and distort signal integrity
Solution Approach 1:
The patent segments the voltage measurement function into two independent parts: a differential-mode amplifier that only amplifies the differential signal (Vp - Vn) and a separate common-mode control loop that independently regulates the common-mode voltage (Vcm). This segmentation allows each component to optimize its function without interference, preventing common-mode swings from overwhelming the amplifier input range while maintaining accurate differential-mode measurement.
Solution Approach 2:
The patent introduces an intermediary common-mode control loop that acts as a mediator between the power switching nodes and the differential-mode amplifier. This control loop includes a common-mode sensor that detects Vcm and a common-mode amplifier that adjusts it to maintain Vcm within the amplifier's input range, thereby protecting the amplifier from harmful common-mode voltage swings while allowing accurate differential signal amplification.
2Adaptability or versatility
If the amplifier input range is increased to accommodate large common-mode voltage swings, then the amplifier can handle higher voltages, but the differential-mode signal measurement precision deteriorates due to overwhelming common-mode interference
Solution Approach 1:
The patent segments the voltage handling function by separating differential-mode amplification from common-mode voltage management. The differential-mode amplifier maintains a fixed, limited input range optimized for precise differential signal measurement, while a separate common-mode control loop independently handles the full range of common-mode voltage swings, preventing them from interfering with differential signal accuracy.
Solution Approach 2:
The patent implements a feedback mechanism through the common-mode control loop that continuously monitors the common-mode voltage (Vcm) and adjusts it to maintain Vcm within the amplifier's optimal input range. This feedback ensures that the amplifier always operates in its precision measurement zone regardless of the overall voltage level in the circuit, thereby maintaining high differential-mode measurement precision while adapting to varying voltage conditions.
Data Source
AI summary
Systems and methods implementing an improved DVCS amplifier are described. The integrated circuit can include a controller. The integrated circuit can further include an amplifier configured to measure a common mode voltage across a capacitor of a switching converter. The integrated circuit can include a circuit configured to receive a differential input being provided to the amplifier. Based on the differential input, the circuit can further be configured to maintain the common mode voltage to regulate the amplifier within an operating range of the amplifier.