AGC Demodulation Circuit for ASK Decoding in Wireless Power Transfer
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Solution Overview
Problem
Existing wireless power transfer systems face inefficiencies in in-band data transfer due to varying relative positions and orientations of sender and receiver, leading to signal strength changes that can cause previously readable signals to become faint or saturated, requiring more computational resources for accurate demodulation.
Innovation Solution
A wireless power transfer system with a demodulation circuit that applies automatic bias control and gain control to detect signal slope changes, using operational amplifiers and digital potentiometers to adjust resistance values based on sensed current and coupling strength, allowing for efficient decoding of ASK signals regardless of position changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If in-band data transfer is used in wireless power transfer systems, then data communication capability is improved, but signal detection accuracy deteriorates when relative positions vary
Solution Approach 1:
The patent implements dynamic gain adjustment in the demodulation circuit, where the gain is automatically adjusted based on the detected signal strength. When the receiver moves closer to the transmitter, the gain is reduced to prevent saturation; when moved farther, the gain is increased to maintain detection accuracy. This dynamic adaptation resolves the contradiction by making the signal detection system flexible rather than fixed.
Solution Approach 2:
The patent changes the electrical parameters (gain, bias voltage) of the demodulation circuit based on operating conditions. By monitoring the signal characteristics and adjusting the circuit parameters accordingly, the system maintains optimal detection accuracy across varying coupling conditions, thus resolving the contradiction between adaptability and measurement precision.
2Reliability
If additional antennas and circuitry are used for data communication, then communication reliability is improved, but device complexity increases
Solution Approach 1:
The patent makes the power transfer circuitry perform dual functions: both power transfer and data communication. By modulating the power transfer signal itself to carry data (using the same antenna and circuit), the system achieves reliable communication without adding separate communication hardware, thus resolving the contradiction between reliability and complexity.
Solution Approach 2:
The patent merges the power transfer and data communication functions into a single integrated system. The same transmitter antenna and receiver circuitry used for power transfer are also used for data communication by encoding data in the power signal characteristics. This consolidation improves reliability through unified hardware while reducing overall device complexity.
3Measurement precision
If higher computational resources are allocated for signal demodulation, then demodulation accuracy is improved, but processing time increases
Solution Approach 1:
The patent performs preliminary signal conditioning in the demodulation circuit before digital processing. By pre-amplifying, filtering, and conditioning the analog signal in hardware, the circuit prepares the signal for more efficient digital demodulation. This preliminary analog processing reduces the computational burden on the processor, achieving high accuracy without excessive processing time.
Solution Approach 2:
The patent replaces computationally intensive digital signal processing with analog circuit-based demodulation. By implementing the demodulation function in hardware (analog circuit) rather than software (digital processing), the system achieves accurate signal detection with minimal processing time, as the analog circuit performs the demodulation in real-time without requiring complex computational algorithms.
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 solution reduces computational resources needed for data signal decoding, allows for cheaper processor usage, and maintains accurate data transfer across varying coupling conditions, ensuring efficient and stable data transmission.
Implementation Method 1
The transmitter antenna is configured to couple with at least one other antenna of at least one other system and transmit alternating current (AC) wireless signals to the at least one other antenna
Implementation Method 2
The first demodulation circuit is configured to apply automatic bias control and gain control to the first electrical information
Data Source
AI summary
A wireless receiver and transmission systems include a receiver antenna, a sensor, a demodulation circuit, and a controller. The sensor is configured to detect electrical information superimposed on an AC wireless signal. The demodulation circuit is configured to receive the electrical information from the at least one sensor, apply automatic bias control and gain control to generate modified electrical information, detect a change in the modified electrical information and determine if the change in the modified electrical information meets or exceeds one of a rise threshold or a fall threshold. If the change exceeds one of the rise threshold or the fall threshold, an alert is generated. Alerts are decoded into the electrical information.