Transceiving Circuit Voltage Stability via Capacitive Divider
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing transceiving circuits for contactless communication, such as NFC and RFID, face instability in voltage at the receiving path due to varying loads on the antenna, leading to detuning and a high dynamic range that complicates signal demodulation.
Innovation Solution
Incorporating a capacitive voltage divider using two DC decoupling capacitors in the transmitting path and branching the receiving path between them, along with an electromagnetic compatibility filter and impedance matching network, to maintain a stable voltage at the receiving path, and optionally using a phase adjusting capacitor and ohmic resistor for optimal demodulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the receiving path branches off from the transmitting path at a fixed location, then the circuit structure is simple, but the voltage at the receiving path becomes unstable under varying antenna loads
Solution Approach 1:
The patent applies dynamics by making the voltage division ratio adjustable rather than fixed. The receiving path can be connected to different tapping points on the transmitting path, allowing the system to adapt to varying antenna loads and maintain stable voltage at the receiving path under different operating conditions.
Solution Approach 2:
The patent changes the parameter of voltage division ratio by introducing adjustable tapping points. By varying the position of the receiving path branching point along the transmitting path, the voltage division ratio can be optimized for different load conditions, thereby maintaining voltage stability without increasing circuit complexity.
2Manufacturing precision
If the antenna is tuned for one load state during manufacturing, then the impedance matching is optimized for that state, but the antenna becomes detuned under varying loads
Solution Approach 1:
The patent makes the system adaptable to varying loads by allowing dynamic adjustment of the receiving path connection point. This enables the system to maintain optimal performance across different load conditions without requiring complex retuning mechanisms, as the voltage division ratio can be adjusted to compensate for load variations.
Solution Approach 2:
The patent achieves universality by designing a system that can handle multiple load states through a single adjustable configuration. The receiving path can be connected to different tapping points to accommodate various antenna load conditions, making the circuit universally applicable across different operating scenarios without requiring separate optimization for each load state.
3Adaptability or versatility
If the voltage at the receiving path varies with antenna load, then the receiver must handle a high dynamic range, but this complicates signal demodulation
Solution Approach 1:
The patent introduces an intermediary voltage division mechanism through the adjustable tapping points on the transmitting path. This intermediary structure acts as a buffer between the transmitting path and the receiving path, stabilizing the voltage at the receiving path and reducing the dynamic range that the receiver must handle, thereby simplifying signal demodulation.
Solution Approach 2:
The patent implements a form of feedback by allowing the receiving path to be connected to different tapping points based on the actual antenna load conditions. This feedback mechanism enables the system to automatically adjust the voltage division ratio to maintain optimal voltage levels at the receiving path, reducing the dynamic range and simplifying demodulation without requiring complex automatic gain control circuits.
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 configuration ensures a stable voltage at the receiving path, reducing the dynamic range and allowing for higher voltage levels that enhance signal demodulation performance, even under varying loads and external influences.
Implementation Method 1
Incorporating a capacitive voltage divider using two DC decoupling capacitors in the transmitting path and branching the receiving path between them
Implementation Method 2
along with an electromagnetic compatibility filter and impedance matching network
Implementation Method 3
transmitter means being adapted to generate an electromagnetic carrier signal, to modulate the carrier signal according to transmitting data and to drive an antenna with the modulated carrier signal
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A transceiving circuit (1) for contactless communication comprises transmitter means (3) to generate an electromagnetic carrier signal, to modulate the carrier signal according to transmitting data and to drive an antenna (5) with the modulated carrier signal, and receiver means (4) to sense response signals being received at the antenna (5) and to demodulate the response signals. The transmitter means (3) are connected to the antenna (5) by at least a first transmitting path (TX1), wherein a first DC decoupling capacitor (C1b) is switched into the first transmitting path (TX1). A receiving path (RX) branches off from the first transmitting path (TX1) to the receiver means (4). A second DC decoupling capacitor (C1c) is switched into the first transmitting path (TX1) in series to the first DC decoupling capacitor (C1b). The receiving path (RX) branches off from the first transmitting path (TX1) at a branching point (C) between the first and second DC decoupling capacitors (C1b, C1c).