Half-Duplex RFID Oscillation Circuit With Self-Adaptive Pulse Injection
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Solution Overview
Problem
Existing oscillation maintenance circuits for half-duplex passive RFID transponders face inefficiencies in energy consumption and frequency drift issues, with complex circuit structures and high power consumption, limiting communication distance and reader reception accuracy.
Innovation Solution
A half-duplex RFID oscillation maintenance circuit with trigger-based pulse generation, utilizing a Schmitt trigger circuit to generate self-adaptive rectangular wave signals for controlling current injection into the L-C resonance circuit, ensuring efficient energy use and maintaining oscillation amplitude without frequency drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex peak detection circuit and fast injection method are used to maintain oscillation amplitude, then oscillation magnitude can be maintained above threshold, but circuit complexity increases and power consumption increases
Solution Approach 1:
The patent extracts and removes the complex peak detection circuit from the oscillation maintenance system, replacing it with a simplified trigger circuit that generates injection pulses based on fixed voltage thresholds, thereby reducing circuit complexity while maintaining oscillation amplitude
Solution Approach 2:
The oscillation maintenance circuit uses the existing L-C resonance circuit's own oscillation signal to trigger the injection pulses through voltage threshold comparison, eliminating the need for external complex detection circuits and achieving self-service operation
2Reliability
If fast injection method with peak detection is used, then oscillation amplitude is maintained, but power consumption increases due to continuous monitoring
Solution Approach 1:
The patent implements periodic current injection based on fixed voltage thresholds rather than continuous peak detection, creating discrete injection pulses that maintain oscillation amplitude while significantly reducing power consumption by eliminating continuous monitoring
Solution Approach 2:
The patent removes the power-consuming peak detection circuitry and replaces it with simple voltage threshold comparison using trigger circuits, thereby maintaining oscillation reliability while dramatically reducing power consumption
3Reliability
If current injection is performed without frequency synchronization, then oscillation maintenance is achieved, but frequency drift occurs affecting reader reception
Solution Approach 1:
The patent employs feedback by using the L-C resonance circuit's own oscillation signal to trigger the injection pulses through voltage threshold comparison, ensuring that current injection is automatically synchronized with the oscillation frequency, thereby preventing frequency drift while maintaining oscillation continuity
Solution Approach 2:
The oscillation maintenance circuit uses the oscillation signal itself to control the timing of current injection, making the system self-regulating and automatically maintaining frequency synchronization without external frequency reference 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
The solution improves current injection efficiency, reduces power consumption, and increases communication distance by precisely controlling current injection duration and frequency alignment with the RF signal, enhancing the transponder's energy utilization and communication reliability.
Implementation Method 1
a passive transponder receives the RF field energy with an L-C resonance circuit formed by a resonance inductor L (also called antenna) and a resonance capacitor C
Implementation Method 2
a rectifier circuit in the transponder converts an alternating current into a direct current to be used by internal circuitries of the transponder, and stores electrical energy obtained through rectification in a storage capacitor CL
Implementation Method 3
The trigger circuit is configured to sample an oscillation voltage at the first antenna end to generate rectangular wave signals for controlling OFF/ON timing of the switch unit
Implementation Method 4
a switch unit connected in series between the storage capacitor and the L-C resonance circuit, and configured to control timing of current injection into the L-C resonance circuit
Data Source
AI summary
A half-duplex RFID oscillation maintenance circuit with trigger-based pulse generation is provided, including: a resonance inductor and a resonance capacitor forming an L-C resonance circuit coupled to an external radio frequency field to generate alternating current for a rectifier circuit, which is connected to an energy-storage capacitor. A first antenna end is connected to a trigger circuit through a switch unit and a resistor connected in series; and an output end of the trigger circuit is connected to a control end of the switch unit. The trigger circuit is configured to sample an oscillation signal at the first antenna end to generate a rectangular wave signal, whose pulse width can be self-adaptively adjusted, to control OFF/ON of the switch unit and, when the switch unit is ON, to form a current injection loop from the energy-storage capacitor to the L-C resonance circuit.