Controllable Rectifying Bridge for Transponder Power Management
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Solution Overview
Problem
Electromagnetic transponders with batteries face signal interpretation errors due to modulation index instability when switching between battery power and remote-supplied power modes, especially when the battery charge level affects the power draw from the electromagnetic field.
Innovation Solution
Incorporating a controllable rectifying bridge with MOS transistors, whose gate voltage is representative of the battery charge level, to maintain the modulation index by disconnecting the rectifying bridge when the battery voltage is sufficient, ensuring exclusive battery power usage, and activating it when the battery voltage is insufficient for remote-supplied operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the transponder draws power from both battery and electromagnetic field during mixed operation, then the available power is increased, but the modulation index becomes unstable causing signal interpretation errors
Solution Approach 1:
The transponder automatically monitors its own battery charge level and autonomously switches between battery mode and remote-supply mode without external intervention. The battery management circuit detects when battery voltage falls below a threshold and activates the rectifying bridge to draw power from the electromagnetic field, ensuring continuous reliable operation based on self-diagnosed power status
Solution Approach 2:
The system dynamically adjusts its power source configuration based on real-time battery charge level. When battery voltage is sufficient, the system operates in battery mode with the rectifying bridge disconnected. When battery voltage drops below the threshold, the system transitions to remote-supply mode by activating the rectifying bridge to extract power from the electromagnetic field, maintaining stable modulation index throughout the transition
2Duration of action of moving object
If the transponder operates in remote-supplied mode to extend battery life, then energy consumption from battery is reduced, but the system becomes vulnerable when electromagnetic field power is insufficient
Solution Approach 1:
The battery management circuit continuously monitors battery voltage and provides feedback to the control logic. When battery voltage falls below a predetermined threshold, the feedback signal triggers activation of the rectifying bridge to draw power from the electromagnetic field. This closed-loop feedback mechanism ensures the system switches to remote-supply mode at the optimal moment to extend battery life while maintaining reliable power supply
Solution Approach 2:
The power management system is designed to handle multiple power source scenarios: battery-only mode, remote-supply mode, and the ability to switch between them. The rectifying bridge can operate in different configurations depending on power availability, making the power supply system universal and adaptable to various operating conditions without compromising reliability
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 stabilizes the modulation index, enhancing signal reliability by preventing power draw from both the battery and the electromagnetic field during mixed operation modes, thus maintaining accurate data decoding and simplifying the switching between power modes.
Implementation Method 1
A transmission from a terminal to a transponder is generally performed in amplitude modulation of a high-frequency carrier (for example, at 13.56 MHz)
Implementation Method 2
a first rectifying bridge having A.C. input terminals connected across the oscillating circuit and having at least two rectifying elements controllable with the voltage supplied by the battery
Implementation Method 3
said two controllable rectifying elements are two first MOS transistors
Implementation Method 4
Since the carrier must be able to supply power to the transponder when it is not powered by its battery, the modulation index is generally smaller than 100% so that the carrier is always present
Data Source
AI summary
An electromagnetic transponder includes an oscillatory circuit, a battery and a first rectifier bridge. Alternating current input terminals of the rectifier bridge are connected to the terminals of the oscillatory circuit, and at least two rectifier elements of the rectifier bridge are controllable on the basis of the voltage supplied by the battery.