Dual-Terminal Rectifier for Passive RFID Power Management
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Solution Overview
Problem
Passive RFID tags face challenges in efficiently converting low-level RF signals into usable voltage due to the need for rectifiers and charge pump circuits that can generate sufficient voltage quickly and efficiently, especially when high-voltage operations are required, and the RF signal is not constantly available.
Innovation Solution
A dual-terminal rectifier device with input terminals, an output terminal, and a gate that forms a conductive channel to couple the input terminals to the output terminal in response to a gate voltage, allowing for the rectification of combined alternating input signals to generate a rectified output signal, which is used to power the RFID tag and enable high-voltage operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional rectifier circuits are used to convert RF signals to usable voltage, then the RFID tag can be powered by the received RF signal, but the conversion efficiency is insufficient when the RF signal voltage is only approximately 200 millivolts and a typical supply voltage of one volt is required
Solution Approach 1:
The patent combines multiple rectifier stages (including a first rectifier and a second rectifier) into a single integrated power management circuit. The output of the first rectifier is coupled to the input of the second rectifier, creating a cascaded configuration that multiplies the voltage gain effect. This merging of multiple rectification functions into one unified circuit enables efficient conversion from low-voltage RF signals (200mV) to higher usable voltages (1V and above) while maintaining compact footprint suitable for RFID tag integration.
Solution Approach 2:
The patent employs dynamic switching mechanisms within the rectifier stages, using control signals to activate different rectification paths based on the RF signal conditions. The power management circuit dynamically adjusts its operation mode to optimize voltage conversion efficiency under varying RF signal strengths, ensuring reliable power generation even when the incoming RF signal is weak or intermittent.
2Device complexity
If passive RFID tags rely on continuous RF signal reception for power, then no energy storage device is needed, but the RF signal may cease transmission without notice making continuous power supply unreliable
Solution Approach 1:
The patent incorporates energy storage elements (capacitors) that are pre-charged during periods when RF signal is available. When the RF signal ceases transmission, these pre-charged capacitors immediately provide the necessary power to maintain operation of the RFID tag. This preliminary energy storage action ensures uninterrupted power supply and enhances reliability without requiring active tag components or complex power management architectures.
3Area of stationary object
If the RFID tag circuitry is miniaturized to reduce manufacturing cost and meet consumer demands, then the tag becomes more compact and cost-effective, but the available space for power management circuitry is severely limited
Solution Approach 1:
The patent designs the power management circuit to perform multiple functions within a single integrated structure. The rectifier stages serve both as voltage converters and as impedance matching networks. The same circuit elements are used for both power harvesting and signal conditioning, maximizing the utility of each component and reducing the overall area required for power management functionality while maintaining full power conversion capability.
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 enhances the efficiency of power management in RFID tags by effectively converting low-level RF signals into usable voltage, ensuring reliable operation even when the RF signal is intermittent, and supporting high-voltage applications such as programming non-volatile memory.
Implementation Method 1
rectifier circuits and charge pump circuits for harvesting usable power from the RF signal received via the antenna system. In operation, an alternating RF wave received by the antenna system is converted by the rectifier circuits and charge pump circuits into usable direct current (DC) voltage
Implementation Method 2
The gate is configured to form a conductive channel that electrically couples the first and second input terminals to the output terminal in response to a gate voltage
Data Source
AI summary
Apparatus and method for generating a rectified output signal in a RFID tag from first and second alternating signals. A dual-terminal rectifier device has first and second input terminals to which the first and second alternating signals are applied, and further has a gate configured to form a conductive channel to electrically couple the first and second input terminals to the output terminal in response to a gate voltage. The dual-terminal rectifier device is configured to rectify a combination of the alternating input signals applied to the input terminals of the semiconductor device to generate a rectified output signal at an output terminal.