RFID Rectifier Limiter Circuits Prevent Parasitic Transistor Activation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
RFID tags face instability in signal reception due to large signal reception when close to a reader/writer, leading to unstable communication, especially at short distances, due to high input power causing parasitic bipolar transistors to turn on and lower the output voltage, disrupting stable operation.
Innovation Solution
A semiconductor device with a multistage rectification circuit using capacitors and diodes, along with limiter circuits that clamp node potentials to prevent parasitic bipolar transistors from turning on, ensuring stable operation by suppressing negative potential changes and maintaining output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the RFID tag is designed to operate with small power for long distance communication, then the communication range is extended, but the reception performance becomes unstable when close to the reader/writer due to large signal input
Solution Approach 1:
The patent applies preliminary anti-action by introducing limiter circuits that preemptively clamp the input signal voltage to a predetermined level before the signal can cause instability in the rectification circuit. This prevents the harmful effect of large signals from occurring in the first place, allowing the RFID tag to handle both weak distant signals and strong near signals reliably.
2Power
If high transmission power is used when close to the reader/writer, then the signal strength is sufficient, but the base current increases and turns on parasitic bipolar transistors, lowering the output voltage
Solution Approach 1:
The patent converts the harmful large input signal into a beneficial controlled condition by using limiter circuits to clamp the voltage. This prevents the activation of parasitic bipolar transistors while still allowing the rectification circuit to generate sufficient output voltage for stable operation, effectively transforming a potential harm into a controlled operating condition.
3Reliability
If a voltage limit circuit is provided to limit output voltage, then the output voltage stability is improved, but the circuit complexity increases
Solution Approach 1:
The patent uses limiter circuits as intermediary elements positioned at the input stage of the rectification circuit. These limiters act as mediators that control the input signal voltage before it reaches the rectification circuit, preventing voltage instability without requiring complex feedback control circuits at the output stage.
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
Enables stable communication even at short distances by preventing the lowering of output voltage and reducing base current, thus maintaining stable power supply to RFID tag circuits.
Implementation Method 1
a rectification circuit that includes unit rectification circuits connected in multistage and generates a power supply voltage from the wireless signal received by the antenna
Implementation Method 2
limiter circuits that are turned on at a voltage larger than an on-voltage of the diodes
Data Source
AI summary
In a semiconductor device that generates a power supply voltage from an RF carrier signal received by an antenna through the use of a rectification circuit, rectification circuits, each including a plurality of capacitors and a plurality of diodes, are connected in multistage. The rectification circuits includes limiter circuits that are turned on at a voltage larger than an on-voltage of the diodes, clamp cathodes of the diodes at a first voltage. The limiter circuits and the diodes are connected in parallel between the capacitors connected to the antenna connection terminal and a node supplied reference potential VSS of the power supply voltage.