RFID Transponder Chip Low-Voltage Wake-Up Trimming
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional passive RFID transponder chips have poor sensitivity due to high initial power-on reset voltage, requiring close proximity to the reader for initial wake-up and subsequent communication, and are affected by manufacturing and temperature variations, leading to variability in power-on reset voltage.
Innovation Solution
An RFID transponder chip with a low-voltage non-volatile memory directly connected to the power-on reset circuit, allowing trim values to be applied at a rectified voltage level below the wake-up voltage, enabling trimming of the power-on reset circuit to improve sensitivity and reduce variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the initial power-on reset voltage is set high to ensure stable operation, then the chip can operate reliably, but the sensitivity is poor and the reader-chip distance must be reduced
Solution Approach 1:
The non-volatile memory is configured to operate at a lower voltage threshold than the power-on reset circuit, allowing it to read trim values and program the power-on reset voltage before the main chip circuit wakes up. This preliminary action enables the system to achieve both high reliability and good sensitivity by setting the appropriate power-on reset voltage in advance.
2Measurement precision
If the power-on reset voltage is trimmed to reduce variation, then the sensitivity specification is improved, but the non-volatile memory must be read after wake-up which requires closer proximity to the reader
Solution Approach 1:
The non-volatile memory is designed to operate at a lower voltage threshold, enabling it to read stored trim values and program the power-on reset circuit before the main chip circuit wakes up. This eliminates the need to wait until after wake-up to apply trim values, allowing the chip to achieve optimal sensitivity from the first communication attempt without requiring closer proximity to the reader.
3Ease of operation
If the rectified voltage is increased to wake-up the chip, then the chip can communicate with the reader, but the distance between reader and chip must be reduced or reader RF power increased
Solution Approach 1:
The invention changes the voltage threshold parameter of the non-volatile memory to operate at a lower level than the power-on reset circuit. This parameter change allows the memory to be activated at lower rectified voltage levels, enabling it to retrieve and apply trim values that optimize the power-on reset voltage, thereby improving the chip's ability to communicate at greater distances with lower RF power requirements.
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 enhances communication sensitivity by allowing the chip to wake up and communicate at a lower voltage, reducing the required RF power and variability, thus improving the chip's ability to connect with readers at greater distances and achieving consistent performance across a range of chips.
Implementation Method 1
an antenna to pick-up radio-frequency signals
Implementation Method 2
a rectifier to store charge on capacitors at a rectified voltage from the picked-up radio-frequency signals
Data Source
Figure 1
Figure 2
AI summary
An RFID transponder chip includes at least one antenna to pick-up and transmit radio-frequency signals, a rectifier to store charge on at least one capacitor at a rectified voltage from the picked-up radio-frequency signals, a power-on reset circuit to maintain a logic unit in a reset state if the rectified voltage level is less than a power-on reset or wake-up voltage of the power-on reset circuit for operating the logic unit. The RFID transponder chip further includes a non-volatile memory, in which are stored one or several trim values. Said non-volatile memory is directly connected to the power-on reset circuit to be able to provide at least one trim value to trim the power-on reset circuit at a rectified voltage level below a wake-up voltage level.