RFID Tag IC Counter Increment via Power-Up Phase and Flag Control
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Solution Overview
Problem
RFID tag ICs compliant with standards like ISO 15693 (T5T) do not allow sufficient time for incrementing a counter value due to short time slots between read commands and responses, making it impossible to update the counter value efficiently.
Innovation Solution
The RFID tag IC initiates a power-up when coupled with an HF field, incrementing the counter value during this time, using an increment flag to ensure stability and efficiency, and resetting it after a successful increment to allow further updates only during subsequent power-ups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the RFID tag IC increments the counter value during the time slot between read command and response, then the counter value can be updated, but the standard time slot duration is insufficient to complete the increment operation
Solution Approach 1:
The patent applies preliminary action by incrementing the counter value during the power-up phase, which occurs before the read command is executed. This shifts the counter update operation to an earlier time window (power-up time) that is sufficient for completing the memory write operation, thereby resolving the time slot constraint imposed by the RFID standard.
2Duration of action of moving object
If the counter value is incremented during power-up time, then sufficient time is available for the increment operation, but the counter may be incremented multiple times if the tag remains in the HF field
Solution Approach 1:
The patent implements feedback through the increment flag mechanism. After a successful counter increment during power-up, the processing unit sets the increment flag to '1' state, which prevents further increments during subsequent power-up events while the tag remains in the HF field. This feedback mechanism ensures that the counter is incremented exactly once per read command cycle, maintaining reliability and accuracy.
3Reliability
If the increment flag is set after successful increment, then further increments are blocked during read command fulfillment, but the flag must be reset afterward to allow next increment
Solution Approach 1:
The system applies self-service by automatically resetting the increment flag to '0' state after the read command is fulfilled and the counter increment is complete. This automatic reset mechanism eliminates the need for manual flag management and ensures the system is ready for the next increment operation, reducing complexity while maintaining reliability.
4Productivity
If the counter increment operation is performed during the read command time slot, then the counter can be updated, but the operation may fail due to insufficient time and cause data loss
Solution Approach 1:
The patent performs the counter increment operation preliminarily during the power-up phase, which provides sufficient time for the memory write operation to complete successfully. This preliminary execution of the increment operation before the read command ensures data accuracy and prevents loss, while still achieving the goal of updating the counter value.
Data Source
AI summary
There is described an RFID tag IC, comprising:i) an NFC interface configured to initiate a power-up, when coupled with an HF field, and receive a read command from an RFID device;ii) a non-volatile memory, wherein the non-volatile memory is configured to store a counter value; andiii) a processing unit configured to increment the counter value when coupled with the HF field, set an increment flag, when the increment is successful, and thereby block a further increment of the counter value, in particular when fulfilling the read command, and reset the increment flag after fulfilling the read command. Further, a communication system and a method of operating are described.