Method and apparatus for controlled persistent ID flag for RFID applications
US7116240B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 18, 2004 |
| Grant date | Oct 3, 2006 |
| Priority date | — |
| Expiry date | Apr 27, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K19/0723
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A Radio-Frequency Identification (RFID) transponder is provided. The RFID transponder may include a basic ID flag circuit having a VDD voltage node, an output voltage node, and a capacitor coupled to the VDD voltage node and the output voltage node to store an ID flag. The persistence duration of the state of the ID flag is controlled by maintaining a charge and leakage circuit. The charge and leakage circuit includes an NMOS device having a source, a drain and a gate, the source node of the NMOS device being coupled to the capacitor and the drain node of the NMOS device being coupled to a first CMOS inverter. The first CMOS inverter is powered by a regulated supply voltage such that the voltage on the capacitor is not dependent on the forward voltage drop of the NMOS device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.