Circuit for detecting presence or absence of proximity IC card device
US6536673B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 15, 2000 |
| Grant date | Mar 25, 2003 |
| Priority date | — |
| Expiry date | Feb 15, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K19/0723
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A circuit, of a simple structure, for detecting the presence or absence of a proximity IC card (PICC) in a proximity coupling device (PCD) which transmits data to and receives data from the PICC. This circuit includes an antenna for receiving a carrier signal outputted to a proximity IC card, a D.C. detecting device for rectifying a carrier signal received from the antenna and for detecting a D.C. component of the received carrier signal, and a level judgment device for determining the level of the D.C. component detected by the D.C. detecting device and for judging, when the level of the direct component is within a predetermined range that a proximity IC card is present in an RF field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.