# US 12,001,908 B2 · Method for identifying a passive RFID card > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,001,908 B2 - Document ID: US12001908B2 - Status: Granted - Kind: B2 - Application number: 17/801,010 - Filed: 2021-01-15 - Published: 2023-03-30 - Granted: 2024-06-04 - Earliest claimed: 2020-02-20 - Assignees: Continental Automotive Technologies GmbH - Applicants: Continental Automotive Technologies GmbH - Inventors: Serban Craciun - Web page: https://patentgrep.com/patent/US12001908B2 ## CPC - G06K 7/10009: {sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves} - G06K 7/10366: {the interrogation device being adapted for miscellaneous applications} - H02J 7/47: Arrangements for checking compatibility or authentication between one component, e.g. a battery or a battery charger, and another component, e.g. a power source - H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices - H02J 50/10: using inductive coupling - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY ## Abstract Disclosed is a method for identifying an RFID card as a passive or an active RFID card comprising sending a first RFID command, while keeping an RFID field on; receiving, from the RFID card a corresponding first answering signal; populating a first list with each corresponding first answering signal from the RFID card; sending a second RFID command, wherein the RFID field is paused for a predefined pausing period after sending the second RFID command; receiving, from at least zero active RFID cards, a corresponding second answering signal; populating a second list with each corresponding second answering signal from the at least zero active RFID cards; comparing the entries of the first list with the entries of the second list; identifying each of the at least zero passive RFID cards by having the corresponding first answering signal in the first list but not in the second list. ## Claims ### Claim 1 A method for identifying an RFID card as a passive RFID card or an active RFID card, the method comprising the steps of: sending a first RFID command, while keeping an RFID field on; receiving, from each of at least zero passive RFID cards and at least zero active RFID cards, a corresponding first answering signal; populating a first list with each corresponding first answering signal from the at least zero passive RFID cards and the at least zero active RFID cards; sending a second RFID command, wherein the RFID field is paused for a predefined pausing period after sending the second RFID command; receiving, from the at least zero active RFID cards, a corresponding second answering signal; populating a second list with each corresponding second answering signal from the at least zero active RFID cards; comparing entries of the first list with entries of the second list; identifying each of the at least zero passive RFID cards by having its corresponding first answering signal in the first list but not in the second list; wherein the predefined pausing period is a first period that is specified for unloading an energy of the passive RFID card, the predefined pausing period is a second period that is specified for answering to the second RFID command, and/or the predefined pausing period is long enough to disturb any one of RFID protocol levels, and wherein the first period is between 50 μs and 10 μs, and the second period is between 5 μs and 0.1 μs. ### Claim 2 (depends on 1) The method of claim 1, further comprising the step of: identifying each of the at least zero active RFID cards by having its corresponding first answering signal both in the first list and in the second list. ### Claim 3 (depends on 1) The method of claim 1, wherein the first RFID command and/or the second RFID command is an RFID command according to at least one of NFC-A, NFC-B, NFC-F and NFC-V protocol. ### Claim 4 (depends on 1) The method of claim 1, wherein a wireless charging is only started if exactly zero passive RFID cards are identified, and/or the charging is performed with reduced charging energy. ### Claim 5 (depends on 1) An RFID card identifying device, which is configured to support and/or execute the method according to claim 1. ### Claim 6 (depends on 5) A multiband wireless charging interface comprising an RFID card identifying device according to claim 5. ### Claim 7 (depends on 5) A vehicle comprising a passive RFID card identifying device according to claim 5. ### Claim 8 (depends on 1) A non-transitory computer-readable medium containing program instructions, wherein execution of the program instructions by one or more processors of a computing system causes the one or more processors to carry out the method according to claim 1. ### Claim 9 (depends on 1) Distinguishing the passive RFID card from the active RFID card, and preventing the passive RFID card from being damaged by charging, by using the method according to claim 1. ### Claim 10 (depends on 1) The method of claim 1, wherein the second period is about 1 μs. ### Claim 11 (depends on 1) The method of claim 1, wherein the first period is about 20 μs. ### Claim 12 (depends on 11) The method of claim 11, wherein the second period is about 1 μs.