METHOD FOR CONTROLLING RESONANCE FREQUENCY OF NEAR FIELD COMMUNICATIONS DEVICE, AND NEAR FIELD COMMUNICATIONS DEVICE AND ELECTRONIC SYSTEM HAVING SAME

摘要

A method for controlling a resonance frequency of a near field communications (NFC) device that includes a resonance unit to transmit and receive data through electromagnetic waves and an NFC chip comprises the following steps: detecting whether an NFC card or NFC reader exists around the NFC device; setting a resonance frequency of the resonance unit as a first optimal frequency based on the magnitude of a voltage generated from the resonance unit while a carrier wave is radiated to the NFC card through the resonance unit when the NFC card is detected; and setting a resonance frequency of the resonance unit as a second optimal frequency based on at least one of the magnitude of a voltage generated from the resonance unit in response to an electromagnetic wave received from the NFC reader and the magnitude of an inner current generated from the NFC chip in response to the electromagnetic wave received from the NFC reader when the NFC reader is detected. The method can independently set a resonance frequency as an optimal frequency with respect to each of a reader mode and a card mode.;COPYRIGHT KIPO 2014