Near field communication device, terminal device having the same, and operation method of the near field communication device

Abstract

A near field communication (NFC) device includes a phase detector for receiving a reference clock signal, detecting a phase of the reference clock signal, outputting a generated clock signal having a frequency synchronized with the reference clock signal, and storing phase information of the generated clock signal as a first digital code. A phase delay calculator compares the phase of the generated clock signal applied from the phase detector and a reference phase to calculate a delta value while performing an active load modulation (ALM) operation and stores the delta value as a second digital code. A transmission clock signal generator reflects phase information stored as the first digital code and the second digital code to output a transmission clock signal. Accordingly, the NFC device controls the phase of the transmission clock signal applied to the antenna of the reader device to have optimal load modulation amplitude (LMA).