Patent ID: 8923383

Claim:
A near field communication (NFC) transmitter comprising: a delay-locked loop (DLL) that outputs a reference clock and a delayed clock using a value of a duty code and the reference clock which are input; a clock output unit that receives the reference clock and the delayed clock, outputs only the reference clock in either of a high logic level and a low logic level of input data, and outputs a converted clock having a duty ratio using both the reference clock and the delayed clock in the other of the high logic level and the low logic level of the input data to generate a Pulse Width Modulation (PWM) signal corresponding to the input data; and an RF signal generator that generates an RF signal using the PWM signal input from the clock output unit, wherein the delay-locked loop includes: a charge pump that changes a current value to be output using the duty code, a loop filter that converts the current value input from the charge pump into a voltage value and outputs the voltage value, a voltage controlled delay line that outputs the delayed clock which is obtained by delaying the input reference clock in accordance with a voltage control signal, and a phase/frequency detector that inputs an up signal or a down signal to the charge pump on the basis of the comparison result of the reference clock and the delayed clock in phase and frequency.