Receiver of NFC device and NFC device including the same

摘要

A receiver of a near field communication device includes a local oscillator, a first channel, and a second channel. The local oscillator may be configured to generate a first local oscillating signal. The first channel may be configured to process an input signal by mixing the input signal with the first local oscillating signal. The second channel may be configured to process the input signal by mixing the input signal with a second local oscillating signal that has a phase difference of 90 degrees with respect to the first local oscillating signal. Each of the first and second channels may include a comparator unit that includes a comparator configured to compare, in a comparator mode, an amplifier output signal with a reference voltage whose level increases in a step-wise manner and the comparator unit may be configured to set a level of the reference voltage to be used in a normal mode based on an output signal of the comparator.

主权项

1. A receiver of a near field communication (NFC) device, the receiver comprising:
a local oscillator configured to generate a first local oscillating signal; a first channel configured to process an input signal by mixing the input signal with the first local oscillating signal; and a second channel configured to process the input signal by mixing the input signal with a second local oscillating signal that has a phase difference of 90 degrees with respect to the first local oscillating signal, wherein each of the first and second channels comprises a comparator unit that includes a comparator configured to compare, in a comparator mode, an amplifier output signal with a reference voltage whose level increases in a step-wise manner and the comparator unit is configured to set a level of the reference voltage to be used in a normal mode based on an output signal of the comparator, wherein the first channel comprises: a first mixer configured to mix the input signal with the first local oscillating signal to generate a first mixed signal; a first low-pass filter configured to filter the first mixed signal; a first variable gain amplifier configured to amplify an output of the first low-pass filter to provide a first amplifier output signal; and a first comparator unit that includes a first comparator configured to compare, in the comparator mode, the first amplifier output signal with a first reference voltage whose level increases in the step-wise manner, wherein the first comparator unit comprises: a programmable counter configured to perform, in the comparator mode, an up-counting operation to generate a counting value; a step reference voltage generator configured to generate, in the comparator mode, the first reference voltage whose level increases in the step-wise manner in response to the counting value; the first comparator configured to compare, in the comparator mode, the first amplifier output signal with the first reference voltage to provide a first comparator output signal; and a reference voltage setting unit configured to detect, in the comparator mode, a level of the first comparator output signal and configured to determine a level of the first reference voltage to be used in the normal mode based on the first comparator output signal whose level is not changed during M times, M being an integer greater than one.