Abstract: A temperature-compensated oscillator and a device including the same include an oscillation unit configured to generate an oscillation signal using an operating current and an operating voltage, a bias circuit configured to control the operating current so that a frequency of the oscillation signal increases as a temperature increases, and a voltage generation unit configured to generate the operating voltage that varies with the temperature.

Abstract: A near field communication (NFC) terminal includes a first signal generator configured to generate a first received signal using a radio frequency (RF) signal received through an antenna, and generate a reduced first received signal by reducing a size of the first received signal when the size of the first received signal is equal to or greater than a predetermined RF value. The NFC terminal further includes a second signal generator configured to generate a second received signal using the RF signal. The NFC terminal further includes an operation unit configured to generate an operation signal by performing an operation on the reduced first received signal and the second received signal, and transmit the operation signal to a demodulator.

Abstract: A voltage generator of a contactless integrated circuit (IC) card includes a regulator configured to generate a first internal voltage based on an input voltage and a first reference voltage, the input voltage being received through an antenna of the contactless IC card. The voltage generator includes an internal voltage generator configured to generate a second internal voltage, the second internal voltage being used to operate an internal circuit of the contactless IC card. The voltage generator includes a reference voltage generator configured to generate a second reference voltage based on the first internal voltage, the second reference voltage being generated without regard to a fluctuation component of the first internal voltage. The voltage generator includes a switching unit configured to provide one of the first and second internal voltages as the first reference voltage in response to first and second switching control signals.

Abstract: A demodulator for near field communication may include: a scale down circuit configured to receive first and second modulated signals from first and second power electrodes, and configured to provide a scale down signal to a first node by scaling down magnitudes of the first and second modulated signals; a current source coupled between the first node and a ground voltage, and configured to generate a constant current flowing from the first node to the ground voltage; a charge store circuit coupled between the first node and ground voltage, and configured to perform charge and discharge operations alternately, based on the scale down signal and constant current, to output an envelope signal, which corresponds to an envelope of the scale down signal; and/or an edge detector configured to generate input data, which correspond to the first and second modulated signals, based on a transition of the envelope signal.

Abstract: A semiconductor device including a PLL providing candidate clocks of different phases in response to a first clock received from a reader via an antenna, a phase difference detector detecting a phase difference between the first clock and a clock from the candidate clocks, a phase difference controller that selects another clock from the candidate clocks, and a driver that provides transmission data synchronously with the another clock to the reader.

Abstract: A voltage adjusting circuit includes an inducing circuit configured to induce a voltage from electromagnetic waves, a first rectifying circuit configured to rectify an output signal of the inducing circuit, a second rectifying circuit configured to rectify the output signal of the inducing circuit, a first regulator configured to regulate an output signal of the first rectifying circuit, and a second regulator configured to regulate an output signal of the second rectifying circuit.

Abstract: A Near Field Communication (NFC) device, system, and method are provided. The NFC device includes a resonance unit configured to emit a first electromagnetic wave to communicate with an external NFC card in a reader mode, and an NFC chip configured to measure an antenna voltage generated by the resonance unit while the resonance unit emits the first electromagnetic wave, and configured to control the resonance unit to stop emitting the first electromagnetic wave when a magnitude of the antenna voltage oscillates.

Abstract: A contactless card includes an inductive circuit configured to send and receive signals, a rectifier circuit coupled to the inductive circuit and configured to generate a DC voltage from an AC voltage generated by the inductive circuit, a clamp circuit configured to limit the DC voltage, a regulator circuit configured to regulate the DC voltage and a control circuit configured to selectively enable and disable the clamp circuit and the regulator circuit.

Abstract: A near field communication (NFC) terminal includes a first signal generator configured to generate a first received signal using a radio frequency (RF) signal received through an antenna, and generate a reduced first received signal by reducing a size of the first received signal when the size of the first received signal is equal to or greater than a predetermined RF value. The NFC terminal further includes a second signal generator configured to generate a second received signal using the RF signal. The NFC terminal further includes an operation unit configured to generate an operation signal by performing an operation on the reduced first received signal and the second received signal, and transmit the operation signal to a demodulator.

Abstract: A temperature-compensated oscillator and a device including the same include an oscillation unit configured to generate an oscillation signal using an operating current and an operating voltage, a bias circuit configured to control the operating current so that a frequency of the oscillation signal increases as a temperature increases, and a voltage generation unit configured to generate the operating voltage that varies with the temperature.

Abstract: A voltage adjusting circuit includes an inducing circuit configured to induce a voltage from electromagnetic waves, a first rectifying circuit configured to rectify an output signal of the inducing circuit, a second rectifying circuit configured to rectify the output signal of the inducing circuit, a first regulator configured to regulate an output signal of the first rectifying circuit, and a second regulator configured to regulate an output signal of the second rectifying circuit.

Abstract: An internal voltage generating circuit includes a first voltage application unit, a second voltage application unit, a first regulator, a second regulator, and a controller. The first and second voltage application units respectively provide a first voltage and a second voltage. The controller generates a bulk voltage, a first control signal, and a second control signal from the first and second voltages. The first regulator is enabled or disabled according to the first control signal and generates and outputs the first internal voltage based on the bulk voltage, the first voltage, and a first reference voltage. The second regulator is enabled or disabled according to the second control signal and generates and outputs the second internal voltage based on the bulk voltage, the second voltage, and a second reference voltage.

Abstract: A voltage adjusting circuit includes an inducing circuit configured to induce a voltage from electromagnetic waves, a first rectifying circuit configured to rectify an output signal of the inducing circuit, a second rectifying circuit configured to rectify the output signal of the inducing circuit, a first regulator configured to regulate an output signal of the first rectifying circuit, and a second regulator configured to regulate an output signal of the second rectifying circuit.

Abstract: A voltage generator of a contactless integrated circuit (IC) card includes a regulator configured to generate a first internal voltage based on an input voltage and a first reference voltage, the input voltage being received through an antenna of the contactless IC card. The voltage generator includes an internal voltage generator configured to generate a second internal voltage, the second internal voltage being used to operate an internal circuit of the contactless IC card. The voltage generator includes a reference voltage generator configured to generate a second reference voltage based on the first internal voltage, the second reference voltage being generated without regard to a fluctuation component of the first internal voltage. The voltage generator includes a switching unit configured to provide one of the first and second internal voltages as the first reference voltage in response to first and second switching control signals.

Abstract: An apparatus includes a reference clock signal generator circuit configured to generate a reference clock signal in response to a carrier signal and a clock selection signal generator circuit configured to generate a clock selection signal in response to the carrier signal. The apparatus further includes a multiplexer (MUX) circuit configured to selectively output the reference clock signal and a PLL output clock signal in response to the clock selection signal and a phase-locked loop (PLL) circuit configured to receive the selectively output signal between the reference clock signal and the PLL output clock signal at a reference input thereof and to generate the PLL output clock signal therefrom. An ISO 14443 type A smart card may include such apparatus.

Abstract: An NFC (near field communication) device can include a resonance unit and an NFC chip. The resonance unit may communicate with an external device through an electromagnetic wave. The NFC chip can provide output data to the resonance unit, receive input data from the resonance unit, and can reduce a Q factor (quality factor) of the resonance unit when a signal receive operation is performed in a card mode, and can maintain the Q factor of the resonance unit in a reader mode and when a signal transmit operation is performed in the card mode.

Abstract: A method of controlling a resonance frequency of a Near Field Communication (NFC) device that includes a resonance unit to transceive data through an electromagnetic wave and an NFC chip may comprise: detecting whether an NFC card or reader exists around the NFC device; when the NFC card is detected, setting a resonance frequency of the resonance unit as a first optimal frequency based on a magnitude of a voltage generated from the resonance unit while a carrier wave is radiated to the NFC card through the resonance unit; and/or when the NFC reader is detected, setting the resonance frequency of the resonance unit as a second optimal frequency based on the magnitude of the voltage generated from the resonance unit in response to the wave received from the NFC reader and/or a magnitude of an inner current generated from the NFC chip in response to the wave.

Abstract: An apparatus includes a reference clock signal generator circuit configured to generate a reference clock signal in response to a carrier signal and a clock selection signal generator circuit configured to generate a clock selection signal in response to the carrier signal. The apparatus further includes a multiplexer (MUX) circuit configured to selectively output the reference clock signal and a PLL output clock signal in response to the clock selection signal and a phase-locked loop (PLL) circuit configured to receive the selectively output signal between the reference clock signal and the PLL output clock signal at a reference input thereof and to generate the PLL output clock signal therefrom. An ISO 14443 type A smart card may include such apparatus.

Abstract: A contactless card includes an inductive circuit configured to send and receive signals, a rectifier circuit coupled to the inductive circuit and configured to generate a DC voltage from an AC voltage generated by the inductive circuit, a clamp circuit configured to limit the DC voltage, a regulator circuit configured to regulate the DC voltage and a control circuit configured to selectively enable and disable the clamp circuit and the regulator circuit.

Abstract: An internal voltage generating circuit includes a first voltage application unit, a second voltage application unit, a first regulator, a second regulator, and a controller. The first and second voltage application units respectively provide a first voltage and a second voltage. The controller generates a bulk voltage, a first control signal, and a second control signal from the first and second voltages. The first regulator is enabled or disabled according to the first control signal and generates and outputs the first internal voltage based on the bulk voltage, the first voltage, and a first reference voltage. The second regulator is enabled or disabled according to the second control signal and generates and outputs the second internal voltage based on the bulk voltage, the second voltage, and a second reference voltage.