Near field communication device, electronic system having the same and method of controlling power in near field communication device
First Claim
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1. A near field communication (NFC) device, comprising:
- a resonance unit configured to emit an electromagnetic wave to communicate data with an external card in a reader mode; and
an NFC chip configured to estimate a distance between the NFC device and the external card based on an antenna voltage generated by the resonance unit while the resonance unit emits the electromagnetic wave, and configured to adjust a magnitude of the electromagnetic wave based on the estimated distance,wherein the NFC chip is configured to provide an output current to the resonance unit, the resonance unit is configured to emit the electromagnetic wave, wherein the magnitude of the electromagnetic wave corresponds to the output current, and the NFC chip is configured to measure the antenna voltage while the resonance unit emits electromagnetic wave and adjust a magnitude of the output current based on a magnitude of the antenna voltage,wherein the NFC chip comprises;
a transmit unit configured to provide the output current to the resonance unit through a transmission electrode, wherein the magnitude of the output current corresponds to a power control signal;
a distance estimation unit configured to receive the antenna voltage from the resonance unit through a power electrode, and configured to convert the antenna voltage to a digital value; and
a central processing unit (CPU) configured to detect whether the external card is near the resonance unit based on the digital value, and configured to generate the power control signal based on the digital value in response to the external card being detected near the resonance unit,wherein the transmit unit comprises;
a voltage generation unit configured to generate a transmission supply voltage based on a first power control signal, wherein the power control signal includes the first power control signal and a second power control signal;
first through n-th pull-up transistors coupled in parallel between the transmission supply voltage and the transmission electrode, wherein n is an integer equal to or greater than two;
first through n-th pull-down transistors coupled in parallel between a ground voltage and the transmission electrode; and
a driving unit configured to select k pull-up transistors and k pull-down transistors from among the first through n-th pull-up transistors and the first through n-th pull-down transistors based on the second power control signal,wherein the driving unit is further configured to turn off the first through n-th pull-down transistors and unselected (n-k) pull-up transistors and turn on the selected k pull-up transistors, or turn off the first through n-th pull-up transistors and the unselected (n-k) pull-down transistors and turn on the selected k pull-down transistors based on output data, wherein k is a positive integer equal to or less than n.
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Abstract
A near field communication (NFC) device includes a resonance unit and an NFC chip. The resonance unit emits an electromagnetic wave to communicate data with an external NFC card in a reader mode. The NFC chip estimates a distance between the resonance unit and the external NFC card based on an antenna voltage generated by the resonance unit while the resonance unit emits the electromagnetic wave, and adjusts a magnitude of the electromagnetic wave based on the estimated distance.
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Citations
14 Claims
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1. A near field communication (NFC) device, comprising:
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a resonance unit configured to emit an electromagnetic wave to communicate data with an external card in a reader mode; and an NFC chip configured to estimate a distance between the NFC device and the external card based on an antenna voltage generated by the resonance unit while the resonance unit emits the electromagnetic wave, and configured to adjust a magnitude of the electromagnetic wave based on the estimated distance, wherein the NFC chip is configured to provide an output current to the resonance unit, the resonance unit is configured to emit the electromagnetic wave, wherein the magnitude of the electromagnetic wave corresponds to the output current, and the NFC chip is configured to measure the antenna voltage while the resonance unit emits electromagnetic wave and adjust a magnitude of the output current based on a magnitude of the antenna voltage, wherein the NFC chip comprises; a transmit unit configured to provide the output current to the resonance unit through a transmission electrode, wherein the magnitude of the output current corresponds to a power control signal; a distance estimation unit configured to receive the antenna voltage from the resonance unit through a power electrode, and configured to convert the antenna voltage to a digital value; and a central processing unit (CPU) configured to detect whether the external card is near the resonance unit based on the digital value, and configured to generate the power control signal based on the digital value in response to the external card being detected near the resonance unit, wherein the transmit unit comprises; a voltage generation unit configured to generate a transmission supply voltage based on a first power control signal, wherein the power control signal includes the first power control signal and a second power control signal; first through n-th pull-up transistors coupled in parallel between the transmission supply voltage and the transmission electrode, wherein n is an integer equal to or greater than two; first through n-th pull-down transistors coupled in parallel between a ground voltage and the transmission electrode; and a driving unit configured to select k pull-up transistors and k pull-down transistors from among the first through n-th pull-up transistors and the first through n-th pull-down transistors based on the second power control signal, wherein the driving unit is further configured to turn off the first through n-th pull-down transistors and unselected (n-k) pull-up transistors and turn on the selected k pull-up transistors, or turn off the first through n-th pull-up transistors and the unselected (n-k) pull-down transistors and turn on the selected k pull-down transistors based on output data, wherein k is a positive integer equal to or less than n. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An electronic system, comprising:
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a near field communication (NFC) device configured to communicate with an external device through NFC; a memory device configured to store output data and input data; and an application processor configured to control operations of the NFC device and the memory device, wherein the NFC device comprises; a resonance unit configured to emit an electromagnetic wave to transmit the output data to the external device and to receive the input data from the external device in a reader mode; and an NFC chip configured to estimate a distance between the resonance unit and the external device based on an antenna voltage generated by the resonance unit while the resonance unit emits the electromagnetic wave, and configured to adjust a magnitude of the electromagnetic wave based on the estimated distance, wherein the NFC chip is configured to provide an output current to resonance unit, the resonance unit is configured to emit the electromagnetic wave wherein the magnitude of the electromagnetic wave corresponds to the output current, and the NFC chip is configured to measure the antenna voltage while the resonance unit emits the electromagnetic wave and adjust a magnitude of the output current based on a magnitude of the antenna voltage, wherein the NFC chip comprises; a transmit unit configured to provide the output current to the resonance unit through a transmission electrode, wherein the magnitude of the output current corresponds to a power control signal; a distance estimation unit configured to receive the antenna voltage from the resonance unit through a power electrode, and configured to convert the antenna voltage to a digital value; and a central processing unit (CPU) configured to detect whether the external device is near the resonance unit based on the digital value, and configured to generate the power control signal based on the digital value in response to the external device being detected near the resonance unit, wherein the transmit unit comprises; a voltage generation unit configured to generate a transmission supply voltage based on a first power control signal, wherein the power control signal includes the first power control signal and a second power control signal; first through n-th pull-up transistors coupled in parallel between the transmission supply voltage and the transmission electrode, wherein n is an integer equal to or greater than two; first through n-th pull-down transistors coupled in parallel between the ground voltage and the transmission electrode; and a driving unit configured to select k pull-up transistors and k pull-down transistors from among the first through n-th pull-up transistors and the first through n-th pull-down transistors based on the second power control signal, wherein the driving unit is further configured to turn off the first through n-th pull-down transistors and unselected (n-k) pull-up transistors and turn on the selected k pull-up transistors, or turn off the first through n-th pull-up transistors and the unselected (n-k) pull-down transistors and turn on the selected k pull-down transistors based on output data, wherein k is a positive integer equal to or less than n. - View Dependent Claims (14)
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Specification