The present disclosure discloses an electronic tag and a control method thereof. The electronic tag comprises: a power supply module configured to supply power to the electronic tag; a display module configured to display a display screen required by the electronic tag; an electronic tag circuit configured to control the electronic tag to operate in a state that the electronic tag is powered by the power supply module; and a switch circuit configured to disconnect the power supply module from the electronic tag circuit when the display screen does not need to be updated.

A wireless communication device includes: an antenna for transmitting and receiving a radio wave, a rectifying circuit that is connected to the antenna and rectifies the radio wave received by the antenna to generate voltage, an internal circuit that operates by the voltage generated by the rectifying circuit, and a switch circuit that is disposed contactlessly with respect to the antenna and operates on the basis of an output signal of the internal circuit, wherein the switch circuit includes a coupling wiring and a switch element, and the operation of the switch element varies the impedance of the antenna so that communication can be carried out.

To prevent damage on an element even when a voltage high enough to break the element is input. A semiconductor device of the invention operates with a first voltage and includes a protection circuit which changes the value of the first voltage when the absolute value of the first voltage is higher than a reference value. The protection circuit includes: a control signal generation circuit generating a second voltage based on the first voltage and outputting the generated second voltage; and a voltage control circuit. The voltage control circuit includes a transistor which has a source, a drain, and a gate, and which is turned on or off depending on the second voltage input to the gate and thus controls whether the value of the first voltage is changed based on the amount of current flowing between the source and the drain. The transistor also includes an oxide semiconductor layer.

An interface device for providing Intrinsic Safety to a Smart Identity Module (SIM) card includes a buffer circuit including a voltage regulator and a voltage level translator including drivers. Baseband processor side pins include at least an input/output (IO) pin for receiving data signals, first SIM reset (RST) pin, core power supply (VCC) pin, a clock (CLK) pin, a battery power supply (VBAT) pin, and SIM side pins include at least a VCC pin, a SIM CLK pin, second SIM RST pin, and a SIM IO pin. There is at least one series resistor (R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5) in series with each of the baseband processor side pins.

An example wireless power transmitter includes a ground plate, a conductive wire offset from the ground plate, and a signal-conveyance member. The conductive wire of the wireless power transmitter forms a loop antenna that is configured to radiate a radio frequency (RF) signal for wirelessly powering a receiver device. And the signal-conveyance member of the wireless power transmitter is configured to selectively feed a waveform to a connection point of a plurality of connection points along the conductive wire, wherein the waveform, when provided to the conductive wire, causes the loop antenna to radiate the RF signal.

Provided is a smart card that can prevent malfunction in the smart card and improve stability of radio frequency communication by removing interference of an AC signal generated at the antenna terminal of the smart card. The smart card includes: a dual antenna configured of a first antenna and a second antenna for performing radio frequency communication with a card reader; an IC chip electrically connected to the first antenna to perform radio frequency communication through the first antenna; a power generation unit for generating DC power by converting a radio frequency signal received through the second antenna; a control unit for receiving the DC power generated from the power generation unit to control various modules; and a cut-off unit arranged between the first antenna and the IC chip to cut off a radio frequency signal received through the first antenna under the control of the control unit.

An internal voltage generation circuit of a smart card to perform fingerprint authentication and a smart card includes a first contact switch, a second contact switch, a switched capacitor converter and a bidirectional switched capacitor converter. The first contact switch selectively switches a contact voltage to a first node based on a first switching enable signal, in a contact mode. The second contact switch selectively switches the contact voltage to a second node based on a second switching enable signal, in the contact mode. The bidirectional switched capacitor converter steps down a first driving voltage of the first node to provide a second voltage to the second node in the contactless mode and either steps down the first driving voltage or boosts a second driving voltage of the second node based on a level of the contact voltage to provide a boosted voltage to the first node in the contact mode.

A bi-directional voltage converter of a smart card includes switching elements connected between an input node and an output node and a start-up transistors whose channel width over channel length is smaller than a channel width over channel length of the switching element. The bi-directional voltage converter stores a driving voltage applied to an output node in a storage capacitor during a booting operation and provides the voltage stored in the storage capacitor to an input node. The bi-directional voltage converter may boost another driving voltage at the input node step-wisely and may perform bi-directional voltage converting with reduced occupied area and high efficiency.

A smart card with improved power stability is provided. The smart card comprises a rectification signal line through which a rectification signal extracted from a radio frequency (RF) signal is provided; a regulator configured to regulate a voltage of the rectification signal line to a first voltage; a power circuit configured to extract a power component from the rectification signal using an output of the regulator; a logic circuit configured to receive the power component and generate a reception enable signal on the basis of the power component; a demodulator which is enabled by the reception enable signal provided from the logic circuit and configured to extract a signal component from the rectification signal; a capacitor controller which is enabled by the reception enable signal provided from the logic circuit and configured to generate a capacitor enable signal; and a capacitor circuit which is connected to the rectification signal line and has capacitance changed according to the capacitor enable signal.

A fingerprint recognition card is provided to perform authentication and security functions by recognizing a fingerprint of a user and includes a fingerprint recognition unit configured to detect a fingerprint of a user, a control unit configured to perform registration authentication for the detected fingerprint of the user, a communication unit configured to perform tagging to an external reader depending on the registration authentication of the control unit, and an inductive current generator configured to generate an inductive current in response to approaching the external reader. The inductive current generator generates the inductive current when a distance to the external reader is within a predetermined distance, converts the generated inductive current to a direct current (DC), and supplies the output voltage, which is generated by reducing the input voltage of the converted DC, to the fingerprint recognition unit, the control unit, and the communication unit.