Abstract: A reference voltage generating circuit with ultra-low power consumption, which includes: a constant current circuit part generating a first constant current from a supply voltage; a current mirror circuit part mirroring the constant current and supplying a second constant current; a voltage control circuit part receiving the second constant current and generating a first reference voltage by using substrate transistors driven by a PTAT (Proportional To Absolute Temperature) voltage and MOS transistors driven by a CTAT (Complementary To Absolute Temperature) voltage; and an output circuit part amplifying an output voltage from the voltage control circuit part to generate second to fourth reference voltages, and feeding back at least one of the second to fourth reference voltages to the voltage control circuit part so that the magnitude of an output voltage is adjusted.

Abstract: Provided are a schottky diode having an appropriate low breakdown voltage to be used in a radio frequency identification (RFID) tag and a method for fabricating the same. The schottky diode includes a silicon substrate having a structure in which an N-type well is formed on a P-type substrate, an insulating layer surrounding a circumference of the N-type well so as to electrically separate the N-type well from the P-type substrate, an N+ doping layer partly formed in a portion of a region of an upper surface of the N-type well, an N? doping layer partly formed in the other portion of a region of the upper surface of the N-type well, a cathode formed on the N+ doping layer, and an anode formed on the N? doping layer.

Abstract: A planar small antenna and a small strip radiator are provided which have increased bandwidth. The small strip radiator has a main strip pattern and a plurality of convoluted strip patterns terminating the main strip pattern at each end. The plurality of convoluted strip patterns are arranged in mirror-symmetrical arrangement with reference to the longitudinal axis of the main strip such that one pair of convoluted strip patterns is convoluted clockwise while another pair is convoluted counterclockwise. As a result, an electrically small antenna radiator requires less metal or conductive material than conventional radiators, and also can operate without adversely affecting the radiation characteristics of the antenna.

Abstract: A capacitive type temperature sensor includes a first electrode layer, a second electrode layer, a dielectric layer positioned between the first and second electrode layers and having a dielectric of which a volume is changed in response to a temperature change, and a temperature calculation unit calculating a temperature corresponding to an electric potential difference between the first and second electrode layers. Accordingly, the capacitive type temperature sensor has a good sensitivity of measuring the temperature and a good accuracy, does not consume a large amount of power, and allows a process of fabricating the same to be simplified.

Abstract: A small rectenna including a thin conductive layer formed on a surface of a dielectric substrate and a slot pattern arranged within the thin conductive layer. The small rectenna for an RFID transponder includes: a dielectric substrate; a thin conductive layer formed on a surface of the dielectric substrate; a slot pattern configured within the thin conductive layer so that the rectenna has an enhanced gain and a greater operating bandwidth; and an inlet of an electronic chip including an ASIC in the slot pattern.

Abstract: A radio frequency identification tag, used in a radio frequency identification system, includes an antenna unit for receiving an external magnetic wave to generate an induced current; a driving voltage generating unit for converting the induced current into a constant voltage and outputting the constant voltage; and a state detecting unit for detecting information about a change in an operational state of the driving voltage generating unit. The tag further includes a memory for storing temperature data corresponding to the information about the change in the operational state and data needed for identification; and a controlling unit for reading out, from the memory, the temperature data dependent on the information about the change in the operational state detected by the state detecting unit and the identification data. The read temperature and identification data are transmitted via an antenna unit.

Abstract: A small planar antenna with an enhanced bandwidth and a small rectenna for RFID (Radio Frequency Identification) and wireless sensor transponder are provided. The small planar antenna includes a dielectric substrate, a metal layer formed on an upper part of the dielectric substrate, a main slot formed in pattern on the metal layer, and a plurality of sub-slots connected to the main slot and winding in a specified direction, and the plurality of sub-slots form a pair of symmetric sub-slot groups around the main slot. According to the small planar antenna, the antenna region that substantially takes part in the radiation is substantially increased, and thus an enhanced bandwidth can be obtained without affecting the radiation pattern, radiation efficiency, polarization purity, etc., of the antenna.

Abstract: A radio frequency identification (RFID) barcode is provided. The RFID barcode includes a plurality of sets of conductive strips and a plurality of inductors, wherein each of the plurality of sets of conductive strips respectively includes a plurality of conductive strips separated by at least one gap, and each of the plurality of inductors is disposed in the at least one gap of a corresponding set of conductive strips and connects two of the plurality of conductive strips of the corresponding set of conductive strips. The sets of conductive strips are arranged in parallel and separated from one another in a predetermined distance. The RFID barcode may further include a dielectric substrate supporting the sets of conductive strips and the inductors, and a metal layer provided on all of a rear surface of the dielectric substrate.

Abstract: A limiter for controlling an overvoltage and an RFID tag having the same are provided. The limiter includes a first limiter part and a second limiter part serially connected to the first limiter part. The second limiter part has at least one limit diode whose threshold voltage is lower than that of elements in the first limiter part. Accordingly, if an overvoltage is input, the limiter can maximize the input current drop so that the limiter can maximize the leakage voltage. As a result, the RFID tag can prevent the RFID driving part from being damaged due to the overvoltage. In addition, the RFID tag can normally operate regardless of the intensity of the driving voltage input from the RFID reader, so that the yields of products can improve.

Abstract: Provided are an RFID tag capable of limiting an over-voltage and a method for controlling an over-voltage thereof. The RFID tag includes: an antenna unit receiving external electromagnetic waves to induce an input voltage; a voltage generator rectifying the input voltage to generate a driving voltage; a voltage limiter adaptively turned on and/or off depending on whether the input voltage is high or low to limit an intensity of the input voltage input into the voltage generator; and a logic controller controlling the antenna unit to generate authentication information based on the driving voltage and transmit the authentication information.

Abstract: A radio frequency identification tag (RFID) that extends a read range of an RFID reader, and an RFID system including the RFID tag. The RFID tag includes a tag antenna, an IC, and a bonding part electrically connecting the tag antenna to the IC. A complex conjugate of an impedance of the tag antenna is a value obtained by adding an impedance of the IC to an impedance of the bonding part. Thus, the RFID tag can achieve accurate impedance matching between the tag antenna and the bonding, smoothly perform data communication with the RFID reader, and extend the read range of the RFID reader.

Abstract: A planar small antenna and a small strip radiator are provided which have increased bandwidth. The small strip radiator has a main strip pattern and a plurality of convoluted strip patterns terminating the main strip pattern at each end. The plurality of convoluted strip patterns are arranged in mirror-symmetrical arrangement with reference to the longitudinal axis of the main strip such that one pair of convoluted strip patterns is convoluted clockwise while another pair is convoluted counterclockwise. As a result, an electrically small antenna radiator requires less metal or conductive material than conventional radiators, and also can operate without adversely affecting the radiation characteristics of the antenna.

Abstract: An over-voltage protection circuit (i.e., a limiter), includes: a first switching block having a plurality of semiconductor elements, serially connected to each other and turned on in sequence according to the magnitude of an input voltage; and a plurality of second switching blocks, in which each of the second switching blocks includes a pair of serially connected semiconductor elements having different current properties. The second switching blocks are connected in parallel to the first switching block. By minimizing a leakage current when an input voltage is below a reference voltage and by maximizing a leakage current when the input voltage is above the reference voltage, the limiter prevents excessive current from flowing into the RF tag circuit when the input voltage is below the reference voltage, and ensures that a sufficient amount of current is supplied to a regulator when the input voltage is below the reference voltage.

Abstract: A radio frequency identification reader and a radio frequency identification tag that use an ultrahigh frequency band, and action methods of the radio frequency identification reader and the radio frequency identification tag. The radio frequency identification reader includes: a data generator generating data to be transmitted to a radio frequency identification tag; if a command to control the radio frequency identification tag has to be authenticated, a reader controller controlling the data generator to generate the data including an authentication code; and a reader transmitter transmitting the data to the radio frequency identification tag. As a result, securing of communications of a specific command between the radio frequency identification reader and the radio frequency identification tag can be reinforced.

Abstract: An ultra low power oscillator includes a current supply unit converting current supplied from an external bias power source into first and second low currents of predetermined amounts, and an oscillation unit oscillating and creating a predetermined frequency signal if the first and second low currents are supplied from the current supply unit. The oscillation unit includes a plurality of inverters connected in series, and the current supply unit includes a current limit circuit composed of NMOS and PMOS transistors connected to the respective inverters. The current flowing when the transistors in the respective inverters are simultaneously turned on is limited, and thus the power consumption can be reduced.

Abstract: A reference voltage generating circuit with ultra-low power consumption, which includes: a constant current circuit part generating a first constant current from a supply voltage; a current mirror circuit part mirroring the constant current and supplying a second constant current; a voltage control circuit part receiving the second constant current and generating a first reference voltage by using substrate transistors driven by a PTAT (Proportional To Absolute Temperature) voltage and MOS transistors driven by a CTAT (Complementary To Absolute Temperature) voltage; and an output circuit part amplifying an output voltage from the voltage control circuit part to generate second to fourth reference voltages, and feeding back at least one of the second to fourth reference voltages to the voltage control circuit part so that the magnitude of an output voltage is adjusted.

Abstract: A low leakage Schottky diode and fabrication method thereof. The Schottky diode includes a n-type semiconductor; an anode having a circular periphery formed in a region above the n-type semiconductor; and a cathode formed in a region above the n-type semiconductor and having a pattern surrounding and set apart from the outer periphery of the anode. Because there are no edges at the anode and cathode interface, leakage current is minimized.

Abstract: Disclosed is a rectifier for supplying double voltage and an RFID tag thereof. The rectifier includes a charging part for charging an input voltage induced to input ends by a received radio frequency (RF) signal; a power provider for charging a sum voltage corresponding to the sum of the input voltage induced to the input end and the voltage charged in the charging part as a power voltage, and discharging the charged power voltage to provide a direct current (DC) power; and a switching part for switching to supply the input voltage induced at the input ends to the charging part during a first interval and switching to supply the sum voltage to the power provider during a second interval. Accordingly, double voltage can be supplied to other electric elements formed in the RFID tag and overcurrent caused by overvoltage can be prevented from flowing into the elements.

Abstract: A voltage transform circuit transforms a transferred voltage to a desired magnitude of voltage. The voltage transform circuit includes: a first power supply unit for providing a digital voltage (Vdd-1) of a first magnitude; a second power supply unit for providing an analog voltage (Vaa-2) of a second magnitude; and a voltage transform unit formed with a plurality of MOS transistors, wherein the MOS transistors operate to transfer the digital voltage (Vdd-1) from the first power supply unit, and output a digital voltage (Vdd-3) of a third magnitude corresponding to the analog voltage (Vaa-2) transferred from the second power supply unit. By using an analog voltage (Vaa-2) that is higher than the digital voltage (Vdd-1), it becomes possible to increase the magnitude of the output digital voltage (Vdd-3). By supplying this high digital voltage (Vdd-3) to a charge pump, the level of the charge pump is lowered.

Abstract: A semiconductor device using schottky diodes for removing noise, a fabrication method, and an electrostatic discharge prevention device are provided. The semiconductor device includes a P-well substrate; insulation layers deposited on etched regions of the substrate; an N-well layer deposited on an etched region of the P-well substrate between the insulation layers; P+ type implants injected to a first region and a second region of the N-well layer; and first and second metals formed in schottky contact on the first and second regions, respectively. The method includes etching away regions of a P-well substrate and depositing an insulation substance; etching away the P-well substrate and depositing the insulation substance between the insulation layers to create an N-well layer; injecting P+ type implants to a first region and a second region of the N-well layer; and forming first and second metals in schottky contact on the first and second regions, respectively.