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 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: 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: 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 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 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.