Abstract: The present invention relates to a broadband voltage controlled oscillator and a method for generating a broadband oscillation frequency; and, more particularly, to a broadband voltage controlled oscillator and a method for generating a broadband oscillation frequency capable of operating over a wide frequency band by including a weighted current cell to select two frequency band modes, generating various levels of total 64 oscillation frequencies by including a variable frequency tank and a capacitor bank, and further facilitating adjustment of the total 64 oscillation frequencies distributed over the wide frequency band by including a control signal generator for generating control signals each of which is applied to the weighted current cell, the variable frequency tank and the capacitor bank by a BDD(Binary Decision Diagram) technique.

Abstract: Provided is a low-power radio frequency (RF) direct current (DC) rectifier. The low-power RF DC rectifier includes a rectification circuit with first and second to n-th rectification units sequentially rectifying an RF signal input through a first input terminal and a second input terminal. The first rectification unit is disposed between the first and second input terminals and a first output terminal of the first rectification unit. The second rectification unit is disposed between the first rectification unit and a second output terminal of the second rectification unit, is biased by the first rectification unit. The n-th rectification unit is disposed between an immediately previous rectification unit and a rectification output terminal of the rectification circuit, is biased by a rectified voltage output from an immediately preceding rectification unit, and outputs the rectified RF signal through the rectification output terminal.

Abstract: A micropower RC oscillator comprises a current generating section including a current source that generates a current; and a variable resistor of which the magnitude is variably set and which is configured by combining resistor elements at a predetermined ratio, the resistor elements having opposite characteristics to each other with respect to a temperature change, the variable resistor adjusting the magnitude of the generated current; a start-up circuit section connected to the current generating section and fixing a bias operating point to a constant value such that the current generating section stably generates a current; a charge and discharge circuit section including a variable capacitor, of which the magnitude is variably set, and a plurality of transistors, the charge and discharge circuit section charging and discharging the variable capacitor by using the current generated from the current generating section and the plurality of transistors; an oscillation signal output section connected to the ch

Abstract: An antenna diversity receiver includes a plurality of antennas, an antenna selector unit, an RF module unit, a logic gate unit, a power detector unit, and a selection controller unit. The antenna selector unit selects one of the antennas. The RF module unit converts an RF RX signal received from the antenna selector unit into a baseband RX signal. The logic gate unit controls a power detection mode for detecting the power levels of RX signals and an operation mode for selecting one of the antennas. The power detector unit detects the power level of the RX signal. The selection controller unit controls the antenna selector unit to sequentially select the antennas in the power detection mode, and controls the antenna selector unit to select the antenna with a relatively good RX sensitivity among the antennas.

Abstract: Provided is an apparatus for controlling lighting brightness through PFM, the apparatus including a lighting control unit that generates a control signal for controlling the brightness of a plurality of lightings; a PFM signal generating unit that is controlled by the control signal so as to generate a plurality of PFM signals having a different frequency from each other; and a driving voltage generating unit that composes the generated PFM signals in accordance with a preset combination, thereby generating driving voltages for driving the lightings.

Abstract: An oscillation stabilization detecting circuit comprises a T flip flop receiving a pulse-type oscillation signal generated by oscillating a crystal oscillator and then dividing the oscillation signal to output; a pulse control unit including inverters and transistors, the pulse control unit converting the signal output from the T flip flop into a pulse-type signal starting from a high level and then outputting the converted signal; and an oscillation stabilization detecting unit including a capacitor charged with the signal output from the pulse control unit; and a plurality of transistors. The oscillation stabilization detecting unit controls charging time of the capacitor by adjusting a bias current and, after the charging time passes, outputs a stabilization signal to a CPU, the stabilization signal representing that the oscillation signal is stabilized.

Abstract: The invention relates to a frequency divider operated digitally and capable of satisfying the Zigbee standard, and a phase locked loop system using the same. The frequency divider includes a plurality of latches in a ring structure with an output of a latter end latch is connected to an input of a former end latch. The frequency divider also includes an input end connected in common to clock ends of the latches, receiving a signal to be divided, and a plurality of output ends connected to the output ends of the latches, outputting divided signals of different phases. The phase locked loop system of the invention has a dividing means dividing an output frequency by 1/P and 1/P+0.5 using the frequency divider, thereby generating the Zigbee channel frequencies at a 5 MHz spacing.

Abstract: There is provided a sleep current adjusting circuit of a system on chip including: a regulator supplying a turn-on voltage and a normal current when a mode selection signal is a normal mode signal, and a turn-off voltage when the mode selection signal is a sleep mode signal; a switching device turned on by the turn-on voltage of the regulator to supply the normal current from the regulator to a main circuit part and a sleep operation circuit part, respectively, and turned off by the turn-off voltage of the regulator to block the normal current from being supplied to the main circuit part and supply the sleep current to the sleep operation circuit part; and a current limit device limiting an operating current flowing in response to the operating voltage and supplying the sleep current to the sleep operation circuit part.

Abstract: In a voltage controlled oscillator, a resonant circuit generates a resonant frequency in response to a tuning voltage. A differential oscillator includes first and second transistors differentially cross-coupled to the resonant circuit. The first and second transistors supply energy to the resonant circuit to oscillate the resonant frequency from the resonant circuit, thereby generating first and second oscillation signals having a phase difference of 180 degree. Also, the first and second transistors adjust the first and second oscillation signals to a uniform level in response to a body bias voltage. In addition, an output level detector detects a level of the first and second oscillation signals from the differential oscillator and supplies the body bias voltage corresponding to the detected level to a body of each of the first and second transistors.

Abstract: A micropower RC oscillator comprises a current generating section including a current source that generates a current; and a variable resistor of which the magnitude is variably set and which is configured by combining resistor elements at a predetermined ratio, the resistor elements having opposite characteristics to each other with respect to a temperature change, the variable resistor adjusting the magnitude of the generated current; a start-up circuit section connected to the current generating section and fixing a bias operating point to a constant value such that the current generating section stably generates a current; a charge and discharge circuit section including a variable capacitor, of which the magnitude is variably set, and a plurality of transistors, the charge and discharge circuit section charging and discharging the variable capacitor by using the current generated from the current generating section and the plurality of transistors; an oscillation signal output section connected to the ch

Abstract: An oscillation stabilization detecting circuit comprises a T flip flop receiving a pulse-type oscillation signal generated by oscillating a crystal oscillator and then dividing the oscillation signal to output; a pulse control unit including inverters and transistors, the pulse control unit converting the signal output from the T flip flop into a pulse-type signal starting from a high level and then outputting the converted signal; and an oscillation stabilization detecting unit including a capacitor charged with the signal output from the pulse control unit; and a plurality of transistors. The oscillation stabilization detecting unit controls charging time of the capacitor by adjusting a bias current and, after the charging time passes, outputs a stabilization signal to a CPU, the stabilization signal representing that the oscillation signal is stabilized.

Abstract: A sub-harmonic frequency conversion device includes: a voltage controlled oscillator for generating first to eighth oscillation frequency (LO) signals having a constant phase difference; a first mixer for performing a switching operation to mix the first to fourth LO signals having a phase difference of 90° and input signals, and outputting first IF signals; and a second mixer for performing a switching operation to mix the fifth to eighth LO signals having a phase difference of 90° and the input signals, and outputting second IF signals. Accordingly, the sub-harmonic frequency conversion device can use the low-frequency LO signal, and the power consumption can be reduced. In addition, because the mixers are implemented using a symmetric structure of the MOS transistors, the circuit configuration can be easily implemented.

Abstract: In a voltage controlled oscillator, a resonant circuit generates a resonant frequency in response to a tuning voltage. A differential oscillator includes first and second transistors differentially cross-coupled to the resonant circuit. The first and second transistors supply energy to the resonant circuit to oscillate the resonant frequency from the resonant circuit, thereby generating first and second oscillation signals having a phase difference of 180 degree. Also, the first and second transistors adjust the first and second oscillation signals to a uniform level in response to a body bias voltage. In addition, an output level detector detects a level of the first and second oscillation signals from the differential oscillator and supplies the body bias voltage corresponding to the detected level to a body of each of the first and second transistors.