Patent application number | Description | Published |
20090121909 | DYNAMIC ELEMENT-MATCHING METHOD, MULTI-BIT DAC USING THE METHOD, AND DELTA-SIGMA MODULATOR AND DELTA-SIGMA DAC INCLUDING THE MULTI-BIT DAC - Provided are a dynamic element-matching method, a multi-bit Digital-to-Analog Converter (DAC), and a delta-sigma modulator with the multi-bit DAC and delta-sigma DAC with the multi-bit DAC. The dynamic element-matching method relates to preventing periodic signal components (in-band tones) from being generated from a delta-sigma modulator of a delta-sigma Analog-to-Digital Converter (ADC) and a multi-bit DAC used in a delta-sigma DAC. Unit elements are selected in a new sequence according to a simple algorithm every time that each of unit elements is selected once, and thus the unit elements are not periodically used. Consequently, it is possible to prevent in-band tones caused by a conventional Data Weighted Averaging (DWA) algorithm. | 05-14-2009 |
20090128230 | BAND-GAP REFERENCE VOLTAGE GENERATOR FOR LOW-VOLTAGE OPERATION AND HIGH PRECISION - Provided is a band-gap reference voltage generator for low-voltage operation and high precision. The band-gap reference voltage generator minimizes voltage drop by connecting resistors in parallel to bipolar transistors, and cancels temperature dependence by properly adjusting a resistor of an output stage, so that it can provide a stable reference voltage that is unaffected by a change in temperature in spite of a low power supply voltage. Further, the band-gap reference voltage generator minimizes variation of the reference voltage caused by offset noise by switching of input and output voltages at input and output stages of a feedback amplifier, so that it can provide a precise reference voltage. | 05-21-2009 |
20100090756 | SWITCHED CAPACITOR CIRCUIT WITH REDUCED LEAKAGE CURRENT - Provided is a switched capacitor circuit which prevents leakage current by equalizing voltages at nodes where leakage current tends to flow in a sampling mode, and prevents errors in an output signal by minimizing voltage drop caused by leakage current in an integrating mode. | 04-15-2010 |
20100156534 | GAIN CONTROL DEVICE AND AMPLIFIER USING THE SAME - Provided are a gain control device and an amplifier using the gain control device. The gain control device includes a first input resistance unit having a first variable resistor whose resistance is linearly variable and a first fixed resistor respectively receiving a first input signal and a second input signal having a sign different from the first input signal and outputting current through a first output terminal, and a second input resistance unit having a second fixed resistor and a second variable resistor whose resistance is linearly variable respectively receiving the first input signal and the second input signal and outputting current through a second output terminal. | 06-24-2010 |
20100156686 | PULSE GENERATOR AND CONTINUOUS-TIME SIGMA-DELTA MODULATOR - Provided is a clock generator employed in a continuous-time sigma-delta modulator. The clock generator includes an oscillator configured to generate pulses in response to an enable signal, a counter configured to count the number of pulses generated by the oscillator and output the total pulse count, and an output circuit configured to output an inactivated output signal if the pulse count of the counter is equal to a pulse-width control bit. The oscillator includes an astable multi-vibrator. Since the astable multi-vibrator capable of generating a low-jitter pulse from a jittered clock is used as the oscillator, a signal-to-noise ratio is improved. A simple configuration using only digital circuits makes it easier to design a circuit and adjust pulse width. Moreover, according to the structure of the astable multi-vibrator, it is possible to design a circuit to optimally modulate pulse width in connection with process variations of resistors and capacitors used in the continuous-time sigma-delta modulator. | 06-24-2010 |
20100158277 | READ-OUT CIRCUIT WITH HIGH INPUT IMPEDANCE - Provided is a read-out circuit that is connected to a microphone and configured to linearly amplify a current signal generated by the microphone and output the amplified current signal. The read-out circuit includes an amplification unit and a feedback resistor. The amplification unit has an amplification gain between 0 and 1. The feedback resistor is connected between input and output terminals of the amplification unit. As the amplification gain of the amplification unit becomes closer to 1, an input impedance becomes higher. A preamp of the read-out circuit can have a high input impedance due to the amplification gain, and the read-out circuit can be manufactured using a CMOS process. | 06-24-2010 |
20110025537 | ACTIVE RESISTANCE-CAPACITOR INTEGRATOR AND CONTINUOUS-TIME SIGMA-DELTA MODULATOR WITH GAIN CONTROL FUNCTION - Provided are an active resistance-capacitance (RC) integrator and a continuous-time sigma-delta modulator, which have a gain control function. The active RC integrator includes an amplifier, a first base resistor connected between a first input node and a positive input port of the amplifier, a second base resistor connected between a second input node and a negative input port of the amplifier, a first resistor unit connected between the second input node and the positive input port of the amplifier, and a second resistor unit connected between the first input node and the negative input port of the amplifier. A resistor network including resistors and switches is configured to vary an input resistance, so that an active RC integrator may have a gain control function. | 02-03-2011 |
20110140940 | COEFFICIENT MULTIPLIER AND DIGITAL DELTA-SIGMA MODULATOR USING THE SAME - Provided are a coefficient multiplier and digital delta-sigma modulator using the same. The coefficient multiplier has the average of output signals of respective dependent multipliers as an effective coefficient using a coefficient averaging technique without employing an adder that has a complex structure and occupies a large chip area. Accordingly, the coefficient multiplier has a simple hardware constitution and small chip area in comparison with a canonical signed digit (CSD) coefficient multiplier, and the digital delta-sigma modulator employing the coefficient multiplier has a simple structure and small size. | 06-16-2011 |
20120098688 | CLOCK TIMING ADJUSTMENT DEVICE AND CONTINUOUS TIME DELTA-SIGMA MODULATOR USING THE SAME - Provided is a clock timing adjustment device for adjusting a time difference of clocks and a delta-sigma modulator. The clock timing adjustment device includes a power detection unit and a timing adjustment unit. The power detection unit receives input signals which are generated using pairs of first and second clocks having a plurality of clock time differences and respectively correspond to the clock time differences, detects powers of the input signals, and outputs a control signal corresponding to a clock time difference where the power is minimized. The timing adjustment unit receives a reference clock and the control signal and outputs the first and second clocks having the clock time difference where the power is minimized from the reference clock according to the control signal. | 04-26-2012 |
20120154028 | BIAS CIRCUIT AND ANALOG INTEGRATED CIRCUIT COMPRISING THE SAME - Disclosed is a bias circuit which includes a bias voltage generating part configured to generate a bias voltage using a reference current and a variable current; a reference current source part configured to provide the reference current to the bias voltage generating part; and a current adjusting part configured to provide the variable current to the bias voltage generating part and to adjust the amount of the variable current according to voltage levels of at least two input signals. The bias circuit prevents an increase in power consumption and improves a slew rate at the same time. | 06-21-2012 |
20120154189 | CURRENT SWITCH DRIVING CIRCUIT AND DIGITAL TO ANALOG CONVERTER - Provided are a current switch driving circuit generating a signal for driving a current switch, and a digital-to-analog converter using the same. The current switch driving circuit includes a first PMOS transistor in which a source terminal is connected to a power supply terminal, a gate terminal receives an input signal, and a drain terminal outputs a driving signal, an NMOS transistor in which a drain terminal is connected to the drain terminal of the first PMOS transistor, and a gate terminal receives the input signal, a second PMOS transistor in which a source terminal is connected to a source terminal of the NMOS transistor, a gate terminal is connected to a bias voltage terminal, and a drain terminal is connected to a ground terminal, and a control current source allowing the second PMOS transistor to be maintained constantly in an ON state. | 06-21-2012 |
20130099868 | SOUND DETECTING CIRCUIT AND AMPLIFIER CIRCUIT THEREOF - Disclosed is a sound detecting circuit which includes a sensing unit configured to generate an AC signal in response to a sound pressure level of a sound signal; an amplification unit configured to amplify the AC signal; and a bias voltage generating unit configured to generate a bias voltage to be provided to the amplification unit. The bias voltage generating unit comprises a current source configured to provide a power current; and a current-voltage converting circuit configured to convert the power current into the bias voltage and to reduce a noise due to the power current. | 04-25-2013 |
20130148456 | VOLTAGE REGULATOR WITH IMPROVED LOAD REGULATION AND VOLTAGE REGULATING METHOD - Provided is a voltage supply circuit using a charge pump. The voltage supply circuit enhances charge pump output voltage fluctuation characteristics depending on load variation of a charge pump voltage generator (load regulation characteristics) when receiving an operation power supply voltage of the charge pump through a regulator. The voltage supply circuit is configured to feed back fluctuation of a charge pump output voltage to a charge pump voltage regulator. The fluctuation of the charge pump output voltage is compensated through fluctuation of an output voltage of the charge pump to active enhance the load regulation characteristics. | 06-13-2013 |
20140079254 | MEMS MICROPHONE USING NOISE FILTER - An MEMS microphone is provided which includes a reference voltage/current generator configured to generate a DC reference voltage and a reference current; a first noise filter configured to remove a noise of the DC reference voltage; a voltage booster configured to generate a sensor bias voltage using the DC reference voltage the noise of which is removed; a microphone sensor configured to receive the sensor bias voltage and to generate an output value based on a variation in a sound pressure; a bias circuit configured to receive the reference current to generate a bias voltage; and a signal amplification unit configured to receive the bias voltage and the output value of the microphone sensor to amplify the output value. The first noise filter comprises an impedance circuit; a capacitor circuit connected to a output node of the impedance circuit; and a switch connected to both ends of the impedance circuit. | 03-20-2014 |
20140132326 | PULSE NOISE SUPPRESSION CIRCUIT AND PULSE NOISE SUPPRESSION METHOD THEREOF - Provided is a pulse noise suppression circuit. The pulse noise suppression circuit includes a filter circuit converting an input signal of a pulse type into an increasing or decreasing filter signal, a level reset circuit resetting the filter signal in response to the input signal and an output signal and an output circuit converting the filter signal into the output signal of a pulse type, wherein the level reset circuit resets the filter signal to have a high level when the input signal and the output signal all have a high level, and resets the filter signal to have a low level when the input signal and the output signal all have a low level. | 05-15-2014 |