Patent application number | Description | Published |
20100181978 | Booster circuit and PWM signal generator - A PWM signal generator used for a booster circuit including a voltage-boosting coil that is connected to a main power supply, and a driving transistor that drives the voltage-boosting coil to generate boosted voltage, the PWM signal generator including a first amplifier that generates intermediate voltage based on a voltage value of the boosted voltage, a triangular wave generator that generates a triangular wave signal, a comparator that compares a voltage level of the intermediate voltage with a voltage level of the triangle wave signal to generate an intermediate PWM signal, a driver that generates a PWM signal supplied to the driving transistor based on the intermediate PWM signal, and a second amplifier that generates a driver power supply supplied to the driver based on magnitude of a voltage value of the intermediate voltage. | 07-22-2010 |
20100277226 | Boost circuit and liquid crystal display device using boost circuit - A charge pump circuit has boost capacitors and a charge switch supplying supply voltage to the boost capacitors, and a step-up ratio thereof is variable by switching a connection relationship of the boost capacitors. A control circuit unit controls switching of the step-up ratio and selects first operation or second operation depending on a sum-based voltage corresponding to a sum of the supply voltage and a under-charge boost capacitor voltage. The first operation is to turn ON/OFF the charge switch in synchronization with a boost clock signal, while the second operation is to turn OFF it irrespective of the boost clock signal. A value of the sum-based voltage with which the first and second operations are switched is a reference value. When switching the step-up ratio from a first ratio to a second ratio lower than the first ratio, the control circuit unit switches the reference value from a first value corresponding to the first ratio to a second value corresponding to the second ratio, and then switches the connection relationship. | 11-04-2010 |
20110084675 | BOOSTER CIRCUIT - A booster circuit according to the present invention includes a booster that connects a boosting condenser that is charged and a direct-current power source in series through a switch for a boosting operation in order to generate a boosted voltage and charges a smoothing condenser with the boosted voltage through a switch for an outputting operation. The switch for the boosting operation is composed of a plurality of switches connected in parallel and at least one of the plurality of switches can be controlled independently. | 04-14-2011 |
20110141092 | DIFFERENTIAL AMPLIFIER AND CONTROL METHOD FOR THE SAME - A liquid crystal display apparatus includes a signal generating circuit configured to generate a first control signal and a second control signal; and a differential amplifier. The differential amplifier includes: a first differential pair of transistors configured to receive a differential input signal; a first constant current source connected with said first differential pair of transistors; and a first switch connected in parallel with said first constant current source and configured to increase current which flows through said first differential pair of transistors, in response to said first control signal which is active for a first time period in a level transition of said differential input signal. | 06-16-2011 |
20110199157 | DIFFERENTIAL AMPLIFIER, METHOD FOR INVERTING OUTPUT POLARITY OF THE SAME, AND SOURCE DRIVER - A differential amplifier includes: an output amplifier circuit; a bias circuit; and a pulse applying circuit. The output amplifier circuit receives a positive gradation voltage and a negative gradation voltage alternately by an input stage circuit and supplies a drive voltage generated based on the gradation voltage to a display panel. The bias circuit generates a bias voltage in synchronization with a strobe signal which is a trigger for a polarity inverting operation of the gradation voltage and applies the bias voltage to a constant current source controlling a current of the input stage circuit. The pulse applying circuit generates a pulse voltage having a voltage level higher than a voltage level of the bias voltage and couples the pulse voltage to the bias voltage. | 08-18-2011 |
20120019502 | SOURCE DRIVER FOR A LIQUID CRYSTAL DISPLAY DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE USING THE SAME - In a source driver for a liquid crystal display device, a slew rate is increased while an increase in power consumption is suppressed. The source driver for a liquid crystal display device includes multiple output amplifiers that drive multiple data lines in response to an input signal, and a bias control circuit having a dummy amplifier consistent with an electric characteristic of the output amplifiers. The bias control circuit controls high bias periods of the output amplifiers on the basis of an output transition period of the dummy amplifier when the dummy amplifier receives voltages of a γ resistor circuit, which are input to the output amplifiers. | 01-26-2012 |
20120092322 | LIQUID CRYSTAL DISPLAY DRIVE CIRCUIT AND METHOD FOR DRIVING SAME - A liquid crystal display drive circuit includes first and second buffer circuits, first to fourth switches, and a control signal generation circuit (CSGC). The first buffer circuit drives a first or second data line, and the second buffer circuit drives the second or first data line. Closing the first switch makes the first buffer circuit drive the first data line responsive to a first control signal. Closing the second switch makes the second buffer circuit drive the second data line. Closing the third switch makes the first buffer circuit drive the second data line in responsive to a second control signal. Closing the fourth switch is makes the second buffer circuit drive the first data line. The CSGC generates the first-third control signals for causing respective outputs of the first buffer circuit, and the second buffer circuit to be in high impedance state on the basis of a strobe signal. | 04-19-2012 |
20130002644 | DIFFERENTIAL AMPLIFIER, METHOD FOR INVERTING OUTPUT POLARITY OF THE SAME, AND SOURCE DRIVER - A differential amplifier includes: an output amplifier circuit; a bias circuit; and a pulse applying circuit. The output amplifier circuit receives a positive gradation voltage and a negative gradation voltage alternately by an input stage circuit and supplies a drive voltage generated based on the gradation voltage to a display panel. The bias circuit generates a bias voltage in synchronization with a strobe signal which is a trigger for a polarity inverting operation of the gradation voltage and applies the bias voltage to a constant current source controlling a current of the input stage circuit. The pulse applying circuit generates a pulse voltage having a voltage level higher than a voltage level of the bias voltage and couples the pulse voltage to the bias voltage. | 01-03-2013 |
20130335050 | SWITCHING REGULATOR CONTROL CIRCUIT - In the related art, there is a problem that the condition of a load is monitored in an indirect manner so that an efficiency enhancing effect is not obtained. A switching regulator control circuit includes an oscillator for generating a carrier signal and a transistor drive circuit for driving a switching transistor and a synchronous rectification transistor based on a PWM signal generated based on the carrier signal. The oscillator switches the frequency of the carrier signal based on the direction of a source-drain voltage of the synchronous rectification transistor. | 12-19-2013 |