Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A display panel drive apparatus is provided with: a drive circuit outputting drive voltages to a display panel in response to a timing control signal used for timing control of image display on the display panel; and a booster circuit feeding a boosted power supply voltage to the drive circuit. The booster circuit includes a charge pump circuit generating the boosted power supply voltage by boosting an input power supply voltage in response to a boosting clock; and a pulse skip circuit monitoring a voltage level of the boosted power supply voltage and controlling an boosting operation of the charge pump circuit in response to the voltage level of the boosted power supply voltage. The pulse skip circuit is configured to allow the charge pump circuit to initiate the boosting operation in synchronization with the timing control signal.

Abstract: 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.

Abstract: A display panel drive apparatus includes a source driver that drives each unit dot in accordance with a time-divisional clock, and a booster circuit that generates a supply voltage to be supplied to the source driver based on a clock having a rising edge and a falling edge each coinciding with an off-period of the time-divisional clock. The display panel drive apparatus performs a time-divisional driving operation during one horizontal period.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 ? resistor circuit, which are input to the output amplifiers.

Abstract: 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.

Abstract: 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.

Abstract: A fuse trimming circuit includes trimming pads, a fuse resistance, an input circuit and current limit units. The fuse resistance is configured to be connected to the trimming pads and blown out by a trimming current which flows through the trimming pads. The input circuit is configured to output one of a first potential and a second potential based on whether or not the fuse resistance is blown out. The current limit units are configured to be provided on paths from one of the trimming pads through the fuse resistance to at least one of a first power line feeding the first potential and a second power line feeding said second potential, and paths from another of the trimming pads through the fuse resistance to said at least one of the first power line and the second power line.

Abstract: 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.

Abstract: A signal line driving circuit according to an exemplary aspect of the present invention includes: a first amplifier; a second amplifier; a first charge share switch connected between an output terminal of the first amplifier and an output terminal of the second amplifier; a first output switch connected between an output node of the first amplifier and the output terminal of the first amplifier; a second charge share switch connected between a node between the first output switch and the output terminal of the first amplifier and an input terminal of the first amplifier; and a first input switch connected to the input terminal of the first amplifier.

Abstract: 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.

Abstract: 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.