Abstract: In a protection circuit connected, via lines including an inductance component, to a circuit to be protected, a first transistor is arranged on a path to ground from a connection point of the protection circuit and the line. A second transistor is arranged on a path to ground from a connection point of the circuit to be protected and the line, and extracts, from a connection point, a current corresponding to a current flowing in the first transistor. The first and the second transistors are NPN bipolar transistors having a base and an emitter are commonly connected. A resistor is connected between the base and the emitter of the first transistor, and a diode is connected between the base and a collector.

Abstract: A step-up DC/DC converter uses N-channel field-effect transistors as both an output transistor and a synchronous-rectification transistor and includes a first driver making the gate voltage of the output transistor pulsate between a ground voltage and an input voltage and a second driver making the gate voltage of the synchronous-rectification transistor pulsate between a switching voltage and a bootstrap voltage equal to the switching voltage plus at least the ON threshold voltage of the synchronous-rectification transistor. With this configuration, the converter operates with improved power efficiency and performs synchronous rectification unhindered even with a small input-output voltage difference.

Abstract: A step-up/step-down regulator circuit wherein a switch (N2) has a terminal connected to an end of an inductor (L1), another terminal grounded, and a control terminal connected to an end of a switch (N1). In this way, performing an open/close control of the switch (N1) can indirectly perform an open/close control of the switch (N2), thereby solving the problem that the structure and operation of a switch control circuit will be complicated when the switching between step-up and step-down operation is realized.

Abstract: A DC/DC converter is supplied such that the desired output setting voltage can be obtained as the load-side output, even when the difference between the power supply voltage and the output setting voltage of the load-side output is large. This DC/DC converter comprises a switching device, a voltage divider, an error amplifier, an oscillator which outputs a oscillation clock, a slope circuit which receives the oscillation clock and outputs a sawtooth waveform voltage having a slope which begins at the leading edge of the oscillation clock, a comparator which compares the sawtooth waveform voltage and the output voltage of the error amplifier, and a logic circuit which is set by the trailing edge of the oscillation clock, and is reset by the output of the comparator.

Abstract: A DC/DC converter is supplied such that the desired output setting voltage can be obtained as the load-side output, even when the difference between the power supply voltage and the output setting voltage of the load-side output is large. This DC/DC converter comprises a switching device, a voltage divider, an error amplifier, an oscillator which outputs a oscillation clock, a slope circuit which receives the oscillation clock and outputs a sawtooth waveform voltage having a slope which begins at the leading edge of the oscillation clock, a comparator which compares the sawtooth waveform voltage and the output voltage of the error amplifier, and a logic circuit which is set by the trailing edge of the oscillation clock, and is reset by the output of the comparator.

Abstract: A charge pump circuit (1) includes first and second rectifier elements (10 and 11) connected in series between input and output terminals (7 and 9), provides a predetermined voltage from the output terminal (9) by passing charges successively through the rectifier elements (10 and 11) and accumulating the charges in an output capacitor (12), and further includes an integrator (15) integrating a difference between a feedback voltage provided from the output terminal (9) and a reference voltage, a boost capacitor (17) having an end connected to a node between the first and second rectifier elements (10 and 11), and a clock inverter (16) having power-supply-side and ground-side transistors (30 and 31) receiving a clock signal (CLK), and a variable current supply (32) supplying a current depending on the output voltage of the integrator (15) to one of the transistors, and having an output connected to the other end of the boost capacitor (17).

Abstract: A display device includes a gamma correction circuit that includes a gamma correction data output circuit that outputs a plurality of gamma correction data that correspond with a detected temperature, a plurality of registers that input and hold each of a plurality of gamma correction data, and a plurality of D/A converters each of which converts the data of each of the plurality of registers into an analog voltage to output gamma-corrected set voltages, a display panel driver to which image data are input and which outputs applied voltages that have been corrected correspondingly with the image data via a plurality of gamma-corrected set voltages of the gamma correction circuit, a display panel which includes display elements to which the applied voltages from the display panel driver are applied, a nonvolatile memory which saves a plurality of gamma correction data, and a temperature sensor which generates an electrical signal that corresponds with a temperature.

Abstract: A step-up DC/DC converter uses N-channel field-effect transistors as both an output transistor and a synchronous-rectification transistor and includes a first driver making the gate voltage of the output transistor pulsate between a ground voltage and an input voltage and a second driver making the gate voltage of the synchronous-rectification transistor pulsate between a switching voltage and a bootstrap voltage equal to the switching voltage plus at least the ON threshold voltage of the synchronous-rectification transistor. With this configuration, the converter opeates with improved power efficiency and performs synchronous rectification unhindered even with a small input-output voltage difference.

Abstract: A DC/DC converter is supplied such that the desired output setting voltage can be obtained as the load-side output, even when the difference between the power supply voltage and the output setting voltage of the load-side output is large. This DC/DC converter comprises a switching device, a voltage divider, an error amplifier, an oscillator which outputs a oscillation clock, a slope circuit which receives the oscillation clock and outputs a sawtooth waveform voltage having a slope which begins at the leading edge of the oscillation clock, a comparator which compares the sawtooth waveform voltage and the output voltage of the error amplifier, and a logic circuit which is set by the trailing edge of the oscillation clock, and is reset by the output of the comparator.

Abstract: A DC/DC converter is supplied such that the desired output setting voltage can be obtained as the load-side output, even when the difference between the power supply voltage and the output setting voltage of the load-side output is large. This DC/DC converter comprises a switching device, a voltage divider, an error amplifier, an oscillator which outputs a oscillation clock, a slope circuit which receives the oscillation clock and outputs a sawtooth waveform voltage having a slope which begins at the leading edge of the oscillation clock, a comparator which compares the sawtooth waveform voltage and the output voltage of the error amplifier, and a logic circuit which is set by the trailing edge of the oscillation clock, and is reset by the output of the comparator.

Abstract: A constant voltage generator is comprised of a band gap reference circuit, a current supply circuit, a starting circuit and a voltage-current conversion circuit, and the starting circuit is further comprised of a first and second load elements, a first transistor which is connected to the first load element, a second transistor of which current capability is larger than the first transistor and which shares the voltage of the base with the first transistor and is connected to the second load element, a first resistor which is connected to the first transistor, and a second resistor which is connected to the second transistor, and the output of the voltage-current conversion circuit is input to the connection point between the second transistor and the second resistor, and the current at the connection point between the second load element and the second transistor controls the current supply circuit.

Abstract: When an output voltage output from a buffer approaches a ground voltage, a MOS transistor turns off, so that clamp for a gate of the MOS transistor is released.

Abstract: The power supply unit is provided with a power supply circuit adapted to generate an output voltage in accord with an instruction voltage, an output condenser Co connected to the output end of the power supply circuit, and an auxiliary output voltage setting circuit adapted to compare the instruction voltage and the output voltage and to cause the output condenser to discharge its electric charge when the instruction voltage becomes lower than the output voltage. Because of the auxiliary output voltage setting circuit, the power supply circuit quickly generates an output voltage in accord with the instruction voltage if the instruction voltage is lowered.

Abstract: A constant voltage generator is comprised of a band gap reference circuit, a current supply circuit, a starting circuit and a voltage-current conversion circuit, and the starting circuit is further comprised of a first and second load elements, a first transistor which is connected to the first load element, a second transistor of which current capability is larger than the first transistor and which shares the voltage of the base with the first transistor and is connected to the second load element, a first resistor which is connected to the first transistor, and a second resistor which is connected to the second transistor, and the output of the voltage-current conversion circuit is input to the connection point between the second transistor and the second resistor, and the current at the connection point between the second load element and the second transistor controls the current supply circuit.

Abstract: A power supply circuit comprising a charge pump circuit supplies a supply voltage to a gate driver. A timing controller supplies a predetermined timing signal to a NAND circuit, a shutdown terminal of the charge pump circuit, and a gate shading circuit including a capacitor, a resistor, a NOT circuit, and a transistor. When this timing signal is high, the charge pump circuit makes a normal operation and the gate shading circuit is deactivated. When this timing signal is low, the charge pump circuit stops operating and the gate shading circuit is activated to drain an electric charge from the output of the charge pump circuit.

Abstract: A constant voltage generator is comprised of a band gap reference circuit, a current supply circuit, a starting circuit and a voltage-current conversion circuit, and the starting circuit is further comprised of a first and second load elements, a first transistor which is connected to the first load element, a second transistor of which current capability is larger than the first transistor and which shares the voltage of the base with the first transistor and is connected to the second load element, a first resistor which is connected to the first transistor, and a second resistor which is connected to the second transistor, and the output of the voltage-current conversion circuit is input to the connection point between the second transistor and the second resistor, and the current at the connection point between the second load element and the second transistor controls the current supply circuit.

Abstract: The present invention provides a DC/DC converter that can include a capacitor constituting a soft start circuit in a semiconductor integrated device. This DC/DC converter is comprised of a switching element for supplying power from a power supply (Vcc) to a load side output terminal (OUT) by switching, an error amplifier for amplifying the voltage from the load side output terminal (OUT), a differentiation circuit for differentiating the voltage from the load side output terminal (OUT) and adjusting the output current according to the value thereof, a soft start circuit comprising a constant current source and a capacitor, both of which are connected to the output terminal of the differentiation circuit, and a comparator for comparing the triangular wave voltage from a triangular wave generator (TRI) with the voltage from the soft start circuit or the output voltage of the error amplifier, and controlling the switching of the switching element according to the comparison output thereof.

Abstract: One frame of a color image data is resolved into three frames of R, G, and B colors, which are displayed in sequence. In synchronism with the R, G, B frames, a power supply voltage for displaying each of the three frames is altered to predetermined levels set for the respective frames. Output voltage data for determining the voltage levels for red-, green-, and blue-frame are stored in rewritable forms, which are provided to the power supply circuit so that its output voltage is equilibrated to a reference voltage based on that output voltage data provided. The invention enables suppression of color temperature deviation due to variations in transmissivity of color filters while setting a common gradation level for the R, G, an B frames.

Abstract: The power supply unit is provided with a power supply circuit adapted to generate an output voltage in accord with an instruction voltage, an output condenser Co connected to the output end of the power supply circuit, and an auxiliary output voltage setting circuit adapted to compare the instruction voltage and the output voltage and to cause the output condenser to discharge its electric charge when the instruction voltage becomes lower than the output voltage. Because of the auxiliary output voltage setting circuit, the power supply circuit quickly generates an output voltage in accord with the instruction voltage if the instruction voltage is lowered.

Abstract: The power supply unit is provided with a power supply circuit adapted to generate an output voltage in accord with an instruction voltage, an output condenser Co connected to the output end of the power supply circuit, and an auxiliary output voltage setting circuit adapted to compare the instruction voltage and the output voltage and to cause the output condenser to discharge its electric charge when the instruction voltage becomes lower than the output voltage. Because of the auxiliary output voltage setting circuit, the power supply circuit quickly generates an output voltage in accord with the instruction voltage if the instruction voltage is lowered.