Abstract: In one embodiment, a buffer circuit includes a first transistor, a second transistor, a first current source, a third transistor, a fourth transistor, a second current source, and a third current source. The first transistor has a control terminal connected to an input terminal, and a first terminal connected to an output terminal. The second transistor has a control terminal connected to the input terminal, a first terminal connected to the output terminal, and a second terminal connected to a first power source. The third transistor has a first terminal connected to the output terminal. The fourth transistor has a first terminal connected to the second terminal of the first transistor, a control terminal applied bias voltage, and a second terminal connected to a control terminal of the third transistor.

Abstract: According to an embodiment, an analog-to-digital converter includes a first AD (analog-to-digital) conversion circuit and a second AD conversion circuit. The first AD conversion circuit performs AD conversion of a first input signal to generate an upper-bit digital signal. The second AD conversion circuit performs AD conversion of a sampled signal to generate a lower-bit digital signal. The sampled signal is obtained by sampling a residual signal corresponding to a residue of the AD conversion in the first AD conversion circuit. A period during which the second AD conversion circuit performs AD conversion of the sampled signal overlaps a period during which a second input signal subsequent to the first input signal is settled.

Abstract: In one embodiment, a current amplifier circuit includes a first transistor, a first resistor, a second transistor, a second resistor, a first passive element, and a control circuit. The first transistor has a first terminal, a second terminal, and a control terminal. The first resistor has one end connected to the first terminal of the first transistor. The second transistor has a first terminal, a second terminal, and a control terminal. The second resistor has one end connected to the first terminal of the second transistor. The first passive element is connected between the first terminals of the first transistor and the second transistor. The control circuit controls at least one of voltage at the control terminals of the first transistor and the second transistor such that the voltage at the other end of the first resistor becomes equal to the voltage at the other end of the second resistor.

Abstract: In one embodiment, an AD converter includes a first (second) oscillation circuit, a first (second) counter, a first (second) arithmetic circuit, a first (second) subtracting circuit, an adder circuit, and a feedback circuit. The first oscillation circuit generates a first pulse signal having a frequency corresponding to a level of a first analog signal. The first counter counts the first pulse signal. The first arithmetic circuit generates a first signal corresponding to a change amount of a count value. The first subtracting circuit outputs a digital signal corresponding to a difference between the signals generated by the first and second arithmetic circuits. The adder circuit generates a sum signal of the signals generated by the first and second arithmetic circuits. The second subtracting circuit generates a difference signal between the sum signal and a reference signal. The feedback circuit inputs the difference signal to the first oscillation circuit.

Abstract: In one embodiment, a differential amplifier circuit includes a first input terminal, a second input terminal, a first transistor, a second transistor, a third transistor, a current source, a first output terminal, a second output terminal, a first passive element, and a second passive element. The first (second) transistor has a control terminal connected to the first (second) input terminal. The third transistor has a control terminal. The control terminal is applied predetermined bias voltage. The current source is connected to a first terminal in each of the first transistor, second transistor, and third transistor. The first (second) output terminal is connected to a second terminal of the first (second) transistor. The first (second) passive element is connected between the first (second) input terminal and the first (second) output terminal.

Abstract: There is provided A DA converter in which the N current switch cells each include: a current source having one end connected to a first power source; and first and second switch transistors differentially operating each other, each having a control terminal receiving a digital signal, the first combining node combines a current output from the first switch transistor in each current switch cell, the second combining node combines a current output from the second switch transistor in each current switch cell, the first output impedance element has ends connected to the first combining node and a second power source, the second output impedance element has ends connected to the second combining node and the second power source, the controller controls the current source in each current switch cell to reduce variation in amount of a current flowing from the first power source.

Abstract: According to an embodiment, a signal processing device includes an integrator, a setting unit, and an analog-to-digital converter. The integrator is configured to integrate an electrical charge corresponding to electromagnetic waves. The integrator includes a capacitor configured to store the electrical charge corresponding to the electromagnetic waves and a discharging circuit configured to discharge the capacitor. The setting unit is configured to set a period of integration of the electrical charge with respect to the integrator. The analog-to-digital converter includes a comparator configured to compare an integration output and a threshold value and a counter configured to output, as digital data of the electrical charge, the number of times for which a value of the integration output becomes not less than the threshold value. The converter is configured to discharge the capacitor during the period of integration by supplying a comparison output of the comparator to the discharging circuit.

Abstract: According to an embodiment, a signal processing device includes an integrator, a first analog-to-digital converter, and a histogram creator. The integrator is configured to integrate an electrical charge corresponding to electromagnetic waves. The first analog-to-digital converter is configured to perform an analog-to-digital conversion operation that generates digital data of the electrical charge using an integration output from the integrator, on a parallel with an integration operation performed by the integrator. The histogram creator is configured to create a histogram that represents an energy distribution of the electromagnetic waves, from the digital data generated by the first analog-to-digital converter.

Abstract: According to an embodiment, a signal processing device includes an integrator, a setting unit, and an analog-to-digital converter. The integrator is configured to integrate an electrical charge corresponding to electromagnetic waves. The integrator includes a capacitor configured to store the electrical charge corresponding to the electromagnetic waves and a discharging circuit configured to discharge the capacitor. The setting unit is configured to set a period of integration of the electrical charge with respect to the integrator. The analog-to-digital converter includes a comparator configured to compare an integration output and a threshold value and a counter configured to output, as digital data of the electrical charge, the number of times for which a value of the integration output becomes not less than the threshold value. The converter is configured to discharge the capacitor during the period of integration by supplying a comparison output of the comparator to the discharging circuit.

Abstract: There is provided a reference voltage generating apparatus including: a reference voltage source, a voltage retaining circuit, a switch and a controller. The reference voltage source generates a reference voltage. The voltage retaining circuit includes a first element circuit and a second element circuit, and the voltage retaining circuit outputs a voltage of a connection node between a first terminal of the first element circuit and a second terminal of the second element circuit. The switch is connected between the connection node and the reference voltage source. The controller controls the reference voltage source and the switch. The first element circuit includes at least a resistance component and the first element circuit is supplied with a first voltage at a third terminal and the second element circuit includes a resistance component and a capacity component and the second element circuit is supplied with a second voltage at a fourth terminal.

Abstract: The first amplifier operates according a first clock, changes voltages of a first terminal and a second terminal from a first fixed voltage to a second fixed voltage according to a voltage of an input signal and a first reference voltage, respectively, when an on period of a first clock starts, and keeps the voltages of the first and second terminals at the second fixed voltage, respectively, after the voltages of the first and second terminals reach the second fixed voltage and until the on period of the first clock ends, and the first comparator generates first and second logic signals that have logical levels different from each other, based on a difference between the voltages of the first and second terminals when the on period of a second clock whose on period at least partially overlaps with that of the first clock starts.

Abstract: A bias circuit according to an embodiment is a bias circuit that supplies a bias voltage to an amplifying element. The bias circuit of the embodiment includes a first current source that has a characteristic of varying an output current with the surrounding temperature variations, and a second current source that has a different output characteristic from the first current source and that can control the output current. The bias circuit of the embodiment also includes a comparator for comparing the output current of the first current source with the output current of the second current source, and a bias supply part that controls the output current of the second current source on the basis of the comparison result of the comparator and supplies a bias voltage to the amplifying element in accordance with the comparison result.

Abstract: According to one embodiment, a circuit comprises a first resistor configured to have one end to which a first voltage is input and the other end which outputs a second voltage and a first amplifier configured to have an inverting input connected to the other end of the first resistor and a noninverting input to which a third voltage is input. The circuit further comprises a first capacitor configured to have one end to which an output of the first amplifier is input and the other end to which the other end of the first resistor is connected. An output of the first amplifier or an output of a second amplifier connected to the other end of the first resistor is a fourth voltage. In the circuit, the first resistor and a mirror capacitance composed of the first capacitor and the first amplifier constitute a low-pass filter.

Abstract: An inverter control circuit has a quantizer configured to generate a switching signal which changes over switches of a main circuit converting a DC voltage into an AC voltage, and a filter circuit configured to generate a signal having specific transfer characteristic by using a signal correlated with an output voltage of an LC filter which smooths the AC voltage and an instruction signal corresponding to a target value of an output voltage of the main circuit, wherein the quantizer generates the switching signal by quantizing an output signal of the filter circuit.

Abstract: This A/D convertor includes: a first D/A conversion unit configured to sample an analog input signal, and to generate a first difference signal by performing successive comparison of the analog input signal based on a reference voltage; a precharge capacitor unit configured to hold the reference voltage; a first comparing unit configured to compare the first difference signal with a reference value to generate a first digital signal; and an amplifying unit configured to calculate by using the first difference signal and the reference voltage to generate a residual signal.

Abstract: There is provided a signal interpolation device, including: a first amplifier to generate a first signal representing a difference between an input signal and a first reference voltage; a second amplifier to generate a second signal representing a difference between the input signal and a second reference voltage; a first output amplifier to amplify the first signal to generate a first output signal; a second output amplifier to amplify the second signal to generate a second output signal; a third output amplifier to amplify a sum of a first interpolation signal and the first signal to generate a third output signal, the first interpolation signal representing a voltage generated by dividing a difference between the first reference voltage and the second reference voltage by “2^n”; and a fourth output amplifier to amplify a difference between the second signal and the first interpolation signal to generate a fourth output signal.

Abstract: An embodied ADC includes a sampling unit sampling differential input signal to output differential sampled signal which has first and second sampled signals. The ADC includes a reference signal generator generating first and second reference signals and a preamplifier amplifying the differential sampled signal to output a differential amplification signal having first and second amplified outputs. The preamplifier has a first differential amplifier amplifying the first sampled signal using the first reference signal and a second differential amplifier amplifying the second sampled signal using the second reference signal. The ADC includes a comparator comparing the first and second amplified outputs and a correction controller controlling common-mode voltage levels of the first and second reference signals or common-mode voltage levels of the first and second sampled signals in accordance with the operations of the first and second differential amplifiers.

Abstract: A semiconductor device has a silicon substrate, a shield which is disposed on the silicon substrate and comprises a conductive material, a capacitor electrode disposed on the shield, and at least one pillar member which is provided between the shield and the silicon substrate and comprises a conductive material. The pillar member may be disposed at a location other than a location of the through-hole.

Abstract: According to some embodiments, there is provided a controller that performs communication with a plurality of power supply units each of which outputs electric power to a load. The controller includes a receiving unit, a control information generating unit and a transmitting unit. The receiving unit receives operation information from the power supply units by radio, the operation information being information on electric power output to the load from the power supply units, respectively. The control information generating unit generates control information to control the power supply units based on the operation information. The transmitting unit transmits the control information to the power supply units by radio.

Abstract: A DC-DC converter converts an input voltage into an output voltage and includes an input terminal, an output terminal, a power stage, a switch driving circuit, a charge pump, and a capacitor. The power stage includes a high-side switch, a low-side switch and an inductor. The switch driving circuit generates a high-side switch driving signal and a low-side switch driving signal. The charge pump generates a first polarity current according to the high-side switch driving signal, and generates a second polarity current having an opposite polarity to the first polarity current according to the low-side switch driving signal. The capacitor generates a first voltage by integrating the first and second polarity currents generated by the charge pump. The switch driving circuit generates the high-side switch driving signal and the low-side switch driving signal according to a difference between the first voltage and a reference voltage.