Abstract: A ringing suppression circuit for a communication circuit that performs communication through a transmission line includes a high side switch connected between a high potential reference point and a high side line of the transmission line, a low side switch connected between a low potential reference point and a low side line of the transmission line, and a ringing suppression section. The ringing suppression section turns on the high side switch based on a difference between a potential of the high side line and a potential applied to a control terminal of the high side switch. The ringing suppression section turns on the low side switch based on a difference between a potential of the low side line and a potential applied to a control terminal of the low side switch.

Abstract: When a transmission signal is detected as having been changed from a high level to a low level, two transmission lines are connected for only a predetermined time through a diode by a first transistor and a second transistor. The diode is arranged such that its forward direction is from a high-side transmission line to a low-side transmission line. The diode turns on, when a potential of the high-side transmission line becomes higher than that of the low-side transmission line by ringing and a potential difference therebetween exceeds a forward drop voltage of the diode. As a result, a peak wave level of a positive side in the ringing is limited to the forward drop voltage of the diode.

Abstract: A power conversion apparatus includes main circuits, in which switching elements are connected in parallel with diodes, respectively. An auxiliary circuit, which is formed of a series-connected second switching element and a capacitor, is connected in parallel with the diode operating as a freewheeling diode. The switching element of the main circuit, which is opposite to the auxiliary circuit, is set to turn on at a reference time. The second switching element of the auxiliary circuit is set to turn on in advance of the reference time by an interval of a discharging time period of the capacitor in a dead time period.

Abstract: A ringing suppression circuit for a communication circuit that performs communication through a transmission line includes a high side switch connected between a high potential reference point and a high side line of the transmission line, a low side switch connected between a low potential reference point and a low side line of the transmission line, and a ringing suppression section. The ringing suppression section turns on the high side switch based on a difference between a potential of the high side line and a potential applied to a control terminal of the high side switch. The ringing suppression section turns on the low side switch based on a difference between a potential of the low side line and potential applied to a control terminal of the low side switch.

Abstract: A control circuit connects a capacitor to an input terminal and an output terminal of an operational amplifier and applies a signal charge to charge the capacitor with a switch being turned off. Thus, a conversion voltage corresponding to the signal charge is outputted from the operational amplifier. The control circuit then sets charges, which correspond to the conversion voltage, in capacitors and reallocates the charges among the capacitors by connecting non-common electrodes of the capacitors to either one of a plurality of reference voltage lines in accordance with a conversion result of an A/D conversion circuit with the capacitor being connected to the input terminal and the output terminal of the operational amplifier. The control circuit thereafter performs, a number of times, charge setting, initialization and subsequent charge reallocation in accordance with a residual voltage outputted from the operational amplifier.

Abstract: An A/D converter device is provided, which has a D/A conversion function and changes a resolution of A/D conversion and D/A conversion. The A/D converter device is configured to selectively execute an A/D conversion operation and a D/A conversion operation, by the operation of a control circuit controlling switching of switches according to an ADC/DAC function switching signal supplied from an external side. The A/D conversion operation performs A/D conversion of an input signal voltage inputted via a signal input terminal from an external side and outputs an A/D conversion value of 12 bits. The D/A conversion operation outputs, via a signal output terminal, an analog voltage produced by performing D/A conversion of a digital value supplied from the external side.

Abstract: An amplifier circuit is provided to be switchable between a single end output configuration and a differential output configuration without increasing a circuit area. When first and fourth switches are turned off and a second switch is turned on, a load circuit functions as an active load on a differential pair and a first output terminal is internally disconnected. The amplifier circuit is provided with a single end output configuration and differentially amplifies input voltages inputted to input terminals and outputs an imbalanced signal from a second output terminal. When the first and fourth switches are turned on and the second switch is turned off, the load circuit functions as a load on the differential pair and the first output terminal is internally connected. The amplifier circuit is provided with a differential output configuration and differentially amplifies the input voltages inputted to the input terminals and outputs balanced signals from the output terminals.

Abstract: A power conversion apparatus includes main circuits, in which switching elements are connected in parallel with diodes, respectively. An auxiliary circuit, which is formed of a series-connected second switching element and a capacitor, is connected in parallel with the diode operating as a freewheeling diode. The switching element of the main circuit, which is opposite to the auxiliary circuit, is set to turn on at a reference time. The second switching element of the auxiliary circuit is set to turn on in advance of the reference time by an interval of a discharging time period of the capacitor in a dead time period.

Abstract: A synchronous-rectifier type DC-DC converter includes a high-side main switch element, a low-side rectifying switch element, and a control drive circuit. The rectifying switch element includes a rectifying transistor element and a rectifying diode element connected in antiparallel with the rectifying transistor element. The control drive circuit detects an input voltage to the main switch element and determines the input voltage or a rate of increase in the input voltage. When the determined value exceeds a predetermined reference value, a complementary ON/OFF operation of the main switch element and the rectifying transistor element is released, and a state where both the main switch element and the rectifying transistor element are kept OFF for a time period that is longer than a dead-time during the complementary ON/OFF operation is set.

Abstract: When a transmission signal is detected as having been changed from a high level to a low level, two transmission lines are connected for only a predetermined time through a diode by a first transistor and a second transistor. The diode is arranged such that its forward direction is from a high-side transmission line to a low-side transmission line. The diode turns on, when a potential of the high-side transmission line becomes higher than that of the low-side transmission line by ringing and a potential difference therebetween exceeds a forward drop voltage of the diode. As a result, a peak wave level of a positive side in the ringing is limited to the forward drop voltage of the diode.

Abstract: An A/D converter device is provided, which has a D/A conversion function and changes a resolution of A/D conversion and D/A conversion. The A/D converter device is configured to selectively execute an A/D conversion operation and a D/A conversion operation, by the operation of a control circuit controlling switching of switches according to an ADC/DAC function switching signal supplied from an external side. The A/D conversion operation performs A/D conversion of an input signal voltage inputted via a signal input terminal from an external side and outputs an A/D conversion value of 12 bits. The D/A conversion operation outputs, via a signal output terminal, an analog voltage produced by performing D/A conversion of a digital value supplied from the external side.

Abstract: An amplifier circuit is provided to be switchable between a single end output configuration and a differential output configuration without increasing a circuit area. When first and fourth switches are turned off and a second switch is turned on, a load circuit functions as an active load on a differential pair and a first output terminal is internally disconnected. The amplifier circuit is provided with a single end output configuration and differentially amplifies input voltages inputted to input terminals and outputs an imbalanced signal from a second output terminal. When the first and fourth switches are turned on and the second switch is turned off, the load circuit functions as a load on the differential pair and the first output terminal is internally connected. The amplifier circuit is provided with a differential output configuration and differentially amplifies the input voltages inputted to the input terminals and outputs balanced signals from the output terminals.

Abstract: A control circuit connects a capacitor to an input terminal and an output terminal of an operational amplifier and applies a signal charge to charge the capacitor with a switch being turned off. Thus, a conversion voltage corresponding to the signal charge is outputted from the operational amplifier. The control circuit then sets charges, which correspond to the conversion voltage, in capacitors and reallocates the charges among the capacitors by connecting non-common electrodes of the capacitors to either one of a plurality of reference voltage lines in accordance with a conversion result of an A/D conversion circuit with the capacitor being connected to the input terminal and the output terminal of the operational amplifier. The control circuit thereafter performs, a number of times, charge setting, initialization and subsequent charge reallocation in accordance with a residual voltage outputted from the operational amplifier.

Abstract: A ringing suppression circuit for a communication circuit that performs communication through a transmission line includes a high side switch connected between a high potential reference point and a high side line of the transmission line, a low side switch connected between a low potential reference point and a low side line of the transmission line, and a ringing suppression section. The ringing suppression section turns on the high side switch based on a difference between a potential of the high side line and a potential applied to a control terminal of the high side switch. The ringing suppression section turns on the low side switch based on a difference between a potential of the low side line and potential applied to a control terminal of the low side switch.

Abstract: A sample and hold circuit includes an op-amp, inverting-side capacitors, and non-inverting-side capacitors paired with the inverting-side capacitors. At least one capacitor pair serves as a feedback capacitor in a holding phase. A total capacitance of the inverting-side capacitors to which an input voltage is applied in a sampling phase is ?, a total capacitance of the non-inverting-side capacitors to which the input voltage is applied in the sampling phase is ?, a total capacitance of the inverting-side capacitors to which the input voltage is applied in a holding phase is ?, and a total capacitance of the non-inverting-side capacitors to which the input voltage is applied in the holding phase is ?. ? is substantially different from ?. A total capacitance of a feedback capacitor pair is substantially equal to (?????+?)·(N/2), where N is a positive number.

Abstract: A variable gain amplifier for amplifying an input voltage at a gain defined by a binary code includes: a signal input terminal; a signal output terminal; a charge division means that accumulates a charge, divides an accumulated charge, and accumulates a divided charge; a charge cumulation means that accumulates a charge, adds or subtracts an accumulated charge with or from the divided charge in the charge division means, and accumulates a resultant charge; and a controller that initially executes to accumulate the charge corresponding to the input voltage in the charge division means, executes to accumulate the charge corresponding to the input voltage or a predetermined voltage in the charge cumulation means, executes a charge dividing operation according to each bit of the binary code sequentially from a most significant bit, and executes a charge adding or subtracting operation according to an data value in each bit.

Abstract: A synchronous-rectifier type DC-DC converter includes a high-side main switch element, a low-side rectifying switch element, and a control drive circuit. The rectifying switch element includes a rectifying transistor element and a rectifying diode element connected in antiparallel with the rectifying transistor element. The control drive circuit detects an input voltage to the main switch element and determines the input voltage or a rate of increase in the input voltage. When the determined value exceeds a predetermined reference value, a complementary ON/OFF operation of the main switch element and the rectifying transistor element is released, and a state where both the main switch element and the rectifying transistor element are kept OFF for a time period that is longer than a dead-time during the complementary ON/OFF operation is set.

Abstract: A multi-channel sample and hold circuit includes an operational amplifier, plural electric charge setting channels. Each of the electric charge setting channels includes an input terminal, an electric charge setting capacitor, an electric charge setting switch connected between the input terminal and the electric charge setting capacitor, a channel separating switch connected between the electric charge setting capacitor and the input terminal of the operational amplifier and a holding switch and a control circuit for selecting one of the electric charge setting channels to hold a signal that is inputted to the input terminal thereof.

Abstract: A sample and hold circuit includes an op-amp, inverting-side capacitors, and non-inverting-side capacitors paired with the inverting-side capacitors. At least one capacitor pair serves as a feedback capacitor in a holding phase. A total capacitance of the inverting-side capacitors to which an input voltage is applied in a sampling phase is ?, a total capacitance of the non-inverting-side capacitors to which the input voltage is applied in the sampling phase is ?, a total capacitance of the inverting-side capacitors to which the input voltage is applied in a holding phase is ?, and a total capacitance of the non-inverting-side capacitors to which the input voltage is applied in the holding phase is ?. ? is substantially different from ?. A total capacitance of a feedback capacitor pair is substantially equal to (?????+?)·(N/2), where N is a positive number.

Abstract: A variable gain amplifier for amplifying an input voltage at a gain defined by a binary code includes: a signal input terminal; a signal output terminal; a charge division means that accumulates a charge, divides an accumulated charge, and accumulates a divided charge; a charge cumulation means that accumulates a charge, adds or subtracts an accumulated charge with or from the divided charge in the charge division means, and accumulates a resultant charge; and a controller that initially executes to accumulate the charge corresponding to the input voltage in the charge division means, executes to accumulate the charge corresponding to the input voltage or a predetermined voltage in the charge cumulation means, executes a charge dividing operation according to each bit of the binary code sequentially from a most significant bit, and executes a charge adding or subtracting operation according to an data value in each bit.