Abstract: A pulse signal sending circuit that outputs pulse signals from an output terminal includes: an output transistor; an inverter circuit; and a delay circuit. The output transistor includes a drain terminal connected to the output terminal. The inverter circuit is connected to a gate terminal of the output transistor and outputs a signal to be input to the gate terminal of the output transistor. The delay circuit receives a pulse signal as an input and delays rising or falling of the input pulse signal. The pulse signal delayed by the delay circuit is input to the inverter circuit.

Abstract: A pulse signal sending circuit that outputs pulse signals from an output terminal includes: an output transistor; an inverter circuit; and a delay circuit. The output transistor includes a drain terminal connected to the output terminal. The inverter circuit is connected to a gate terminal of the output transistor and outputs a signal to be input to the gate terminal of the output transistor. The delay circuit receives a pulse signal as an input and delays rising or falling of the input pulse signal. The pulse signal delayed by the delay circuit is input to the inverter circuit.

Abstract: A step-up/down DC-DC converter and switching control circuit are described. According to one implementation, a switching control circuit generates on/off signals of a first switching device supplying a current to a voltage conversion inductor of a step-up/down DC-DC converter and a second switching device receiving a current from the inductor. The switching control circuit includes an error amplifier circuit, an inverter amplifier circuit, a waveform generator circuit, a first voltage comparator circuit, a second voltage comparator circuit, and a voltage generator circuit. An inverting reference voltage supplied to the inverting amplifier circuit is set to an electric potential so as not to fall below a highest electric potential of triangle waves supplied to the first and second voltage comparator circuits.

Abstract: A step-up/down DC-DC converter and switching control circuit are described. According to one implementation, a switching control circuit generates an on/off signal of a first switching device supplying a current to a voltage conversion inductor of a step-up/down DC-DC converter and a second switching device receiving the current from the inductor. The switching control circuit includes an error amplifier circuit, an inverting amplifier circuit, a waveform generator circuit, a first voltage comparator circuit, a second voltage comparator circuit, and a peak-value detector circuit. The peak-value detector circuit detects a peak value of triangle waves generated at the waveform generator circuit and supplies a voltage corresponding to the peak value to the inverting amplifier circuit as a reference voltage.

Abstract: A step-up/down DC-DC converter and switching control circuit are described. According to one implementation, a switching control circuit generates on/off signals of a first switching device supplying a current to a voltage conversion inductor of a step-up/down DC-DC converter and a second switching device receiving a current from the inductor. The switching control circuit includes an error amplifier circuit, an inverter amplifier circuit, a waveform generator circuit, a first voltage comparator circuit, a second voltage comparator circuit, and a voltage generator circuit. An inverting reference voltage supplied to the inverting amplifier circuit is set to an electric potential so as not to fall below a highest electric potential of triangle waves supplied to the first and second voltage comparator circuits.

Abstract: A step-up/down DC-DC converter and switching control circuit are described. According to one implementation, a switching control circuit generates an on/off signal of a first switching device supplying a current to a voltage conversion inductor of a step-up/down DC-DC converter and a second switching device receiving the current from the inductor. The switching control circuit includes an error amplifier circuit, an inverting amplifier circuit, a waveform generator circuit, a first voltage comparator circuit, a second voltage comparator circuit, and a peak-value detector circuit. The peak-value detector circuit detects a peak value of triangle waves generated at the waveform generator circuit and supplies a voltage corresponding to the peak value to the inverting amplifier circuit as a reference voltage.

Abstract: A DC-DC converter including, an inductor; and a driving switching element for performing switching to a flow path to flow an electric current through the inductor; wherein the DC-DC converter drives the driving switching element by PWM control using a PWM control pulse to convert a direct-current input voltage supplied from a direct-current power source and to output a direct-current voltage having a piece of electric potential different from that of the direct-current input voltage, and wherein the DC-DC converter drives the driving switching element by the PWM control under a first condition, and the DC-DC converter makes the driving switching element be in an on-state continuously while the output direct-current voltage is lower than a desired level under a second condition.

Abstract: Provided is a DC-DC converter comprising: a drive switching element so that a current flows to an inductor, the drive switching element being driven by a PWM control pulse or a PFM control pulse, wherein a direct-current input voltage supplied from a direct-current power source is converted so as to output the converted direct-current voltage having a different potential, and wherein a PWM control is performed when a load is larger than a predetermined value and a PFM control is performed when the load is smaller than the predetermined value, the DC-DC converter further comprising: a pulse width regulation section to regulate the PWM control pulse so as not to have a pulse width smaller than a predetermined pulse width, at least when the PFM control is switched to the PWM control.

Abstract: A switching power-supply unit which controls current flowing through an inductor in a switchable manner and outputs a voltage different from input voltage, the unit including: a terminal-potential detecting circuit which monitors terminal potential of the inductor and outputs a predetermined signal; a comparator which compares an output feedback voltage with a threshold voltage; and a logic circuit which generates a signal for controlling a switching element based on an output from the comparator and an output from the terminal-potential detecting circuit, wherein the comparator compares a first threshold voltage with the feedback voltage in a period in which the output voltage rises, and compares a second threshold voltage which is lower than the first threshold voltage with the feedback voltage in a period in which the output voltage drops.

Abstract: Disclosed is a direct-current power supply device, including: an inductor; a switching element to intermittently supply a current to the inductor; an external terminal to which an output current of an external unit is fed back; a control circuit to generate a pulse signal having a pulse width corresponding to an output voltage of the external terminal, generate a drive signal for driving the switching element in response to the pulse signal, and output the drive signal to the switching element; a variable current source which is connected to the external terminal and which is turned on and off in response to a shutdown signal; and a discharge unit which is connected between the external terminal and a ground point and which is turned on in response to the shutdown signal so that the output current fed back to the external terminal is discharged into the ground point.

Abstract: Disclosed is a direct-current power supply device, including: an inductor; a switching element to intermittently supply a current to the inductor; an output terminal connected to an external unit; a rectifying element connected between the inductor and the output terminal; a PFM comparator to generate a first pulse signal having a pulse width corresponding to a voltage proportional to an output current of the external unit; a duty control circuit to generate a second pulse signal by controlling a pulse width of an oscillation signal having a predetermined frequency in response to an externally-supplied current control signal; a logic circuit configured to output the second pulse signal during a period when the first pulse signal is at a predetermined level; and a drive circuit to generate a drive signal for driving the switching element based on the second pulse signal.

Abstract: A multi-output type DC/DC converter including: a reactor connected to a direct-current power supply; a first switching circuit to apply a current to the reactor; a second switching to switch an output from the reactor to any one of output terminals; output voltage detection units to detect voltages of the output terminals; comparison circuits to compare outputs of the output voltage detection units with a waveform signal of a predetermined frequency; and an output selection unit to receive outputs of the comparison circuits as inputs, the output selection unit selecting an output of a comparison circuit, the output having an earlier rise or an earlier fall, to generate a plurality of control signals pertaining to on and off of the first switching circuit and/or the second switching circuit, the output selection unit treating the plurality of control signals in accordance with a predetermined priority order when the outputs of the plurality of comparison circuits change almost at the same time, wherein a curre

Abstract: A DC-DC converter including, an inductor; and a driving switching element for performing switching to a flow path to flow an electric current through the inductor; wherein the DC-DC converter drives the driving switching element by PWM control using a PWM control pulse to convert a direct-current input voltage supplied from a direct-current power source and to output a direct-current voltage having a piece of electric potential different from that of the direct-current input voltage, and wherein the DC-DC converter drives the driving switching element by the PWM control under a first condition, and the DC-DC converter makes the driving switching element be in an on-state continuously while the output direct-current voltage is lower than a desired level under a second condition.

Abstract: Provided is a DC-DC converter comprising: a drive switching element so that a current flows to an inductor, the drive switching element being driven by a PWM control pulse or a PFM control pulse, wherein a direct-current input voltage supplied from a direct-current power source is converted so as to output the converted direct-current voltage having a different potential, and wherein a PWM control is performed when a load is larger than a predetermined value and a PFM control is performed when the load is smaller than the predetermined value, the DC-DC converter further comprising: a pulse width regulation section to regulate the PWM control pulse so as not to have a pulse width smaller than a predetermined pulse width, at least when the PFM control is switched to the PWM control.

Abstract: Disclosed is a direct-current power supply device, including: an inductor; a switching element to intermittently supply a current to the inductor; an external terminal to which an output current of an external unit is fed back; a control circuit to generate a pulse signal having a pulse width corresponding to an output voltage of the external terminal, generate a drive signal for driving the switching element in response to the pulse signal, and output the drive signal to the switching element; a variable current source which is connected to the external terminal and which is turned on and off in response to a shutdown signal; and a discharge unit which is connected between the external terminal and a ground point and which is turned on in response to the shutdown signal so that the output current fed back to the external terminal is discharged into the ground point.

Abstract: Disclosed is a direct-current power supply device, including: an inductor; a switching element to intermittently supply a current to the inductor; an output terminal connected to an external unit; a rectifying element connected between the inductor and the output terminal; a PFM comparator to generate a first pulse signal having a pulse width corresponding to a voltage proportional to an output current of the external unit; a duty control circuit to generate a second pulse signal by controlling a pulse width of an oscillation signal having a predetermined frequency in response to an externally-supplied current control signal; a logic circuit configured to output the second pulse signal during a period when the first pulse signal is at a predetermined level; and a drive circuit to generate a drive signal for driving the switching element based on the second pulse signal.

Abstract: In a multi-output type DC/DC converter, a controller controls, in accordance with first and second output voltages, turning on/off of a switch circuit and selection in an output selection circuit. The controller controls an ON time interval in each time slot of the switch circuit so as to always constant in a steady state without reference to weight of first and second loads.

Abstract: Disclosed a multi-output type DC/DC converter including: a reactor connected to a direct-current power supply; a first switching circuit composed of switches to apply a current to the reactor; a second switching circuit composed of switches to switch an output from the reactor to any one of output terminals; output voltage detection sections to detect voltages of the output terminals; comparison circuits to compare outputs with a waveform signal of a predetermined frequency; and an output selection circuit to receive inputs form comparison circuits, and to select an output of a comparison circuit, the output having the earliest rise or the earliest fall, so as to generate a control signal pertaining to on and off of the first and/or second switching circuit, wherein a current generated by a discharge of energy accumulated in the reactor is output to any one of the terminals in accordance with the control signal.

Abstract: A multi-output type DC/DC converter including: a reactor connected to a direct-current power supply; a first switching circuit to apply a current to the reactor; a second switching to switch an output from the reactor to any one of output terminals; output voltage detection units to detect voltages of the output terminals; comparison circuits to compare outputs of the output voltage detection units with a waveform signal of a predetermined frequency; and an output selection unit to receive outputs of the comparison circuits as inputs, the output selection unit selecting an output of a comparison circuit, the output having an earlier rise or an earlier fall, to generate a plurality of control signals pertaining to on and off of the first switching circuit and/or the second switching circuit, the output selection unit treating the plurality of control signals in accordance with a predetermined priority order when the outputs of the plurality of comparison circuits change almost at the same time, wherein a curre

Abstract: Disclosed a multi-output type DC/DC converter including: a reactor connected to a direct-current power supply; a first switching circuit composed of switches to apply a current to the reactor; a second switching circuit composed of switches to switch an output from the reactor to any one of output terminals; output voltage detection sections to detect voltages of the output terminals; comparison circuits to compare outputs with a waveform signal of a predetermined frequency; and an output selection circuit to receive inputs form comparison circuits, and to select an output of a comparison circuit, the output having the earliest rise or the earliest fall, so as to generate a control signal pertaining to on and off of the first and/or second switching circuit, wherein a current generated by a discharge of energy accumulated in the reactor is output to any one of the terminals in accordance with the control signal.