Abstract: A fast transient switching voltage regulator includes a reference signal generator to provide a reference in a feedback path to control switching. The reference signal generator is operative to incorporate a voltage offset into the reference signal timed with the control pulses used to control the switching. The voltage offset moves the reference signal out of the way of pulses introduced in the feedback path due to capacitance ESL in the output capacitor of the switching voltage regulator.

Abstract: Disclosed are various embodiments for a power stage that can drive various types of loads. The power stage includes a first capacitor and a second capacitor that are coupled to the load. The power stage also includes switches that are operable in a first power stage state and a second power stage state. When the switches are in the first power stage state, the first capacitor discharges to the load, and the second capacitor charges. When the switches are in the second power stage state, the second capacitor discharges to the load, and the first capacitor charges.

Abstract: A switching regulator includes a high side driver electrically coupled with a power line that is configured to provide a supply voltage. A low side driver is electrically coupled between the high side driver and ground. A regulator control circuit is electrically coupled with a gate of the high side driver and a gate of the low side driver. The regulator control circuit is configured to pre-charge a first node between the regulator control circuit and the gate of the high side driver to a first voltage level and to boost the first node to a second voltage level that is higher than the first voltage level to turn on the high side driver.

Abstract: A kilowatt-scale high-frequency electrical power conversion system adapted for variable output power delivery is described, in which switching frequency of switchable power delivery circuitry is dynamically modulated in transition of the system to a low power regime that is substantially below maximum power output, in order to at least partially attenuate thermal overload from heat generation of switching components in such transitions. The system is useful in high-efficiency charging of rechargeable batteries of electrical vehicles, e.g., e.g., automotive, industrial, and other motive power vehicles.

Abstract: A power circuit is described that includes a half-bridge and a driver for controlling a first switch of the half-bridge. The driver is configured to cause the first switch to transition between operating in an on-state of the first switch and an off-state of the first switch based at least in part on a driver signal and a voltage at the half-bridge.

Abstract: An output voltage is compared to a reference voltage, comparison signals are generated, and control signals and mode signals are generated in response thereto. The output voltage is generated in response to the control signals. A speed of the comparing is increased in response to the mode signals indicating that the output voltage is being increased. The speed is reduced in response to the mode signals indicating that the output voltage is being reduced. For increasing the speed, a path is enabled to conduct current. While the path is enabled, at least one switched voltage is connected to vary an amount of the current conducted through the path. The switched voltage is at least one of the reference voltage and the output voltage. For reducing the speed, the path is disabled against conducting current. While the path is disabled, the switched voltage is disconnected from varying the amount.

Abstract: There is provided a DC-DC converter which converts an input voltage into an output voltage for supply to a load, in which an input terminal receives the input voltage, an output terminal outputs the output voltage, power stages each includes: a high side switch, a low side switch and an inductor, the control unit executes a first mode and a second mode wherein the first mode controls the high side switch and the low side switch in each of the power stages so that a ratio of an output current in each of the power stages to a load current flowing through the load becomes a set value and the second mode controls the high side switch and the low side switch in each of the power stages so that duty ratios of the high side switch and the low side switch are equalized among the power stages.

Abstract: Embodiments for at methods, apparatus and systems for operating a voltage regulator are disclosed. One method includes generating, by a switching controller, a switching voltage through controlled closing and opening of a series switch element and a shunt switch element, and generating an output voltage by filtering the switching voltage with an output inductor and a load capacitor. The method further includes generating an assisting current based on a value of current conducted through the output inductor, and assisting the load current by summing the assisting current with the current conducted through the inductor.

Abstract: A modulation method is provided. The modulation method includes the steps of receiving multiple sinusoidal signals, obtaining the maximum value of the sinusoidal signals, obtaining the median value of the sinusoidal signals, and obtaining the minimum value of the sinusoidal signals within a period to generate a difference between the maximum value and the minimum value, generating a difference according to an upper limit and a lower limit of a predetermined comparison value, and comparing the two differences to generate an optimized modulation signal.

Abstract: There is described a buck-boost converter comprising: a voltage source; an inductor, wherein a first terminal of the inductor is switchably connected to the voltage source; and a plurality of capacitors switchably connected to a second terminal of the inductor, wherein a respective plurality of output voltages are formed across the plurality of capacitors, further comprising: an error determination means, for determining an error in each of the plurality of voltages, an inner control loop adapted to switchably connect one of the plurality of capacitors to the second terminal of the inductor in dependence on the determined errors; and an outer control loop adapted to control switching between buck mode and boost mode in dependence upon the determined errors.

Abstract: A switching regulator comprises a PWM controller that controls switching of a power converter via a PWM control signal. The switching regulator detects load transients in the load driven by the power converter. Responsive to the detection of a load transient, the switching regulator resets a PWM clock synchronously with a fast clock operating at a higher frequency than the PWM clock. By doing so, the switching regulator beneficially responds more quickly to changes in the load than with conventional architectures that utilize only the slower PWM clock. This provides improved transient response without sacrificing power efficiency.

Abstract: An integrated power supply and modulator system includes integrated power supply and modulator system includes three subsystems: a switched-capacitor voltage balancer stage; a magnetic regulation stage; and at least one output switching stage. In one embodiment, the integrated power supply and modulator system further includes startup circuitry, feedback/feedforward circuitry and control circuitry.

Abstract: In one embodiment, a method of detecting a voltage can include: (i) generating a first current according to a first voltage and a converting resistor; (ii) charging a detection capacitor by the first current during a first time period of a switching cycle of a switching power supply; (iii) charging the detection capacitor by a second current during a second time period of the switching cycle; (iv) detecting a voltage across the detection capacitor to obtain a detection voltage at an end time of the second time period, where the first time period includes a rising portion of a current flowing through the inductor, and the second time period includes a decreasing portion of the inductor current; and (v) determining a state of a present output voltage of the switching power supply according to the detection voltage.

Abstract: A half-bridge of a bidirectional converter is divided into a first and a second conduction path connected in parallel. In each of the conduction paths a switching element and a freewheeling diode are connected in series, and the center points of the conduction paths are connected via a second inductor. The second inductor is connected in series with a first inductor which is connected to the center point of the second conduction path. The half-bridge has two operating modes. In each of the two operating modes the switching element in one of the two conduction paths is clocked at a high frequency to cause a flow of energy in one of two directions between a pair of high voltage-side connections and a pair of low voltage-side connections to the half-bridge. The two switching elements are of different types, the switching element in the first conduction path causing higher switching losses.

Abstract: A power supply apparatus includes a power supply section and a control section. The power supply section includes a first switch which performs switching of power-supply output, an inductor and a capacitor which form an LC circuit that resonates current flowing through the first switch, and a second switch which changes capacitance of the capacitor. The control section finds in advance a correspondence between a time ratio of a switching pulse of the first switch and a resonance frequency which matches an edge of a switching pulse having each time ratio, and controls switching of the second switch so as to resonate the LC circuit at a resonance frequency corresponding to a time ratio at operation time.

Abstract: A rapidly regulable high-voltage supply for the electrical focusing of an electron beam using a high-voltage final stage is provided. The high-voltage final stage includes a plurality of amplification elements that are interconnected in a series configuration with a first high-voltage connection, and a potential dividing chain including a series of potential dividing elements. The potential dividing chain is interconnected with the first high-voltage connection and has a signal interconnection with the plurality of amplification elements, so that when a voltage is applied across the potential dividing chain, a difference in voltages between a signal input to any amplification element of the plurality of amplification elements and a signal input to a next amplification element of the plurality of amplification elements has a same sign.

Abstract: A method and circuit for generating a clock signal. A power factor correction circuit has n channels operating out of phase and independently. The circuit is able to generate a clock signal for each channel according to the current cycle duration of each channel.

Abstract: A control circuit for controlling a power supply including a first switch and a second switch coupled in series between a first potential and a second potential. The control circuit includes a detection circuit that detects a magnitude relation of a voltage value at a node between the first and second switches and a reference value during a period in which the first switch and the second switch are inactivated. The detection circuit generates a control signal corresponding to the magnitude relation. A regulation circuit regulates a switching timing of the second switch in response to the control signal to decrease a difference between the voltage value at the node and the reference value.

Abstract: In one embodiment, a control circuit configured for an interleaved switching power supply having first and second voltage conversion circuits, can include: a feedback compensation signal generation circuit that generates a feedback compensation signal; a first power switch control circuit that activates a first on signal when a first voltage signal that represents an inductor current of the first voltage conversion circuit is less than the feedback compensation signal, a first power switch of the first voltage conversion circuit being turned on based on the first on signal, and turned off after a predetermined time; and a second power switch control circuit that activates a second on signal after half of a switching period from a rising edge of the first on signal, and a second power switch control signal to turn on a second power switch of the second voltage conversion circuit based on the second on signal.

Abstract: A power supply circuit including a DC/DC converter having switching elements and configured to receive an input voltage in an input line and generate an output voltage in an output line; and a linear regulator configured to receive the output voltage and supply a stabilized voltage to a load. The DC/DC converter switches between a switching mode to switch the switching elements and a bypass mode to put a switching element existing on a path from the input line to the output line, of the switching elements, in a full-on state and stop switching of the other switching element.

Abstract: In one implementation, a circuit for producing an average output inductor current indicator in a voltage converter is configured to start a counter when a high side power switch turns on, to sense a sample current through an output inductor of the voltage converter after the high side power switch turns off and when a low side power switch is on, and to register a first count of the counter when the low side power switch turns off. The circuit is further configured to register a second count of the counter when the high side power switch subsequently turns on, and to produce the average output inductor current indicator based on the sample current and the first and second counts of the counter.

Abstract: In one embodiment, a control circuit configured for an interleaved switching power supply, can include: (i) a feedback compensation signal generation circuit configured to sample an output voltage of the interleaved switching power supply, and to generate a feedback compensation signal; (ii) a first switch control circuit configured to compare a first branch voltage signal that represents an inductor current of a first voltage regulation circuit against the feedback compensation signal, where when the first branch voltage signal is consistent with the feedback compensation signal, a first switch on signal is generated to control a first main power switch of the first voltage regulation circuit to be on for a predetermined time, and then off; and (iii) a second switch control circuit configured to compare a second branch voltage signal that represents an inductor current of a second voltage regulation circuit against the feedback compensation signal.

Abstract: A DC-DC converter includes a voltage conversion circuit unit, a control unit, and a capacitor check unit. The voltage conversion circuit unit converts an input voltage to a first voltage. The control unit controls the voltage conversion circuit unit based on a feedback voltage and a reference voltage. The capacitor check unit determines whether a capacitor is coupled to a capacitor coupling terminal based on sensing a voltage of the capacitor coupling terminal, which is selectively coupled to the first control unit.

Abstract: A power supply unit has a first power supply circuit that supplies a voltage to a load driving unit and a second power supply circuit that supplies a voltage to circuits other than the load driving unit. A first switching unit connects any one of a power supply that supplies a power supply voltage and a voltage step-down circuit that supplies a step-down voltage of the power supply voltage to the first power supply circuit. A second switching unit connects any one of the power supply and the voltage step-down circuit to the second power supply circuit. A control unit controls the connection by the first switching unit and the connection by the second switching unit to switch the voltage supplied to the first power supply circuit and the voltage supplied to the second power supply circuit in accordance with properties of the load driving unit.

Abstract: An energy-based oriented switching mode power supply includes a bi-directional converter having an energy input and a load output, and an energy based pulsed generator connected between the energy input and the load output for outputting a gate voltage signal controlling how much energy is supplied from the energy input. The energy based pulsed generator receives a clock signal and outputs the gate voltage signal according to the load output of the bi-directional converter when the clock signal is at a high level. Accordingly, the switching mode power supply achieves a hybrid of PWM and PFM, depending on the energy demand of the load output, for a fast transient response and a small voltage ripple whilst improving power efficiency over a wide load range.

Abstract: Systems and methods are provided for regulating the state of charge of a battery. An exemplary electrical system includes a fuel cell coupled to a bus and a battery coupled to the bus via a switching arrangement coupled to a capacitor. An exemplary method for operating the electrical system involves operating the switching arrangement such that a voltage of the battery is substantially equal to a voltage of the fuel cell when a state of charge of the battery is greater than a lower threshold value and less than an upper threshold value, and operating the switching arrangement to couple the capacitor electrically in series between the battery and the bus when the state of charge of the battery is not between the lower threshold value and the upper threshold value.

Abstract: A buck/boost voltage regulator generates a regulated output voltage responsive to an input voltage and a plurality of control signals. The buck/boost voltage regulator includes a plurality of switching transistors responsive to the plurality of control signals. Control circuitry monitors the regulated output voltage and generates the plurality of control signals responsive thereto. The control circuitry controls the operation of the plurality of switching transistors to enable a charging phase in a first mode of operation, a pass through phase in a second mode of operation and a discharge phase in a third mode of operation within the buck/boost voltage regulator to eliminate occurrence of a four switch switching condition.

Abstract: A method and apparatus for controlling the output voltage of a boost converter including a number n of bridge devices connected in series, each bridge device including plural switches and a capacitor. The method and apparatus provide control of the switches according to a selected periodical matrix pattern including a number N of time intervals, N being a positive integer greater than 2, and in that in each time interval, the voltage between the input and the output of each ith bridge device with i from one to n, is equal to one of a null value, a number ki times a positive value, and minus the number ki times the positive value, the positive value being the result of the division of the output voltage of the boost converter including the n bridge devices by the number of time intervals N of the periodical matrix pattern.

Abstract: There is disclosed an asynchronous switch mode power supply comprising: a subtractor for subtracting an output of the switch mode power supply from a reference signal; a filter for filtering the subtracted output; a quantiser for generating a plurality of quantiser outputs in dependence on the integrated subtracted output; and a power switch stage for connecting one of a plurality of supply voltages to the output of the switch mode power supply in dependence on the quantiser outputs.

Abstract: A buck converter includes a pulse width modulation unit, a first switch, a second switch, an inductance, and a sensor near the inductance. The pulse width modulation unit controls the first switch and the second switch power to allow or disallow electrical conduction. The sensor senses the state of the inductance in respect of a sound event, a vibration event, and a drop in current level. When the inductance is saturated and gives rise to one or more of the foregoing events, the sensor sends a signal to the pulse width modulation unit, which controls the first switch to cut off power and the second switch to allow conduction, allowing the inductance to release all its electrical energy.

Abstract: A load drive apparatus (1) includes a pulse drive circuit (51) which applies a pulse voltage PS to a resistive load (4); current detection means (S14) for detecting the current flowing to the resistive load (4) through the pulse drive circuit (51); level detection means (S1, S7) for determining whether an output terminal voltage VD of the pulse drive circuit (51) is a high potential level or a low potential level; anomaly detection means (S8, S9, S18) for detecting a wire breakage anomaly, a short-to-power anomaly, and a short-to-ground anomaly based on the level of the output terminal voltage VD detected by the level detection means (S1, S7) and the current detected by the current detection means (S14), when the pulse drive circuit 51 is turned on and off.

Abstract: One example of generating a clock signal via an oscillator system includes increasing a first comparison voltage at a first comparison node from a first magnitude to a second magnitude in response to a clock signal. A second comparison voltage is increased at a second comparison node from the first magnitude to the second magnitude in response to the clock signal. The clock signal changes state in response to the second comparison voltage increasing to a magnitude that is greater than the first comparison voltage. The first comparison voltage decreases from the second magnitude to the first magnitude in response to the clock signal. The second comparison voltage decreases from the second magnitude to the first magnitude in response to the clock signal. The clock signal changes state in response to the second comparison voltage decreasing to a magnitude that is less than the first comparison voltage.

Abstract: A switching regulator circuit provides forward mode operation where a voltage provided at an input port can be boosted or bucked to produce a regulated voltage at an output port of the circuit. In accordance with the present disclosure, the switching regulator circuit includes two or more input ports. The switching regulator circuit provides a reverse boost operation in which a voltage provided at the output port of the circuit can be boosted to produce a regulated voltage at both of the input ports of the circuit.

Abstract: A control circuit of a step-up/step-down DC/DC converter includes: a hysteresis comparator configured to receive a feedback voltage and a reference voltage, compare the feedback voltage with a threshold voltage corresponding to the reference voltage, and generate a pulse signal indicating a result of the comparison; a logic unit configured to fix a second switching transistor at an OFF state and switch a first switching transistor based on the pulse signal in a step-down mode and fix the first switching transistor at an ON state and switch the second switching transistor based on the pulse signal in a step-up mode.

Abstract: Embodiments of systems, methods and apparatuses of a switching voltage regulator are disclosed. One switching voltage regulator includes a series switch element, a shunt switch element, a PWM controller, and a mode controller. The PWM controller includes an error amplifier and a switching controller. The error amplifier generates an error signal based on a difference between a reference voltage and an output voltage. Further, the switching controller is operative to generate switch element control voltages based on the error signal, for controlling opening and closing of the series switch element and the shunt switch element, wherein the opening and closing of the series switch element and the shunt switch element generates a switching voltage. The mode controller is operative adjust a gain of the error amplifier over a selected range of frequencies based on a parameter indicative of a likelihood of oscillations in the output voltage.

Abstract: A switching regulator arrangement utilizes internal capacitors rather than external capacitors for driving output power transistors. Low-dropout linear voltage regulators together with a dip compensation circuit provide an intermediate supply voltage for driving power transistors under circumstances in which a supply voltage is greater than a gate drive voltage of the power transistor, allowing for a more efficient absorption of transient current.

Abstract: An embodiment of a power-supply controller includes switching circuitry and an adjuster circuit. The switching circuitry is configured to cause a charging current to flow until the charging current has a predetermined relationship to a threshold, and to cause a discharging current to flow after the charging current. The adjuster circuit is configured to adjust the threshold in response to at least one of a charging period during which the charging current flows and a discharging period during which the discharging current flows. For example, a power supply may include such a power-supply controller to maintain a length of a current pulse, or of a portion thereof, within a particular range, such as approximately at a particular value, during a pulse-frequency-modulation (PFM) mode despite variations in one or more parameters such as input voltage, output voltage, filter capacitance, phase inductance, charging-current-sense impedance, and load, from their respective nominal values.

Abstract: A switch mode power supply has a first and second branch of an inductive element; a first switching element and a second switching element connected in series. Both branches are coupled to a power source in parallel. A controller controls said switching elements for operating said switch mode power supply in a plurality of consecutive time periods, wherein more than two of said switching elements are closed, i.e. at least one in each branch. The power supply has a polarity switching element coupled between said branches for receiving a pulsed voltage for providing an output voltage of a switchable polarity. The controller receives a feedback signal corresponding to the output voltage, compares the feedback signal to a reference waveform, and controls said switching elements and the polarity switching element in dependence of said comparing for generating the output voltage according to the reference waveform.

Abstract: A switching power voltage regulator includes a pulse width modulation (PWM) signal generator, an output circuit and a feedback circuit. The PWM signal generator is configured to generate a PWM signal. The feedback circuit is configured to provide a feedback signal to the output circuit according to an output voltage of the output circuit. The output circuit includes an inductor, a plurality of inverters, and a driver. Each of the inverters includes a first transistor and a second transistor. When the inductor needs to be charged, the driver selectively switches one or more corresponding first transistors on according to the feedback signal.

Abstract: A DC-DC converter includes: an inductor; a first capacitor and a second capacitor; a plurality of switching elements coupled to the inductor, the first capacitor, and the second capacitor; a control circuit configured to control the plurality of switching elements to be switched ON/OFF such that a connection form of the inductor, the first capacitor, and the second capacitor is alternately switched between a first form where the inductor, the first capacitor, and the second capacitor are coupled in series such that the first capacitor and the second capacitor are charged and a second form where the inductor, the first capacitor, and the second capacitor are coupled in parallel such that the first capacitor and the second capacitor are discharged; and a detection circuit configured to detect a difference between each of a voltage across the first capacitor and a voltage across the second capacitor.

Abstract: A switching regulator includes a first switching element and a second switching element in a pair to be switched over to convert an input voltage to a certain constant voltage, and an operation monitor to monitor an operation state of the first switching element, in which a switching of the second switching element is changed according to a result of the monitoring by the operation monitor.

Abstract: In a power converter, a circuit determines an average value of an inaccessible current from an average value of an accessible current and a value of the operating duty cycle of the converter. A method of measuring an average value of an inaccessible current from a measured value of a current in a power converter by a duty cycle of a pulse width modulated (PWM) signal representing a duty cycle of the power converter. Coupling a voltage representing the measured value to an input of a low pass filter during a time period (D) and coupling the input of the low pass filter to a reference voltage during a time period (1?D).

Abstract: A switching regulator includes a multiphase converter which includes a plurality of main phases configured to covert a power supply voltage to a lower voltage for application to an electronic device at different load conditions. The switching regulator also includes an auxiliary phase configured to operate in a pulse frequency modulation mode during a light load condition so that power is supplied to the electronic device by at least the auxiliary phase during the light load condition.

Abstract: In an embodiment, a power-supply controller includes switching circuitry and an adjuster circuit. The switching circuitry is configured to cause a charging current to flow until the charging current has a predetermined relationship to a threshold, and to cause a discharging current to flow to an output node that carries an output voltage after the charging current. And the adjuster circuit is configured to adjust the threshold such that a ripple voltage superimposed on the output voltage has an approximately constant magnitude. For example, a power supply may include such a power-supply controller to maintain the magnitude of the output ripple voltage within a particular range during a pulse-frequency-modulation (PFM) mode despite variations in one or more parameters such as input voltage, output voltage, filter capacitance, phase inductance, and charging-current-sense impedance, from their respective nominal values.

Abstract: A driving device is provided with: a power circuit in which it is possible to modify an output current value of an output terminal configured to have a load connected thereto; an output capacitor connected between the output terminal of the power circuit and a reference potential node; a switching element connected between the output terminal of the power circuit and the reference potential node; and a control unit that controls the output current value of the power circuit. The control unit turns the switching element ON and OFF and controls the output current value of the power circuit during a period in which the switching element is ON such that the voltage of the output terminal of the power circuit during this period is equal to or lower than the voltage applied to the load during a period when this load is OFF.

Abstract: A power converter having a bootstrap refresh control circuit and a method for controlling the power converter. The bootstrap refresh control circuit is configured to monitor a bootstrap voltage across a bootstrap capacitor and to provide an enhanced high side driving signal to a high side switch of the power converter. The bootstrap refresh control circuit is further configured to controlling the charging of the bootstrap capacitor through regulating the on and off switching of the high side switch and a low side switch based on the bootstrap voltage. The bootstrap refresh control circuit can refresh the bootstrap voltage in time to support driving the high side switch normally, without causing large spikes in an output voltage of the power converter and without influencing the power conversion efficiency of the power converter.

Abstract: An embodiment of a power-supply controller includes a switching circuit and a transition circuit. The switching circuit is configured to generate a regulated output voltage by generating first current pulses at an approximately fixed frequency during a first mode, and generating second current pulses at a variable frequency during a second mode. And the transition circuit is configured to transition the switching circuitry from the first mode to the second mode in response to a length of one of the first current pulses. For example, a power supply may include such a power-supply controller to transition the supply from a PWM mode to a PFM mode under light-load conditions. To cause this transition at a predictable load point, the controller may monitor the lengths of the current pulses during the PWM mode, and may transition the supply to a PFM mode in response to the lengths being below a threshold.

Abstract: A system and method capable of injection locking the phases of a peak-valley multiphase regulator includes comparing an output voltage error signal with a ramp control signal and providing a corresponding slope reset signal, using transitions of the slope reset signal to develop a equally spaced high side ramp signals and equally spaced low side ramp signals, and injecting a corresponding one of the high side signals and a corresponding one of the low side ramp signals into each of the phases which correspondingly develop equally spaced pulse control signals for multiphase operation. Such injection locking allows the additional phases to operate out of phase with the first phase and allows operation at high duty cycles.

Abstract: An organic light emitting display device includes a DC-DC converter to supply first and second voltages to one or more pixels. The DC-DC converter includes a first voltage supply to convert an input voltage to a first voltage and a second voltage supply to convert the input voltage to a second voltage. The first and second voltages are coupled to opposing ends of the one or more pixels. The first voltage supply includes a first inductor between a first input terminal and first node, a first transistor between the first node and a reference potential, a second transistor between the first node and first output terminal, a first diode between the first node and a second node, a second diode between the second node and first output terminal, and a first switch between the second node and first output terminal.

Abstract: An inductor L2 is inserted in series between an input power supply E and a switching device Q1. An input smoothing capacitor C2 is provided between a connecting point of the inductor L2 and the switching device Q1 and a ground point. Herein, let L2 be an inductance value of the inductor, C2 be an electrostatic capacity of the input smoothing capacitor, and T1 be a time since the switching device Q1 is switched from an ON state to an OFF state until the switching device Q1 is switched to an ON state again according to an output signal from a drive circuit DR, then T1 is set so as to satisfy 0<T1<??{square root over (L2×C2)} By lowering a voltage applied to a switching device when the switching device switches OFF from ON, it becomes possible to use a switching device having low breakdown voltage in a step-down DC-to-DC converter.