Abstract: A DC-DC converter includes: an inductance element and a rectifier element connected in series between a voltage input terminal to accept input direct current voltage and a first output terminal; a switching element connected between a connection node of the inductance element and the rectifier element and a reference potential point; and a controlling circuit to form a signal to control on/off of the switching element. The controlling circuit controls on/off of the switching element to control current through the inductance element, and a voltage applied to the voltage input terminal to accept the input direct current voltage is output via a second output terminal as a reference potential of a circuit at a latter stage, so that an output voltage is controllable from a lower to higher voltage than the input direct current voltage without switching step-up and step-down operations.

Abstract: A converter including an inductor (L), a first switch (SW1, S1) connected between an input terminal (Vin) and the inductor, a diode/switch (D1, S2), connected between the first end of the inductor and ground, a diode/switch (D2, S3) connected between the inductor and an output terminal (Vout), and a second switch (SW2, S4) coupled between inductor and ground. A current sensor senses current in the first switch (SW1, S1) as a measure of inductor current. Waveform generators (31, 32) generate buck and boost slope compensation ramps (RMP-BUCK, RMP-BOOST). Control logic (10) opens and closes the switches every clock period at individual duty cycles determined using a feedback signal derived from the output terminal, the sensed current and the slope compensation ramps. The slope compensation ramps are mutually offset such that current sensing is needed only while the first switch (SW1, S1) is closed.

Abstract: A step-up/step-down regulator circuit wherein a switch has a terminal connected to an end of an inductor, another terminal grounded, and a control terminal connected to an end of a switch. In this way, performing an open/close control of the switch can indirectly perform an open/close control of the switch, 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: An emulator circuit for forming a signal representative of current flow in an inductor of a switched mode power supply, where the inductor is associated with a switching arrangement operational to connect a first node of the inductor to a first voltage (Vin) or to one of a reference voltage (gnd) or a current flow path, a second node of the inductor to a second voltage (Vout) or to one of a second reference voltage (gnd) or the current flow path, and wherein the emulator circuit forms a emulator output signal representing the integral with respect to time for which the first and second node of the inductor are connected to the first voltage and the second voltage respectively.

Abstract: A buck-boost switching regulator which includes a first switch, a first diode, an inductor, a second switch, a second diode, and a controller for controlling the first switch and the second switch, the controller being configured to receive a current signal indicative of a inductor current flowing in the inductor, and generating a signal indicative of an average current flowing in the inductor, the average current being utilized to control the first switch and the second switch, wherein the controller includes a first compensator circuit for outputting a voltage error signal, a second compensator circuit for outputting a current error signal and a modulator circuit to output a first control signal to control the first switch and a second control switch to control the second switch.

Abstract: A power conversion circuit capable of varying an output voltage within a range from a negative voltage lower than a ground voltage to a positive voltage higher than a supply voltage, and a driving method and a drive unit are provided. A power conversion circuit includes a transformer with a 1:1 ratio between the primary winding and secondary winding, a voltage outputting capacitor, and four switches. The power conversion circuit can be operated as a DC-DC converter of a step-up type, a step-up-and-down type, a step-down type, an inverted-output step-up-and-down type, or an inverted-output step-up type by selecting two switches used for control from among the four switches and alternately turning the two switches on. By switching the operating modes of the power conversion circuit, the output voltage can be varied within a range from a negative voltage to a positive voltage higher than a supply voltage.

Abstract: A switching voltage regulator control device, includes first and second half-bridges each comprising a switch. The first half-bridge is located between an input voltage and a reference voltage and the second half-bridge is located between an output voltage and the reference voltage. The regulator comprises a detector for detecting the error between a reference voltage representative of the output voltage and another reference voltage and an integrator for integrating said error. The control device is suitable for providing a first duty cycle for driving the switch of the first half-bridge that is proportional to the integrated error divided by the input voltage and a second duty cycle for driving the switch of the second half-bridge that is proportional to the value of the input voltage divided by the integrated error.

Abstract: A step-up converter includes input and output terminals, step-up conversion circuitry, a first feedback path and a drive circuit. The input terminals are configured to receive an input DC voltage and the output terminals configured to provide an output DC voltage. The step-up conversion circuitry is coupled between the input terminals and the output terminals and includes a switching element. The first feedback path has a regulator arrangement configured to provide a regulating signal which is dependent on the output voltage. The drive circuit is configured to provide a pulse-width-modulated drive signal for the switching element and is supplied with the regulating signal, wherein the drive circuit is configured to generate the drive signal in a manner that corresponds to the input voltage.

Abstract: A control circuit of a multi-mode buck-boost switching regulator and a method thereof are provided. The control circuit imposes ON/OFF timing sequences on switches according to the relationship between two controlling triangle waves and the load fluctuation. In each working cycle of each mode of the regulator, at most two switches perform switching operations. The control circuit is simple to design, which only includes simple digital elements, such as comparators, logic gates etc., instead of complicated analog circuits.

Abstract: A power supply device for powering equipment from at least one network supplying AC and at least one battery supplying DC, the power supply device comprising: a first branch that is connected to the main network and that comprises a transformation member for transforming the AC voltage into an equivalent DC voltage; a second branch that is connected to the battery and that comprises a voltage booster for raising the DC voltage supplied by the battery to an output voltage close to the DC voltage equivalent to the AC voltage; the first branch and the second branch being connected by a switch member to a converter arranged to transform the DC voltage equivalent to the AC voltage of the network into at least one DC voltage for powering the equipment.

Abstract: A new topology for a buck-boost switching regulator is provided herein. Embodiments provide an efficient buck-boost switching regulator that provides a regulated output voltage from an unregulated input voltage. Embodiments include a buck-boost switching regulator topology, where the operating mode is determined separately from the pulse-width modulated (PWM) control signal. This topology, in one embodiment, provides a better transient response than typical buck-boost switching regulator topologies, where PWM control circuitry and operating mode circuitry are combined. Furthermore, embodiments provide a buck-boost switching regulator that allows for high efficiency when the output voltage is close to the input voltage.

Abstract: A supply circuit (1) comprising an inductor (2) coupled to switching means (7) and comprising a capacitor (4) is provided with an impedance (3) located between the inductor (2) and the capacitor (4), with a current injector (5) and with a feedback loop comprising a converter (6) for controlling the current injector (5) for compensating a ripple in an output voltage across the capacitor (4). The impedance (3) allows injection of a compensating current at a location different from an output location. This increases a number of possible detections of ripples in the output voltage and allows a ripple in an output voltage to be detected even in case of loads introducing much noise across the capacitor (4). The converter (6) detects a detection signal via the impedance (3) by measuring a voltage across the impedance (3) or across a serial circuit comprising the impedance (3) and the capacitor (4). The impedance (3) comprises a resistor or a further inductor.

Abstract: A buck or boost converter, which includes a first inductor, a controlled switch, a main diode, and an output capacitor, also includes a snubber circuit to reduce losses. The snubber circuit includes a second inductor in a path in series with the switch and main diode of the converter, a series-connected resistor and diode connected directly in parallel with the second inductor, and a capacitance in parallel with the main diode and which can be constituted partly or entirely by parasitic capacitance of the main diode.

Abstract: This invention prevents undershoot, etc., occurring in the output during the transition from intermittent control mode to continuous control mode to hinder stability, responsiveness, and low power consumption.

Abstract: A buck or boost converter, which includes a first inductor, a controlled switch, a main diode, and an output capacitor, also includes a snubber circuit to reduce losses. The snubber circuit includes a second inductor in a path in series with the switch and main diode of the converter, a series-connected resistor and diode connected directly in parallel with the second inductor, and a capacitance in parallel with the main diode and which can be constituted partly or entirely by parasitic capacitance of the main diode.

Abstract: A step-up/down DC-DC converter is disclosed that includes: a step-up/down part generating an output voltage by stepping up or down an input voltage; and a control part generating an error signal indicating an error between a voltage value obtained by dividing the output voltage and a predetermined reference voltage, and causing the step-up/down part to perform a step-up or step-down operation based on the comparison between the error signal and first and second triangle wave signals. The control part includes a first circuit generating the first triangle wave signal for step-down control and a second circuit generating the second triangle wave signal for step-up control. The first circuit generates a clock signal synchronized with the first triangle wave signal, and outputs the clock signal to the second circuit. The second circuit generates the second triangle wave signal synchronized with the first triangle wave signal based on the input clock signal.

Abstract: A PWM buck-or-boost converter is provided. The converter includes an error amplifier, a rectifier/splitter, a first comparator, and a second comparator. The rectifier/splitter provides two signals proportional to the departure of the error voltage from a central value but increasing in value from zero. Only one of the two signals departs from zero depending on the error voltage. The first comparator compares one of the two signals to a modulating waveform (e.g. a sawtooth waveform), and the second comparator compares the other of the two signals to the modulating waveform. Only one of the two signals intersects the modulating waveform depending on the error voltage. During buck regulation, the first comparator controls the buck switches and the output of the second comparator remains high. During boost regulation, the second comparator controls the boost switches and the output of the first comparator remains high.

Abstract: A disclosed step-up/step-down switching regulator includes a step-up/step-down part using an inductor for stepping up or stepping down an input voltage from an input terminal and outputting the stepped-up/stepped-down voltage from an output terminal according to a control signal, and a control part for controlling the stepping-up/stepping-down by the step-up/step-down part according to a voltage difference between a voltage proportional to the voltage output from the step-up/step-down part and a predetermined reference voltage.

Abstract: A Single Ended Primary Inductance Converter (SEPIC) fed BUCK converter includes: a first switch configured to open or close according to a first signal; a SEPIC portion coupled to the first switch and coupled to an energy source, the SEPIC portion comprising a first set of one or more passive components; a BUCK converter portion coupled to the first switch, the BUCK converter portion comprising a second set of one or more passive components. While the first switch is closed, the SEPIC portion is configured to store energy from an energy source in at least some of the first set of passive components and deliver energy to the BUCK portion, and the BUCK converter portion is configured to deliver energy to a load and to store energy in at least some of the second set of passive components. While the first switch is open, the SEPIC portion is configured to deliver at least some of its stored energy to the load, and the BUCK converter portion is configured to deliver at least some of its stored energy to the load.

Abstract: Measured or otherwise known operating characteristics of a DC/DC power converter are used to determine, without measuring, an operating characteristic of the DC/DC power converter.

Abstract: A unidirectional DC-DC converter which has a simple control circuit without using multiple insulated power supplies or a transformer, uses an auxiliary inductor of a comparatively small capacitance, reduces the size and weight of the converter, and has a very great capacitance without switching of supply current. For example, a unidirectional DC-DC converter equipped with main IGBT101 which supplies and shuts off current for first inductor 108a and diode 107 which discharges energy from main inductor 108a to an the output. The DC-DC converter is further equipped with auxiliary IGBT104 which applies current to back-to-back-connected diode 102 by using energy stored in auxiliary inductor 108b which is magnetically coupled with main inductor 108a. This applies current to the back-to-back-connected diode in a short period including a time period in which the first switching element is turned on and accomplishes ZVZCS.

Abstract: A switching regulator that performs voltage regulation using synchronous rectification in step-up and step-down modes includes input and output terminals, an inductor, first through fourth transistors, an overcurrent detection unit, and a control unit. The input terminal receives an input voltage. The inductor generates an output voltage. The output terminal provides the output voltage. The first and second transistors perform switching in the step-down mode. The third and fourth transistors perform switching in the step-up mode. The overcurrent detection unit detects an overcurrent condition. The control unit controls operation of the transistors, causes the first and third transistors to be off and the second and fourth transistors to be on when the overcurrent condition is detected in a first state, and causes the first and fourth transistors to be on and the second and third transistors to be off when the overcurrent condition is detected in a second state.

Abstract: In a maximum duty control state of a switching regulator control circuit, a period of time during which any one of a step-up switching circuit and a synchronous rectification switching circuit is always off is ensured, thereby preventing the switching efficiency from being remarkably deteriorated. In a maximum duty control state, a voltage difference is provided between a limiter voltage that is inputted to a comparator that controls the switching operation of the step-up switching circuit and a limiter voltage that is inputted to a comparator that controls the switching operation of the synchronous rectification switching circuit, to thereby ensure the period of time during which any one of the step-up switching circuit and the synchronous rectification switching circuit is always off.

Abstract: In a standby mode, a voltage step up DC/DC converter 5 supplies a power output voltage equal to or higher than a second set voltage which is lower than a first set voltage in a normal operating mode to a microcomputer (load) 1 with current supply performance which is smaller than in the normal operating mode. On the other hand, in the normal operating mode, a voltage step up/step down DC/DC converter 4 supplies the first set voltage in the normal operating mode to the microcomputer 1.

Abstract: A DC-DC converting apparatus including a step-up and step-down circuit stepping up/down an input voltage to generate an output voltage and a PWM control circuit. The PWM control circuit generates an error signal, first to third voltages, a first triangular wave signal varying between the first and second voltages, and a second triangular wave signal varying between the third voltage and a fourth voltage determined based on the first to third voltages. The PWM control circuit compares the error signal with the first and second triangular wave signals and causes the step-up and step-down circuit to step up/down the input voltage based on the comparison. The first to fourth voltages V1 to V4 satisfy V1<V4<V2<V3 and V4=V3?(V2?V1). At least one of the first to third voltages is variably set to make a time in which voltage ranges of the first and second triangular wave signals overlap longer than a delay time caused by the comparison.

Abstract: A current-mode switching regulator is provided. In one embodiment, the regulator is a multi-mode buck-boost regulator that operates as follows. When the operating mode changes, a gain associated with the inner current loop changes, and the loop compensation changes. The inner current loop gain and the loop compensation are adjusted when the operating mode changes such that the post-mode change feedback variable values are roughly the same as the pre-mode change feedback variables values.

Abstract: A PFM buck-or-boost converter is provided. The converter includes, inter alia, a hysteretic comparator, current sense circuitry, a logic circuit, drivers, current sense circuitry, a first buck switch, and a first boost switch. The current sense circuitry asserts signal Z if the current through the boost switch (from the load to the inductor) is greater than zero, and unasserts Z otherwise. Additionally, the current sense circuitry asserts signal I if the current through the buck switch is greater than a fixed current limit value, and unasserts I otherwise. The logic circuit employs the hysteretic comparator output, signal Z, and signal I to control the switches, and to determine whether to operate in buck regulation mode or boost regulation mode.

Abstract: According to an exemplary embodiment, a method includes the step (910) of driving a buck section of a DC/DC converter with a buck signal that has a buck duty cycle and concurrently with driving the buck section, driving a boost section of the DC/DC converter with a boost signal that has a boost duty cycle, a difference existing between the buck duty cycle and the boost duty cycle. The method also includes the step (920) of monitoring an input voltage that is coupled to the buck section for a change in the input voltage, and in response to a change in the input voltage, the step (930) of changing the buck duty cycle and the boost duty cycle such that the difference between the buck duty cycle and the boost duty cycle is substantially constant.

Abstract: There is provided a power-supply circuit for supplying voltage to a load, having a power supply that generates power-supply voltage, an inverted outputting circuit having a positive voltage terminal for outputting positive voltage based on the power-supply voltage and a negative voltage terminal for outputting negative voltage generated based on the power-supply voltage and having different polarity from the positive voltage and outputting the positive and negative voltage while keeping the same direction in terms of directions of electric current flowing between the positive voltage terminal and the outside and of electric current flowing between the negative voltage terminal and the outside, a step-down output circuit for outputting predetermined step-down output voltage to the outside by connecting the positive and negative voltage terminals to the outside while switching them with a predetermined duty ratio and a step-up output circuit for supplying step-up output voltage whose absolute value is greater t

Abstract: A switched regulator circuit provides step-up and step-down operation in which the level of the input voltage can be greater, equal to, or less than a preset controlled output voltage. A four switch arrangement or two switch arrangement provides buck, boost, and buck-boost regulation under variable frequency valley-peak current mode control. A single sense resistor may be utilized for sensing inductor current during each duty cycle.

Abstract: An electrical DC-to-AC power conversion apparatus is disclosed that is primarily intended for use with solar photovoltaic sources in electric utility grid-interactive applications. The invention improves the conversion efficiency and lowers the cost of DC-to-AC inverters. The enabling technology is a novel inverter circuit topology, where throughput power, from DC source to AC utility, is processed a maximum of 1½ times instead of 2 times as in prior-art inverters. The AC inverter output configuration can be either single-phase, split-phase or poly-phase.

Abstract: A charging device that may perform charging with larger current is provided. The charging device comprises a switching element for increasing or decreasing charging power, a PWM controlling circuit for intermittently turning the switching element on or off, a current detecting circuit for detecting current flowing through the switching element, and a rectifying circuit for rectifying output voltage of the current detecting circuit in response to power supply voltage. The PWM controlling circuit has a limiter terminal for turning off the switching element when voltage equal to or above a determined value is input, and rectified voltage from the rectifying circuit is input to the limiter terminal. In this charging device, an amount of temperature increase of the switching element is suppressed so as to remain within a fixed range, and the charging power is not restricted unnecessarily.

Abstract: A DC to DC converter comprising an inductor, first and second electronically controllable switches and a controller, wherein the first electronically controlled switch is interposed between an input node and a first terminal of the inductor and the second electronically controllable switch extends between a second terminal of the inductor and the ground and where a first rectifier extends between the ground and the first terminal of the inductor and a second rectifier connects the second terminal of the inductor to an output node, wherein the controller controls the operation of the first and second switches to perform voltage step down or voltage step up, as appropriate, to achieve a desired output voltage; and wherein the controller is arranged such that the order in which the first and second switches are operated is maintained irrespective of whether the converter is stepping up the input voltage or stepping down the input voltage.

Abstract: When both step-up PWM control and step-down PWM controls are executed, the offset of the ON/OFF switching timing for step-up PWM control and/or the offset of ON/OFF switching timing for step-down PWM control are changed to become identical. By synchronizing ON/OFF switching timing for step-up PWM control and ON/OFF switching timing for step-down PWM control, the loss on switching can be reduced.

Abstract: A PWM regulator is operated either a buck mode or a boost mode depending on whether the input voltage is above or below the desired regulated output voltage. The technique uses two sawtooth ramps 180 degrees out of phase. Where the two ramps cross each other is a buck/boost transition level. An error voltage, corresponding to a required duty cycle to achieve a regulated voltage, is compared to the two ramps. The transition from one mode to the other occurs when the error voltage passes the buck/boost transition level of the two ramps. A logic circuit supplies PWM pulses to either buck switching transistors or the boost switching transistors in a power stage of the regulator, depending on the whether the error voltage is above or below the buck/boost transition level, to achieve the regulated voltage.

Abstract: A switched regulator circuit provides step-up and step-down operation in which the level of the input voltage can be greater, equal to, or less than a preset controlled output voltage. A four switch arrangement or two switch arrangement provides buck, boost, and buck-boost regulation under constant frequency valley-peak current mode control. A single sense resistor may be utilized for sensing inductor current during only a short period during each duty cycle. As an alternative to the sense resistor, the switches themselves can be used to sense current during operation.

Abstract: A step-up/down DC-DC converter is disclosed that includes: a step-up/down part generating an output voltage by stepping up or down an input voltage; and a control part generating an error signal indicating an error between a voltage value obtained by dividing the output voltage and a predetermined reference voltage, and causing the step-up/down part to perform a step-up or step-down operation based on the comparison between the error signal and first and second triangle wave signals. The control part includes a first circuit generating the first triangle wave signal for step-down control and a second circuit generating the second triangle wave signal for step-up control. The first circuit generates a clock signal synchronized with the first triangle wave signal, and outputs the clock signal to the second circuit. The second circuit generates the second triangle wave signal synchronized with the first triangle wave signal based on the input clock signal.

Abstract: High-performance low-power isolated bootstrapped gate drive apparatus and methods are disclosed for driving high-side and floating transistors. The gate drivers use edge-triggered capacitive-coupled inputs. The gate drivers may include detection and delay circuitry to facilitate zero-voltage-switching of the high side or floating transistor and providing more robust rejection of false triggering. A capacitively coupled differential input edge triggered gate driver provides exceptional immunity to false triggering. The gate drivers may be used in transformer coupled drive circuits using transformers that need only support coupled pulses wide enough to be recognized as an edge by the input circuit.

Abstract: A boost control module operates semiconductor switches of a boost converter circuit in an avalanche mode to precharge a boost output capacitor. The boost control module comprises a switching module that complementarily transitions a first semiconductor switch and a second semiconductor switch between ON and OFF states when a current does not exceed a maximum current threshold. The switching module transitions the first semiconductor switch and the second semiconductor switch to the OFF state when the current exceeds the maximum current threshold. The switching module maintains the first semiconductor switch and the second semiconductor switch in the OFF state until at least one of the inductor current is less than or equal to a minimum current threshold.

Abstract: A power supply, including a step-up converter, a resonant converter, and control unit. The step-up converter is connected to the resonant converter; the step-up converter and the resonant converter are each connected to the primary control unit.

Abstract: The present invention is a switching power converter that supports both a boost mode of operation and a buck mode of operation, uses one energy storage element, transitions smoothly between boosting and bucking, and avoids simultaneous boosting and bucking. The switching power converter uses a common duty-cycle timing signal and a common duty-cycle setpoint signal to provide a smooth transition between boosting and bucking, and to eliminate overlap between boosting and bucking. A voltage input error integrator is used to integrate out errors between an output voltage and a setpoint voltage to provide the common duty-cycle setpoint signal. Duty-cycle error integrators are used to integrate out errors between the common duty-cycle setpoint signal and the actual duty-cycle of either the buck converter or the boost converter. Non-overlapping boost operating and buck operating ranges are provided by the common duty-cycle setpoint signal.

Abstract: A current detection circuit of the present invention has a switching device 1; an auxiliary switching device 2; an offset voltage source comprising an offset resistor device 7 and a current source circuit 8; a compensation circuit, comprising a differential amplifier 4 and a compensation transistor 5, for adjusting the output current of the auxiliary switching device 2 so that the potential obtained by subtracting the voltage drop across the offset resistor device 7 from the output potential of the switching device 1 is equal to the output potential of the auxiliary switching device 2, being configured that the detection level of the current flowing in the switching device 1 is shifted by an offset amount.

Abstract: There is provided a process for operating a switch mode power supply circuit (Switcher) connectable to a load, the circuit having a first buck switch, a second boost switch and an inductor in a buck boost circuit, the process including applying input voltage to the circuit, selectively activating each of the buck switch and boost switch, and selectively limiting the ON-time of the buck switch, for accelerating discharge of the inductor.

Abstract: A buck topology that provides voltage step up and polarity change is disclosed. In one embodiment a converter includes an input for receiving an input voltage, a switching circuit coupled to the input for receiving a first driving signal, a floating voltage source coupled to the switching circuit for producing an offset voltage, and an output coupled to the floating voltage source for generating an output voltage. The output voltage exhibits a voltage level that is directly proportional to a duty cycle of the first driving signal.

Abstract: A dual output buck-boost power converter operates with a single inductor to achieve high efficiency with automatic or inherent load balancing. Switches associated with the opposite polarity outputs are driven based on feedback signals, with one feedback signal being a reference voltage and another feedback signal being related to an opposite polarity output. The opposite polarity feedback signal is provided to a comparator with a reversed polarity to achieve a simple balanced control that maintains polarity outputs. The power converter delivers power to each output with each switching cycle and uses a single inductor to achieve high efficiency performance.

Abstract: A PFC circuit comprises a first converter and a second converter and a multi-port electromagnetic device. The first converter has a first inductive element and the second converter has a second inductive element. The multi-port electromagnetic device comprises a first magnetic core having a first closed flux path and a second magnetic core having a second closed flux path, with the first closed flux path being independent of the second closed flux path. The first inductive element of the first boost circuit comprises a first winding that electromagnetically couples the first magnetic core to the second magnetic core and the second inductive element of the second boost circuit comprises a second winding that electromagnetically couples the first magnetic core to the second magnetic core independent of the electromagnetic coupling of the first winding such that current application in one windings does not induce a substantial voltage in the other.

Abstract: Voltage regulators and methods for regulating voltages are disclosed. A switching circuit with an inductor and a plurality of switches may be used to produce a regulated voltage from an unregulated voltage source. A control circuit may be used to monitor the voltages at the input and output of the voltage regulator, and operate the switches in either a buck, boost, or buck-boost mode depending on the relationship between the voltages at the input and output of the voltage regulator.

Abstract: A DC-DC converting apparatus including a step-up and step-down circuit stepping up/down an input voltage to generate an output voltage and a PWM control circuit. The PWM control circuit generates an error signal, first to third voltages, a first triangular wave signal varying between the first and second voltages, and a second triangular wave signal varying between the third voltage and a fourth voltage determined based on the first to third voltages. The PWM control circuit compares the error signal with the first and second triangular wave signals and causes the step-up and step-down circuit to step up/down the input voltage based on the comparison. The first to fourth voltages V1 to V4 satisfy V1<V4<V2<V3 and V4=V3?(V2?V1). At least one of the first to third voltages is variably set to make a time in which voltage ranges of the first and second triangular wave signals overlap longer than a delay time caused by the comparison.

Abstract: The object of this invention is to improve efficiency in the step-up/down mode and eliminate ringing in the output voltage when switching between the step-up mode and the step-up/down mode. This DC-DC converter has a local feedback control pre-processing circuit 12 arranged between voltage input terminal IN and one of the terminals of choke coil 10 or node Nx as well as an output feedback control booster circuit 14 arranged between the other terminal of choke coil 10 and the voltage output terminal OUT. Pre-processing circuit 12 has switching elements 16 and 18 and control circuit 20 that turns on/off switching elements 16 and 18 in a complementary manner. Control circuit 20 has error amplifier 22, reference voltage generating circuit 24, PWM comparator 26, inverter 28, and low-pass filter (LPF) 30.

Abstract: A low-ripple power supply includes a storage capacitor coupled across load terminals, and an inductor connected to a source of voltage including a varying or pulsatory component and a direct component, for causing a flow of current to said capacitor through the inductor. The varying component of the inductor current flowing in the capacitor results in ripple across the load. A winding is coupled to the inductor for generating a surrogate of the varying inductor current. The surrogate current is added to the inductor current to cancel or reduce the magnitude of the varying current component. This cancellation effectively reduces the varying current component flowing in the storage capacitor, which in turn reduces the ripple appearing across the load terminals.