Sanken Electric Co., Ltd.

Honda Giken Kogyo Kabushiki Kaisha

Ge Medical Systems Global Technology Company, LLC

Taiho Industries Co., Ltd.

Hiroshi Usui

Yukinari Fukumoto

Koichi Morita

Syohei Osaka

Akihiro Uchida

Masaaki Shimada

Yoichi Kyono

Ryuichi Furukoshi

Tomoyasu Yamada

Mitsuhiro Nozaki

Toru Ashikaga

Takashi Kawaguchi

Yukihiro Kaminaga

Hiroshi Isono

Tamio Okamura

Jaehee Cho

Yasuhiro Rikiishi

Syouhei Osaka

A converter includes a rectifying circuit of an AC voltage of an AC power source into a rectified voltage, an input smoothing capacitor Ci, a first series circuit connected to the input smoothing capacitor and including a first and a second switching elements, a second series circuit connected to a connection point of the first and second switching elements and a first end of the input smoothing capacitor and including a primary winding of a transformer and a first capacitor Cri, a controller to alternately turn on/off the first and second switching elements, a rectifying-smoothing circuit (D, Co) to rectify and smooth a high-frequency voltage of a secondary winding of the transformer into a DC output voltage, and a second capacitor connected between a connection point of the primary winding of the transformer and the first capacitor and a first end of the AC power source.

PFC AC/DC converter reducing harmonics, switching loss, and switching noise

The present invention provides a DC-DC converter including: a first series circuit which is connected to the two ends of a direct-current power source Vi, and in which a first switching element Qand a second switching element Qare connected together in series; a control circuitconfigured to alternately turn on and off the first switching element and the second switching element; a second series circuit which is connected to the two ends of the first switching element, and in which a first capacitor Ci, a first reactor Ls and a second reactor Ll having a larger value than the first reactor are connected together in series; and rectifying/smoothing circuits (Do, Co) configured to rectify and smooth a voltage between the two ends of the second reactor, and to output a direct-current output voltage.

DC-DC converter

A DC-DC converter includes a plurality of switch elements connected in series between both ends of a DC power source, a series circuit of a primary winding of a transformer and a capacitor, connected between a connection point of the plurality of switch elements and an end of the DC power source, a rectifying-smoothing circuit to rectify and smooth a voltage generated by a secondary winding of the transformer into a DC voltage, and a controller to change a switching frequency of the plurality of switch elements according to a feedback signal generated from the DC voltage and alternately turn on/off the plurality of switch elements. The controller includes a nonlinear response unitto nonlinearly change the switching frequency according to a feedback amount represented by the feedback signal.

The present invention includes: a plurality of switching elements connected in series and connected between two ends of a DC power supply; a first control circuit to alternately turn on and off the switching elements in response to a constant oscillation frequency signal; a series circuit including a primary winding of a transformer and a capacitor connected together in series, and being connected to a connecting point between the switching elements, and to an end of the DC power supply; a rectifying/smoothing circuit to rectify and smooth a voltage in a secondary winding of the transformer thereby to output a DC voltage; a control switching element connected to two ends of the primary or secondary winding of the transformer; and a second control circuit to control the DC voltage at a predetermined voltage by turning on and off the control switching element.

Output controlled DC-to-DC converter

The resonant switching power supply device is equipped with switching elements QH and QL connected in series to an input direct-current power source Vin, a transformer Thaving secondary windings Sand Sand a primary winding P, a resonant circuit where the primary winding Pand a current resonant capacitor Cri are connected in series and which is connected in parallel to any one of the switching elements, and a rectifying circuit (D+D+Co) connected to the secondary winding to obtain an output voltage Vo; the transformer Tis equipped with a primary winding Pclosely coupled to the primary winding P, one terminal of the primary winding Pis connected to one or the other terminal of the primary winding P. By the other terminal is an open circuit at any time, it suppresses the switching frequency raised at the time of light load.

Resonant switching power supply device which suppresses a switching frequency raised at the time of light load

A power source apparatus has a power source unit (AC, DB, Ci), a pair of reactors Land Leach having a winding, and a controllerto accumulate energy of the power source unit in the pair of reactors and control the accumulated energy by turning on/off a switching element Q. The windings of the pair of reactors are arranged so that the windings face each other and the polarities of magnetic flux from the windings are opposite to each other.

Power source apparatus

A cold cathode fluorescent lamp inverter apparatus includes a series circuit connected to a DC power source and including first and second switching elements, a series circuit connected between a connection point of the first and second switching elements and the DC power source and including a primary winding of a transformer, a reactor, and a capacitor, a cold cathode fluorescent lamp connected to a secondary winding of the transformer, a current detector connected to the cold cathode fluorescent lamp and to the secondary winding, to detect a value of a current passed through the cold cathode fluorescent lamp, and a controller to turn on/off the first and second switching elements alternately with each other according to the detected current value. The current detector detects a ripple component in the DC power source, and corrects the current of the cold cathode fluorescent lamp according to the detected ripple component.

Cold cathode fluorescent lamp inverter apparatus

A DC-DC converter includes a series circuit of a switch element Qand a switch element Qconnected to a DC power source, a series circuit of a primary winding Pof a transformer and a capacitor connected in parallel with one of the switch elements, a rectifying-smoothing circuit of a voltage generated by a secondary winding (S, S) of the transformer, a controller to alternately turn on/off the switch elements according to an output of the rectifying-smoothing circuit, first and second timing detectors to detect ON/OFF states of the switch elements, and an ON time storing part to operate in response to a detection signal from the second timing detector and store an ON time of the switch element Qbased on an OFF time of the switch element Q. The controller turns on the switch element Qonly during the stored ON time.

An AC-DC converter includes a rectifier DB for rectifying an alternating current supplied from an alternating power source AC, a power factor controllerconnected to an output side of the rectifier DB to improve a power factor and also output either a power or a current limited to a predetermined value, a DC-DC converterthat converts a voltage outputted from the power factor controllerto another voltage, a capacitor EDLC for storing an energy and a two-way converterhaving one input/output terminals connected to the output side of the power factor controllerand the other input/output terminals connected to the capacitor to carry out a two-way power conversion.

AC-DC converter

A current resonant DC-DC converter of multi-output type is provided which comprises an output-regulatory MOS-FETconnected between a secondary windingof a transformerand a smoothing capacitorin a second rectifying smoother, and an output control circuitfor controlling the on-off operation of output-regulatory MOS-FETbased on voltage Vfrom smoothing capacitorin second rectifying smoother. By turning the on-off operation of output-regulatory MOS-FETin synchronization with switching frequency of first or second MOS-FETs, an ideal cross regulation among respective DC outputs can be obtained, providing the inexpensive converter with simple circuit alteration capable of producing highly stable DC outputs with high power conversion efficiency, high accuracy and less power conversion loss.

Current resonant DC-DC converter of multi-output type

For providing a flexible printed circuit board in which the distance between each of plural wiring patterns is a desired distance by cutting the flexible printed circuit board having plural wiring patterns, plural wiring patterns are formed so as to extend on the surface of an electrically insulative base film, and each of the plural wiring patterns is formed so as to include a portion where the distance between each of them is narrowed along the extending direction of the base film.

Method of manufacturing an ultrasonic probe

An AC-DC converter includes a rectifier DB for rectifying an alternating current supplied from an alternating power source AC, a power factor controllerconnected to an output side of the rectifier DB to improve a power factor, a DC-DC converterthat converts a voltage outputted from the power factor controllerto another voltage and also outputs either a power or a current limited to a predetermined value, a capacitor for storing an energy and a two-way converterhaving one input/output terminals connected to output terminals of the DC-DC converterand the other input/output terminals connected to the capacitor to carry out a two-way power conversion.

When an AC power supply () is powered up, a constant current supply section () supplies a constant current to a capacitor (C) to charge the capacitor (C). When a voltage across the capacitor (C) becomes equal to or greater than a predetermined voltage, a switch control section () sets a switch () off. When an output current drops to lead to a light load, a load detecting circuit () stops the operation of a PWM control circuit () and activates a timer (). The timer () supplies a switch-ON signal to the switch control section () when it is activated and a predetermined time measured elapses. When supplied with the switch-ON signal, the switch control section () sets the switch () on. When the switch () is set on, the capacitor (C) is charged again, applying a voltage to the PWM control circuit ().

Power supply and its controlling method

A discharge-lamp lighting apparatus includes first and second cold cathode fluorescent lamps (CCFLs) and first and second transformers. The second transformer has a primary winding connected in parallel to one of primary and secondary windings of the first transformer, a first secondary winding, and a second secondary winding. Each of the first and second secondary windings of the second transformer is connected to the secondary winding of the first transformer with polarities being set so that a voltage of each secondary winding of the second transformer becomes additive to a voltage of the secondary winding of the first transformer. The first CCFL is connected in parallel to a series circuit that includes the secondary winding of the first transformer and the first secondary winding of the second transformer.

Discharge-lamp lighting apparatus

The ON duration of an N channel MOS transistor is set based on a target voltage at a node between a resistor and a light receiving element of a photocoupler. A comparator compares the target voltage with a reference voltage at a node between a variable resistor and a resistor. A normal mode and a low frequency operation mode are switched from one to the other based on an output signal from the comparator. The resistance of the variable resistor becomes low when an input voltage from a power source is high. Even when the input voltage is high, therefore, the ON duration of the N channel MOS transistor at the transition between the normal mode and the low frequency operation mode becomes short. This reduces the switching energy in low frequency operation mode, thereby suppressing noise.

Growing community of inventors

Niiza, Japan

Hiroshi Usui