Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Nobuyoshi Nagagata

Takuya Ishii

Koji Yoshida

Makoto Kitabatake

Kazuhiro Nobori

Kazuhiko Asada

Masanori Ogawa

Hideki Omori

Hidekazu Yamashita

Hiroshi Saito

Mamoru Takeda

Toshiaki Kurachi

Satoshi Kominami

Takeshi Shimamoto

Kouji Miyazaki

Kenichirou Takahashi

Osamu Hiromura

Toshinari Ueyama

At least two switching devices each including a substrate formed of a wide bandgap semiconductor, source and gate electrodes formed in a principal surface side of the substrate, and a drain electrode formed on the back surface of the substrate are stacked so that respective upper surface sides of the switching face each other.

Sustaining circuit with bi-directional device

Stacked semiconductor transistors

In order to supply controlled DC voltages to a plurality of loads at high efficiency by using smaller number of components, a multiple output DC-DC converter in accordance with the present invention comprises a first main switch, one terminal of which is connected to the negative electrode of an input DC power source, a first rectifying meansand a first smoothing meansconnected to the other terminal of the first main switch, a second main switch, one terminal of which is connected to the positive terminal of the input DC power source, a second rectifying meansand a second smoothing meansconnected to the other terminal of the second main switch, an inductorconnected between the other terminal of the first main switchand the other terminal of the second main switch, and a control circuitfor driving the respective switches at predetermined ON/OFF period ratios.

Multiple output DC-DC converter for providing controlled voltages

An electrode-less discharge lamp lighting apparatus which is electrically connected to a dimming unit () is provided with: an electrode-less fluorescent lamp (); and a lighting circuit () operable to apply a high-frequency voltage to the electrode-less fluorescent lamp (), wherein the lighting circuit () includes: an AC/DC converting unit () operable to convert a phase-controlled AC voltage outputted from the dimming unit () into a DC voltage; a DC/AC converting unit () operable to convert the DC voltage into a high-frequency voltage; and a dimming controlling unit () that includes a resistor (), a switching element (), and a timer circuit () so as to detect a timing of a turn-on of the phase-controlled AC voltage and to, based on the detected timing, allow a current whose value is at least a threshold to flow across output terminals of the AC/DC converting unit () for at least a duration of a time lag between the turn-on of the phase-controlled AC voltage and the generation of the high-frequency voltage by the DC/AC converting unit ().

Electrode-less discharge lamp lighting apparatus, bulb-shaped electrode-less fluorescent lamp, and discharge lamp lighting apparatus

The voltage measuring apparatus of the present invention comprises: a capacitor configured of a plurality of capacitor elements and divided at a connection point into two sections of the same capacitance; a first switching device for connecting a voltage source to be measured to both terminals of the capacitor; a differential amplifier; a second switching device for connecting both terminals of the capacitor to inputs of the differential amplifier; and a third switch for connecting the connection point in the capacitor to signal reference potential of the differential amplifier in time synchronization with the second switching device.

Voltage measuring instrument with flying capacitor

A horizontal deflection circuit is provided which is useful in a television receiver and a video apparatus using a cathode ray tube, and which generates a deflection current for horizontally deflecting electron beams by changing a magnetic field applied to the cathode ray tube, and in which a resonance circuit using LC parts is not employed, and the vertical line distortion correction and the control of the horizontal deflection current in the multiscan are conducted by changing the duty ratios of switch elements, thereby simplifying the circuit configuration, and reducing the cost and the loss. [CONSTRUCTION] The horizontal deflection circuit has: a series circuit of first and second switch means and connected to positive and negative terminals of a DC power source; a series circuit of a horizontal deflection coil and a first capacitor and connected across the first switch means; control means for controlling closing and opening operations of the first and second switch means; and first and second diodes respectively connected across the first and second switch means. The control means controls the first and second switch means so that the first and second switch means are alternately closed and opened in synchronism with a horizontal synchronizing signal. The control means further controls the first and second switch means so that close and open periods of the first and second switch means are changed in synchronism with a vertical synchronizing signal. Accordingly, a horizontal deflection circuit which is simplified in configuration, minituarized, and reduced in cost and loss is obtained.

Horizontal deflection circuit

A switching power supply supplies a regulated output voltage for an electronic apparatus in industrial or commercial use and suppresses generation of a spike voltage and a spike current due to a transformer, and a recovery voltage of a rectifying diode due to switching and it results in reduction of noise interference and power loss. A series connection of a first switching means and a second switching means repeating on/off action alternately is connected to a d-c source. A series connection of a first capacitor and a primary winding of a transformer is connected in parallel with the second switching means. An induced voltage in a secondary winding is supplied to an output through a rectifying/filtering means. A series resonance current in a closed circuit comprising the first capacitor and a leakage inductance suppresses spike voltage, spike current, and recovery voltage of the rectifying diode.

Switching power supply

A switching power supply supplies a regulated output voltage and suppresses spike voltage and spike current generated by a switching action of transformers, and suppresses switching frequency drift due to load variation. Output stability of multi-output design is improved and recovery of rectifying diodes by a current resonance are suppressed. A reduction of noise interference to electronic equipments and power loss in the switching power supply itself results. A series connection of a primary winding of a first transformer and a first switching means, which repeats an on/off action is connected across a d-c power source. A series connection of a second switching means, which repeats an on/off action alternately with the first switching means, and a first capacitor is connected in parallel with the primary winding of the first transformer. A series connection of a primary winding of the second transformer and a second capacitor is connected in parallel with the second switching means. Regulated d-c outputs are taken out from each secondary winding of the transformers through rectifiers/filters. A control circuit supplies on/off signals, which on/off-ratios are varied according to one of the regulated d-c outputs, to the first and the second switching means.

Switching power supply without switching induced spike voltages

Disclosed is a switching power source device for supplying a DC stabilized voltage to industrial or household electronic appliances. The power source device can restrict a change in the switching frequency due to the change in load so that low noise and high efficiency can be realized. The power source device includes a first rectifying and smoothing circuit and a second rectifying and smoothing circuit. The first rectifying and smoothing circuit includes a rectifying diode and a smoothing capacitor. The second rectifying and smoothing circuit includes a rectifying diode and a smoothing capacitor. In a closed circuit composed of the first rectifying and smoothing circuit and second rectifying and smoothing circuit which are connected by a transformer, leakage inductance between the primary winding and secondary winding of the transformer is caused to resonate with the first or second rectifying and smoothing circuit so that a resonance current due to the resonance is taken as the current from the secondary winding to restrict occurrence of noise.

Regenerative control type switching power source device

A switching power supply comprises first switching circuit for making an input voltage on and off, a transformer having a primary winding connected in series with the first switching circuit, first rectifying and smoothing circuit connected to a secondary winding of the transformer and a second switching circuit for releasing the output of the rectifying and smoothing circuit back to the secondary winding of the transformer during the off-period of the first switching circuit. The switching power supply may further comprise a control circuit for controlling on or off the second switching circuit in response to the output of the first rectifying and smoothing circuit. The power supply may alternatively comprise a second rectifying and smoothing circuit connected to additional secondary winding to control on or off of the first switching circuit. Thus a stabilized switching power supply is provided with lower power loss, higher efficiency and lower noise.

Growing community of inventors

Kyoto, Japan

Nobuyoshi Nagagata