Yokogawa Electric Corporation

Yokogawa Hokushin Electric Corp.

Kiyoharu Inou

Hitoshi Saito

Shunsuke Hayashi

Hitoshi Yasui

Makoto Imamura

Yuichi Suzuki

Hideaki Matsumura

Takanori Komuro

Shuichi Matsuda

Yasunobu Iwata

Kenji Fujino

Yoshihiro Sampei

Kiyoshi Yokoshima

Hisanaga Takano

Yoshio Hasegawa

Seiichi Naito

Katsuji Sakimoto

Yoshiaki Koide

An indirect feedback type flyback converter that compares favorably with the direct feedback type flyback converter in controllability of secondary output voltage, wherein the converter is arranged so that a switching signal, which is induced in a secondary winding when a direct current input voltage, applied to a primary winding, is turned ON and OFF by a switching element, is smoothed by rectification and fed to a load and that an output voltage is detected using a switching signal induced in an auxiliary winding to transmit a control signal to the switching element for the purpose of stabilizing the output voltage; wherein the primary, secondary and auxiliary windings are formed on respective coil formation surfaces of a coil laminate as convoluted shaped conductor patterns disposed between a core hole at the center of the pattern and the border of the coil formation surface, with the auxiliary winding being disposed to be near the border of the coil formation surface.

Switching power supply using printed coil type transformer

A switching power supply wherein high speed switching and high output voltages are obtained by utilizing an auxiliary power supply and a synchronizing signal having a sawtooth shaped waveform, whereby delay time in a control signal to an FET switch is substantially reduced. The switching power supply comprises a secondary output circuit which is supplied with a square waveform voltage and utilizes an FET switch which controls the width of pulses chopped from the square waveform voltage and causes the output circuit to produce a direct current output voltage having a set value. The control signal to the FET switch is produced by a control circuit which is independently powered by the auxiliary power supply and supplied with the synchronizing signal.

Multi-output switching power supply having an improved secondary output

A switching power supply comprising a converting circuit; an analog-to-digital converter for converting a signal referring to an output signal from the converting circuit into digital form; a parallel-to-series converter for converting a bit train signal containing the output signal from the analog-to-digital converter into a pulse train; an isolation means for transmitting the pulse train to the primary winding of a transformer while concurrently electrically isolating the pulse train; a series-to-parallel converter for demodulating the pulse train into a parallel signal; and a control circuit. The converting circuit has a switching device which turns ON and OFF the voltage applied across the primary winding. The converting circuit provides rectification and smoothing of voltage induced in the secondary winding of the transformer, and supplies an output DC voltage to a load. The control circuit calculates control output for regulating the output voltage from the converting circuit which is received also by the series-to-parallel converter, to a given voltage. The control circuit further acts to produce an output signal which turns ON and OFF the switching device.

Switching power supply

A signal conditioner comprising a receiving part, a transmitting part, and a power supply part, wherein the main functions of these components are digitalized and common circuit elements are used for different functions. Signal conditions may be of several different types, each of which is a hardware which can accommodate various transmitters and actuators.

Signal conditioner

A ringing choke converter power supply device comprising a ringing choke converter power supply for stabilizing an output voltage by an indirect feedback system; a variable impedance element provided on a primary or secondary side of the power supply; and a control circuit for transmitting a control signal to the variable impedance element in such a direction that an error signal obtained by comparing the output voltage of the power supply with a predetermined reference voltage becomes zero. The variable impedance element, which is preferably a saturable reactor, is interposed between a voltage detection winding and a feedback diode or between the feedback diode and a capacitor when the element is provided on the primary side; and is interposed between a transformer secondary winding and a rectifier circuit, when the element is provided on the secondary side.

Ringing choke converter

A switching type DC/DC converter wherein a switching control circuit is disposed at the primary winding thereof, and a detection signal, in a secondary winding, is insulated by a transformer and fed back to stabilize output voltages. Current consumption is reduced by using a transformer to act as an insulator, and the size of a stabilizing feedback circuit is reduced by using resistors and diodes so that the rate of production thereof is improved. A switching signal in a secondary winding of a main transformer is used as an excitation energy for an insulating transformer of the stabilizing feedback circuit, the excitation energy being supplied through an impedance device. The output voltage supplied to a load is supplied as a stabilizing signal to a primary winding of an insulating transformer by means of the stabilizing feedback circuit. In a secondary winding of the insulating transformer, the excitation energy is used to supply a pure stabilizing signal to the control circuit to stabilize the output voltage. The stabilizing signal is defined as an error signal obtained by comparing the output voltage with a predetermined reference voltage in the primary or secondary winding of the insulating transformer.

DC power supply with improved output stabilizing feedback

The optical communication system of the invention comprises an optical transmission line, optical coupling devices, each having a varying coupling ratio, connected to the transmission line, and stations connected to the optical coupling devices; wherein the coupling ratio of the device is changed to a predetermined value by a control signal applied by its associated station, depending on the state of transmission and reception, level of received signal, operating state of the station, and the like, to thereby provide high reliability, reduced transmission delay and low error rate, as well as to thereby decrease the amount of attenuation between transmitting and receiving stations.

Optical communication system

A DC/DC converter which may be used as a power supply of high capacity. The DC/DC converter comprises first and second converters having their primary terminals connected in series so as to insure high output power and high breakdwon voltage; a first diode for forming a closed circuit together with a transformer of the first converter and a capacitor of the second converter when a switching element of the first converter is turned 'off'; and a second diode for forming a closed circuit together with a transformer of the second converter and a capacitor of the first converter when a switching element of the second converter is turned 'off'.

DC/DC converter

A DC/DC converter for producing a plurality of output voltages, comprising a transformer having a primary coil and a plurality of secondary coils; a switching circuit adapted to turn ON and OFF the supply of input DC voltage to the primary coil; rectifying and smoothing circuits for rectifying and smoothing the AC voltages obtained in the secondary coils; a circuit means connected in series with the rectifying and smoothing circuits to obtain the sum of the output voltages from the respective rectifying and smoothing circuits; and a control circuit adapted to receive the lowest DC output voltage from the rectifying and smoothing circuits and to control the ON - OFF operation of the switching circuit so that the lowest voltage is maintained at a constant level, and wherein the DC voltages from the respective rectifying and smoothing circuits are obtained by making use of one of the output terminals of the lowest DC voltage as a common terminal.

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Tokyo, Japan

Kiyoharu Inou