Abstract: A restart circuit for a power supply of an electronic system such as a computer system for delaying the restart of the power supply until a power supply output is in compliance with a specified parameter. In one embodiment, the specified parameter is a particular threshold voltage level and the power supply output is in compliance when it is less than the particular threshold voltage level. In another embodiment of a restart circuit, the specified parameter is a rate of decay in a voltage level and the power supply output is in compliance when it is decaying at a rate less than the predetermined rate. In one embodiment, delaying the restart of the power supply permits components of the system to be reset when the voltage level of the power supply output is in a known state.

Abstract: A method and a power conversion apparatus having a substantially direct current input voltage, an output transformer having a primary inductor and at least a secondary winding, and a transistor for controlling the transfer of energy from the primary inductor to the secondary winding and coupled to a controller for switching the transistor on and off at a predetermined rate. A sensor for sensing the power required at the output of the conversion apparatus and for generating a voltage representative thereof is provided, as is provided a sensor for sensing the peak current in the primary inductor and for developing a voltage representative thereof.

Abstract: A process for preparing a conjugated polymer, which comprises polymerizing in a reaction mixture (a) an aromatic monomer having at least two reactive boron derivative groups selected from a boronic acid group, a boronic ester group and a borane group, and an aromatic monomer having at least two reactive halide functional groups; or (b) an aromatic monomer having one reactive halide functional group and one reactive boron derivative group selected from a boronic acid group, a boronic ester group and a borane group, wherein the reaction mixture comprises a catalytic amount of a palladium catalyst, and an organic base in an amount sufficient to convert the reactive boron derivative groups into —B(OH)3− anions.

Abstract: To produce a constant voltage at the output of a converter in the form of a step-up converter, current-mode control of the converter is superimposed by voltage-mode control in the range in which the input voltage applied to the inputs of the step-up converter differs slightly from the voltage produced at its outputs.

Abstract: A switching power supply system is disclosed for powering electrical equipment while minimizing disturbance to an AC power line source. The system includes first and second AC switches which are operated at alternate intervals with respect to each other to permit current to flow between the AC power line source and the load over intervals of the AC voltage cycle. An energy storage element is included in an output filter and stores energy during intervals of the AC voltage cycle and releases the stored energy during the alternate intervals of the AC voltage cycle. By the disclosed switching power supply, the voltage applied to the load and the current flow between the source and the load are sinusoidal, have minimal energy in frequencies other than the fundamental AC power line frequency, have minimal harmonic distortion, result in a power factor close to unity, and are steady and non fluctuating.

Abstract: A power supply circuit including a first rectifying smoother for generating a DC output when connected to an AC power source. A standby power source that provides a plurality of DC outputs when supplied with the DC output from the first rectifying smoother. A second rectifying smoother converts the AC input into a DC output, which is converted by the main power source into a desired DC voltage. On the primary side of the main and standby power source, a relay controller, supplied with power by one of the DC outputs from the standby power source, responds to an actuation of a main switch. A relay switch connects the AC power source to the second rectifying smoother upon actuation of the relay controller. The standby power source also supplies power to the control means, which is disposed on the secondary side of the main and standby power source.

Abstract: A switching power supply (10) uses a switching regulator (18) that is capable of operating in a dual mode with either primary side regulation or secondary side regulation. The primary and secondary side regulation schemes generate opposite phase feedback signals. The switching regulator has first (56, 62) and second (70, 74) detectors on the feedback input which detect when the feedback signal is less than a first value and also detect when the feedback signal is greater than a second value. By monitoring either case, the switching regulator can enable and disable a gate drive signal in response to opposite phases of the feedback signal and thereby regulate the switching power supply.

Abstract: A method and apparatus for calculating an accurate estimate of an unregulated DC bus voltage to be used with a DC-to-DC converter including a transformer having a primary winding and a secondary winding, the primary winding in series with a switch between the positive and negative rails of the unregulated DC bus voltage, an electrically insulating coupler linked to a switch control line to provide a trigger pulse to a sample and hold circuit, and a sample and hold circuit linked to the transformer secondary winding for measuring the secondary winding voltage when the sample and hold circuit is triggered, the sample and hold circuit providing an output voltage which can be used to calculate the DC bus voltage estimate.

Abstract: A power supply device of a switching mode comprises a transformer, a direct current power supply circuit connected at an output end thereof with a first end of a primary winding of the transformer, a switching element connected at a first end thereof with a second end of the primary winding of the transformer and at a second end thereof with a ground, a control circuit connected at an output end thereof with the control end of the switching element for providing the switching element with a driving signal, a direct current output circuit connected at an input end thereof with the output end of a secondary winding of said transformer, a leakage current detection circuit connected at an input end thereof with a secondary side ground end of the transformer and at an output end thereof with a primary side ground end of the transformer for forming a leakage current loop and transmitting a leakage current signal at such time when a leakage current takes place.

Abstract: A switching power supply comprising a main converter that turns ON and OFF a DC current applied to a primary winding of a main transformer by a main switching element and outputs a main output voltage to a secondary circuit by rectifying and smoothing current induced in a secondary winding; an error amplifier generating an error voltage between the main output voltage and a first reference voltage; an over-voltage protection circuit that generates an over-voltage protection signal when the main output voltage exceeds a second reference voltage; a PWM circuit to control a drive signal for the main switching element to minimize error voltage outputted by the error amplifier; and a shut-down execution circuit that stops the main converter operation when the over-voltage protection signal is generated; wherein are provided a device to superimpose the over-voltage protection signal on the error signal of the main output voltage induced in the secondary winding and to transmit the superimposed signal to the primary

Abstract: A switched-mode power supply circuit having an operating mode and a stand-by mode, includes a functional ON/OFF switch. The switched-mode power supply circuit includes a transformer and a controllable switch connected to a primary winding of the transformer for switchably connecting the primary winding to a source of d.c. voltage. In the stand-by mode, based on a detected voltage level at an input of a controller IC, the switched-mode power supply circuit is arranged to switchable connect the primary winding to the d.c. voltage source in bursts which occur at a low frequency. By switchably connecting this input to a power source for the switched-mode power supply circuit, the controller IC detects the absence of this power source, and turns off the switched-mode power supply circuit allowing a minimum current consumption by the switched-mode power supply circuit.

Abstract: A self-oscillation type switching power supply includes a transformer having a primary winding, a secondary winding, a feedback winding, and a control winding as required, a switching transistor to turn on and off a current flowing in the primary winding, a controlling transistor to control a positive feedback signal from the feedback winding or the control winding to said switching transistor, and a time constant circuit to charge a generated voltage across the feedback winding or the control winding with a fixed time constant and to give a controlling voltage to said controlling transistor. A delay transistor to delay the turn-on of said switching transistor is contained in a controlling signal input portion to said switching transistor, and a delay circuit is provided to delay a positive feedback signal from the control winding or the feedback winding with a fixed time constant and to give the delayed signal as a controlling signal to said delay transistor.

Abstract: A switched-mode power supply includes a transformer having a primary winding, a secondary winding and an auxiliary winding. A switching device is included in series with the primary winding for alternately interrupting the flow of current through the primary winding. The switched-mode power supply further includes a controller circuit connected to the auxiliary winding for receiving information related to an output voltage across the secondary winding and for controlling the switching of the switching device so as to maintain the information at a desired level. The controller circuit including a sample-and-hold circuit which is controlled to sample the information related to the output voltage only when there is current flowing in the secondary winding.

Abstract: An output current limiting coupling for a switched-mode power supply is arranged to produce a feedback signal on the basis of the output current of the switched-mode power supply and to transmit it from the secondary side of the switched-mode power supply to its primary side by means of an opto-isolator (3). The coupling may include the following parts implemented with passive components: a bias voltage coupling (25, 26, 27, 28; 30, 31, 32, 33; 42, 43, 44, 45, 46) for forming a certain first potential to the first electrode of the light-emitting diode (3a) contained in the opto-isolator, and an input coupling (24) for producing a second potential formed on the basis of the output current to the second electrode of the light-emitting diode contained in the opto-isolator. The coupling is suitable for switched-mode power supplies regardless of whether the lighting of the light-emitting diode of the opto-isolator indicates a low or high value of the output current.

Abstract: In an electronic circuit having an input stage, an output stage having an output voltage, and a feedback element including a coupler having a transmitter coupled to said output stage and a receiver coupled to said input stage, said receiver being galvanically isolated from said transmitter, said transmitter sending an output signal that is a function of said output voltage to said receiver, said receiver generating a receiver output in response to receiving said output signal, a feedback control circuit for said feedback element, said feedback control circuit comprising: a transmitter drive circuit coupled to said transmitter for adjusting said output signal as a function of said output voltage, said transmitter drive circuit comprising an error signal generation stage, said error signal generation stage using a voltage that is a function of the output voltage to generate a feedback control signal, and a non-linear stage, said non-linear stage outputting a transmitter drive signal to said transmitter as a fun

Abstract: An AC-DC switching converter converts AC mains power into regulated DC power into a load. It is desired to electrically isolate the load from the mains, and this requires isolation in both the forward power transfer path and the reverse feedback path. The forward path is isolated by use of a transformer, and the feedback signal is transferred through an optocoupler. In a typical pulsewidth modulation control loop design, it is difficult to achieve good loop dynamics when using low cost optocouplers, because of the wide variation of their transfer function gain. However, in the disclosed invention, the loop is operated as a nonlinear limit cycle ("bang--bang") controller. In this mode, the optocoupler gain variation has an insignificant effect on loop operation. The converter switching signal is provided by an inexpensive 555 timer oscillator, and the optocoupler is connected to the reset pin of this timer to turn it ON and OFF in short bursts, as is characteristic of this type of controller.

Abstract: This invention provides an inverter driving circuit for brushless d.c. motor adapted to pass PWM signal to switching elements of the inverter, enabling reduction of the manufacturing cost, the circuit including a general-purpose photo-coupler for producing the PWM by virtue of an internal photo-coupling thereof, a reference voltage generating unit for producing the reference voltage signal, and a comparator which compares a signal from the general-purpose photo-coupler with the reference voltage from the reference voltage generating unit, and passes the resultant as a switching element driving signal to appropriate switching element.

Abstract: The power-supply controller of a computer can minimize power-consumption as shown in the following description. The operation mode will convert to a sleep-mode reducing the power-consumption below a constant voltage if there is no input to operate a computer system for a predetermined period of time. If the condition of no input for operating a computer system persists, the power supply controller cuts off the power-supply once again. In order to achieve this object, this invention is composed of a power-supply, a power-controller, and a power-mode-controller. The power-supply includes a first rectifier that converts an AC voltage to a DC voltage, a DC/AC converter which converts a DC voltage into an AC voltage, a switching mechanism which outputs a pulse signal used to operate the DC/AC converter, a second rectifier which converts to a DC voltage from an AC voltage received from the DC/AC converter, and a driver which provides an operation voltage to operate the switching mechanism.

Abstract: A noncontacting power transfer apparatus, a noncontacting signal transfer apparatus and a separate machine apparatus that uses these couplers are disclosed. The power coupler is composed of a primary side and a secondary side that are fixed to a static unit and rotatable unit of the machine apparatus, respectively, such that its output does not vary with arbitrary rotation by the rotatable unit. The signal coupler is composed of receiving side portion having a electric-to-light conversion device that converts an electric signal to an optical signal of rotational symmetry relative to the axis of rotation of the rotatable unit and a photoelectric conversion device that converts an optical signal to an electric signal. Accordingly, the rotatable unit can be supplied with power from the static unit even while rotating, and moreover, can communicate with the static unit. Further, the rotatable unit can be easily attached to the static unit and can be removed from the static unit.

Abstract: A silicon-on-silicon dual MCM apparatus comprising a printed circuit board having a voltage isolation boundary contained therein supporting a pair of multi-chip modules on either side of the voltage isolation boundary. The MCMs safely convey signals across the isolation boundary via discrete optical coupling means or the like. The optical coupling means allow safe and efficient conveyance of signals across the voltage isolation boundary enabling a designer to group high voltage components on one side of the boundary and low voltage components on the other side of the boundary. This obviates to a degree the need for multi-layered PCBs. A relatively large number of passive components (resistors and capacitors) are integrated into a silicon substrate with flip-chip analog integrated circuits (ICs). Operational characteristics of the controller are verified after integration and are compared to the discrete version.

Abstract: A power supply for a computer system having at least one energy demanding component. The power supply includes a transformer having a primary side coupled to an AC main and a secondary side coupled to an output line, a charging circuit coupled between the secondary side of the transformer and the output line, an optical switch coupled to the secondary side of the transformer and comprised of an optical transmitter and an optical receiver, a secondary side power switch coupled to the optical receiver, a pulse width modulator coupled to an output of the optical receiver and a transformer switch coupled to an output of the pulse width modulator. The pulse width modulator generates a pulse sequence which alternates between first and second states, each having respective durations and frequencies. At each change between the first and second states, the transformer switch selectively connects or disconnects the primary side of the transformer with the input line.

Abstract: A power supply for a computer system includes a transformer having a primary side coupled to an AC main and a secondary side coupled to an output line, a charging circuit coupled between the secondary side of the transformer and the output line, an optical switch coupled to the secondary side of the transformer and comprised of an optical transmitter and an optical receiver, a secondary side power switch coupled to the optical receiver, a short circuit protection circuit coupled to the charging circuit, the output line and the optical receiver, a pulse width modulator coupled to an output of the optical receiver and a transformer switch coupled to an output of the pulse width modulator. The pulse width modulator generates a pulse sequence which alternates between first and second states, each having respective durations and frequencies. At each change between the first and second states, the transformer switch selectively connects or disconnects the primary side of the transformer with the input line.

Abstract: A power control system in a DIN rail mount assembly for switching power in a low cost, compact, and solid state for controlling electric heaters. The system can be used for single phase, three phase-two leg, and three phase-three leg. Current switching capabilities range from 30A to 50A. Variable time base, 4-20 mA process control or VAC/DC input contactor configurations can be utilized. The DIN Rail back plate includes a sliding mechanical configuration. A potting fence provides for potting of the electrical substrate and also provides a heat sink. A large cover covers finger palm safer terminals. The DIN rail assembly can also be used for supporting electrical, electromechanical, optical or other types of assemblies.

Abstract: A wall mounted power supply for a remote instrument handle has a novel self compensating voltage regulating circuit that remains in precise calibration despite variable voltage drops in the load, cabling, and control switches. Power output is enabled by an infrared emitter-detector combination disposed in the device's cradle that senses the absence of the instrument handle therein.

Abstract: A device for supplying a power supply voltage to an electronic circuit, in particular to an electronic circuit associated with a current sensor for measuring the electrical current in a high-tension line, comprises a current transformer having a primary circuit and a secondary circuit, a rectifier bridge shunting the secondary circuit and output terminals of the rectifier bridge, a first capacitor in parallel with a first resistor across which said power supply voltage is obtained, and a first switch disposed between the output terminals of the rectifier bridge. It includes between the output terminals of the rectifier bridge a branch comprising in series a second capacitor, a second switch and a second resistor. The first switch is controlled by a first threshold detector shunting the second capacitor. The second switch is controlled by a second threshold detector shunting the first capacitor.

Abstract: An object of the present invention is to reduce a cost and a power consumption, eliminating a voltage source for generating a reference voltage in an isolated switching power source achieving a feedback from an output side of the power source to a control circuit in an input side of the power source through a photo-coupler. A voltage V.sub.1 obtained by dividing an output voltage V.sub.0 by a voltage dividing resistors 8, 9 is applied to a base of a transistor 11-1 for an error amplifier, and a photo-coupler light emitting element 10-1 is connected between an emitter of the transistor 11-1 and a negative side of an power source output. A forward dropping voltage of the photo-coupler light emitting element becomes approximately constant (approximately 1.1 v) over a variation range of a current flowing to the photo-coupler light emitting element at actually using time.

Abstract: A signal isolator circuit employing a pulse transformer overcomes the disadvantages of both prior art opto-coupler and pulse transformer signal isolator circuits by employing an active signal retrieval circuit which, in a higher accuracy configuration, repetitively performs the following steps on the electrical side of the pulse transformer where the signal information is required: 1) drives a current pulse into the pulse transformer; 2) samples or detects the voltage across the pulse transformer after it has been stabilized; 3) holds or stores the sampled voltage for a full cycle of operation; and, if necessary, 4) filters the sampled signal. On the other electrical side of the pulse transformer, the retrieval circuitry is configured such that when the pulse transformer is being driven by the current pulse, the voltage will be clamped by the source signal reset.

Abstract: An input voltage U.sub.IN to a voltage level converter 10 having a high input impedance charges a storage element which periodically discharges current to an LED 16 which periodically provides a light pulse for generating a level converted version of the input voltage U.sub.IN. A resistor R.sub.p 22 connected to the storage element allows the storage element to discharge noise voltage spikes in the input voltage U.sub.IN.

Abstract: An improved pulse width modulation type switching power supply uses an opto-isolator as an output voltage error amplifier which feeds back an error signal to control pulse width modulation as well as to provide isolation between the primary and secondary voltages of the power supply.

Abstract: An optical power conversion circuit converts an optical energy signal from an optical source, such as a laser diode, to a regulated D.C. electrical voltage using a single photodetector. A buck-boost circuit uses electrical current from the photodetector in response to the optical energy signal to store energy in an inductor during one polarity of a control signal, and transfers the energy from the inductor to an output capacitor during the other polarity of the control signal. The duty cycle of the control signal determines the regulated D.C. electrical voltage. A switch drive circuit generates the control signal as a pulse width modulated signal from the regulated D.C. electrical voltage and a reference voltage. The control signal is A.C. coupled to a pair of FET switches in the buck-boost circuit to alternately energize and charge the inductor and capacitor respectively.

Abstract: A circuit arrangement for generating a constant output voltage has a decoupling diode at the output side and has a circuit for actual value formation that is connected to the output of the circuit arrangement. In order, given high precision of the output voltage, to prevent voltages appearing at the user and applied in some other way to the user from causing the regulator to inhibit the circuit arrangement, a reference potential terminal of the regulator lies at one side of the decoupling diode and the voltage divider lies at the other side of the decoupling diode. The circuit arrangement is particularly suited for redundant feed of equipment in electrical communications transmission technology.

Abstract: Procedure and apparatus for the control of electric power, by which procedure the electric power supplied to a load is regulated by means of a regulator, e.g. a thyristor regulator. The regulator control signals, e.g. thyristor firing pulses, are produced by a separate control unit (6), from where they are passed in the form of optical signals via at least one optical fibre (2) to a socket or equivalent and further to a photosensitive device (Q), which converts the signals into electrical form and applies them to at least one controllable solid-state component, e.g. thyristor, in the power stage of the regulator.

Abstract: An improved interface isolation and selection circuit for a local area network. The invention includes a power supply effective to provide an isolated output voltage. An opto-isolator transforms a first control signal to a second control signal effective to activate the interface. The opto-isolator includes an optical emitter for providing an optical signal in response to the first control signal and an optical detector for receiving the optical signal and providing the second control signal in response thereto. The second control signal is effective to activate the interface by applying the isolated power thereto. In particular implementations, the isolated power and the power for the opto-isolator are provided by a single power supply and a field effect transistor is activated by the opto-isolator and, in turn, activates the interface.

Abstract: A light emitting diode driving circuit for supplying a driving pulse to a light emitting diode to thereby cause the light emitting diode to intermittently emit light is disclosed which comprises a clamping circuit, a photodiode disposed in the vicinity of the light emitting diode for detecting the optical output power of the light emitting diode, an AC amplifier having its DC operating point stabilized by means of a DC feedback circuit for AC amplifying the detected output from the photodiode, a shaping circuit for shaping the output amplified signal from the AC amplifier, and a comparison circuit for comparing for voltage the output shaped signal from the shaping circuit and a reference voltage, in which the clamping voltage of the clamping circuit is controlled by the output of the comparison circuit and, thereby, the optical output power of the light emitting diode is maintained constant.

Abstract: A constant-current circuit includes a circuit current source for generating a circuit current necessary for the constant-current circuit, and a light-emitting element current source for passing a first current which is part of the circuit current through a light-emitting element in response to an input signal. A current control circuit detects a change in the first current and generates a control signal based on the change in the first current. A controlled current source passes a second current which is part of the circuit current and changes the amount of the second current on the basis of the control signal so that the circuit current has a fixed amount.

Abstract: A non-contact type load-dispatching equipment having a power supply side core and a receiving side core both provided with a plurality of teeth wound by winding, each of teeth top surfaces formed by respective teeth is oppositely positioned to each other via a gap being magnetically connected for supplying power without contact at the time of power supply, whereinteeth top surfaces of respective teeth of the power supply side core and receiving side core are disposed oppositely on the respective circumferences with a gap therebetween which allows coupling-uncoupling of the cores therethrough;light signal generating circuit for generating light signals which indicate receiving side voltages is provided in the power receiving side;voltage signal generation circuit which generates corresponding voltage signals on receiving the light signals and cut-off circuit for cutting off power supply when the generated voltage signal is lower than the predetermined value, where the voltage signal generation and cut-off circ

Abstract: An optical voltage reference for providing an alternative to a battery source. The optical reference apparatus provides a temperature stable, high precision, isolated voltage reference through the use of optical isolation techniques to eliminate current and impedance coupling errors. Pulse rate frequency modulation is employed to eliminate errors in the optical transmission link while phase-lock feedback is employed to stabilize the frequency to voltage transfer function.

Abstract: There are provided a resistor having a low resistance and inserted in a d.c. current path of which an overcurrent is detected, and a bias circuit for generating substantially a constant d.c. voltage. A voltage obtained by superposing a voltage across the resistor upon a voltage supplied from the bias circuit is monitored. When the monitored voltage reaches a predetermined threshold value, an overcurrent detection signal is generated by means of a photocoupler.

Abstract: In a switching regulator, input voltage is applied to a primary coil of a transformer through a location between a collector and an emitter of a switching transistor connected in series to the primary coil of the transformer. A pair of output terminals are connected to a secondary coil of the transformer through a rectifier smoothing circuit. A comparator compares output voltage occurring between the output terminals with reference voltage to generate an output signal. On the basis of the output signal, a control circuit applies a drive control signal to a base of the switching transistor. The reference voltage is given such that first voltage maintained substantially constant and second voltage such as outside input voltage or the like capable of being regulated over a relatively large varying width are added to each other.

Abstract: An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits.

Abstract: An output circuit provided with a photo coupler for transmitting a control signal from a control circuit to an output side in an electrically isolated condition, a load driving transistor (15), and a power supply stabilizing circuit (15) for supplying an electric power for driving the load driving transistor (13) from a load side power supply (13). The power supply stabilizing circuit includes a low voltage detection circuit and an input/output short-circuiting circuit, and the input/output short-circuiting circuit is made conductive when an input voltage to the power supply stabilizing circuit is determined to be lower than a predetermined voltage. As a result, even if the load side power supply has a low voltage, it can drive the load driving transistor, and thus the load side power supply can be used over a wide range of voltages.

Abstract: A method and apparatus for protecting thyristors in a power converter from overvoltages. Voltage detectors determine if the forward voltage of each thyristor has increased in the converter. If such an overvoltage occurs during a predetermined period after the conduction of the thyristor, forced triggering of all the thyristors prevent damage to the thyristors.

Abstract: In a domestic appliance such as a washer, dishwasher, dryer, beverage preparation device or the like having several control circuits driven by varying voltage supplies, the input control circuit is supplied with a relatively low voltage and is electrically isolated from higher voltages within the circuitry of the appliance. An optical isolator is provided in the communication channel between the input control circuit and a power control circuit which is connected to circuit elements connected to the A.C. line voltage. The low voltage supply driving the input control circuit is also isolated from the A.C. line voltage. All operator accessible components are coupled to the input control circuit and are therefore isolated from the A.C. line voltage.

Abstract: A multiphase stepping transformer wherein a closed vacuum interrupter at each phase is opened before a respective stepping switch is advanced is controlled by continuously monitoring current flow through the interrupters. Before the interrupters are opened an error signal is generated unless all of the monitored current flows lie to one side of a predetermined threshold. After the interrupters are opened an error signal is generated if current flow is detected through any of the interrupters. Advance of the stepping switches is blocked on generation of any error signal. The apparatus includes for each interrupter a respective current detector, a light-emitting diode energized by the respective detector, a light receiver associated with each diode, and a light-transmitting cable connecting each diode with the respective receiver.

Abstract: According to this invention, in a power supply circuit of a switching power supply apparatus, a circuit arrangement capable of adjusting the resistance values of a plurality of resistors in accordance with an input voltage condition is realized so that the switching power supply apparatus can be applied to a wide range of input voltages.

Abstract: An electrically isolated high speed optical switching arrangement for use as a computer over-voltage sensing circuit utilizing first and second optoisolator devices, the first having an input, a first signal from the output of a bus sensing circuitry which provides two complementary outputs, with the output voltage of the optoisolator controlling power-down circuitry for the computer in response to an over-voltage condition. A second control optoisolator has its output in parallel with a resistor in the base to emitter path of the first optoisolator. The complementary signal of the bus-sensing circuitry provides the input to the second optoisolator. During normal power conditions, the first optoisolator is conductive and the second is non-conductive.

Abstract: A high-frequency induction heating apparatus of an inverter type includes a high-frequency oscillator using a plurality of switching elements turning on and off at a high speed. A control unit for controlling the high-frequency oscillator includes a plurality of driving circuits for driving the switching elements and a control circuit for controlling the respective driving circuits, and interconnection between the driving circuits and the control circuit is made by optical fiber cables so that influence by external electromagnetic induction is not effected to operate the high-frequency induction heating apparatus effectively.

Abstract: In order to obtain a stable dc output from a switching regulator of a type in which a switching control arrangement is provided with an optical coupler, an A-D converter is arranged to provide the optical coupler with a digital error signal. This error signal corresponds to a difference between the regulated dc output and a reference voltage. The digital output of the optical coupler is converted into a corresponding analog signal at a D-A converter. The output of the D-A converter is applied to a comparator and is compared thereat with a reference signal voltage for controlling a switching device.

Abstract: A power supply receives and rectifies mains voltage using bridge D1-D4. This is used by a pair of transistors Q1 and Q2 to alternate the supply to a transformer T via capacitor C8. Outputs are available from secondary windings T2, T6 and T7. Further windings T4 and T5 provide an internal power source for system circuitry which includes optical regulation via IC1 and optical switching control using IC2.

Abstract: A self-oscillation type converter comprises a transformer and a switching transistor. The switching transistor is connected in series to a primary winding of the transformer. A start current is applied from a power supply line to the switching transistor through a start resistor, so that the switching transistor is rendered conductive. A positive feedback is performed through an application of a constant current from a constant current circuit to a base of the switching transistor in response to a voltage generated from a feedback winding, whereby the switching transistor is turned on rapidly. A CR time constant circuit is connected to an output of the constant current circuit. An output of the CR time constant circuit is applied to the base of the transistor, a transistor Q2 is turned on after a lapse of time determined by a time constant of the time constant circuit, so that the switching transistor is forcibly turned off.