Abstract: A system is provided for sensing a motor current from a three phase inverter. A first resistor is coupled between a first transistor of the inverter and a supply voltage, and a second resistor is coupled between a second transistor of the inverter and ground. Circuitry coupled to the first and second resistors generates an upper and lower current. When the first transistor is active, the upper current is proportional to the sum of a reference voltage and a voltage across the first resistor, and the lower current is proportional to the reference voltage. When the second transistor is active, the upper current is proportional to the reference voltage, and the lower current is proportional to the sum of the reference voltage and a voltage across the second resistor. Based on the difference of the lower and upper currents, the circuitry provides an output current proportional to the motor current.

Abstract: A power supply for a satellite receiver system includes a dual input supply voltage arrangement. When a higher output voltage is selected, a source of a lower supply input voltage is coupled to an input main current conducting terminal of a series pass transistor. On the other hand, when a lower output voltage is selected, a source of a lower supply input voltage is coupled to the input main current conducting terminal of the series pass transistor. A comparator senses a magnitude of an output voltage produced by the series pass transistor. When, as a result of an over current condition, the output voltage is lower than a reference threshold level, any selection of the higher output voltage is automatically overridden and the source of the lower supply input voltage, instead, is coupled to the input main current conducting terminal of the series pass transistor.

Abstract: In a PWM space vector modulation inverter motor drive system, PWM cycles are modified to permit motor phase currents to be reconstructed as observable on the DC bus link. The PWM cycles are modified near sector boundaries so that measurements taken at the DC bus link correspond to actual motor phase currents. With this technique, a single DC bus current measure can be used to reconstruct all motor phase currents, while also providing fault protection.

Abstract: A system including a current sensor to sense a current provided by an electronic power converter, the current sensor includes an output; an overcurrent detection circuit with an input coupled to an output of the current sensor; and a logic control circuit configurable to maintain the current provided by the electronic power converter in response to the sensed current having a short circuit magnitude, the logic control circuit including an input coupled to an output of the overcurrent detection circuit and at least one output coupled to at least one switch of the electronic power converter.

Abstract: A system and method is provided for determining a voltage output of a programmable power converter based on programming voltage data received from one of a variety of alternate sources. Specifically, in one embodiment of the present invention, a control unit is adapted to monitor a digital data serial interface, a digital data parallel interface, and an analog data interface to determine whether programming voltage data has been received. If programming voltage data has been received, the data is used to determine an output voltage for the programmable power converter. If more than one set of programming voltage data has been received, a determination is made as to which set of data takes priority. The selected set of data is then used to determine an output voltage for the programmable power converter.

Abstract: The present invention discloses to a multi-period cycle-alternative switching mode power supply control device, comprising: a power transfer control unit, a dimming bias control, a burst timing control, and a steering logic; wherein said device has a variable multi-period control cycle to effectively control certain power transfer elements of specific nature and assure those elements and the loading at the rear end can operate more efficiently in a reliable range of specific nature.

Abstract: The invention describes a method of regulating a rectifier inverter system (1), whereby electrical power is generated and/or supplied via a power source (6) and is transmitted from at least one d.c.-to-d.c. converter (3) to an intermediate circuit (4), from where it is fed via a d.c.-to-a.c. converter (5) to an alternating voltage supply (8) and/or delivered to a consumer. The d.c.-to-d.c. converter (3) is regulated in such a way that a virtually constant current flow is applied from the input of the d.c.-to-d.c. converter (3), in other words from the power source (6), to the output of the d.c.-to-d.c. converter (3), in other words the intermediate circuit (4), during a pre-settable period irrespective of the power drawn off from the intermediate circuit (4), whereas during this same period power is drawn off from the intermediate circuit (4) to feed it to the alternating voltage supply (8) or deliver it to the consumer. A controller or a control system of the d.c.-to-d.c.

Abstract: A switching power supply device of the present invention comprises a transformer having at least a first primary coil, a first secondary coil, a second secondary coil, a second primary coil, and laminated in the sequence of the first primary coil, the first secondary coil, the second secondary coil, the second primary coil, and having a configuration wherein a center tap is drawn out from a connecting part between one end of said first secondary coil and one end of said second secondary coil; a switching part for alternately applying a voltage in a forward direction and an inverse direction to said transformer; a rectifying part for rectifying the voltage induced across the center tap of the transformer and the other end of the first secondary coil or the other end of the second secondary coil; a smoothing part for smoothing the voltage of the rectifying part; and a control part for controlling the on-off of the switching part so that the output voltage becomes stable.

Abstract: An induction heating power supply is disclosed. It includes a power circuit having at least one switch and a power output. The output circuit includes an induction head. The output circuit is coupled to the power output. A controller has at least one feedback input connected to the output circuit, and has a control output connected to the switch. The controller predicts the switch zero crossing and preferably soft switches the switch. Current feedback is obtained from a coil placed between the bus bars. Each bus bar is comprised of multiple plates to increase current capacity.

Abstract: A full wave sense amplifier for sensing a periodic current flowing through a discharge lamp is disclosed. The full wave sense amplifier comprises a first circuit for sensing the positive going portion of the periodic current. The amplifier also includes a second circuit for sensing the negative going portion of the periodic current. Finally, an output circuit for combining the negative going portion and the positive going portion into a current flow signal is provided.

Abstract: An apparatus for reducing power supply noise in the power supply system of a clock driver has been developed. The apparatus includes a clock driver with a power supply system connected to the clock driver and a shunting resistor connected across the power supply system in parallel with the clock driver.

Abstract: A sine wave filter including an inductor for each phase (three inductors) and three delta- or Y-connected capacitors is employed within a borehole power system, coupled within a three phase power system at the surface between the output of a variable frequency drive and a three phase power cable transmitting power to a borehole location, and boosts the output voltage of the drive. The sine wave filter is designed to have a resonant frequency higher than the maximum operational frequency of the drive, and a Q such that, at the maximum operational frequency of the drive, the filter provides a voltage gain equal to the ratio of the desired voltage to the drive's maximum output power at the maximum operational frequency. The sine wave filter also smooths the voltage waveform of a pulse width modulated variable frequency drive.

Abstract: The protection circuit for a power supply unit comprises a switching stage, at which at least two output voltages to be monitored are connected, these voltages being isolated from one another by means of resistors. Arranged here in the connection path of the output voltages is a diode, which turns on and thereby triggers the switching stage in the event of a fault, when there is a drop in one of the output voltages. In this way, the switching stage provides information which acts on a control loop of the power supply unit, so that the power supply unit switches off. The protection circuit also includes a passive network with a resistor and a capacitor, which prescribes a time constant, after which the protection circuit permits renewed starting of the power supply unit. The switching stage may be realized, for example, by a transistor stage, which provides the information signal for the event of a fault for the power supply unit when turning on occurs.

Abstract: An apparatus for reducing power supply noise in the power supply system of a clock driver has been developed. The apparatus includes a clock driver with a power supply system connected to the clock driver and a shunting resistor connected across the power supply system in parallel with the clock driver.

Abstract: A method for determining the effect of load impedance on the magnitude and phase of loop gain of a power converter apparatus to aid in predicting stability of the converter apparatus under various operating conditions. The converter apparatus has an open-loop output impedance and provides an output signal to an output locus.

Abstract: The invention relates to a power supply for an illumination system used to expose photo-initiated adhesives. The illumination system includes an arc lamp to provide light. As the lamp ages, its electrodes deteriorate, reducing the amount of light directed into a light guide and ultimately onto the adhesive. The power supply provides an increasing power input to the lamp to increase the light output of the lamp, countering this deterioration at least in part. The voltage and current drawn by the lamp are measured and a skewed control signal which magnifies the level is used to control the power input to the lamp.

Abstract: The present invention relates to a power factor compensation device for a motor driving inverter which can improve a power factor of a voltage and a current inputted to the inverter driving a motor. The present invention detects a zero crossing point of an utility alternating current power, and outputs a driving signal corresponding to a plurality of sine wave form voltage values stored in a memory according to a detection result, when the zero crossing point of the utility alternating current power is detected in a state where the plurality of sine wave form voltage values corresponding to a voltage of the utility alternating current power and frequencies are stored in the memory. A switching transistor is switched according to the driving signal, and the voltage applied to the inverter is switched according to the switching operation, thereby improving the power factor.

Abstract: A reverse level shift circuit that is low in cost and excellent in reliability is provided by employing no Pch-DMOS transistor and forming it together with a level shift circuit on one semiconductor substrate. An input voltage signal (VIN) on high side is converted to a current signal by a voltage-current conversion circuit (CV1) and a current source (CS1). Using a Nch-DMOS transistor (ND1) of common gate construction as a high breakdown voltage resistance, the current signal is then transferred to low side, on which the current signal is converted to a voltage signal by a current source (CS2) and a current-voltage conversion circuit (CV2). Thereby, the signal change of the signal (VIN) using potential (HGND) as a reference potential can be outputted as a signal change of signal (VOUT) that uses potential (GND) as a reference potential.

Abstract: An apparatus for supplying and controlling electrical power having a power source for supplying electrical power to a primary load and a secondary load, a capacitor connected to an input to the secondary load and control means operable to cause an operating condition of the apparatus to temporarily change from, a operating condition in which power from the power source is supplied to the primary and secondary loads to an alternative operating condition in which power from the power source is supplied to the primary load but is supplied to the secondary load thereby increasing the minimum voltage the capacitor can maintain at the input to the secondary load.

Abstract: An analog voltage isolation circuit includes an error amplifier-integrator having an error-output voltage, which is compared to a selected value referenced to the same ground potential as the input signal being measured. The comparator output varies the current flowing through the series-connected light-emitting diodes of first and second opto-isolators. The output of the first opto-isolator, with respect to the input ground potential, generates a first current fedback to the error amplifier-integrator, to establish both the frequency and duty-cycle of a rectangular-wave signal periodically varying proportional to the magnitude of the input voltage.

Abstract: A variable frequency RF power delivery system is used with a control system that adjusts the output frequency of the RF power delivery system. Frequency adjustments are made so as to maintain the required input current and input voltage within the capabilities of the input current and input voltage source.

Abstract: A circuit protects a power conversion system with a feedback control loop from a fault condition. The circuit has an oscillator having an input for generating a signal with a frequency and a timer connected to the oscillator input and to the feedback control loop. The timer disables the oscillator after a period following the opening of the feedback control loop to protect the power conversion system.

Abstract: An induction heating power supply is disclosed. It includes a power circuit having at least one switch and a power output. The output circuit includes an induction head. The output circuit is coupled to the power output. A controller has at least one feedback input connected to the output circuit, and has a control output connected to the switch. The controller predicts the switch zero crossing and preferably soft switches the switch. Current feedback is obtained from a coil placed between the bus bars. Each bus bar is comprised of multiple plates to increase current capacity.

Abstract: A radio frequency (RF) power system for providing RF power to a load. The RF power system comprises a tank circuit; a direct current (DC) voltage source that provides a DC voltage within a first predetermined range; an amplifier, coupled to said DC voltage source, to provide an alternating voltage to said tank circuit; a frequency controller, coupled to said amplifier, to control a frequency of said alternating voltage provided by said amplifier; and a power sensor being coupled to said tank circuit for providing a signal to said frequency controller, wherein said frequency controller controls said frequency of said alternating voltage based on said signal provided from said power sensor.

Abstract: To display the sum of power generation in a photovoltaic power generation system having a plurality of independently-operating inverters in real time, an information display device receives information indicative of amounts of power generation respectively outputted from the plurality of inverters, calculates the sum of power generation in the plural inverters based on the received information, and displays the result of calculation.

Abstract: An intelligent power module (IPM) is formed of an inverter having power elements, a predriver for driving the inverter, and a protect circuit, and all these components are integrated into the same package. A shunt resistor is provided at an output of the inverter so that an end-to-end voltage of the shunt resistor can be output to an external device. This configuration enables an output current from an inverter apparatus incorporating the IPM to be detected without using a current transformer that requires a large installation space. In addition, the module terminals of the IPM and the terminal blocks of the inverter apparatus are integrated together to eliminate the need for wire rods and set screws for connections which are used to connect the module terminals and the terminal blocks together.

Abstract: A circuit arrangement (10) for the batteryless power supply of the electronic control of a portable machine driven by an internal combustion engine, which machine possesses a d.c. voltage generator driven by the internal combustion engine, which delivers a generated voltage dependent on the number of revolutions of the internal combustion engine, which is transferred to a rated d.c. voltage (Vcc). The circuit arrangement (10) includes a first rectifier circuit (D1, C1), which converts the generator voltage (Ug) into an intermediate d.c. voltage (Uz), which permits the same, without booster batteries, to reliably and controllably supply the electronics of an engine-driven machine, especially in the starting phase, with the requisite rated d.c. voltage.

Abstract: A circuit for interfacing between a conventional traffic signal's control monitor and a plurality of light emitting diodes (LEDs) replacing an incandescent lamp of the traffic signal is disclosed. The interface circuit includes a current source for driving the LEDs with a regulated power factor corrected current. Compatibility with traditional conflict monitors is achieved through a circuit that short circuits incoming current to indicate full turn off of the signal and opens up to indicate full turn on of the signal, and through an "OFC" circuit which presents an open circuit to the conflict monitor upon failure of the traffic signal LEDs. Quick turn-off of the traffic signal LEDs is accomplished with a switching circuit that reduces current flowing through the LEDs below the range for visible turn-off.

Abstract: The invention provides a voltage regulating device for regulating the operating voltage of a CPU in a computer system. The voltage regulating device includes a voltage identification signal regulator and a voltage identification signal bridge. The voltage identification signal regulator is controlled by a controlling signal to output a voltage identification regulating signal to the voltage converter. In this case, the voltage converter outputs the operating voltage of the CPU according to the voltage identification regulating signal. Meanwhile, a voltage monitor is used to monitor the operating voltage. When the voltage identification signal regulator outputs the voltage identification regulating signal, a voltage identification signal bridge blocks a default voltage identification signal output from the voltage identification signal setting device.

Abstract: A current converter that includes stored information about the converter can provide that information to an electronic device, such as a computer system, when the current converter is in use with the device. The current converter information can include manufacturer and model identity information, compatibility information, electrical characteristics, current converter type information, and current source information. A storage device in the current converter is coupled to a data bus for connecting to the electronic device, or can make use of one or more of the existing power output terminals to provide current converter information to the electronic device. Based on the information provided to the electronic device, the device can determine whether to allow operation of the device, and if so, under what circumstances and conditions.

Abstract: In one embodiment of the present invention, a system for ride-through of an adjustable speed drive for voltage sags is provided. The system comprises an adjustable speed drive including a three phase electric utility, a diode rectifier, a dc-link, an inverter, and a motor. Coupled to the adjustable speed drive is a ride-through circuit which includes a controller having a first input and a second input, the first input operable to receive the voltage from each phase of the three phase electric utility and determine the magnitude and phase of the voltage sag, and the second input operable to receive the dc-link voltage to ensure that the rated dc-link voltage is not exceeded. Also included is an IGBT coupled to an output of the controller and operable to switch on and off rapidly based on the amount of voltage sag. An inductor associated with the IGBT and operable to store energy when the IGBT is switched on and to transfer energy to the dc-link when the IGBT is off is also included.

Abstract: The power supply to a load in a power supply circuit is controlled by a power supply switch which in turn is controlled by a control circuit and by a feedback signal representing a voltage drop across the load. The control circuit provides at its output a high level signal, a low level signal, and a high impedance signal level, whereby the high signal level initially closes the power supply switch, and the feedback signal normally keeps the power supply switch in its closed "ON-state" as long as said high impedance level prevails. The switch is caused to open and assume its "OFF-state" in response to a circuit fault as signified by said feedback signal or in response to said low level signal. A monitor detects the "ON" or "OFF" state of the switch under normal operating conditions and also the "OFF" state when a circuit fault such as a short occurred in the power supply circuit.

Abstract: A system having reduced quiescent current drawn from a power supply. The system includes a device having a status. Moreover, the system includes a microcontroller, having an active and a sleep mode of operation, for polling the status of the device during the active mode, initiating a function in response to a change in the status during the active mode, and for conserving quiescent current drawn from the power supply during the sleep mode. The microcontroller generates an output signal at a first voltage level during the active mode and generates the output signal at a second voltage level during the sleep mode. The microcontroller, additionally, includes a sensor for switching the microcontroller from the sleep mode to the active mode. Furthermore system includes a storage device for charging to the first voltage level during the active mode, and for discharging to a third voltage level during the sleep mode for triggering the sensor to switch from the sleep mode to the active mode.

Abstract: This circuit arrangement comprises a transformer (2) for transmitting a measurement current (I), which is output by a sensor arrangement (1) at a measurement location situated in an intrinsically safe area (10), to a non-intrinsically safe area (20), in which a current measuring resistor (5) is situated. A DC converter (3) serves for the power supply of the sensor arrangement. A transformer (2) belongs to the DC converter (3), has a primary winding, which faces the non-intrinsically safe area, two identical partial windings (21, 22) connected in series in the same sense, and a single secondary winding (23), which faces the intrinsically safe area. A first end of the current measuring resistor (5) is connected to a circuit zero-point (SN) and a second end to a center tap of an output stage (31) of the DC converter (3). The center tap is connected to the input of an offset adjusting stage (6), an output of which is connected to the input of a voltage/current converter (7).

Abstract: A bridge-type power converter has, in each phase, a inductor (L.sub.1) connected between a connection point of said two switching elements (Q.sub.1, Q.sub.2) and an output terminal; capacitors (C.sub.1, C.sub.2) connected between the output terminal and a positive or negative side of a d.c. bus for changing an output voltage along a curve determined by a phenomenon of resonance with the reactor (L.sub.1) when the semiconductors switching elements (Q.sub.1, Q.sub.2) operate, causing abrupt changes of a voltage at the connection point; diodes (D.sub.3, D.sub.4) for changing a current path at a time when the resonance goes approximately one quarter of period to thereby stop the resonance; and constant voltage diodes (ZD.sub.1, ZD.sub.2) for absorbing the energy stored in the inductor (L.sub.1) during the resonance.

Abstract: The present invention discloses a sequence and circuitry for powering a mixed logic voltage computer system wherein power is delivered to the system hardware in increasing order according to the power consumption level of the particular system hardware such that system power consumption during system startup is minimized.

Abstract: A method and apparatus for generating an AC voltage with user defined inductance and resistance values in series therewith is described. The output voltage of the AC source is sampled and a signal indicative of the total current being generated is derived. The signal is scaled to model a series resistance and scaled and differentiated to model a series inductance. The modelled series resistance and inductance are then combined with the output voltage. Different inductances and resistances can be modelled merely by changing the user's input to the microcontroller that controls the operation of the present invention.

Abstract: A control circuit is disclosed which uses AC power input and provides DC power output which is not limited by DC semiconductor switch power dissipation capabilities. Switching is performed on the AC signal to provide time proportional AC power which is then transformed and rectified to provide relatively high proportional or adjustable power to a DC load without electrical noise. The DC load is monitored for a controlled characteristic, such as temperature, and a monitor signal is provided to a control for controlling the time proportional AC power output, in accordance with the DC load demand. A dimensionally stable temperature controlled semiconductor test chuck is described presenting a DC heater load for the control circuit.

Abstract: A superconducting magnetic energy storage system for applying power to a load includes a superconducting magnet, the inductor of which is supplied with current via a source which may be preset to a desired value of current, and wherein a feedback loop responsive to a sensed current adjusts the source to provide the desired current. Energy from the superconducting magnet is transferred via a series of pulses of current from the magnet to a first capacitor for charging the capacitor to a desired voltage greater than the voltage at the superconducting magnet. A further transfer of energy, via a series of pulses of current, results in a charging of a second capacitor to a voltage lower than the voltage of the first capacitor. The second capacitor feeds the load.

Abstract: A motor control system (10) for controlling a multiple number of motors, each motor having a multiple number of phases. System (10) can be used to dynamically vary the step sizes from microsteps to full steps (i.e. "syncro-stepping the motor").

Abstract: Methods, circuits, and kits for converting battery powered smoke detectors to AC power include a power converter which converts standard household AC voltage to a DC voltage suitable for use by a battery powered smoke detector and a battery clip connector for connecting the power converter to the battery clips of a battery powered smoke detector. According to one embodiment of the invention, a light emitting diode is coupled to the battery clip connector to indicate the presence or absence of DC voltage at the smoke detector. According to another embodiment of the invention, several battery powered smoke detectors are coupled to a single power converter. In yet another embodiment of the invention, several battery powered smoke detectors are provided with an AC power supply having an automatic battery back-up power supply. Preferred aspects of the invention include: providing the battery backed-up AC power supply with a battery tester and providing fuses for each smoke detector and for the battery.

Abstract: The present invention provides a switching device incorporating a simple circuit capable of avoiding the flash-on of a transistor when a power supply is turned on and off thereby reducing the OFF delay time. The output circuit comprises a FET (145) having a drain and a source connected in series to a current line for supplying a current from a power supply (VD) to an output detector (load) (L), and a photocoupler (149) for applying a driving voltage across the gate and the source of the FET (145) according to the output of an internal circuit (151), a differentiation circuit comprising a capacitor (7) and resistors (5,9) is connected across the drain and the source of the FET (145), and second transistor (3) having a collector and an emitter connected to the gate and the soruce of the FET (145) is driven by a charging current for charging the capacitor (7).

Abstract: A motor drive particularly suited for decelerating an AC motor includes a signal converting circuit, a monitoring circuit and a control circuit. The signal converting circuit is coupled to a source of DC power via a DC bus and a capacitive circuit is coupled across the DC bus to store energy produced by the motor during deceleration of a primarily inertial load. The signal converting circuit produces and applies drive signals to the motor based on control signals from the control circuit. The control circuit produces control signals for generating an output waveform duty cycle for the drive signals suitable for maintaining a predetermined voltage-to-frequency relationship. The frequency of the output signals is selectable to control the output speed of the motor. During deceleration, the monitoring circuit detects rises in the DC bus voltage, indicating that the motor is tending to slow at a rate less than the desired deceleration rate.

Abstract: A detection circuit for use in an electrical power converter having at least one negative output rail, for detecting the voltage of the negative output rail and for converting the voltage to a positive output voltage. The detection circuit includes an input port for receiving the negative output rail voltage from an electrical power converter, an output port, a ground reference potential, a node having a voltage that is positive with respect to the ground reference potential, and a circuit for generating a measurement current from the node to the ground reference potential. The value of this measurement current is a function of the negative output rail voltage received at the input port. A circuit is further provided for generating an output voltage at the output port that is positive with respect to said ground reference potential and whose value is a function of said measurement current.

Abstract: A regulated supply (10) includes a charge pump (12), an output (14), a sensing circuit (16), and a control circuit (18). The charge pump (12) includes a variable capacitor (33) whose capacitance C.sub.v may be varied to compensate for changing loads and input power supply levels. The sensing circuit (16) senses the voltage level at the output (14) and provides feedback signals (66) and (68) to the control circuit (18). The voltage at the output (14) is dependent upon the capacitance C.sub.v of the variable capacitor (33). Therefore, responsive to the feedback signals (66) and (68) from the sensing circuit, the control circuit (18) varies the capacitance C.sub.v of the variable capacitor (33). The control circuit (18) then may vary the value of C.sub.v in a step-like manner to correct for the voltage at the output (14).

Abstract: The present invention utilizes the advantages of a switching regulator, such as, for example, the one shown in the National Semiconductor September 1992 publication, without the addition of additional complex control circuitry to provide a highly efficient controller for controlling the average optical output from a laser diode.

Abstract: A stabilized voltage supply has a semiconductor and an output transistor formed on the semiconductor substrate and responsive to a power voltage. When the power voltage decreases to a level equal to or lower than a predetermined level, the output transistor is saturated. At this time, the semiconductor substrate is heated. The stabilized voltage supply also has a voltage dividing resistor for converting the output current of the output transistor into a stabilized output voltage which in turn is divided to form a feedback voltage. The stabilized voltage supply further has a differential amplifier for amplifying a differential voltage between the feedback voltage and a predetermined reference voltage, the differential voltage being then applied to the control electrode of the output transistor. The control electrode of the output transistor receives a current corresponding to the current applied thereto.

Abstract: A three-phase active filter for connection into a three-phase power distribution system to compensate undesirable harmonic deviations. A converter is electrically connected between the power distribution system and a DC energy storage element. The converter is selectively controlled by control means to effectuate a flow of energy between the system and the storage element to offset the harmonic deviations. To improve the dynamic response of the filter, the control means utilize vector control principles. Specifically, a synchronous fundamental vector of AC energy waveforms in the power distribution system is derived in a rotating reference frame. Fundamental reference signals are then produced in a stationary reference frame which are compared with corresponding actual condition signals. Error signals thus produced are then utilized to operate the converter.

Abstract: A voltage regulator circuit is provided for a sensor that is connected in a two-wire scheme to a circuit comprising a power supply and a load. The circuit regulates the current flowing through the load when the sensor output is inactive and provides power to the sensor during periods of time when the input power of the regulator circuit is insufficient to do so. A current monitor and a voltage monitor are provided which utilize common circuit elements to control the current flowing through the circuit. The operational characteristics of a MOSFET device are used advantageously to control the magnitude of current flowing through the sensor and regulate the current as a function of both the magnitude of current and the magnitude of a voltage potential across a bulk capacitor.

Abstract: A DC resistance welding apparatus includes a pair of welding electrodes for sandwiching workpieces to be welded therebetween and a circuit connected to the welding electrodes for supplying a welding current to said welding electrodes. The circuit includes a plurality of parallel-connected rectifying circuits each having a welding transformer and rectifying circuit. The circuit allows a large welding current to be supplied to workpieces, and makes the DC resistance welding apparatus small in size and light in weight.