Abstract: Two or more gated type power switches, particularly mosfets, are disclosed in a protection circuit which protects the other power switches should one of them short to its respective gate. The circuit includes elements for sensing the occurrence of the failure, for carrying or diverting excess current from the gates, and increasing the impedance of the gates to minimize any damage. The circuit prevents the failure of one mosfet in a drain to gate short mode from destroying or damaging the other parallel mosfets. The invention results in easier analysis and repair of any damage should a breakdown occur, and for the first time makes practical the use of many mosfets in parallel for power switching applications.

Abstract: A load, such as a control circuit for a DC/DC converter, is initially operated by an initial load powering voltage developed by a power consuming regulator until another voltage, such as the DC/DC converter's output voltage derived from an input voltage used by the voltage regulator to establish the initial load powering voltage, reaches a predetermined level. A switching control circuit initially allows the regulator to operate and connects its output to the load. The switching control circuit, however, responds to the other voltage so that when this other voltage reaches the predetermined magnitude, the switching control circuit prevents the regulator from further operating and thus from further dissipating energy. The switching control circuit then connects the other voltage to power the load. The switching control circuit is designed so that it dissipates less energy than the regulator when the switching control circuit disables the regulator and allows the other voltage to power the load.

Abstract: A device for supplying a control terminal of a three-terminal controllable electric valve connected between positive and negative lines. The device includes a transformer having a primary and a secondary windings, a first capacitor connected to the primary winding, and a second capacitor connected with the secondary winding. The first capacitor is adapted to be charged when the electric valve is turned off and to discharge through the primary winding when the electric valve is turned on. The current induced in the secondary winding by the discharging current is supplied, as an operating current, to the circuit for driving the electric valve.

Abstract: The invention is a locally isolated regulated power supply providing a regulated dc power output from an ac current source having a large dynamic range. The power supply comprises an ac-to-dc converter for providing a rectified dc output from an ac current input. The converter includes a current transformer in combination with a rectifier. The current transformer has a saturable magnetic core for receiving primary and secondary windings. The current transfomer produces a reduced secondary output voltage that is a function of the ac system current characterized by the decreased coupling between the core and secondary winding as the core approaches saturation during substantial increases in the ac system current. One or more secondary windings and associated circuitry can be provided. In addition, an electronically controlled switch or shunt having as inputs a predetermined reference voltage and the dc output voltage of the rectifier or a signal equivalent thereto is connected across the converter.

Abstract: A voltage compensated bias generator voltage source includes an all NPN active collector load circuit operatively coupled between the line voltage V.sub.cc and the collector of the shunt regulator transistor of the bias generator. The all NPN active collector load circuit logarithmically reduces variation in shunt regulator transistor collector current with variations in the line voltage V.sub.cc. A transistor of the active collector load circuit also provides in combination with an output transistor of the bias generator a Darlington transistor pair of ECL current source voltage V.sub.cs. A temperature variation countervailing third transistor is also operatively coupled in the active collector load circuit to compensate for temperature variation problems introduced by the active collector load circuit itself.

Abstract: This power supply device comprises a voltage regulating element, a constant-current source, first and second constant-current circuits, and a current switching circuit interposed between the first and second constant-current circuits and the constant-current source, and by comparing an input voltage with an output voltage to introduce constant current from the first constant-current circuit to the voltage regulating element when the input voltage is higher than the output voltage, while introducing the constant current from the second constant-current circuit to ground terminal when the input voltage is lower than the output voltage. Thus, a stabilized DC voltage may be produced from a DC voltage including a superposed AC signal without interfering with the AC communications signal.

Abstract: A low-pressure mercury vapor discharge lamp comprises a tubular bulb having an inside diameter of from 22 mm to 35 mm, an electrode-to-electrode distance of from 400 mm to 1,200 mm, and an inner surface coated with a phosphor. A rare gas including Kr and a mercury vapor source are sealed in the bulb, which is energized by an igniting device having a high-frequency power supply connected to a DC power supply for generating a substantially sinusoidal high-frequency output voltage, and a quiescent period generator connected to the high-frequency power supply and including a switch 17 turned on and off at least once during each half cycle to provide a quiescent period and thereby produce a substantially square wave high-frequency output voltage having rise and fall times of 2 .mu.s or less.

Abstract: A hearing-aid has an electronic voltage stabilizing circuit (16) to compensate for change in supply voltage due to battery (18) aging and use. The electret microphone (11) is located within a housing, the voltage stabilizing circuit (16) being located within the same microphone housing, thus requiring no additional space or terminal connections. Preferably, an impedance transformer is provided; the electronic components (31-34) are placed on the same semi-conductor chip as the components (35, 36) of the voltage stabilizing circuit.

Abstract: A device is proposed for generating specific electrical voltage values for consumers associated with an internal combustion engine. The device also encompasses a voltage elevating circuit which can be switched on in the vicinity of the minimum voltages for the consumers. This means that this voltage elevating circuit does not need to be switched on continuously during engine operation, but rather only at times of increased power needs. The voltage elevating circuit has a series circuit of a coil 20 and a diode 21 in a voltage supply line, and the connecting point of these two components is briefly closed off from the other supply line in a clocked manner. The activation of the voltage elevating circuit can be switched on and off in accordance with the input and output voltages and in accordance with the maximum permissible switching current. Depending on the clock frequency of the switch 23, the line inductance of the supply line suffices as an inductance 20.

Abstract: A power supply circuit includes an operational amplifier oscillator, a buffer amplifier and a diode pump connected to provide a negative output relative to the more negative of two supply rails. The supply terminals of the operational amplifier are connected to one supply rail and the output of the diode pump respectively, so that when the circuit is first connected to the supply the operational amplifier is initially connected between the rails through the intermediary of the diodes of the diode pump.

Abstract: A bleeder circuit is utilized to insure proper operation of a filter inductor in a pulsed power system. A control arrangement couples a bleeder resistor to the filter inductor in response to actual current discontinuities in the inductor. The control arrangement responds to actual current discontinuities by responding to a voltage collapse in the inductor and activates a switch to couple the bleeder resistor to the inductor.

Abstract: A circuit arrangement for producing a regulated high dc voltage from three-phase current utilizes a three-phase current bridge rectifier which is connected to lines for the three phases of the three-phase current, and a first circuit having a transistor is arranged parallel to the three-phase current bridge rectifier circuit and includes a base for receiving a control current. In each line of a three-phase supply, a series resistance is connected in front of the connection points of the lines of the three-phase current bridge rectifier.

Abstract: A system for and a method of extracting energy from a capacitive source, for example the energy induced in an insulated section of the overhead wire of an AC transmission line. The energy is extracted from the overhead wire by tapping the primary winding of a voltage step-down transformer which develops at its secondary an AC voltage the value of which is regulated through shunt switching. The shunt switching regulation as such is achieved by power thyristors the firing of which is selectively controlled in accordance with the phase and the amplitude of the output voltage. A comparator is used to compare the output voltage value with that of a signal delivered by an internal ramp generator. Moreover, the firing instant of the thyristors is governed by the output signal of the comparator and also in function of the information on the polarity of the output voltage cycles.

Abstract: A simplified voltage regulator circuit permits varient light intensity photovoltaic recharging of secondary batteries. The regulator circuit electronically shunts serially connected regions of a photovoltaic recharger array to avoid overcharging during periods of high light intensity or full battery charge conditions. The regulator circuitry provides minimal series resistance to the photovoltaic array and requires nominal driving power. The photovoltaic array and the regulator circuitry may comprise discrete components or may share a common substrate body.