Abstract: The semiconductor memory device contains a voltage converting circuit. The voltage converting circuit includes a plurality of reference voltage generating circuits for respectively generating a plurality of reference voltages at different levels. The voltage converting circuit further includes a differential amplifier, an output circuit, a switching circuit and a switching control circuit. The switching control circuit and the switching circuit select one of the plurality of reference voltages and supply the selected reference voltage to the differential amplifier in response to an externally applied control signal. The differential amplifier and the output circuit apply the supplied reference voltage to an internal circuit.

Abstract: A switching circuitry for coupling the power output of one of a plurality of power supplies to a keyboard. In this disclosure, a switching transistor of the circuit is coupled to switch power from a power supply output to a common point to which a plurality of like circuits and a keyboard are coupled. A differential amplifier having one input coupled to the common point and another input coupled to the power output of the respective power supply compares voltage on the common point to the voltage of the power supply. If the power supply voltage is higher than the voltage on the common point, the amplifier provides an enabling signal to the transistor, coupling power from the power supply to the common point. Conversely, if the voltage on the common point is higher than the voltage of the power supply output, the amplifier provides a disabling signal to the transistor, decouping the power supply output from the common point.

Abstract: An electronic apparatus capable of using power sources of different kinds each having a different characteristic is provided with an apparatus for controlling the operating mode of the electronic apparatus on the basis of the discrimination result provided by a discriminating switch, the discriminating switch being provided for discriminating the kind of a power source by means of the configuration of the electrodes of the power source. The electrodes of each kind of power sources are formed to have a different configuration. A recording or reproducing apparatus is also disclosed which controls the execution or non-execution of an erasing operation in accordance with the result of discrimination of the kinds of power sources.

Abstract: A small electronic device includes first and second locking devices which releasably lock the batteries on a first and second mounting portions, first and second detectors which respectively detect that the locked conditions of first and second locking devices have been released, first and second switches for connecting the first and second batteries to a power supply node. The electronic device also includes a control unit which turns on the first switch to connect the first battery to the power supply node, and switches from an off state to an on state the second switch in response to a detection signal from the first detector.

Abstract: When an IC card is attached to a terminal unit, a counter counts pulses of an external clock signal and a switching circuit outputs the external clock signal to an internal circuit in place of an internal clock signal if a NAND gate determines that the count of pulses of the external clock signal by the counter is a predetermined value. When the IC card is ejected from the terminal unit, pulses of the internal clock signal are counted by a counter and when the count attains a predetermined value, the counter is cleared and the switching circuit outputs the internal clock signal to the internal circuit in place of the external clock signal in response to the output of the NAND gate. Thus, it can be correctly determined whether the IC card is operated in the form of a single body or in the form attached to any terminal unit.

Abstract: Uninterruptible power supply apparatus which provides for supplying ac power to equipment even if and when the primary ac power is interrupted is disclosed and comprises an ac to dc converter connected to receive the primary ac power. The output of the ac to dc converter is applied to a dc power source. The resultant output of the ac to dc converter and the dc power source is provided as a dc input to a dc to ac inverter. The dc to ac inverter comprises an output transformer having a center-tapped primary. A first switching device is connected between a first end of the center-tapped primary and the negative terminal of the dc input to provide power pulses to one-half of the center-tapped primary. A second switching device is connected between a second end of the center-tapped primary and the negative terminal of the dc input to provide power pulses to the remaining half of the center-tapped primary.

Abstract: A circuit arrangement for A.C. operation of gas discharge lamps comprises a full-wave rectifier (1) connected to an alternating voltage source. The direct voltage is supplied to a combinatorial circuit part (3 to 8) in the form of a direct voltage converter, to which is connected a bridge circuit (9) which comprises four thyristors. The transverse branch of the bridge circuit includes the lamp (5). The full-wave rectifier (1) is followed by a smoothing capacitor (2) and an electronic switching element (14) is connected parallel to the bridge circuit (9). The switching element is switched to the conducting state in the vicinity of the zero passages of the input alternating voltage. As a result shortcircuits in the bridge circuit are avoided.

Abstract: A pulsed power supply having a filter output and a battery backup includes electronic apparatus to sense when the AC source is failing. When the pulsed supply output has the same pulses as that which would be produced by the battery, the supply switches to battery backup mode. As the AC source returns, the supply switches to AC supply mode when the AC is at a level where the pulses produced by the supply would be the same as are actually being produced by the battery backup.

Abstract: Backup power is provided for primary power supplies that serve several loads by providing fewer backup power supplies than the number of primary power supplies, generating power fault information indicative of the failure status of the primary power supplies, and connecting the backup power supplies each in parallel to one of the failed primary power supplies in response to power fault signals.

Abstract: A battery backup circuit including n pieces of PC boards which are to be supplied with electric power from a main power source, switches to be turned on or off in response to the voltage of the main power source, a main backup battery for supplying each PC board with backup power when the main power source is cut off by the switch, and a backup battery having smaller capacity than the main backup battery provided on each of the PC boards and put in connection with the main backup battery with runaround preventing diodes interposed therebetween, so that each PC board may be independently supplied with backup power and provided with the even rate of electric power consumption, and that the battery backup circuit may be manufactured at low cost.

Abstract: A power supply system including an inverter, a reserved power source and changeover switches for outputting one of outputs of the inverter and reserved power source to supply a load current to a load. The system further includes a control circuit for controlling a phase, a frequency and a voltage of the output of the inverter to coincide with a phase, a frequency of the output of the reserved power source and a specified voltage, respectively. The specified voltage is determined to be a predetermined reference voltage when the load current is below a detection level and to be a reduction voltage decided between zero volt and the voltage of the reserved power source when the load current is equal to or more than the detection level. A method for controlling a power supply system described above is also disclosed.

Abstract: A power distribution system includes a plurality of power sources and load transfer units including transistors and diodes connected in series and leading to a common power output, each of the transistors being controller switchable subject to voltage levels of the respective input and output sides of said transistors, and the voltage and current level of said common power output. The system is part of an interconnection scheme in which all but one of the power sources is connected to a single load transfer unit, enabling the survival of at least a single power source with the failure of one of the load transfer units.

Abstract: Apparatus for a redundant power supply comprises a receptacle and a pair of power supply inserts received therein and having connectors for the input voltage and for the output voltage. The outputs of two or more such power supply inserts are directly connected in parallel to one another. To this end, differently designed or arranged contact members for the input voltage and for the output voltage are provided. In a preferred embodiment, so-called leading contacts are employed for a charging current at the output side via a charging resistor before connecting the output of the insert being plugged in parallel with the output of an operating insert.

Abstract: A subscriber power supply which delivers sufficient power to a subscriber terminal load despite variations in load current due to changes in the number of channels in a telephone carrier system. The power supply also has a back-up unit which operates to deliver power to the load in the event that a fault occurs in the primary supply.

Abstract: A portable type electric appliance powered by incorporated main and reserve batteries. The batteries are connected to an electric load selectively by means of a switching device including a main switch for connecting the main battery to the load and a subsidiary switch for connecting the reserve battery to the load. A lock locks the subsidiary switch in a disconnected position until the main switch is closed. Namely, the subsidiary switch can be closed only after the main switch is closed. Therefore, the main battery is always used prior to the reserve battery, and when the main battery is exhausted, the reserve battery remaining unexhausted is capable of taking over to operate the appliance without requiring immediate replacement of the main battery. Accordingly, the accidental interruption of the operation of the appliance can be avoided.

Abstract: A stored electric power system selectively operates automotive accessories independent of the motive drive force generated by the vehicle heat engine so as to reduce fuel consumption, reduce the generation of pollutants and improve the vehicle performance. The electric power system is charged from sources external to the engine drive.

Abstract: A stabilized power source parallel operation system in which the composite output current is maintained at a predetermined level even if a plurality of the parallel power sources are deenergized. Each power source has a voltage comparator, a current converter and a current comparator. The outputs of each of the voltage comparators are interconnected by an inter-power source voltage bus so that each of the current comparators compare the same current.

Abstract: A plurality of selected fixed hydraulic geometry turbine generators are programmed for operation at rated efficiencies by interrupting flow to the turbines under control of a programmable power controller receiving water level, flow and power monitoring inputs. The turbines selected are of discreet sizes simultaneously operative only under maximum flow conditions of the hydropower source, and otherwise operated in accordance with an optimum duty schedule to match varying flow conditions.

Abstract: An electrically releasable safety ski binding in which a measuring system determines the load applied to a skier's leg during skiing and a release mechanism incorporating an electromechanical converter such as a solenoid acts on a clamp device securing the ski boot to the binding to release the ski boot when the aforementioned load reaches a dangerous level. To prevent the binding becoming inoperative on failure of the electrical power supply the binding is equipped with an auxiliary release mechanism having a first inoperative state and a second operative state which can be selected either manually or automatically should the electrically operated release mechanism fail.

Abstract: A control circuit for automatically controlling and transferring various power sources for a recreational vehicle or the like. More particularly, the system responds to various load demands, contingencies and conditions to control and transfer the power supplied to the recreational vehicle between a land line, a motor generator, and an inverter.

Abstract: The invention provides a bilateral static isolator which is activated by "soft" forced commutation. Between two points in the power line to be interrupted are connected two thyristors in series-opposition, thus cathode to cathode. In antiparallel with each thyristor is mounted a diode. Thus, the two diodes appear in series opposition between the two power line points. A resonant circuit is applied to the conducting thyristor in order to turn it off with a relatively small reverse voltage. This voltage is obtained by resonant discharge of a precharged capacitor C through an inductor L and a diode D connected in reverse with the thyristor. The forward voltage drop of the diodes appears in reverse across the thyristors from the instant the discharge current rises above the line current until the instant the discharge current drops below the level of the line current. It is during this interval that the thyristor is provided with "soft" reverse bias. Subsequently the net current reverses again.

Abstract: A main and an auxiliary energy supply device supply energy to a load normally and during disturbances of the main supply respectively while, for bridging brief disturbances in the load supply, for example naturally brief disturbances or during the short time when a disturbance has begun and the auxiliary supply has not yet come into operation, there is provided an energy store which can receive and store energy from the main supply and make this stored energy quickly available to the load. A control logic system controls the main and auxiliary supply devices and the storage means to ensure substantially constant energy supply to the load. The disturbances in question may comprise voltage rises or reductions and/or waveform distortions for example.

Abstract: A power distribution system includes a plurality of power sources and load transfer units including transistors and diodes connected in series and leading to a common power output, each of the transistors being controller switchable subject to voltage levels of the respective input and output sides of said transistors, and the voltage and current level of said common power output. The system is part of an interconnection scheme in which all but one of the power sources is connected to a single load transfer unit, enabling the survival of at least a single power source with the failure of one of the load transfer units.