Abstract: A control arrangement and method is provided for detecting and responding to disturbances in electrical power systems. In a preferred arrangement, an integration is initiated that is based on a comparison of actual voltage of a source and a reference voltage. When the integration exceeds a predetermined value, the source is considered unreliable. Also in a preferred arrangement, a determination is made as to whether or not the disturbance is a downstream fault condition. For example, this is useful for applications where a transfer is made from a first source to a second source when predetermined disturbances are detected. In this manner, the transfer of the load to a second source is avoided which would continue the supply of the downstream fault. Additionally, the arrangement distinguishes between various degrees of disturbances to permit appropriate response based on the severity and type of disturbance. For example, a first immediate response, i.e.

Abstract: An electrical power cord for providing low-voltage alternating current outputs from a high-voltage alternating current source. The cord includes an input terminal that is operable to receive power from a high-voltage alternating current power source. The cord also includes first and second output terminals that are operable to output low-voltage alternating current. The input terminal includes two distinct neutral wires.

Abstract: A universal interface circuit and an associated method are provided that can supply a computer logic circuit, such as the components mounted upon an adapter card, with first and second inputs having first and second predetermined voltage levels, respectively, based upon power drawn from both first and second supply voltages. The interface circuit typically includes a first power supply circuit for providing the first input having the first predetermined voltage level in response to the first supply voltage. Additionally, the interface surface includes a regulator for generating an output having the second predetermined voltage level in response to the first supply voltage. The interface circuit further includes a second power supply circuit for providing an output that also has the second predetermined voltage level, albeit in response to the second supply voltage.

Abstract: A system and method for integrating communications equipment. The system includes a power supply in which the power supply provides power to telephone equipment located in a centralized unit and at least one power converter for receiving the power from the power supply and having a chassis for supporting at least one power converter module. The power converter converts the power from the power supply into at least one output voltage for powering a second set of communications equipment, and the second set of communications equipment is located in the centralized unit. In one arrangement, the second set of communications equipment can include cable television equipment.

Abstract: An electrical arrangement provides power to a plurality of electrical systems, the electrical arrangement including a plurality of voltage buses; a plurality of voltage sources configured to supply respective electrical voltage potentials, the voltage sources being respectively assigned to the voltage buses, the voltage sources supplying the respective electrical voltage potentials to the respective voltage buses; at least one electrical system assigned to and electrically coupled to each of the voltage buses to receive electrical power; and a DC-DC converter arrangement electrically coupled to the voltage buses, the DC-DC converter being configured to convert at least one of the respective voltage potentials to another one of the respective voltage potentials, the DC-DC converter being mechanically and proximally coupled to at least one of the voltage sources.

Abstract: A high voltage supply device including a power supply rectifying an externally inputted ac voltage and generating a first dc voltage and a second dc voltage, a controller generating a pulse signal having a predetermined duty ratio and a control signal having a first logic level when the first dc voltage is applied, a high voltage generator boosting the second dc voltage based on the pulse signal, and a power supply controller driven when the control signal is in the first logic level, and cutting off an application of the second dc voltage to the high voltage generator when the control signal is in a second logic level. Such a high voltage supply device, when used in electronic devices such as laser printers, facsimile machines and DC-DC converters requiring a high dc voltage, does not generate a surge voltage when the electronic devices are turned off.

Abstract: A control arrangement and method is provided for detecting and responding to disturbances in electrical power systems. In a preferred arrangement, an integration is initiated that is based on a comparison of actual voltage of a source and a reference voltage. When the integration exceeds a predetermined value, the source is considered unreliable. Also in a preferred arrangement, a determination is made as to whether or not the disturbance is a downstream fault condition. For example, this is useful for applications where a transfer is made from a first source to a second source when predetermined disturbances are detected. In this manner, the transfer of the load to a second source is avoided which would continue the supply of the downstream fault. Additionally, the arrangement distinguishes between various degrees of disturbances to permit appropriate response based on the severity and type of disturbance. For example, a first immediate response, i.e.

Abstract: In a DC-DC converter circuit having a plurality of input terminals connected to a plurality of DC power supplies, and an output terminal, the DC-DC converter circuit includes a power supply selection section for selecting a DC power supply of lowest voltage on the condition that the voltage is not less than a predetermined voltage, and a step-down type of regulator section for converting the voltage of the DC power supply selected by the power supply selection section into a predetermined voltage lower than the voltage of the DC power supply selected by the power supply selection section, and outputting the converted voltage through the output terminal.

Abstract: An electrical distribution system and method has storage battery mechanism of very large equivalent capacitance providing excellent ripple filtering and an ideal path to ground, and filter capacitor mechanism of microfarad size providing DC blocking and limited AC path to ground. The storage battery entity is maintained as to its charge by DC supply, which provides regulated DC power in which switching regulation may be involved. The system and method provides dual voltage capability, both DC and AC, in which circuit breakers may be ganged for simultaneous tripping, and in which intrinsic DC circuit(s) may be looped to increase current-carrying capability. A DC isolation capacitor is connected to a common current path, such as to one of the busses, such as, for example, in series with the neutral circuit, as a means for avoiding undesirable DC current paths as may be encountered due to a multitude of established neutral-line connections to earthing grounds established throughout in AC power supply network.

Abstract: A power circuit applicable to an information-processing device includes coupling circuits for transforming several different voltages. The coupling power circuit includes a driving unit and a transforming unit. When the information-processing device requires several different voltages of power, the driving unit provides a driving signal to the transforming unit. Then, the transforming unit transforms several different voltages through electromagnetic coupling for power output to the information-processing device.

Abstract: A method and arrangement for supplying quiescent current to a vehicle having a multi-voltage on-board electrical system with at least two on-board electrical subsystems having different voltage levels during normal operation. The voltage levels of the on-board electrical subsystems are reduced to a uniform value when the engine is stationary.

Abstract: A power supply according to the principles of the inventions comprises two stages. The first stage is a power factor corrector stage. This stage provides the required line regulation, including greater than 95% power factor correction, and provides a range of outputs from approximately 5 volts to 200 volts with good load regulation at low voltages. The second stage is a soft switching power supply having good load regulation from approximately 40 to approximately 175 volts. An intermediate high voltage of the first stage supplies the input to the second stage, thereby achieving extremely good line regulation and low regulation.

Abstract: Method and system for bi-directionally controlling power flow between two separate direct current power sources in a multi-stage power converter system are provided. The method allows providing at least first and second power converter stages coupled in parallel circuit to one another. The method further allows providing a first switching controller coupled to selectively actuate a pair of switching devices in the first power converter stage, and a second switching controller coupled to selectively actuate a pair of switching devices in the second power converter stage. One of the first and second switching controllers is selected as a master controller, and the other one of the first and second switching controllers is selected as a slave controller. An average voltage measurement is determined at a respective node of each the power converter stages. A compensating signal is generated based on the difference of the average voltage measurements at the respective nodes of each of the power converter stages.

Abstract: A battery backup system has a number of batteries and number of switches interconnecting the batteries to either a high-power load or a low-power load. The batteries are selectively connected in series with each other, or in parallel with each other by the switches. When the batteries are in the parallel configuration they are also connected to power the low-power load, and when in series, to power the high-power load. Between switching from the high-power series configuration to the low-power parallel configuration, a transition phase is provided during which a transition battery powers the low-power load.

Abstract: A power supply system contains two batteries and a load device which is connected to the batteries such that, upon failure of one of the batteries, the other takes over the supply of power. The batteries and the load device are connected to one another by a single ground line and arranged such that, upon an interruption between the interconnected grounds of the batteries and the ground of the load device, the load device is fed with the difference voltage of the batteries. A reliably operating power supply system is created which is operational by with only one ground line.

Abstract: An energy management system for a motor vehicle has a first voltage supply terminal having a first nominal voltage and a second voltage supply terminal having a second nominal voltage. At least one of the first and second voltage supply terminals has a battery. A universal bi-directional DC-DC converter is coupled to exchange energy between the first and second voltage supply terminals. A third voltage supply terminal is provided for exchanging energy between the DC-DC converter and an external vehicle electrical system or battery charger. The energy exchanged between the first or second voltage supply terminals and the third voltage supply terminal is independent of the voltage and polarity of the external vehicle electrical system or battery charger.

Abstract: A power supply device for an electric discharge machine for supplying power to a work gap (6) formed between a work piece and a tool electrode, includes a parallel circuit in which a first power supply (8), a second power supply (36) and a capacitor (34) are connected in parallel and the second power supply can supply a larger voltage and a smaller current than the first power supply to the work gap. A switching element is connected between the parallel circuit and the work gap for pulsing power from the parallel circuit.

Abstract: An electrical distribution system and method has storage battery mechanism of very large equivalent capacitance providing excellent ripple filtering and an ideal path to ground, and filter capacitor mechanism of microfarad size providing DC blocking and limited AC path to ground. The storage battery entity is maintained as to its charge by DC supply, which provides regulated DC power in which switching regulation may be involved. The system and method provides dual voltage capability, both DC and AC, in which circuit breakers may be ganged for simultaneous tripping, and in which intrinsic DC circuit(s) may be looped to increase current-carrying capability. A DC isolation capacitor is connected to a common current path, such as to one of the busses, such as, for example, in series with the neutral circuit, as a means for avoiding undesirable DC current paths as may be encountered due to a multitude of established neutral-line connections to earthing grounds established throughout in AC power supply network.

Abstract: A compensation circuit for a DC—DC converter having a low voltage output line and a plurality of high voltage output lines applied to a plurality of loads includes an adjustable impedance source connected to the low voltage output line. The impedance source generates a feedback control signal to the DC—DC converter used to control the transformer duty cycle. A sensing circuit is connected to the plurality of high voltage output lines for generating a control signal which represents variations in the output voltages of the high voltage output lines. The control signal is applied to the impedance source to thereby regulate the feedback control signal which in turn provides regulation for the high voltage output lines.

Abstract: An isolation system and method that electrically couples a device to a bus during cycles associated with or accessing the device, but otherwise isolates the device from the bus. The isolation system includes an isolation device coupled to the device and to the bus that includes an enable input adapted to receive an enable signal, where the isolation device electrically couples the device to said bus while the enable signal is asserted, but otherwise electrically isolates the device from the bus. The isolation system further includes enable logic that detects cycles on the bus and provides the enable signal to the enable input of the isolation device during a cycle if the cycle is associated with the device. The isolation device may comprise a bus switch, one or more discrete isolating devices such as bipolar transistors, field-effect transistors, or any other suitable device for isolating a device from the bus.

Abstract: A power supplying adapter which is connected to an AC power source and generates a predetermined DC voltage is constructed by a power supplying unit in which a small power mode to output a small electric power and a large power mode to output a large electric power can be switched; a current detecting unit for detecting a current outputted from the power supplying unit; a signal receiving unit for receiving a signal transmitted from electronic equipment; and for control means for making the power supplying unit operative in the small power mode and making the signal receiving unit means operative when the current detected by the current detecting unit is equal to or smaller than a reference value. The electronic equipment is constructed by a signal transmitting unit for transmitting a signal to the power supplying adapter; a second control unit for controlling the signal transmitting unit; and a switching unit for switching a power source which is supplied from the power supplying adapter.

Abstract: A power supply that receives an input voltage and provides output power is described. A method for selecting one of a plurality of input voltages by moving first and second links is also described. The power supply includes a housing and the links are inside the housing. The links configure the power supply to receive a selected input voltage from a number of input voltages, depending upon the position they are in. The links depend on one another. Indicators are connected to the links, and show for what input voltage the links are connected. The indicators are visible from outside the housing. The housing includes one or more windows through which the indicators are visible. The indicators are alpha-numeric characters or drawings. The links includes a circuit board with the indicators mounted thereon and a plug or a set of copper bars that are placed in either the first or second position.

Abstract: A heating assembly, for use as an electric blanket or personal heating pad, includes a flexible heating panel and an electric circuit for heating the panel. An electrical heating element is mounted directly on the panel and includes inner and outer coaxial coil conductors separated by an electrically insulating layer and surrounded by an outer electrically insulating layer. A two-core flexible electric cable connects the heating element to the power supply, and to an electric control switch for controlling operation of the heating element, a fuse being located in the circuit to be actuated in the event of a short circuit occurring between the conductors of the heating element, due to breakdown of the inner insulating layer. The electric circuit also includes a device for controlling the temperature of the heating element.

Abstract: A power source device in which, even in case of mistaken connection of a source power supplying cable, the supply of source power can be halted before destruction of an electronic equipment or of the power source device itself at the time of supplying the source power. A micro-computer 8 is started when fed with the source power from a power source circuit 1, and controls a constant current circuit 2 for not impressing a load voltage across a resistor R1. A camera device 30 is fed with a dc current for load resistance detection via a resistor R2 and a diode D1. A comparator 3 sends to a port P1 of the micro-computer 8 a level signal specifying whether or not the resistance RL is higher than a pre-set value. The micro-computer 8 controls the constant current circuit 2 for supplying the source power to the camera device 30 if the level signal supplied to the port 1 is `1`, that is if the load resistance RL is higher than a pre-set value.

Abstract: In a power supplying apparatus for use in an image forming apparatus, when a first transistor is switched on, a first photo-triac coupler and a first triac switch on so that a fixing heater is powered on. After a predetermined time, a second transistor is switched on. A second photo-triac coupler and a second triac are thereby switched on so that the fixing heater is powered on. The first triac is then switched off. The first triac is connected in series to a resistor, so that when the first triac is switched on but the second triac remains off, the voltage applied to the fixing heater is sufficiently low in comparison with the voltage applied thereto when the second triac is switched on. Therefore, when the fixing heater is powered on by switching on the first transistor to switch on the first triac, a large power surge does not occur. When the second triac is switched on, a large power surge does not occur either since the fixing heater has already been powered on.

Abstract: An adapter including: a receiver for receiving first and second voltages as an input; a conversion circuit; and first and second connectors on the receiver. The first connector can be releasably coupled to the conversion circuit in a first manner so that the conversion circuit generates a predetermined output voltage with the first input voltage supplied to the receiver. The second connector can also be releasably coupled to the conversion circuit in a second manner so that the conversion circuit generates an output voltage that is substantially the same as the predetermined output voltage with the second input voltage supplied to the receiver.

Abstract: A semiconductor memory device includes a plurality of external power supply pads P1 to P3. Connection between external power supply pads P1 to P3 and an external power supply is determined in accordance with the voltage of the external power supply to be used, and the connection is switched by bonding. External power supply of a high voltage level is connected to an external power supply pad P2 which is connected to VDC1 and VDC2. A circuit including memory cells operates using the voltage applied from VDC1 or external power supply pad P3, while a group of word line drivers operates using the voltage applied from VDC2 or external power supply pad P1. VDC1 down converts the external power supply voltage, and VDC2 down converts it in accordance with the level of the voltage of the external power supply voltage, and generates internal power supply voltages, respectively. Accordingly, a semiconductor memory device which operates adapted to different external power supplies can be obtained.

Abstract: An overvoltage and surge protection circuit for a hard disk drive is provided. The overvoltage and surge protection circuit is intended for protecting an interior circuit part from a surge voltage caused by an overvoltage generated due to wrong insertion of first and second power supply voltages, and an external condition, in a hard disk drive which receive the first power supply voltage as an operational voltage of an interior circuit device and the second power supply voltage as a device driving voltage. The overvoltage and surge protection circuit includes an overvoltage protection circuit having a first and second power supply input terminals for receiving the first and second power supply voltages, respectively, and a surge protection circuit.

Abstract: An avionics power conversion circuit having a first input adapted to receive an AC input signal, a second input adapted to receive a DC input signal and an output at which converted signals are provided. Power conversion circuitry, coupled to each of the first and second inputs and to the output, provides boost conversion of the AC input signal when the AC input signal is applied to the first input and provides flyback conversion of the DC input signal when the DC input signal is applied to the second input. The power conversion circuitry provides the boost conversion and the flyback conversion using a single transformer coupled between the first and second inputs and the output.

Abstract: When a state of outputting a third power supply potential to an output node is switched to a state of outputting a second power supply potential, connection between a supply unit of the second power supply potential and the output node is made through a first P-channel MOSFET. Further, when the first P-channel MOSFET is turned off, i.e., when the third power supply potential is output to the output node, the third power supply potential is also applied to a gate of the first P-channel MOSFET. Therefore, even when the potential of the output node rises to the third power supply potential, this transistor is not turned on. Thus, the second power supply potential and the output node are appropriately and electrically isolated from each other. The circuit can be used with a flash memory to prevent over programming.

Abstract: An electrical distribution system and method has storage battery mechanism of very large equivalent capacitance providing excellent ripple filtering and an ideal path to ground, and filter capacitor mechanism of microfarad size providing DC blocking and limited AC path to ground. The storage battery entity is maintained as to its charge by DC supply which provides regulated DC power in which switching regulation may be involved. The system and method provides dual voltage capability, both DC and AC in which circuit breakers may be ganged for simultaneous tripping, and in which intrinsic DC circuit(s) may be looped to increase current-carrying capability.

Abstract: A single chip integrated circuit includes a boost regulated DC-to-DC converter and gate drive circuits integrated on the same die with a micro-processor, along with high density digital logic functions, analog functions, etc. The gate drive circuits are used to drive external power FETs, particularly high side NMOS. The micro-processor may also be some type of micro-controller or digital signal processor. By being able to place these functions on a single integrated circuit, a motor or actuator control system can be placed on a single chip. With appropriate sensors to provide feedback to the integrated circuit, a system which is capable of executing actuator move functions, such as position, velocity, velocity profile, torque, etc., and sequencing these events as well is included.

Abstract: A programmable autosynchronizer for use with a system having generator and bus voltages and having a breaker circuit for connecting the generator and bus voltages to each other. The autosynchronizer synchronizes the frequency and phase of the generator and bus AC voltages by controlling the generator voltage. A microprocessor compares the frequencies of generator and bus voltage signals, the microprocessor generating a proportional difference signal having a parameter representative of a proportional difference in frequency between the generator and bus voltage signals. The proportional correction range extends within the synchronization range. The microprocessor permits a sync signal when the frequency difference of the frequencies of the generator and bus voltage signals is within the synchronization frequency range. A first output circuit responsive to the proportional difference signal provides a correction signal to the generator for varying the frequency of the generator.

Abstract: A component card interconnect apparatus for coupling a component card to a computer system. A component card includes a first group of in-line pins with first power pins for conveying a first voltage and a second group of in-line pins with second power pins for conveying a second voltage. The second voltage is lower than the first voltage. Either the first or the second voltage is conveyed at one time.

Abstract: A power supply control apparatus for controlling a power supply circuit for outputting voltages of at least two systems is constructed by a first power supply circuit for generating a first voltage and a second power supply circuit for generating a second voltage, a controller circuit which is driven by the first voltage, a disconnecting circuit for disconnecting the second voltage by the controller circuit in accordance with a predetermined condition, a power supply controller circuit for controlling the second power supply circuit on the basis of the second voltage, and a supplying circuit for supplying a signal indicative of a state in which the second voltage has been outputted to the power supply controller circuit when the second voltage is disconnected by the disconnecting circuit.

Abstract: A multiplexor having a multiplexor control input terminal for selectively providing one of a plurality of conductor voltage levels to a conductor. The multiplexor includes a first switch, which is coupled to the conductor, for providing a first conductor voltage level to the conductor. A second switch is also included and coupled to the conductor for providing a second conductor voltage level to the conductor. To provide a selective discharge path for the conductor during switching, the multiplexor further includes a third switch coupled to the conductor. A discharge circuit is also provided and coupled to the conductor and the third switch for sensing the voltage level of the conductor to turn on the third switch as necessary at the early stage of switching among conductor voltage levels.

Abstract: An autosynchronizer for use with a system having generator and bus voltages and having a breaker circuit for connecting the generator and bus voltages to each other. The autosynchronizer synchronizes the frequency and phase of the generator and bus AC voltages by controlling the generator voltage. A microprocessor compares the frequencies of generator and bus voltage signals, the microprocessor generating a proportional difference signal having a parameter representative of a proportional difference in frequency between the generator and bus voltage signals. The proportional correction range extends within the synchronization range. The microprocessor permits a sync signal when the frequency difference of the frequencies of the generator and bus voltage signals is within the synchronization frequency range. A first output circuit responsive to the proportional difference signal provides a correction signal to the generator for varying the frequency of the generator.

Abstract: An apparatus for sequencing turn-on and turn-off of power converters includes a first DC to DC converter responsive to a control signal for asserting a voltage supply signal and a sense circuit responsive to the output of said first converter to sense the level of voltage at the output of the first converter and to provide an enable signal in response to the output of said first converter when the first converter reaches a desired value. The apparatus further includes a second DC to DC converter responsive to said enable signal to provide a second supply voltage at a second different voltage level. The sequencing control has a circuit responsive to said second supply voltage and the first supply voltage, to short the second DC to DC converter to a reference potential.

Abstract: A regulated power supply automatically accommodates either a positive or negative polarity connection of a power source and without regard as to whether the source is an DC or an AC source, and accommodating a wide range of input voltage sources. The power supply circuit includes a source voltage conditioning unit which includes an input fuse section, a surge protection circuit, a power switch, and a filter rectifier section, coupled in circuit between a set of external power source connection terminals and a set of output terminals from which a rectified and filtered intermediate voltage is derived. An open fuse detector alerts servicing personnel to an open condition of a user-replaceable input fuse. A DC-DC converter section includes a start up supply circuit and a primary drive winding of a power transformer connected to receive the intermediate rectified voltage from the filter rectifier of the input section.

Abstract: A power supply switching apparatus for switching power supplies used to all electronic appliance such as a pager and a portable telephone is described. A battery pack includes a battery and is connectable to an external DC power supply. In the battery pack, a power supply connection detecting circuit detects whether or not the external DC power supply is connected to this battery pack, and a switching circuit switches the battery and the external DC power supply. In an appliance housing a voltage is detected by a voltage detecting circuit to judge whether the detected voltage corresponds to the voltage derived from the battery power supply, or the voltage derived from the external DC power supply, and another switching circuit switches the battery power supply and a power stabilizing circuit. Both of these battery pack and appliance housing constitute the power supply switching apparatus.

Abstract: A power supply system of a high reliability and stability capable of suppressing a cross current flow by establishing rapidly synchronism between a power converter and an AC power source in a parallel operation for changing over the power supply sources. The power supply system comprises a current sensor for detecting an AC current supplied from a power converter, a comparator for making decision as to whether the AC current exceeds a predetermined value, and a regulation input means for fetching an active component of the AC power supplied from the power converter in response to an output signal of the comparator, wherein when the AC current exceeds a predetermined value, an output frequency of the power converter is speedily regulated so as to coincide with an output frequency of the AC power source in accordance with a drooping characteristic of the active component of the AC power, while in an isolated operation of the power converter, the output frequency is set at a predetermined value.

Abstract: A high efficiency power supply for producing two regulated output voltages (i.e. 3.3 and 5 volts) from an unregulated input voltage. The supply includes a 4-15 volt battery pack, a first (5.0 volt) output, a second (3.3 volt) output, and a ground. The positive terminal of the battery is connected directly to the second output. The 3.3 volt differential with ground is maintained by a voltage regulator that couples the negative terminal of the battery pack to ground (i.e. ground floats relative to the battery). A second voltage regulator couples the positive terminal of the battery pack to the first output, and maintains this first output at 5.0 volts relative to ground. This latter regulator is capable of boost operation, permitting a 5.0 volt output to be maintained even if the battery pack voltage is less than this value. Neither regulator includes a transformer, making the supply particularly well suited for use in miniaturized equipment, such as palmtop computers.

Abstract: A DC-DC converter for outputting dc voltage whose peak value is higher than an input dc voltage value and high-frequency voltage corresponding to a command value is superimposed. An insulated switching power supply 27 and a series regulator 26 are connected in parallel to a dc power supply 1. The insulated switching power supply 27 generates output voltage V.sub.2 having a certain level, and the series regulator 26, output voltage V.sub.1 whose voltage varies depending on a command value (command voltage varying at a high frequency). Then, the sum of the output voltages V.sub.1 and V.sub.2 is fed to the load 9.

Abstract: A voltage regulator is provided for producing a predetermined output voltage level. The voltage regulator has a voltage source for providing a plurality of successively increasing voltage levels at a corresponding plurality of output terminals, or taps. A controller is provided for automatically selecting, in response to an electrical control signal, the one of the taps providing a voltage level above the predetermined output voltage level. In a preferred embodiment of the invention, the selected tap is the one of the plurality of taps producing a voltage level closest to, and greater than, the predetermined output voltage level. With such an arrangement, the electronic control signal allows a convenient way to select an output voltage level closest to, and greater in magnitude than, the predetermined voltage level, thereby improving the efficiency of the regulator.

Abstract: An uninterruptible power supply is disclosed which is cheaper and more adaptable to various utility service inputs than presently available power supplies. A storage capacitor is placed between a boost AC/DC converter at the input and a DC/AC inverter at the output. A storage battery for maintaining constant voltage should the utility service power be interrupted is placed at the input, before the boost converter. Thus, a small battery is required because the boost converter is capable of boosting the battery's voltage to the voltage contained on the storage capacitor. A bidirectional semiconductor switch is provided in the boost converter to allow current to flow in both directions between its switch terminals when a AC input is applied. Appropriate control circuitry is provided which monitors the voltage at specific points throughout the circuit and controls operation of the bidirectional switch.

Abstract: An elevator door control apparatus includes an alternating current motor for opening and closing an elevator door. An inverter for converts a DC voltage from a first DC power supply into an AC voltage and supplies it to the motor. A first switching device for connects and disconnects the inverter and the motor, and a second switching device connects and disconnects a second DC power supply and the motor. A detection device detects at least one of an abnormality of the first DC power supply and an abnormality of the motor. A control device, at normal times supplies an AC voltage from the inverter to the motor by means of the first switching device and cuts off a DC voltage from the second DC power supply to the motor by means of the second switching device.

Abstract: The invention relates to a system for processing an electrical power supply signal for a resistive heating element.The circuit provided comprises an a.c. current source, a rectifier and a chopper for supplying the resistive element with a current having two superimposed components one being d.c. and the other being a.c., both at a variable voltage.The invention applies particularly to the supplying, with a signal thus processed, of the resistive element of a connecting piece for electro-weldable plastic tubes, of an electro-heating envelope for the connection or protection of pipes, or of a heat-shrink sheath for operation on a cable having a conductor or conductors used for the carrying of electrical energy or for telecommunications.

Abstract: Power supply apparatus is disclosed which can be configured as a power line filter or an uninterruptible power supply having a battery test on load capability. It comprises an input reversible rectifier connectable between an AC supply and a high voltage internal DC bus, a second reversible rectifier interconnecting storage batteries to the high voltage DC bus, and an output module supplying a desired DC output or an AC output. In use the voltage on the internal DC bus is maintained at a greater level than that of (a) the instantaneous repetitive peak of the incoming voltage, and (b) the peak battery storage voltage. Battery test means is provided by allowing the dumping of the charge stored within the storage batteries for a certain period at the maximum available rate into the internal bus and back into the AC supply through the said reversible rectifiers; meanwhile observing the extent of the battery voatage drop so caused.

Abstract: A solid state latching control circuit for a DC power supply including a pair of series connected DC power sources, such as batteries, which provide both a positive and negative polarity switched supply voltage to a load. A pair of complementary MOSFET transistors are simultaneously rendered conductive and non-conductive by means of the outputs of a latching type of flip-flop circuit comprised of a pair of cross-coupled CMOS NAND gates whose mutually opposite on and off states are switched in response to the operation of a pair of electrical switches, a third CMOS NAND gate and a differentiator circuit coupled to one of the flip-flop inputs, and an R-C charging and discharging network coupled to another of the flip-flop inputs.

Abstract: The control for an AC inverter includes a low voltage microcontroller referenced to ground potential and a waveform generator coupled to the microcontroller through a serial data link including optical isolation devices. The waveform generator floats at the negative bus potential of the DC source for the inverter. The waveform generator produces switching signals for the inverter under control of the microcomputer. The waveform generator, serial communications circuitry and other support circuits are all part of a single application specific integrated circuit.