Abstract: The present invention is a battery transfer circuit connected to a load, a power supply for powering the load with at least a minimum supply voltage during normal operating conditions, and a source of battery voltage for powering the load during a power fail condition when the power supply is unable to power said load at the minimum supply voltage. The battery transfer circuit comprises a first circuit for applying at least the minimum supply voltage to the load during normal operating conditions and a second circuit for charging the battery to an optimal voltage greater than the minimum supply voltage and for down-regulating the optimal charge voltage to a predetermined voltage and for applying the predetermined voltage to the load during the power fail condition, wherein the predetermined voltage is less than the minimum supply voltage.

Abstract: An isolated power input architecture that includes hot swappable input modules that are electrically isolated from each other so that each may provide input power to power supplies for an electronic device without adverse interactions between the voltages provided by each input module. The isolated input modules are each configured to lock the other out so that only one input module is providing power to the power supplies for the electronic device. The power supply for the electronic device preferably includes N+1 power supplies where N power supplies are required by the electronic device. Either of the isolated input modules provides enough power to supply power to all the N+1 power supplies.

Abstract: A system includes a first voltage regulator, a second voltage regulator, a third voltage regulator and a circuit. The first voltage regulator is coupled to receive power from a first power line, and the second voltage regulator coupled to receive power from a second power line. The circuit monitors a voltage of at least one of the first and second power lines and based on the monitored voltage, the circuit selectively couples the third voltage regulator to receive power from one of the first and second power lines.

Abstract: A power controller for controlling an engine-driven generator includes a high voltage DC bus interconnecting various power modules. In electrical communication with the DC bus are: a bi-directional DC-DC converter constructed to transfer electrical power from the DC bus to a battery to charge the battery, and from the battery to the DC bus; a rectifier constructed to rectify electrical power from the generator and to supply the rectified power to the DC bus; an inverter constructed to convert DC bus electrical power to AC electrical power and to supply the AC power to an output connector; and an AC-DC constructed to convert AC electrical power, supplied via an input connector, to DC bus electrical power. The controller may be employed in a power supply on a mobile vehicle or boat, for example. The power modules of the controller cooperate in various combinations to provide a wide variety of power transfer functions.

Abstract: An electrical energy storage system for supplying power to a load comprises a plurality of flywheel energy storage systems, each supplying a power output signal, and a connector circuit. The connector circuit connects the flywheel energy storage systems to the load, but the flywheel energy storage systems are not connected to each other. Each of the flywheel energy storage systems comprises a flywheel turning at an initially predetermined rate, a motor/generator coupled to the flywheel, a bi-directional inverter circuit coupled to the motor/generator and to the load, and a control circuit coupled to the motor/generator and the bi-directional inverter circuit. The control circuit controls the power output signal of the flywheel energy storage system independently of the other flywheel energy storage systems.

Abstract: Systems and methods of universal uninterruptible power supply (UPS) input circuitry are provided. The input circuitry of the present invention enables a UPS system to simply connect and operate in conjunction with any suitable backup power system. In particular, once a user indicates what backup system is attached to the input circuitry, a software unit automatically configures the input circuitry to operate with the coupled backup system. Once configured, the software unit may control portions of the input circuitry such that power is continuously provided to a load. For example, once a user indicates that a flywheel based backup system is attached, the software unit may instruct the input circuitry to maintain a predetermined flywheel speed (e.g., RPM) to ensure that the system is in constant ready state to deliver backup power.

Abstract: For accomplishing an interruption-free power supply operation of a system unit (HDD) in a computer system with a plurality of system computers (Sa; Sb) sharing the system unit (HDD) without having the limitation to a local location, a method and an arrangement is [sic] proposed in accord wherewith the operation of the respective station computers (Sa; Sb) respectively ensues with their own interruption-free power supplies (USVa; USVb) and, for the power supply of the shared system unit (HDD), the shared system unit (HDD) is always connected to an active interruption-free power supply (for example, USVb) by an automatically switching switchover (PCS) that monitors the voltage of its inputs.

Abstract: A method and system for distribution of stand-by electric power via a network separate from the standard or ordinary electric power network is disclosed. Voltages are transformed/produced in voltage sources, TR and then branched off in control devices, S, to devices, A. The devices, A, distribute the voltages to loading equipment, for instance telecommunications devices, network equipment or medical equipment. Furthermore, surveillance devices, Ö, communicate with the voltage sources, the control devices, and the devices, A, to control electronic power drains, and to transfer control orders for execution.

Abstract: An automatic transfer switch is disclosed that features a novel arrangement for detecting a failure of the power source as well as a novel arrangement for preventing cross-conduction between the first and second signal sources during a rapid transfer.

Abstract: A system and method for developing a cost efficient electronic power supply system that handles a range of supported electronic circuits is provided. The electronic power supply system adaptively configures the power applied to electronic circuits. Thereby, eliminating redesign of a power supply system when a newly developed or different electronic circuit is implemented. When an electronic circuit is attached to the electronic power supply, a controller confirms electronic circuit presence and queries for electronic circuit power on requirements. As more electronic circuits are added, the controller examines each electronic circuit power on requirements and determines if a power conflict is present. If a conflict exists, the controller will not supply power to the electronic circuits until the conflict is resolved.

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 standby power supply circuit with a low power consumption including: a voltage converter for rectifying a commercially used AC power source to convert it to a DC voltage; a standby power supplier for receiving the DC voltage from the voltage converter; a voltage comparator for comparing the DC voltage outputted from the voltage converter with pre-set reference voltages and outputting a predetermined pulse signal; and a switch unit for ON/OFF controlling the operation of the voltage converter according to a pulse signal outputted from the voltage comparator. With the construction, a zero cross switch is intermittently turned on or turned off, so that the standby transformer is turned on or turned off, by which the standby power can be reduced when the electric instruments are in a standby state.

Abstract: A system and method for providing an uninterrupted supply of power to a critical load includes at least two uninterruptible power supply UPS modules that receive power from separate utility sources. A controller controls the UPS modules so that the output power from one UPS module is substantially in-phase with the output power from the other UPS module. As a result, the output powers from the UPS modules can be combined with one another to provide a sufficient source of uninterruptible power to the critical load regardless of the phase difference in the power provided by the separate utility sources.

Abstract: A modular power supply (2) suitable for application as an uninterruptable power supply for use with electrical equipment such as computers. A module (6) of the power supply may include a battery (32), a charging circuit for the battery (34), a power supply circuit coupled to mains electricity and the battery (30, 36, 40), and a control circuit (38) for selectively providing power to the electrical equipment (12) by way of the power supply circuit from either mains electricity (10) or the battery as source. The module is also provided with a coupling which is adapted to connect the module in parallel with at least one other module. A housing may be provided to receive a plurality of modules, which are connected together in parallel by way of plugs and sockets when received in the housing. The plugs and sockets and the control circuit may be adapted to enable "hot-swapping" of the modules from the housing.

Abstract: A power distribution unit that can detect system status includes: an optional line filter, a live power source for driving a I2C device, a power sensor which monitors system power status in connection with the I2C device through a I2C BUS, and a relay and on/off switch circuit which turns on/off system power in accordance with the I2C device through the I2C BUS.

Abstract: A power supply system and method provides for smooth transitions between a utility power, transitory instantaneous power, and backup power in the event of a utility power failure of a utility supplying power to a load. As the utility power weakens due to a failure of the normal utility power supply, a synchronous machine becomes immediately a generator and supplies the required instantaneous power to the load. In order to maintain a constant speed on the synchronous machine, a high speed flywheel rotating faster than the synchronous machine provide kinetic energy that is magnetically coupled to the synchronous machine through an electromagnetic clutch to provide the synchronous machine with the required energy until the utility recovers from its failure. The control means enable smooth transitions by phase synchronization when transiting between utility power, instantaneous power and backup power.

Abstract: An arrangement is disclosed for ensuring an uninterrupted current supply to at least one electrical consumer which draws energy from an alternating voltage network and is supplied with energy in the event of a network failure by a fuel cell. The fuel cell (8) is connected at its electrical outputs to at least one current inverter (7) whose output is connected to the minimum of one alternating voltage consumer (1, 2) and to a branch containing a switch (4) on the consumer side of the switch; the switch is connected to an alternating voltage network (6) and is opened in the event of the voltage in the alternating voltage network falling below a predetermined level and closed if the alternating voltage is above that threshold; and the fuel cell operates in stand-by mode if the network voltage is above the threshold, and, if voltage is below the threshold, in a mode in which the energy required by the consumer is supplied via the current inverter (7).

Abstract: A uninterruptible power system in which separate inverters are connected to separate d.c. power sources established by independent power supplies, a.c., d.c. or both, and have their a.c. outputs connected to separate transformer primary windings with the primary to secondary turns ratios of the primary windings establishing different effective secondary voltages for determining the power source for normally supplying the power from the system and the sequence in which the other power sources are used on power failure, the magnitudes of the effective voltages determining the power source for initially supplying the power with any other power source supplying the power when its effective voltage is higher than any other available power source.

Abstract: Disclosed is an electric power supplying unit for use in an electronic apparatus and includes an external AC adapter externally connected to the body of the electronic apparatus for receiving an external AC power source. An internal AC adapter is accommodated into the body of the electronic apparatus for receiving an external AC power source. An AC power source input detection circuit is provided within the internal AC adapter for detecting whether the external AC power source is input to the internal AC adapter. The power supply unit further includes power source switching circuit responsive to the detection output of the AC power source input detection circuit for switching the power supply to the electronic apparatus from the output of the external AC adapter to the output of the internal AC adapter.

Abstract: Apparatus for controlling distribution of d.c. power to a plurality of remote d.c.-powered LAN transceivers, which includes a plurality of primary d.c. power supplies and at least one backup d.c. power supply, all having means for connection to a source of electrical power to provide output d.c. power independently of each other. A plurality of electrical switches are each operable in a first mode of operation to connect one of the primary power supplies to at least one set of output terminals for connection to a remote transceiver. Comparator circuits compare the output voltage at each of the primary power supplies to the output voltage at the backup power supply to indicate a failure condition at one of the primary supplies. Circuitry is responsive to a failure indication for operating one or more of the electrical switches in a second mode of operation in which at least one set of output terminals is connected to the backup power supply.

Abstract: A backup power system for a structural appliance normally operated by a primary source of AC current through a primary circuit includes a backup battery; a charging circuit for connecting the primary source to the backup battery and including a battery charger for charging the backup battery; a backup circuit for connecting the backup battery to the appliance and including a converter for converting DC current from the backup battery to AC current for the appliance; and a switch interposed in the primary circuit and the backup circuit for selectively closing the primary circuit and opening the backup circuit during normal operation of the primary source, and for closing the backup circuit upon at least partial failure of the primary source so as to connect the backup battery to the appliance through the converter, whereby the backup battery is charged and isolated from the appliance during normal operation of the primary source, and the backup battery is connected through the converter to the appliance for su

Abstract: This invention provides a facsimile apparatus which can reduce the consumption power of main power supply control means, and can suppress the charging frequency of a secondary battery without widening the operating voltage range of the main power supply control means.The facsimile apparatus has a main power supply control unit. The main power supply control unit has a DC--DC converter which receives a power from a secondary battery, a solar battery, or a main power supply, and operates to maintain a constant output voltage, and a microcomputer driven by the output voltage from the DC--DC converter. The output voltage from the DC--DC converter is detected by a voltage detect circuit, and a voltage from the secondary battery is detected by another voltage detect circuit. The microcomputer performs control for supplying a power from the secondary battery or the solar battery to the DC--DC converter, control for charging the secondary battery by the main power supply or the solar battery, and the like.

Abstract: An intelligent battery power system having a main battery and a swap battery including a battery presence detector for detecting whether the main battery is present and a power controller for operating the system in a suspend mode and applying power from the swap battery in a suspend mode when the battery presence detector detects that the main battery has been removed and for interrupting the power from the swap battery with power supplied from the main battery to operate the system in a resume mode when the battery presence detector detects that the main battery is present. The system prevents volatile data from being lost when the battery for a portable computer is removed or becomes detached for any reason.

Abstract: A reserve power system for a commercial AC load provides DC power to the load when the primary power fails by providing direct current voltage power from a DC power source which enables the load to continue to operate in a normal fashion. A power system supplying commercial AC derived power to a load provides backup power by coupling DC power to the load when the primary AC power fails. AC power is supplied to a primary winding of a power transformer which also has a secondary winding side. A cable is connected, at a first end, to the secondary winding side and at a second end to a load powered by a commercial AC voltage. A battery DC voltage source and a battery charger are connected to the secondary winding side of the power transformer. The battery charger maintains the integrity of the reserve power. A voltage monitoring circuit connected to the power transformer detects a primary power failure and activates switching circuitry for connecting the DC voltage source directly to the load.

Abstract: A MOSFET switched, redundant power supply has a back-to-back MOSFET switch connecting respectively each power supply to a single load. Each power supply has a positive and negative gate voltage source. In a specific N-channel MOSFET embodiment, the positive (i.e. on) bias is coupled to each switch via a radiation hardened, redundant analogue switch capable of being driven by, for example, a TTL or CMOS microprocessor signal. The negative (i.e. off) bias is coupled to each via a redundant diode pair. In addition, the gates of the back-to-back MOSFET switch for one power source are also connected to the negative bias of the other power source. In this way the MOSFET switch for a failed power supply will be maintained in an off state by the negative bias provided by the redundant supply.

Abstract: An uninterruptible power supply (UPS) system includes a control and display module operational with a UPS when carried by a housing of the UPS and when remote from the housing. An orientation sensing switch carried by the module senses a horizontal or vertical position of the module and provides a signal to a module processor for providing performance diagnostics of the UPS in a horizontal or vertical format as appropriate. The UPS system housing includes support arms extendable from the housing for providing added stability to the housing when in a vertical position. The control and display processor receives manual input from user buttons on the module and communicates with a UPS processor carried by the housing. The UPS includes a battery positioned within the housing for access by removal of a front housing panel for avoiding movement of the UPS system during replacement of batteries.

Abstract: There is disclosed a backup circuit for a memory card where the stored data in an S-RAM is retained even when the card (2) contains a main battery (18) whose output voltage is 3.3 V, an auxiliary battery (20), and a charging prevention diode (22). The main battery (18) and the auxiliary battery (20) are connected in parallel. Between their junction (28) and a built-in power supply (8) of a personal computer (4), the charging prevention diode (22) is provided. Because the second diode (22) is placed in a forward direction running from the junction (28) toward a voltage supply line (10), the auxiliary battery (20) is charged only from the main battery (18), and a charging current from the built-in power supply (8) does not flow into the auxiliary battery (20).

Abstract: The present invention provides a low cost, low complexity, redundant power supply for an electronic data system. The low complexity of the system minimizes system failure rate while the redundancy improves system availability. The redundant power supply interconnect system is comprised of: a first electronic device including a first power supply; a second electronic device including a control means, a second power supply and a third power supply, wherein the first power supply means of the first electronic device is electrically coupled to the control means of the second electronic device; a first dedicated bus electrically coupling the first electronic device to the second electronic device; and a first serial management bus, the first serial management bus electrically coupling the first electronic device to the control means of the second electronic device.

Abstract: A fault tolerant power supply system includes a plurality of devices coupled to a common power distribution bus. The devices are arranged and connected in a hierarchical order. The system provides that the devices of higher rank or position in the hierarchy to obtain priority in drawing power from the bus. Each device is coupled to the next adjacent device via a control status line that indicates whether there has been a failure of the power supply of any device higher up in the hierarchy. In the event that the local power supply of a device fails, it can be selectively connected to the power distribution bus to draw power, only if the control status line indicates that there have no failures in the devices having a higher hierarchical rank. Once connected to power distribution bus, if a higher ranking device should experience a power supply failure, the device will be disconnected from the power distribution bus and the higher ranking device connected to the power distribution bus.

Abstract: A parallel redundant power supply system which does not use any inter-unit signaling is obtained by using the AC output power level of a power system to coordinate load sharing. The necessary information for load sharing is derived solely from each power system's output power level in such a manner that the output of a power system is inherently phase locked to the output of other power systems to which it is connected in parallel. Each parallel connected power system designed in accordance with the invention includes means for generating an AC output voltage from a DC input power source, means for sampling either a DC input voltage from the DC input power source or the AC output voltage from the AC output voltage generating means to provide power level samples, and means for determining the AC output power of the AC output voltage generating means from the power level samples.

Abstract: The present invention disclosed and claimed herein comprises a backup power system to supply current to an electromechanical actuator (50) to position a mechanical device (52) to a fail-safe position upon failure of a primary electric power source (12). A capacitor (40) is provided for storing energy. The capacitor (40) is charged by the primary electric power source (12). A relay device (35) is also provided for disconnecting the primary control signal upon failure of the primary electric power source (12) and connecting the capacitor (40) to the electromechanical actuator (50) to supply electric current to the electromechanical actuator (50) to position the mechanical device (52) to a fail-safe position. The relay device (35) comprises a transistor (32) which is kept turned off by the primary electric power source (12) and upon failure of the primary electric power source (12), turns on and energizes an electric relay coil (34).

Abstract: An electronic apparatus comprises a main circuit having a main CPU and a power supply system which includes plural main batteries for supplying operating power to said main circuit, a back-up battery, a switching circuit connected between each main battery and the main circuit, power means for enabling the operation of the main circuit, a charge detector for detecting the charging level of each main battery, and power controller responsive to the power means and the charge detector and having a sub-CPU for individually controlling the switching circuit according to either a single connection mode or a multiple connection mode. In the single connection mode only one of the main batteries is connected to said main circuit. In the multiple connection mode, at least two main batteries, each in series with a respective diode means, are connected in parallel to the main circuit.

Abstract: A backup apparatus includes a main body power supply for applying a voltage from a main body to loads during a normal operation, a first backup power supply for applying a power supply voltage to a specific load of the loads when a voltage of the main body power supply drops, a second backup power supply for applying a power supply voltage to the specific load when a voltage of the first backup lower supply drops, a first threshold voltage generator for generating a first threshold voltage generated by the first backup power supply, a second threshold voltage generator for generating a second threshold voltage generated by the second backup power supply, a comparator for comparing the first threshold voltage with the second threshold voltage, a first switch circuit for switching the power supply voltage applied to the specific load from the main body power supply to the first backup power supply when the voltage of the main body power supply drops, and a second switch circuit for switching the power supply vo

Abstract: In a computer apparatus including an enclosure and a direct access storage device mounted within the enclosure, a mounting apparatus for the direct access storage device including: a plurality of a relatively rigid shock isolators and at least one stress sensor mounted in series with are of said shock isolators and disposed between the enclosure and the direct access storage device. The enclosure may include a user frame and the mounting apparatus may be disposed between the direct access storage device and the frame. There may be one stress sensor for each of the shock isolators. The shock isolators may be coupled to the direct access storage device. Each stress sensor may include a piezoelectric element. Preferably the shock isolators are rigid enough so that the resonant frequency of said mounting apparatus is at least 800 Hz, but can be 800 Hz or higher.

Abstract: A power management system automatically manages the power to operate a biomedical device, such as an infusion pump containing an internal battery. When external power is available, the management system operates the biomedical device from the external power and controls a recharger to maintain the battery at full charge. The power management system automatically calculates battery charge status and use and provides a run time display of the calculated amount of time that the battery can operate the biomedical device under current power requirements of the biomedical device. The power management system automatically updates the calculated charge status of the battery as well as the calculated capacity of the battery based on environmental factors and battery characteristics. The power management system automatically and periodically performs a deep discharge/recharge cycle to refresh the battery.

Abstract: A method of operating a redundant power supply is disclosed wherein two or more converters are separately connected to a common output node through separate diodes to isolate the converters and allow the outputs to be separately tested for diagnostic purposes. The diodes are selectively bypassed by connecting drain-to-source paths of P-channel MOS field-effect transistors separately across the diodes. During the diagnostic mode of operation, a controller shuts off the MOS transistors, so the diodes are effective in isolating the converters. During the bypass mode of operation, the transistors are turned on by the controller so the diodes are bypassed and their forward voltage drop does not appear in the circuit and so power dissipation is reduced. It is noted that the P-channel MOS transistor is connected such that it's intrinsic PN-junction diode conducts in a forward direction in parallel with the isolation diode, so that isolation during the diagnostic mode is not cancelled.

Abstract: In a backup power system capable of deriving power from alternate AC primary and DC backup power sources to provide continuous AC power to an AC load and including an inverter/switch module having DC and AC inputs and an AC output, a maintenance bypass switch for, and method of decoupling the AC primary and DC backup power sources from the backup power module to allow maintenance to be performed thereon.

Abstract: An UPS system provides a true input power walk-in. The UPS adjusts the level of power supplied from an input port to a load on an output port as a function of a level of current of a power supplied from a backup power source to the load on the output port.

Abstract: An uninterruptible power supply for providing continuous power from a power source line to a load is provided. In particular, the uninterruptible power supply may either operate in an "Off-Line" mode or one of two "On-Line" modes. The uninterruptible power supply operates in the "Off-Line" mode when the power source line voltage is above a first threshold value. The uninterruptible power supply routes power from the power source line to the load in the "Off-Line" mode. The uninterruptible power supply operates in a first "On-Line" mode when the power source line voltage drops below a first threshold value but exceeds a second threshold voltage, or the frequency of the power source line exceeds a predetermined range. The uninterruptible power supply boosts the power source line voltage in the first "On-Line" mode of operation and applies the boosted signal to the load.

Abstract: An energy efficient uninterruptible regulated power supply includes a full wave rectifier that is responsive to AC main power generating an unregulated DC voltage signal, a power factor correcting boost converter coupled to receive and selectively increase the unregulated voltage signal to generate a boosted voltage signal, a battery and a single ended forward converter having a primary winding coupled to receive pulse width modulated energy from the boosted voltage signal and a secondary winding couple bidirectionally to the battery with pulse width modulated control. A first controller pulse width modulates the boosted voltage and battery signals coupled to the primary and secondary windings, respectively, to regulate the output voltage while a second controller operates independently of the first controller pulse width modulate the boost converter to regulate the voltage of a transformer secondary signal that is coupled to the battery.

Abstract: A power supply system for a general purpose computer has plural power supplies for powering selected groups of components. One of the power supplies serves the keyboard and its controller, and the keyboard controller is configured to turn the other power supply or supplies on and off in response to user input at the keyboard. The use of separate power supplies increases the efficiency of the computer when operating in reduced power modes.

Abstract: A programmable power controller for controlling power between a primary power source and a second power source and powering first circuitry, each of which has a voltage, comprises a control register having a first field, which is used to activate circuitry used to direct power from the primary power source to the second power source, and circuitry to compare the first voltage and the second voltage to determine which is greater and then coupling the primary power source or the second power source depending upon which is greater to power the first circuitry. The control register also has a second field used to select an electrical path having a first voltage drop that ensures the primary power source will have a higher voltage when the primary power source is active under normal operating conditions and a third field used to select an electrical path of a plurality of electrical paths, each electrical path having a variety of voltage drops and resistances.

Abstract: An integrated power system includes an engine/generator power supply integrated with storage batteries to provide household-like AC power. For a small load demand, the storage batteries are used to provide electricity. For a large load demand, the engine/generator starts to supply electricity. The engine/generator also recharges the storage batteries if the load demand is smaller than the engine/generator maximum load capacity. For a larger load demand, both the engine/generator and the storage batteries supply electricity in parallel. The engine speed is variable for various loads. The bigger the load, the higher the engine speed is required to produce the necessary power and keep a constant high DC voltage.

Abstract: When a computer is not externally powered, it operates from installed first and second batteries. In top surface of the computer, LEDs are provided which indicates three states of each battery; need of charging, during charging, and completion of charging.

Abstract: A split battery contact arrangement (10) for a low voltage portable electronic product having a first circuit (18) and second circuit (18) comprises a split positive battery contact having a first positive contact point (20) selectively isolatable from a second positive contact point (17), the first positive contact point being coupled to the first circuit (18) and the second circuit (16) being coupled to the second positive contact point. The arrangement further comprises a back-up energy source (24) coupled to the first positive contact point and a removable battery (12), which when removed selectively isolates the first circuit from the second circuit, thereby preventing the back-up energy source from powering the second circuit. When the removable battery is inserted, it couples the first circuit to the second circuit.

Abstract: A voltage conversion circuit of the present invention is equipped with means for generating a first voltage stabilized with respect to ground potential of a semiconductor integrated circuit device including the circuit, means for generating second voltage stabilized with respect to an external supply voltage of the semiconductor integrated circuit device, and selection means for selecting either the first voltage or the second voltage. The first voltage age, stabilized with respect to the ground potential, is selected and used as the voltage at the time of normal operation, and the second voltage, stabilized with respect to the external supply voltage, is selected and used at the time of aging test. In this case, means for trimming the first voltage and/or the second voltage is, preferably, provided to raise the voltage accuracy.

Abstract: A fault tolerant multiple phase clock distribution system for providing synchronized clock signals to multiple circuit loads. Multiple electrically isolated power domains are powered by redundant AC and DC power sourcing circuits to ensure continued operation upon partial failure of the AC or DC power sourcing circuits. Multiple oscillators from the multiple power domains are synchronized to produce a group of simultaneously synchronized clock signals. Multiple synchronized clock signals from this group are then selected by selection circuitry and selection control circuitry, and are distributed to multiple circuit loads requiring simultaneous synchronization. The oscillator circuitry, synchronization circuitry, selection circuitry, and distribution circuitry is all provided in redundant form, so that the partial failure of any of the circuitry will not result in a system stop.

Abstract: The constant power load bank is a flexible tool used for simulating avionics loads such as pulsing radars on a 270 VDC power system. The unique feature of this load bank is that it is designed to realistically simulate an active aperture radar with 0-100% of the load pulsing while the remainder of the load is either "on" or "off". The pulse controls are designed to simulate any type of pulsing scenario from simple (one control signal) to complex (multiple control signals simulating incremental load application and removal such as an active aperture radar load). The constant power load bank realistically simulates avionics loads because of the flexible control features and the constant power load itself is composed of actual avionics power supplies.

Abstract: A secondary battery equipped power supply is provided with charging and related circuitry such that when placed in a location, such as in a DC powered electrical transit system, where there are normal, surge and continuous peak demands placed on the primary DC supply, the battery charges during normal operation and discharges to provide additional power on the occasion of a surge or peak demand.

Abstract: A digital computer is provided having a clock generation circuit for generating a clock signal in response to an input signal from a fixed-frequency oscillator, which includes a first fixed-frequency oscillator and a second fixed-frequency oscillator, each providing an output signal. Also included is failure detection circuit for detecting a failure of either of the fixed-frequency oscillators, wherein a failure occurs when the first fixed-frequency oscillator or the second fixed-frequency oscillator ceases generating an output. A circuit synchronizing the output from the oscillators is coupled to both the first fixed-frequency oscillator and to the second fixed-frequency oscillator. This synchronizing circuit modifies the output from the second fixed-frequency oscillator to produce a synchronized output that is substantially synchronous with the output from the first fixed frequency oscillator.