Abstract: An aircraft electrical energy supply bus supplementing arrangement based on large capacitor or super capacitor storage of electrical energy for bus supplementation. Supplying of bus energy to the large capacitor is addressed in the invention. In this supplying energy is removed from the aircraft bus during quiescent conditions under the control of a energy coupling circuit which has a plurality of different energy removal rates, rates which are selected in response to the yet needed amount of capacitor charging and in a time-constant-controlled manner. Feedback control of this charging time constant selection is employed along with passive electrical device dissipation of major fractions of the time constant apparatus energy losses.

Abstract: A fault tolerant power supply system in which one or more controllers are connected to a battery plant providing a plurality of independent battery power feeds. Each controller includes a microprocessor which provides supervisory control signals to independently operating redundant power converters. Each power converter is provided with an input switching circuit which automatically disconnects the converter from its battery source when the converter input voltage falls below a preset minimum magnitude, thus protecting the battery against deep discharge conditions. When input voltage is removed from the converter, it is disabled so that power continues to be provided to the output load by the other converter(s) which continue to receive input power. When the input voltage is restored to a disabled converter, it is re-enabled only after a predetermined time delay elapses to insure that the input circuit is adequately pre-charged before operation resumes.

Abstract: A power transfer system for applying backup electrical power to electrical systems is described which applies backup power automatically without power interruption and which is straightforward to implement and inexpensive to manufacture. The power transfer system has a direct current (DC) power bus as a common supply point for protected electrical equipment, thereby making prior art systems which provide power transfer between alternating current (AC) power sources and typically provide an AC power bus in common with the protected equipment no longer necessary.

Abstract: An actuator controller capable of preventing various inconveniences that stem when the operation positions of the actuator have not been learned.

Abstract: A semiconductor integrated circuit system includes a first power line which supplies a first source power voltage, and a second power line which supplies a second source power voltage. A first edge detecting unit outputs a first edge detection signal when a rising edge of the first source power voltage is detected. A second edge detecting unit outputs a second edge detection signal when a rising edge of the second source power voltage is detected. An output unit is connected to the first power line, and outputs data to a data terminal in a data output cycle and sets the data terminal in a high-impedance state in response to the first edge detection signal. An output control unit is connected to the second power line, and controls the output unit in accordance with a read-data signal in the data output cycle, and controls the output unit in response to the second edge detection signal, so that the data terminal is set in the high-impedance state by the output unit.

Abstract: A power supply controller is capable of regulating the amount of electrical power supplied to semiconductor fabrication facilities to amounts in accordance with processing conditions of each facility. The apparatus includes a plurality of process status detectors corresponding to the facilities, each status detector detecting an operation mode of each of the facilities and generating a mode detection signal. A plurality of unit controllers are provided, corresponding to the process status detectors, each unit controller generating a power control signal in response to the mode detection signal. A plurality of power supply units are provided, corresponding to the unit controllers, each power supply unit controlling and providing an amount of electrical power from the main power supply to the facilities in response to the power control signal corresponding the operation mode of each facility.

Abstract: An apparatus for sensing the presence of an auxiliary battery connected to a cellular telephone is disclosed. An internal battery and a removable auxiliary battery are connected to the power system of the cellular telephone through first and second switches respectively. Connection of the auxiliary battery creates a current flow that is detected by a current sensing circuit which generates a current signal indicating the detection of current flow. A voltage sensing circuit determines whether the auxiliary battery can provide a predetermined voltage level and generates a voltage signal indicating the results of this test. A processor then utilizes the signals from the voltage sensing circuit and the current sensing circuit to control the pair of switches to connect the main and auxiliary batteries to the power circuitry of the cellular telephone.

Abstract: A power supply for maximizing the life of batteries such as but not limited to 12 volt DC batteries. Two batteries are preferably used. A timer is connected to the first battery output terminals. The timer regulates when a DC motor is turned on and off. The motor is connected to alternator connected to an output of the DC motor. The second battery is connected to and receives a charge from the alternator. An invertor outputs 115 volts at approximately 800 to approximately 1500 watts at 60HZ. The invention allows the first battery and the second battery to have an increased lifespan compared to being used separately. Embodiments for using the invention include computer set-ups, electrical golf carts, electrical car, medical devices, emergency backup power supply, and a portable canister supported container.

Abstract: An aircraft electrical supply bus supplementing arrangement in which electrical energy is stored in a large capacitor and energy flow between the capacitor and the bus is controlled by a bi-directional electrical converter circuit of the switched inductance type. The varying terminal voltage of the energy storing capacitor, a super capacitor, is coupled to the relatively fixed voltage of the aircraft supply bus by way of the voltage changing capability of the converter circuit switched inductance. Current flow levels in this inductance are controlled with a negative feedback regulator circuit. Energy storage efficiency in the converter is enhanced with respect to weight and physical size of the capacitor element by ability of the converter circuit to accept a widely varying input voltage while generating a relatively constant output voltage.

Abstract: In a recording apparatus such as an ink jet type recording apparatus, there are provided a recording unit for performing a recording operation on a recording material in response to a recording signal, the recording unit having a power supply for supplying power to drive the same, and a feeding unit for automatically feeding the recording material to the recording unit. This feeding unit is detachably connected to the recording unit. The recording apparatus further comprises a power supply apparatus installed on the feeding unit, capable of supplying power to the recording unit under such a condition that the feeding unit is connected to the recording unit. The recording unit can be made compact and lightweight. The recording unit is solely operable as a portable recording unit.

Abstract: According to the present invention, an emergency power supply to be coupled to an electric power source providing an incoming AC signal may include an input/output terminal, a battery with a DC voltage, a rectifier coupled directly to the input/output terminal and connected to the battery, an inverter coupled directly to the input/output terminal and connected to the battery, and a control circuit coupled to the rectifier and the inverter so that in a first operational mode the rectifier is coupled to the battery to rectify an incoming AC signal at the input/output terminal to charge the battery and the inverter is decoupled from the battery, and in a second operational mode the inverter is coupled to the battery to invert the DC voltage to provide an outgoing AC signal at the input/output terminal and the rectifier is decoupled from the battery.

Abstract: A method and apparatus for controlling power transferred and regulating voltage in a multi-phase transmission line includes generating a first plurality of voltages, a second plurality of voltages displaced in phase from the first plurality of voltages, and a third plurality of voltages displaced in phase from the first and second plurality of voltages. The first, second and third plurality of voltages are selectively connected in series in each line of the multi-phase transmission line.

Abstract: Method and apparatus for providing alternate current paths to a junction through different sets of gate controlled SCRs coupled to the junction. The method starts with the step of initiating a switch from an active set of SCRs to an inactive set by removing a gate signal from two parallel connected, opposite sense current carrying SCRs which in combination carry AC current in either direction. Removal of the gating signal is often initiated, for example, in response to an indication that one alternating current source is faulty so that a switch to a second source is initiated. Current is then sensed through the two SCRs of the active set to determine a current carrying state for each of those two SCRs. After the state of the current carrying SCRs is determined the current carrying state of the SCRs is confirmed during a delay time period.

Abstract: An apparatus for energizing a large scale medical imaging system, preferably in the form of a CT scanner so that the scanner operates off an uninterruptable power supply in the event that the external power falls below sufficient power to operate the system so that system operation remains uninterruptable. The system is designed to operate off a broad range and types of external power supplies including those providing DC, single or three phase AC power. The system therefore can operate from a common single phase AC outlet. In addition, power factor correction is provided so that the system can correct for phase differences between the voltage and current at the input line created by the input impedance of the system.

Abstract: A un-interruptible power supply (UPS) apparatus for a diffusion furnace used in semiconductor device fabrication. The diffusion furnace consists of a power electronic subsystem coupled to a three-phase utility power source via two series-connected normally-open main circuit breaker switches, an automatic control unit, and a direct-current power supply. The automatic control unit controls the operation of the diffusion furnace. The UPS apparatus includes a UPS unit having a power input connected to a node between the two series-connected normally-open main circuit breaker switches. A first normally-open circuit breaker has a switch connected between the output of the UPS unit and the power input of the automatic control unit. A second normally-open circuit breaker has a switch connected between a first phase power line of the three-phase utility power source and the input of the direct-current power supply. A third normally-closed circuit breaker has a switch connected to the output of the UPS unit.

Abstract: A failure detection system detects a failure in a by-pass switch of a power converter. The by-pass switch switches the electric power supply so that electric power is supplied from a standby power source to a load instead of from a power converter. A switch operation circuit turns the by-pass switch on and off. A first current detector detects the inverted output current of the power converter. A second current detector detects the load current flowing through the load. An operational amplifier adds the outputs of the first and second current detectors. A comparator detects a failure of the by-pass switch. If the addition result given by the operational amplifier is outside a predetermined range of values when the switch operation circuit is turned off, the comparator concludes that the by-pass switch has a failure.

Abstract: A power detection and control unit detects the acceptable power voltage requirements of a removable system resource and either provides the acceptable power voltage to the removable system resource or provides no voltage to the removable system resource if no acceptable power voltage is available. The power detection and control unit has a detection circuitry and a logic circuitry to translate the acceptable power requirement signal into control signals that control the system power supply. In a first embodiment the detection circuitry consists of an A/D converter analog to digital converter, a resistor coupled to a predetermined power supply voltage, a resistor in the removable system resource coupled to ground, and a filtering capacitor coupled to ground. In a second embodiment, the detection circuitry includes a pattern imprinted on the casing of the removable system resource, a wiper circuit for applying onto the pattern and detecting from the pattern a power requirement signal.

Abstract: A power transmission system includes a transmission line unit for three phases connected to three gas insulated transmission lines and a standby transmission line unit for a phase connected to a standby gas insulated transmission line connected with each other. A connection bus is provided at a branch part of each breaker in the transmission line unit for three phases, via the breaker. The connection bus is connected to a branch bus provided between the breaker in the transmission line unit of a gas insulated switch gear for three phases and the main buses, and to the standby transmission line unit.

Abstract: The bus line of an electric power system is connected to an inverter which can be placed in a forward operation mode or in a reverse operation mode, and batteries are connected to the inverter to store the dc energy thereof. When a commercial power source is normal, an ac switch is closed, so that the inverter is placed in the forward operation mode to perform an active filter operation for eliminating harmonic current and reactive current. When necessary, the batteries are charged, and the inverter is placed in the reverse operation mode to perform a peak cut power generation. At loss of the commercial power source or momentary drop of the supply voltage, the switch is opened so that the inverter is placed in the reverse operation mode to perform an UPS operation (emergency power generation). Hence, electric power is supplied without interruption to an important load and the emergency load.

Abstract: A communications adapter card includes a circuit arrangement for causing an electrical voltage to be supplied to the card from a first voltage source, even if a second voltage source is available, and from the second voltage source if the first voltage source is not available. The circuit arrangement includes a Field Effect Transistor (FET) with its gate electrode connected to a control circuit which puts the FET in an off-state to inhibit the second voltage source from supplying voltage to the card if the first voltage source is available, and puts the FET in an on-state to supply voltage to the card if the first voltage source is not available. The invention makes it possible for a single communications adapter card to be used to attache power managed and non-power managed personal computers (PCs) to a Local Area Network (LAN).

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: A power transfer control system for use in an AC electric power generation system comprises a generator control unit (GCU) which senses and controls the output of a generator, and a bus power control unit (BPCU) which communicates with the GCU to control and coordinate a power transfer between the generator and another source. Each unit communicates power transfer information, which eliminates the requirement of redundant sensing circuitry and wiring for the BPCU. The BPCU transmits master power control information and a synchronizing signal indicating a zero phase reference point of a control waveform to which the power transfer will take place. The GCU compares parameters of the output power of its respective source with the master power control information and the synchronizing signal.

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 and apparatus for apportioning standby power implements a first transition mode between standby and run modes of operation in which a control circuit is energized by a standby power supply in a fully active state and generates an on/off command signal responsive to detection of an input signal and a second transition mode between the standby and run modes of operation in which the control circuit is energized by the standby power supply in a partially active state and generates the on/off command signal and a drive signal generator is fully energized by the standby supply. An intermediate transition mode may also be implemented between the first and second transition modes, in which the control circuit and the generator are both energized in a fully active state for a brief interval by the standby power supply and an auxiliary energy source.

Abstract: A power loss detection system for a power supply including a main converter for providing regulated power, an activation circuit for mining on and off the main converter based on an active low activation signal, a standby power circuit for providing a standby power signal, and an internal pullup resistor coupled between the standby power and activation signals. The power supply asserts a power status signal indicative of the status of regulated power. Alternatively, an external detection circuit monitors the regulated power from the power supply and asserts a power loss signal indicative thereof. The control circuit asserts the activation signal low to turn on the main converter or floats the activation signal to turn off the main converter. If the power good or power loss signal indicates loss of regulated power, the control circuit floats the activation signal. If the activation signal goes or remains low after the activation signal is floated, then the power source has failed.

Abstract: A power supply system including a power supply providing power to an electronic device through current share circuitry, which includes a second connector for receiving power from an external power supply. The power supply is preferably a fault-tolerant power supply so that the electronic device receives continuous power in the event of partial failure. When the fault-tolerant power supply partially fails, the external power supply is connected to the second connector of the current share circuitry, which is switched to temporarily provide power to the electronic device from the external power supply. The power supply is then replaced while the external power supply provides power, so that power to the electronic device is continuously maintained. The electronic device thus experiences zero down-time. Even in low-end systems with a single power supply, down-time is substantially reduced. The external power supply is connected internally or through an external connector on the electronic device.

Abstract: An interface cable used for electrically connecting a terminal apparatus to a host apparatus. The host apparatus has an internal power source and a switch for turning on/off the internal power source. A cable means is used for electrically connecting an external power source to the terminal apparatus to supply electrical power from the external power source to the terminal apparatus. The external power source on/off control system includes a switch, such as an electromagnetic relay, incorporated in a module connected to the cable, for detecting the on/off state of the internal power source in the host apparatus and turning on or off the external power source on the basis of the on/off state of the internal power source.

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: 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: Method and apparatus for providing alternate current paths to a junction through different sets of gate controlled SCRs coupled to the junction. The method starts with the step of initiating a switch from an active set of SCRs to an inactive set by removing a gate signal from two parallel connected, opposite sense current carrying SCRs which in combination carry AC current in either direction. Removal of the gating signal is often initiated, for example, in response to an indication that one alternating current source is faulty so that a switch to a second source is initiated. Current is then sensed through the two SCRs of the active set to determine a current carrying state for each of those SCRs. After the state of the current carrying SCRs is determined the current carrying state of the SCRs is confirmed during a delay time period.

Abstract: A broadband communications network having an uninterruptible power supply. The power supply has one input connection to AC line voltage and another input connected to a gas powered electrical generator. The power supply contains an uninterruptible power supply module having a controlled ferroresonant transformer and a battery. The power supply also contains a bypass module having a controlled ferroresonant transformer. Switches are provided to allow either of the inputs to be connected to either the UPS module or the bypass module for the generation of power signals for supplying power to the broadband communications network.

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: A circuit disables an on-board voltage regulator when an upgrade voltage regulator is installed. The system including the voltage regulator disable circuit of the preferred embodiment comprises an on-board voltage regulator circuit, a receptacle, coupled to the on-board voltage regulator circuit, for receiving an upgrade voltage regulator module, and a disable circuit coupled to the on-board voltage regulator circuit and the receptacle, the disable circuit being activated upon insertion of the upgrade voltage regulator module to disable an output of the on-board voltage regulator circuit.

Abstract: A change-over switch performs switching between two different power supplies after connecting both power supplies simultaneously for a given time period. A controller controls the change-over switch to perform the switching operation around a synchronous point of the power supplies. Voltages of the power supplies are monitored to derive a difference voltage therebetween. From the difference voltage, a phase difference between the voltages of the power supplies is monitored. A plurality of low voltage detectors are provided for monitoring the difference voltage. The low voltage detectors are arranged to be operated at voltage values no more than preset values, respectively. The controller outputs a switching command to the change-over switch when time intervals between adjacent operation start time points of the low voltage detectors are all greater than preset values, respectively, and when the low voltage detectors are all operated.

Abstract: A system and method for providing an alternate AC voltage to an electrical load having a main AC voltage. The system and method include a signal generator for generating a main AC voltage signal representing the value of the main AC voltage, and a processor for processing the main AC voltage signal to determine a status of the main AC voltage, a main AC voltage failure time period, and a main AC voltage restoration time period. The system and method also include a control signal generator for generating a control signal in response to the main AC voltage signal, the main AC voltage failure time period, the main AC voltage restoration time period, and a pre-selected delay time period, and a switch for switching the electrical load between the main AC voltage and the alternate AC voltage in response to the control signal.

Abstract: A primary inductive track or path 450 for a resonant inductive power distribution system is made up from a number of modules 453, each supplied as a pre-built and substantially pre-tuned segment of the track. These modules have more than one capacitor 456, 457 and more than one inductance 458, 459 (generally, the inductance is the intrinsic inductance of the length of track) and each capacitor and adjacent inductor is capable of resonating at its own native frequency. A zero-inductance cable 452, carrying a small fraction of the circulating resonant current (comprising a mis-match or an error current), directly connects the capacitors at poles having equal polarity and tends to constrain the system limiting possible frequencies of resonance.

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: Two power sources are connected to a load by a pair of MOSFET control switches, each connected respectively in series between one of the sources and the load, with their integral diodes forwardly biased between the power source and load. An isolating MOSFET switch is connected in series between the pair of MOSFET control switches and the load with its integral diode back biased between the power sources and the load. Two control lines control the on-off state of all three MOSFET switches so that the isolating MOSFET switch is on when either control switch is on and is off when both control switches are off.

Abstract: A power line conditioner in which a plurality of outlets are mounted on a housing for receiving AC plugs from a plurality of electrical components. The housing is connected to a source of AC power which is distributed to each of the outlets, with the AC power associated with the outlets being processed to improve the performance of the components connected to the outlets. The AC power processing at one or more of the outlets differs from the processing at one or more of the other outlets so that the outlets can accommodate components with different electrical characteristics.

Abstract: An apparatus selectively connects a normal power line and an emergency power line to a load, and includes two interlocked switching mechanisms, each having individual interlocks, for selectively connecting the power lines to the load, and an interlock mechanism for interlocking the switching mechanisms in order that only one of the power lines at a time is connected to the load. The switching mechanisms may each have two drawout cassettes including associated switching devices for switching the power lines to the load and, also, including an isolated position for isolation of the associated switching device from at least one of the switched power lines and the load. Each switching device may be a circuit breaker having a trip unit for sensing current flowing from a power line to the load and tripping the circuit breaker. The interlock mechanisms may include keylock mechanisms which selectively disable closing of the switching devices.

Abstract: In a controllable compound voltage high-efficiency DC/AC transforming circuit, including a plurality of identical battery units which are arranged in parallel and/or serial arrangement to provide a step output voltage, an improvement comprising a bridge type solid state switch circuit for the output voltage polarity exchange and AC frequency control. The bridge type solid state switch circuit is controlled by a central control unit.

Abstract: A power supply system for thrusters (e.g., arcjet thrusters) in a spacecraft system comprises lightweight, redundant power supplies that share the power distribution function to the thrusters. Each power supply comprises a plurality of parallel-connected power supply subunits of which the combined power output capability exceeds the required maximum power demand by at least one subunit capacity for each arcjet thruster in the system. Each power supply subunit comprises a lightweight, high-frequency, soft-switching power supply. For arcjet systems comprising arcjet thrusters that do not operate simultaneously, relays are employed to switch between thrusters.

Abstract: A redundancy system switching control system includes two packages and logic circuits. The two packages are alternately switched as an operating system package and a standby system package. The logic circuits are arranged on the two packages, respectively, and each of the logic circuits outputs selection information/non-selection information to a remote package using self-package alarm information, self-package forcible switching information, remote-package alarm information, and selection information/non-selection information as four inputs. Each of the logic circuits, when a self-package serves as the operating system package, outputs selection information to the remote package by receiving any one of non-selection information from the remote package and the self-package alarm information when the self-package does not receive the remote-package alarm information.

Abstract: A battery-powered lap-top computer has a main battery for ordinarily supplying power to the computer circuitry. A reserve battery is connected through a manual switch to the circuitry. When the main battery starts to lose its charge, the manual switch is operated to connect the reserve battery to the circuitry prior to removal of the main battery. A new main battery is installed and the switch is operated to disconnect the reserve battery from the circuitry. Provision is made for the main battery to slowly charge the reserve battery.

Abstract: A connecting system includes a connecting apparatus for connecting selectively a power source of a power supply circuit to a battery or to an electronic apparatus. When a turn-over switch is switched to the electronic apparatus, the information signals is transmitted between the connecting means and the electronic apparatus.

Abstract: The disclosed emergency control links an auxiliary electrical generator having an auto-start mechanism and an outlet socket, with a utility's power distribution socket, to maintain electrical power at a controlled socket in the event of a utility's power outage. The emergency control has a controlled socket into which the plug of a powered apparatus would be inserted, instead of into the utility's socket; a distribution plug that would be inserted into the utility's socket; and a generator plug that would be inserted into the generator outlet socket. These plug-ins allow use of the control without hard-wiring it into the utility's power lines. The control connects the controlled socket to either the distribution socket or to the generator outlet socket.

Abstract: A power supply system for powering a plurality of loads. The system includes a plurality of energizeable power supply circuits each associated with one of the loads for supplying power thereto in response to a power supply circuit control signal. An actuable power sharing arrangement is connected to all of the power supply circuits to facilitate sharing of power among the power supply circuits in response to a power sharing control signal. In addition, a control circuit generates the power supply control signals to individually controlling energization of each of the power supply circuits and the power sharing control signal to maintain the power sharing arrangement in an actuated condition when the power supply circuit control signals are controlling all of the power supply circuits to be energized, and otherwise maintaining the power sharing arrangement in a de-actuated condition.

Abstract: A differential comparator is provided for controlling two switches (40) and (42) to switch two supplies (10) and (12), respectively, to a common output node (22). The decision/control circuit (44) outputs two control signals (46) and (48), the logic state thereof being a function of whether supply (10) is higher than supply (12) or supply (12) is higher than supply (10). The operating power for the decision/control circuit (44) is derived from the supplies (10) and (12), and not from the common output node (22), such that when the switches (40) and (42) are closed and no power is being supplied by either of the supplies (10) and (12), the decision/control circuit (44) has sufficient power to make a decision.

Abstract: A computer-controlled, uninterruptible power supply system is disclosed. The system selectively operates from more than one input source of power, e.g. an AC line input, an external DC input and internal batteries. The system is of the type which utilizes one or more switch mode converters and is well suited for use in computer systems. The switch mode regulator has a PWM clock signal and provides a PWM drive signal. The PWM clock signal frequency is substantially greater than the PWM drive signal frequency. Transferring between the DC power sources is done in a manner substantially transparent to the regulator and the load, generally as follows. A signal indicating a transfer to a selected one of the DC power sources is gated in response to the PWM clock signal to form a first logic signal that is synchronized to the PWM clock signal. The first logic signal is gated in response to the PWM drive signal so as to form a second logic signal that is further synchronized to the PWM drive signal.

Abstract: A parallel operation power supply control system has a plurality of switching power supply modules for supplying electric power in parallel to a logic device, and a parallel operation power supply control module connected to a superior controller for control of the plurality of the switching power supply modules. Each of the plurality of the switching power supply modules comprises a DC-DC converter, a drive pulse generator for driving the DC-DC converter, and an electric current feedback unit for detecting an electric current outputted from the DC-DC converter and for feeding the detected result in the form of a first data to the parallel operation power supply control module.