Abstract: A test mode structure and method of a multi-power-source device provides for the device to remain in a test mode, during which current draw of the device may be accurately measured, even after primary power supply to the device has been greatly reduced or completely removed. Significant reduction or removal of the primary power supply while still remaining in the test mode is necessary to counter the presence of a variable current that would otherwise be normally generated by the multi-power-source device in the test mode; the presence of the variable current during the test mode, if not negated, will not permit an accurate measurement of the current draw of the multi-power-source device. Significant reduction or removal of the primary power supply to the device would typically cause the multi-power-source device to exit the test mode and switch to a secondary supply voltage supplied by the secondary power supply, thereby foiling any attempt to measure the current draw of the device.

Abstract: A battery (102) powers a wireless telephone's power amplifier (106) through a Switch Mode Power Supply (SMPS) (104). The SMPS has a capacity lower than the maximum power requirements of the amplifier. When a controller (116) senses that an amplifier power-requirement threshold has been exceeded, it closes a switch (114) parallel to the SMPS, allowing power to flow from the battery to the amplifier without passing through the SMPS. This architecture allows the use of a smaller SMPS, and eliminates SMPS-generated noise to the amplifier when the amplifier is least able to tolerate such noise, namely, under high power conditions.

Abstract: A power transfer device adapted for interconnection with the electrical system of a building includes a cabinet, a set of switches mounted to the cabinet, and wires adapted to connect the switches to an electrical distribution panel associated with a building electrical system. The power transfer device includes a compartment associated with the cabinet, and a selectively configurable cover arrangement for interconnection with the cabinet so as to enclose the compartment. The cover arrangement varies according to the characteristics or parameters of the power transfer device, to provide an optional plug-type power input and an optional power input monitoring arrangement, either alone or in combination with each other, or to provide neither capability. The cover arrangement includes a series of differently configured cover sections which can be mounted to the cabinet in varying combinations, so as to vary the capability of the power transfer device.

Abstract: A redundant power distribution system and method of operation for transferring electrical power from one of several power sources to a load are disclosed. The system comprises one or more copies of a switching circuit with each switching circuit connectable to a power source. Each switching circuit monitors a voltage representative of its power source. The voltage being delivered to the load is also monitored by each switching circuit to detect a failed-open switching circuit. Arbitration is performed among the switching circuits detecting healthy power sources to select one power source to drive the load. Once a switching circuit has won arbitration, it continues to transfer power to the load until its power source fails or the switching circuit itself fails. The hardware can be partitioned in many ways.

Abstract: A system includes a generator and a circuit. The generator is coupled to provide power to a power grid. The circuit is coupled to the generator and is adapted to use a scheme to detect a shut down of the power grid and prevent the generator from providing power to the power grid in response to the detection of the shut down of the power grid. The circuit is also adapted to receive an indication to modify the scheme and modify the scheme based on the indication.

Abstract: A battery control system for controlling the connection of a plurality of batteries to a load is provided. The system comprises a plurality of switches and a plurality of controllers. Each switch is operable to connect or disconnect one of the batteries from the load. Each controller is operatively coupled to one of the switches. Each controller is operative to cause one of the switches to disconnect one of the batteries from the load.

Abstract: A power source unit is constructed by an AC/DC switching power source circuit 12, a battery unit 16, switching circuits 13 and 15, detecting circuits 18 and 21 corresponding to the switching circuits 13 and 15, and stop signal forming circuits 19 and 20. In the supplying mode, the power source circuit 12 is made operative, the switching circuit 13 is turned on, an output voltage formed by the power source circuit 12 is supplied to the load side, and at the same time, the switching circuit 15 is turned off by a stop output from the stop signal forming circuit 20. In the charging mode, the power source circuit 12 is made operative, the switching circuit 15 is turned on, the output voltage formed by the power source circuit 12 is supplied to the battery unit 16, and at the same time, the switching circuit 13 is turned off by a stop output of the stop signal forming circuit 19.

Abstract: A power system has a first power supply operatively connect in parallel to a second power supply. The output of the first power supply is connected to the input of a switching device, such as a mosfet. The output of the switching device is the output of the power system. A measuring device, such as a differential amplifier measures the polarity between the input and output of the switching device. A controller connected to the switching device permits the switching device to conduct current if a first polarity is present between the input and the output. The controller interrupts current flow if a second polarity is present between the input and the output.

Abstract: A system and method is provided for selecting a test load and/or bias resistor utilized in an expandable load system employing a backup power source. The test load and/or bias resistor is selected based on the actual load present in the expandable system. The backup power source is periodically tested during normal operation of the expandable load system utilizing the test load. A test load is provided that is sized for the actual load of a local load under worse case conditions. If an expansion load is connected to the local load the test load is adjusted, so that the test load is based on the actual load of the local load and the expansion load. Additionally, a bias resistance can be provided for driving a switch that allows power to be provided to the local load during power loss mode. If an expansion load is connected to the local load, the bias resistance is adjusted to correspond to a bias resistance necessary to provide the current for the actual load of the local load and the expansion load.

Abstract: An auxiliary power supply system serves as a consumer's primary power source during selected times and power outages in order to provide the consumer with a continuous supply of AC voltage. A power supply has a rechargeable DC source coupled to an inverter/charger circuit. A first switching means has an input port coupled to an AC voltage source and has an output port. The first switching means, programmable with at least one selected time period, couples the AC voltage source to the output port during a non-selected time period that is different than the selected time period and uncouples the AC voltage source from the output port during the selected time period. A second switching means is coupled to the output port and has a switch coupled between the output port and the inverter/charger circuit. The switch is selectively placed in one of a first position when a normal AC voltage is sensed and a second position when an inadequate AC voltage is sensed.

Abstract: A power plug device has a power plug, at least one switched power socket at least one socket switch, a embedded controller and a telephone jack. The embedded controller can send and receive network signals across a telephone line through the telephone jack, or across a power line through the power plug of the power plug device. The power plug device may switch on or off its power sockets depending on networking signals that come from the power or telephone lines. The power plug device can also send networking signals out along the telephone or power line. The power plug device also has a networking communications port. Two such power plug devices enable two or more computers to communicate with each other using the existing power and telephone lines within a building.

Abstract: A power system has a first power supply operatively connect in parallel to a second power supply. The output of the first power supply is connected to the input of a switching device, such as a mosfet. The output of the switching device is the output of the power system. A measuring device, such as a differential amplifier measures the polarity between the input and output of the switching device. A controller connected to the switching device permits the switching device to conduct current if a first polarity is present between the input and the output. The controller interrupts current flow if a second polarity is present between the input and the output.

Abstract: The invention provides a back up power supply for avionics equipment that can be installed in existing avionics equipment trays without having to rewire the aircraft. According to a preferred embodiment of the invention (described for illustrative purposes in the context of providing a power supply back up for a cockpit voice recorder (CVR)), the power supply/CVR combination is retrofit in an existing CVR rack. The power supply is modular; removable/replaceable; and is “independent” relative to the main aircraft power source and wiring. The modular power supply is designed to fit into a conventional CVR tray; and the modular power supply is designed to accept an existing CVR.

Abstract: Apparatus for automatically selecting one of two or more available power supply voltages for use as a main power supply of a PCI adapter is described. In one embodiment, a power supply selector is designed such that the presence of a positive voltage at a Vaux input thereof prevents power at a Vcc input thereof from driving a main power supply input to a PCI adapter. Conversely, the absence of a positive voltage at the Vaux results in the main power supply input to the PCI adapter being derived from the Vcc input. In an alternative embodiment, jumpers are provided for enabling a user to select which power supply will be used as the “default” power supply for the adapter.

Abstract: Apparatus for automatically selecting one of two or more available power supply voltages for use as a main power supply of a PCI adapter is described. In one embodiment, a power supply selector is designed such that the presence of a positive voltage at a Vaux input thereof prevents power at a Vcc input thereof from driving a main power supply input to a PCI adapter. Conversely, the absence of a positive voltage at the Vaux results in the main power supply input to the PCI adapter being derived from the Vcc input. In an alternative embodiment, jumpers are provided for enabling a user to select which power supply will be used as the “default” power supply for the adapter.

Abstract: In a multiplex communication system, a communication bus is connected to a communication bus disconnect control device. In the communication bus disconnect control device, a control section generates a communication bus disconnect signal when a trouble of the communication bus is detected. A communication bus disconnect device is provided for separating the communication bus into at least two communication bus groups in response to the communication bus disconnect signal.

Abstract: An integrated system for comprehensive control of an electric power generation system utilizes state machine control having particularly defined control states and permitted control state transitions. In this way, accurate, dependable and safe control of the electric power generation system is provided. Several of these control states may be utilized in conjunction with a utility outage ride-through technique that compensates for a utility outage by predictably controlling the system to bring the system off-line and to bring the system back on-line when the utility returns. Furthermore, a line synchronization technique synchronizes the generated power with the power on the grid when coming back on-line. The line synchronization technique limits the rate of synchronization to permit undesired transient voltages.

Abstract: A microcomputer reset device includes a switching circuit for comparing, after a reset of a CPU is released during power-up, a reference voltage Vref with a second divided voltage Vd2 which is proportional to a supply voltage and is adjusted by the CPU, and for switching, when the second divided voltage Vd2 exceeds the reference voltage Vref, a clock source of the CPU from an internal clock signal to an external clock signal. This makes it possible to solve a problem of a conventional microcomputer reset device in that it is not unlikely that the microcomputer starts its operation before its reset has been completed, which hinders the normal operation of the microcomputer.

Abstract: A test mode structure and method of a multi-power-source device provides for the device to remain in a test mode, during which current draw of the device may be accurately measured, even after primary power supply to the device has been greatly reduced or completely removed. Significant reduction or removal of the primary power supply while still remaining in the test mode is necessary to counter the presence of a variable current that would otherwise be normally generated by the multi-power-source device in the test mode; the presence of the variable current during the test mode, if not negated, will not permit an accurate measurement of the current draw of the multi-power-source device. Significant reduction or removal of the primary power supply to the device would typically cause the multi-power-source device to exit the test mode and switch to a secondary supply voltage supplied by the secondary power supply, thereby foiling any attempt to measure the current draw of the device.

Abstract: Disclosed is a power management system for a portable phone, for example, a cellular phone operating according to a specific mobile communications standard GSM. The power management system comprises a switching module which switches automatically from a voltage provided by a battery to a voltage provided by an external power supply when the power management system is connected to an external power supply. Furthermore, the system comprises a module of voltage regulators, each regulator providing a preset voltage, and a first and second voltage converter. The first voltage converter transforms a first input voltage having a first value to an internal voltage having a lower value. The second voltage converter transforms a second input voltage having a second value to an internal voltage having a higher value. An included reset circuit provides an automated reset function. A logic array module is connected to input ports and is associated with a communications interface.

Abstract: The present invention relates to a data processing device (100), notably a chip card, which includes an integrated circuit (10) and a power supply. The power supply includes a voltage converter (12) which converts an output current Iaus (46), powering the integrated circuit (10), into a pulsed input current Iein (44), where Vaus≦Vein.

Abstract: In order to reduce the battery load, a second elevated onboard electrical system voltage is provided at least for high-current consuming components. The voltage is derived from the battery voltage via a step-up switching regulator (SUSR) or is supplied by a starter-generator (SG) via a converter (CONV) in the generator mode of the starter-generator, which is coupled with an internal combustion engine (ICE) of the vehicle. The step-up switching regulator is used for battery supply of a start capacitor (CAP) and the converter is used for triggering of the starter-generator to start the internal combustion engine.

Abstract: A fabrication apparatus including an emergency stop circuit which is an emergency stop switch has a first electromagnetic switch for supplying and shutting off power to the apparatus and a second electromagnetic switch for controlling power supply to an electromagnetic coil of the first electromagnetic switch. Power is supplied to the electromagnetic coil of the first electromagnetic switch from the primary side of the first electromagnetic switch via a contact of the second electromagnetic switch. An uninterruptible power source supplies power to an electromagnetic coil of the second electromagnetic switch via the emergency stop circuit. This emergency stop switch is inserted midway along a power line to the electromagnetic coil of the second electromagnetic switch. This allows a safe emergency stop of the fabrication apparatus for semiconductors and the like.

Abstract: A cable apparatus makes a selection between supply of an internal power to a predetermined interface device and that of an external power to the interface device in compliance with the interface standard applied to the predetermined interface device. The cable apparatus includes an internal power terminal connectable to an internal power source, a plurality of external power terminals connectable to an external power source, and a plurality of power lines connected to the internal power terminal and/or external power terminals.

Abstract: An apparatus for supplying and controlling electrical power having a power source for supplying electrical power to a primary load and a secondary load, a capacitor connected to an input to the secondary load and control means operable to cause an operating condition of the apparatus to temporarily change from, a primary operating condition in which power from the power source is supplied to the primary and secondary loads to an alternative operating condition in which power from the power source is supplied to the primary load but is supplied to the secondary load thereby increasing the minimum voltage the capacitor can maintain at the input to the secondary load.

Abstract: A hot-swap device preventing the crashing of a system which has two power sources when performing power swapping operation between the two power sources by continuously providing spare-power to the system during the switching period.

Abstract: The invention specifies a disconnector for decoupling a load from a supplying AC power supply system. The disconnector comprises a transformer whose primary is connected into the AC power supply system. On the secondary side, a rectifier circuit is provided which has a turn-off thyristor connected to it. In normal operation, the turn-off thyristor is kept closed, so that the power supply system supplies the load. In the event of power supply system faults or interruptions, the turn-off thyristor is opened, which disconnects the power supply system from the load owing to the transformer impedance.

Abstract: A control system for a vessel utilizes a first and second power source to supply a first and second electrical load on the vessel. Each of the power sources is connected to its particular load and motorized switches are provided to allow operation of both the loads with a single power source, conveniently a generator, and to allow connection of each individual load to its own power source and to isolate the two loads and two power sources if both power sources are being used simultaneously.

Abstract: A method eliminates the discharge of the backup battery (42) prior to the primary source of power initially being applied to the device. The method comprises detecting the application of a source of primary power (12) and providing a path by way of a switch (46) in response to receiving the power (14), wherein the path allows the backup battery to power the device. Also, a circuit for maintaining the charge in a backup battery (42) of a device before primary power is applied comprises a sensing circuit (60) for generating an activation signal after initially sensing the application of the primary power to the device, and a switch element (61) coupled the sensing circuit (60) to receive the activation signal. The switch element (61) provides a path for the backup battery (42) to power the device.

Abstract: An electrical junction box or plug connector for auxiliary power, which enables a quick and easy connection of an auxiliary power source, such as a generator, to a single hard wired appliance, such as a gas furnace, pellet stove, fireplace insert, etc., without supplying power to the main power circuit, such as the breaker panel. The junction box includes a male terminal adapted to be connected to a female terminal of an extension cord of a generator, for example, includes a toggle switch to direct power from the generator to only a single appliance, and may include a current breaker or fuse for the electrical circuit. Thus, with an electric power supply outage, the furnace, for example, may be operated by a small generator.

Abstract: An electrical power management system (300) is disclosed comprising a power supply (301) which, when a first switch (302) and a third switch (306) are closed, provides power to a DC-DC step up converter (303) which, in turn, supplies power to a load (310) and simultaneously stores energy in a capacitor (305). In the case where the load momentarily requires more power than can be provided by the power supply, the first switch (302) and the third switch (306) are opened and a second switch (304) is closed. Energy previously stored in the capacitor (305) is now provided to the DC-DC step up converter (303) thereby allowing an efficient use of energy stored in the capacitor.

Abstract: The invention concerns a back-up power supply of the type serving to compensate temporarily for an absence of a DC input voltage (Ve) from a main power supply (15) by delivering a voltage that is higher than a threshold value (Vmin) to a load (10). The main power supply (15) delivers the DC input voltage (Ve) to the load (10) under normal operating conditions, the DC input voltage (Ve) being higher than the threshold value (Vmin), and lying in the range defined by a minimum input voltage (Ve1) and by a maximum input voltage (Ve2). The back-up power supply includes a capacitor (13) charged by the DC input voltage (Ve). According to the invention, the back-up power supply includes means (20, 21) for limiting the charge on the capacitor (13) to a reference voltage (Vr) that is lower than the maximum input voltage (Ve2). The invention makes it possible to reduce the size and the cost of the capacitor (13) of the back-up power supply.

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: 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: A solar array switching (SASU) unit (22) according to the present invention includes a control system (24), a solar cell array (26) and switch circuits (28). The SASU unit (22) is associated with a power card (30) for receiving an output from the array (26). The array (26) has a number (0.5Y) of rows (38) each of which includes a pair of cell strings (42) separated by one of the switch circuits (28). Each of the strings (42) includes a number (X) of cells in electrical series. The SASU (22) switches the array (26) between a short string configuration where the array (26) effectively includes Y strings of X length, and a long string configuration where the array (26) effectively includes 0.5Y strings of 2X length. The SASU (22) thereby facilitates the use of solar power for space missions where solar intensity, operating temperature or other factors vary significantly.

Abstract: The AC electric power of the commercial AC power supply is safely supplied to an electronic appliance functioning as a load during an occurrence of a power interruption by an auxiliary power supply apparatus. In the auxiliary power supply apparatus, normally usable electric power derived from a diode bridge energized by the commercial AC power supply, and auxiliary electric power produced from a DC/DC converter energized by a cell are selectively conducted to an output connector of this auxiliary power supply apparatus via a selection switch and a load connection switch, which are controlled in response to a detection result of a power-interrupt detecting circuit. When an AC plug of a load set is inserted into this output connector, a switch is turned ON, and then, a DC voltage applied from a voltage divider to this connector is changed, depending upon the types of the power supply circuits employed in the load sets, namely, a transformer type power supply circuit and a switching type power supply circuit.

Abstract: A system and method for minimizing disruption of operating power in a high-availability computer as new power supplies are hot-inserted. In the preferred embodiment, the high-availability computer includes a plurality hot-plug power supplies, a logic circuit system, and a power distribution system for distributing operating power from the power supplies to the logic circuit system. Preferably, the output capacitance of each power supply is significantly less than the total capacitance of the logic circuit system and the power distribution system, such that, as each power supply is hot-inserted into the computer, only a minute amount of electric charges will be transferred from the power distribution system and the logic circuit system to the power supply. As a small amount of charge transfer would generate only a small voltage drop, any glitch produced by hot-insertion would be significantly reduced.

Abstract: A plurality of output terminals from which the power from an uninterruptible power supply apparatus is supplied. A timing holding unit holds timing information of power supply start and/or stop of respective ones of the plurality of output terminals, the timing information being set independently for each one of the plurality of output terminals. A timing pulse generating unit generates timing pulses which are used for reading out the timing information from the timing holding unit. Power supply start and/or stop of each output terminal is performed based on the timing information read out from the timing holding unit.

Abstract: Aspects for reporting faults in a redundant power converter are described. An exemplary method aspect includes monitoring at least one node within the redundant power converter. The method further includes tracking values of the at least one node during a predetermined time period, and predicting when a specification of the redundant power converter will be exceeded based on the tracked values.

Abstract: A power supply system is made up of a plurality of power supply devices including M (M is a positive integer number) redundant power supply devices. The power supply system includes redundant abnormality detecting means for detecting that an abnormality occurs in at least one of the M redundant power supply devices in accordance with first signals outputted from the power supply devices. Each of the first signals indicates corresponding one of the power supply devices is in an abnormal state.

Abstract: A switching system having a plurality of positions for separating or interconnecting a generator, a network transformer, and a starter device, the system including a circuit breaker for the generator and a busbar disconnector for separating or interconnecting the generator and the network transformer, and a starter disconnector for separating or interconnecting the generator and the starter device. The busbar disconnector includes a first fixed contact and a first moving contact that co-operates by sliding with the first fixed contact, the first fixed contact and the first moving contact being integrated with the circuit breaker of the generator. The starter disconnector includes a second fixed contact and a second moving contact that co-operates with the second fixed contact by rotation. This organization remains economical to implement even for applications in which the generator is an alternator in a combined cycle or a gas turbine power station.

Abstract: An apparatus for preventing peripherals from back powering a host computer is disclosed. The apparatus use a timer and associated logic circuitry to determine the time period between signals being sent to the host computer from the peripheral device. Under predetermined time-out conditions, the current output by the peripheral is disabled to prevent the peripheral from back powering a main computer.

Abstract: A power supply device produces, on a plurality of accesses, a plurality of voltages coming from a plurality of accumulator assemblies formed by at least one accumulator element and connected in series by at least one series connection. The power supply device includes a back-up provision for mitigating discharges of at least one of the accumulator assemblies.

Abstract: In order to provide an inverter apparatus and a solar power generation apparatus in which when a main AC power system (5) has suffered, e.g., a power failure, the operation mode of an inverter (2) in the tie operation with the main AC power system (5) can be easily and safely switched from the tie operation mode to the self-support operation mode, and electric power can be supplied to a load (4) directly using normal indoor wiring, the open/closed state of a switch (3) for opening/closing a connection between the output terminal of the inverter (2) and the main AC power system (5) is detected, and the self-support operation of the inverter (2) is started when the open state of the switch (3) is detected.

Abstract: A DC power system receives AC electrical power and DC electrical power from separate first and second sources simultaneously. The DC power system delivers DC electrical power to an output for use by a load requiring DC power. The DC power system includes a converter to convert AC electrical power to DC electrical power and a power sharing control device to control and distribute the DC electrical power to an output. The first source of DC electrical power includes a storage battery, which provides standby DC electrical power to the DC power system. It also includes a power sharing device, which maintains the storage battery fully charged for use at peak loads, when the DC output electrical power is insufficient to meet the DC load.

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: The electronic circuit for supplying a voltage at a common output terminal (KI.U) has a number of supply circuits, each of which includes a source (B1, B2, . . . , Bn) of electric current and transistors (T10,T11; T20,T21; . . . ; Tn0,Tn1) connected with the source (B1, B2) to form an analog switch for gating the electric current, each supply circuit being connected with the common output terminal (KI.U); and a circuit device for controlling a potential at the gate electrodes of the transistors (T10,T11; T20,T21; . . . ; Tn0,Tn1) in each supply circuit, whereby the supply voltage (UV) is provided by a selected one of the supply circuits.

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 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 uninterruptible power supply (UPS) for supplying DC power to a load and a method of providing uninterruptible DC power to a load. In one embodiment, the UPS includes: (1) a first stage rectifier that rectifies AC input power received from a primary power source into DC power at an intermediate voltage, (2) a second stage rectifier, coupled to the first stage rectifier, that converts the DC power at the intermediate voltage into DC power for the load at an output voltage that is lower than the intermediate voltage and (3) a solid state transfer switch, coupled between the first stage rectifier and the second stage rectifier, that transfers secondary input power received from a secondary power source to the second stage rectifier only when a voltage of the secondary input power exceeds the intermediate voltage.