Abstract: A power management system and method for multiple redundant power supplies. The present invention provides management and control of N+M power supplies, where N represents the minimum number of power supplies required and where M is the number of redundant power supplies (M>1), where any one of the power supplies may be capable of supplying power to all the loads of the power subsystems. In the preferred embodiment each power subsystem includes a power supply and a controller coupled to a power bus. A communication bus is provided common to each power subsystem. During reset or power-on periods, the controllers are programmed to uniquely delay the start time of each power supply, thereby protecting against an overcurrent/overvoltage condition on the power bus during reset periods. A master controller is provided to monitor normal operating conditions of the power subsystems and communication bus.

Abstract: A backup power supply for a restraint control module is disclosed that includes a main power source that is connected to a backup power source charging circuit. A boost converter control and driver circuit is connected with the main power source and the backup power source such that the boost converter control and driver circuit controls the charging of the backup power source with the main power source during normal operation. A backup power supply control and driver circuit is connected with a backup power supply switching device. The backup power supply control and driver circuit switches the source of power from the main power source to the backup power source when the backup power supply control circuit senses a loss of power from the main power source.

Abstract: Methods and systems for protecting integrated circuits (“ICs”) from power-on sequencing problems provide an interim voltages during power-on sequences in order to prevent over-voltage conditions across IC terminals. Voltages at first and second terminals of a circuit are monitored and an interim voltage to the second terminal is provided when the voltage at the first terminal exceeds a first threshold and a voltage at the second terminal is below a second threshold. The interim voltage protects the circuit from excessive voltage differences across the first and second terminals during power-on sequences, and is deactivated during normal operation so as not to draw excessive current. The method/system helps to insure that multi-supply dependent logic and/or other circuitry does not receive inappropriate voltage levels, and thus helps to insure that lower voltage level based circuitry is not damaged during power-up, transients, and/or glitches.

Abstract: A power system for supplying a power requirement of a load is described and which includes a plurality of DC power sources having at least one fuel cell, and which provides power to a load; and a control electronics assembly is provided and which is electrically coupled to the respective DC power sources, and which selectively reconfigures the plurality of DC power sources to substantially serve the changing power requirements of the load.

Abstract: In an electric power source for supplying an electric power from a battery to an electric power line with boosting a voltage generated by the battery so that the electric power of boosted voltage is supplied to the electric power line, a main switch device prevents the electric power supply into the electric power line from the electric power source and the electric power supply from the electric power line into the electric power source in a case in which the boosted voltage to be supplied to the electric power line is less than a target voltage not less than a voltage of the electric power line, while allowing the electric power supply into the electric power line from the electric power source when the boosted voltage to be supplied to the electric power line is not less than the target voltage.

Abstract: A power supply unit (system power supply IC) has a multiplicity of power supply circuits providing for different supply voltages. Should an abnormal condition take place in any of the multiple power supply circuits, the power supply circuit suffering the abnormality issues an abnormality detection signal that contains a power supply circuit number and an abnormality type, which signal is stored in a nonvolatile memory together with time data indicative of the time of reception of the abnormality detection signal before all the power supply circuits are disabled. Thus, this arrangement protects the system power supply IC and the loads connected thereto, and provides convenient means for analyzing the abnormality and replicating it if necessary, based on the abnormal power supply circuit number, abnormality type and time data stored in the nonvolatile memory.

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: An AC interconnection apparatus has an input terminal for a commercial power system, a connection terminal to a solar cell, an output terminal connected to a load, an inverter for converting the output voltage of the solar cell into an AC voltage, and a current detector arranged on the load side of an AC connection point for connecting the AC output from the inverter and the commercial power. When a power value calculated on the basis of a current detection value by the current detector and the voltage of the commercial power system is less than the output power of the inverter, the output of the inverter is suppressed, thereby suppressing reverse power flow to the commercial power system. When the current value detected by the current detector exceeds a predetermined value, power supply to the load is stopped using a breaker.

Abstract: The power supply in accordance with the present invention provides AC redundancy while also preventing voltages from multiple AC voltage sources from adding at a common node. The adding of voltages is avoided by ensuring that only one AC voltage source at a time is providing the voltage at the output. Even if the other AC voltage sources are connected afterwards, these later AC voltage source are prevented from providing power at the output. In addition, diodes prevent current from back flowing to the AC voltage sources which are not supplying power to the output. Because the power supply in accordance with the present invention neither uses redundant AC to DC power supplies from independent AC voltage sources, nor does it use a costly transfer switch, the power supply in accordance with the present invention is more cost effective than conventional redundant power supplies.

Abstract: In a system having multiple power supplies with outputs connected in parallel, the number of supplies providing current is controlled to improve the overall system efficiency. For example, when the output current of individual power supplies falls below a threshold, one or more supplies may be placed into a standby mode. This increases the output current of the supplies that are in an operational mode, improving the efficiency of the supplies that are in an operational mode.

Abstract: A protective circuit arrangement includes at least two power contactors that have main make contact elements arranged in enable circuits. Each main make contact element of a power contactor is connected in series to a main make contact element of another power contactor in each respective enable current circuit. A respective coil circuit make contact element is provided in the coil current circuit of each coil of each power contactor, whereby the coil circuit make contact elements can be jointly actuated. The main make contact elements of each power contactor are disposed between two respective auxiliary contact units which each have a respective make contact element and a respective break contact element, and which are respectively configured as positively driven contacts. The make contact elements of all auxiliary contact units arc connected in series in a first indicator circuit, and the break contact elements of all auxiliary contact units are connected in series in a second indicator circuit.

Abstract: An AC interconnection apparatus has an input terminal for a commercial power system, a connection terminal to a solar cell, an output terminal connected to a load, an inverter for converting the output voltage of the solar cell into an AC voltage, and a current detector arranged on the load side of an AC connection point for connecting the AC output from the inverter and the commercial power. When a power value calculated on the basis of a current detection value by the current detector and the voltage of the commercial power system is less than the output power of the inverter, the output of the inverter is suppressed, thereby suppressing reverse power flow to the commercial power system. When the current value detected by the current detector exceeds a predetermined value, power supply to the load is stopped using a breaker.

Abstract: A backup power-source module that controls a backup power source for supplying power from a battery charged by an AC input to an electronic device when the AC input is cut off. The backup power-source module includes a selection which generates a selection signal for selecting power supplied by a battery when the electronic device is kept in an electrified state until the electronic device is shifted to a power cutoff state and there is no AC input. I.E., the selection signal causes the power supplied by the battery to be selected only when the electronic device is kept in a power cutoff state and there is no AC input.

Abstract: The present invention relates to a stepped micro electromechanical structure (MEMS) capacitor that is actuated by a plurality of MEMS switches. The MEMS switches may be within the stepped capacitor circuit, or they may be actuated by an independent circuit. The stepped capacitor may also be varied with intermediate steps of capacitance by providing at least one variable capacitor in the stepped MEMS capacitor structure.

Abstract: A method and structure for electric power management that economically satisfies peak power demand and immediately satisfies a sudden substantial increase in power demand. An electric power management system comprises a first circuit element in parallel with a second circuit element, and a load in parallel with the first circuit element. The first circuit element includes a first direct current (DC) energy source in series with a first diode that prevents current backflow into the first energy source. The first energy source may comprise a conventional energy source such as fossil fuel, natural gas, hydroelectric power, etc. Alternatively, the first energy source may comprise an alternative energy source such as, inter alia, fuel cells, solar cells, wind power, and biomass power.

Abstract: A circuit arrangement for supplying electrical energy to a power supply has a fuel cell and an accumulator arrangement. Electrical energy is delivered by the accumulator arrangement during the starting procedure, and is fed into the power supply by the accumulator arrangement via at least one DC/DC converter during starting of the circuit arrangement.

Abstract: The present invention is a control system for a main power supply and a standby power supply. In response to a utility outage, the control initiates operation of the standby power supply and connects the standby power supply to a standby panelboard, whereby certain branches of the residence are powered.

Abstract: An electrical control module, including a control circuit, and voltage rectifier for controlling a solenoid. The control circuit is adapted for use in a transfer switch receiving power from two power sources and sending power to a single load, such as a commercial building or hospital. The control circuit and solenoid are designed to work over a broad range of voltages to quickly and efficiently transfer power from the first power source to the second. The circuit is particularly well suited for use in a closed transition transfer switch where the second source is connected before the first source is disconnected.

Abstract: A battery backup unit can be used to supply backup power to a computer. The battery backup unit includes a charge circuit that is connected to the computer's power supply unit. The charge circuit is also connected to a battery pack that includes a battery. The charge circuit converts an input high DC voltage signal supplied by the power supply unit to a charging signal. The charging signal can be used to charge the battery in the battery pack. The battery backup unit also includes a discharge circuit that is connected to the power supply unit and the battery pack. The discharge circuit converts a battery signal received from the battery pack to an output high DC voltage signal. The output high DC voltage signal can be fed into the power supply unit in order to drive the power supply unit if there is an indication that the AC power input to the power supply unit is inadequate to drive the computer.

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 notebook-sized personal computer representing consumption-side hardware sends electric power data, which indicates an electric power (including voltage, alternating or direct current, cycle and wave shape) suited to the personal computer, to an electric power supply system through a communication line. In the system, the electric power data of the personal computer is analyzed in an allotter, and the allotter sends electric power data, which indicates an electric power required in the allotter, to an electric power supply adapter through a communication line. The electric power supply adapter converts an electric power received from an electric power company into another electric power matching with the electric power data of the allotter and supplies the converted electric power to the allotter through an electric power line.

Abstract: An uninterruptible power supply (UPS) system (3) is to be inserted between a alternating current (AC) power supply (4), interruptions of which are to be compensated for, and at least one load (5), which is to be supplied with alternating current (AC) or direct current (DC).

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: A bi-directional flyback converter (30), as regulated by control circuitry (34), is used to maintain power from a capacitor (36) to aircraft electronics (20) when power from a ground source through bus (12) is switched by a switching relay (16) to the aircraft source through bus (14). When the aircraft is on the ground and prior to engine start up, power is fed through bus (12). Such maintenance of power is necessary during switch-over from the ground to the aircraft power source, to avoid any transitory interruption of power. In operation, once the proper voltage is reached, the circuit turns off, minimizing power consumption. When the input power drops, the bi-directional converter acts as a voltage source, keeping the supply input voltage at a minimum set point by using the energy stored in the capacitor. An anticipation circuit turns on the circuit before power is actually needed so that the response time is instantaneous.

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: A power transfer apparatus includes a first switch operative to couple and decouple a first AC power source to and from an AC power bus responsive to a first control signal and a second switch operative to couple and decouple a second AC power source to and from the AC power bus responsive to a second control signal. A first switch control circuit generates the first control signal responsive to a first AC source voltage produced by the first AC power source and to a first inhibit signal and generates a second inhibit signal responsive to a state of the first switch. A second switch control circuit generates the second control signal responsive to a second AC source voltage produced by the second AC power source and to the second inhibit signal and generates the first inhibit signal responsive to a state of the second switch.

Abstract: Only the standby transformer supplies a current to a control power source while the operation power is off, and supplies a current to a primary power relay when the primary power relay is activated. After activation of the primary power relay, both of the standby transformer and a main transformer supply currents to the control power source and the primary power relay. This makes it possible to reduce the rated current of the standby transformer as well as the standby power.

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: An integrated circuit chip having formed thereon a voltage control circuit supply adapted to provide one of a pair of voltages selectively in accordance with an operating mode of the circuit. The circuit includes a comparator circuit fed by the pair of voltage sources. A first switch is controlled by the comparator circuit. A first one of the pair of voltage sources is fed through a second switch which may be a transistor or a diode. An input of the first switch is fed to a second one of the pair of voltage sources.

Abstract: A battery disconnect system is provided for a device having a battery and load. The battery disconnect system includes a switch that is operative to connect the battery to the load when the switch is in a closed state. The switch is also operative to disconnect the battery from the load when the switch is in an open state. The battery disconnect system also includes a switch controller that is coupled to the switch. The switch controller is operative to cause the switch to enter the closed state in response to receipt of a first signal from a first external source. The switch controller is also operative to cause the switch to enter the open state in response to receipt of a second signal from a second external source.

Abstract: An apparatus comprising a first circuit, a second circuit and a switch. The first circuit may be configured to receive a first supply voltage and may be coupled to a first ground. The second circuit may be configured to receive a second supply voltage and may be coupled to a second ground. The second circuit may be disabled in response to a control signal. The first and second supply voltages may be controlled by a reference voltage. The switch may be coupled between the first and second circuits and may be configured to connect the first and second circuits when the second circuit is disabled.

Abstract: A communication system is presented whereby sequences of video screens sent from a host CPU to a video controller can be stored and subsequently retrieved by a terminal located remote from the host CPU. The host CPU and video controller form part of a server arranged within a distributed computing system. An administrator situated at the remote terminal can retrieve select video screens produced during server operations to determine information regarding the server configuration and possible causes of server failure or future failure. The sequence of video screens thereby represent video screen changes stored upon a server controller adapted for coupling to the server expansion bus. The video screen changes represent a sequence of video screen changes occurring prior to server failure or after server reset. Those changes provide beneficial information to an administrator located remote from the server, and allows the administrator to communicate with the server using several possible communication protocols.

Abstract: A fault tolerant voltage regulator module (VRM) circuit for a processor simultaneously supplies a core voltage to a plurality of processors, has a plurality of main VRMs (VRM) for supplying the same core voltage to the plurality of processors, a stand-by VRM for use upon a fault occurring in the plurality of main VRMs, a plurality of diodes connected in parallel between each of the main VRMs and the stand-by VRM for automatically supplying power to the stand-by VRM, a plurality of first power islands for connecting each of the plurality of main VRMs to the processor and each of output port of the plurality of diodes, a control signal set switch for setting output voltage level of the stand-by VRM and a second power island for connecting the stand-by VRM to input ports of the plurality of diodes and the control signal set switch.

Abstract: A sensing terminal and a receptacle are installed in a charge battery and a charger, respectively. During charging, a charging circuit within the charger will detect whether the battery is pulled out from the charger. If the battery is pulled out, the power source will be turned off in a very short time so that no voltage will be sent from the terminal of the charger in order to protect the charger. As the charge battery is pulled out from the charger, no spark is generated and the battery is prevented from being burned out.

Abstract: An electrical safety receptacle (10) including a dielectric housing (12), first electrical contacts (14) in the housing for electrical connection to one side of an electrical power line, second electrical contacts (16) in the housing for electrical connection to the other side of the electrical power line, and power-interruption members (48) provided as part of the second electrical contacts to interrupt the electrical power when an operating and/or environmental temperature exceeds the thermal rating thereof.

Abstract: A system interconnection device connected between two systems, such as a commercial bus line carrying power from a commercial power line and a private bus line carrying power from a private power generator, is able to connect and disconnect the two systems, and, in the event of a fault, has a current-limiting effect, thus preventing instantaneous voltage drop of the respective bus lines. In the system interconnection device, unit parallel circuits made up of diodes and DC reactors are serially connected so that the diodes thereof have opposite directions. With this structure, in realizing operations equivalent to those of a conventional system interconnection device having a DC reactor between DC terminals of a single-phase rectifying bridge circuit, the number of diodes, which are rectifying elements, can be halved.

Abstract: A redundant power supply with a number of loads is coupled to each half of the redundant supply by a respectively different MOSFET switch, with logic gates coupling control signals to the MOSFET switches. The control signal is coupled as one input to the logic gate and the output of the logic gate is connected to the MOSFET switch. The other input of the logic gates for a particular power supply is the output of an overvoltage detection circuit whose output is coupled as an input to all the gates for that power supply. The output of the gates opens the MOSFET switches in response to detection of an overvoltage condition.

Abstract: A power failure-free power supply apparatus capable of minimizing time required for parallel operation of a power rectifier and a power rectifier/inverter, to thereby minimize a deterioration in operational reliability. The power rectifier converts an output of an AC power supply into DC power. A power inverter converts DC power into AC one. The power rectifier/inverter carries out rectifying/inverting operation. An output of the power rectifier and an AC output of the power rectifier/inverter are fed through a change-over unit to a load. Operation of switches is controlled depending on a detection signal of a current detector for detecting a charging current of a storage battery. A control unit permits parallel operation of the power rectifier and power rectifier/inverter when a residual capacity of the storage battery is at an increased level and permits the storage battery to be charged when the residual capacity is at a reduced level.

Abstract: A method of detecting a condition requiring connection of a user apparatus with a feeder line comprises the steps of low-voltage power supplying the user apparatus through a detection impedance (17, 17a); detecting the waveform at the ends of the detection impedance; operating connection of the user apparatus with the feeder line when the waveform at the ends of the detection impedance is distorted in a manner that has been pre-established to be caused by actuation of a command in the user apparatus and requiring full powering of same. A device in accordance with the method comprises an analysis circuit (19, 37) detecting (by comparison with sample waveforms stored in a memory (20), for example) distortion of the waveform at the ends of the impedance (17, 17a) and consequently operating powering of the user apparatus.

Abstract: Voltage obtained by dividing the voltage of an external power source (101) by means of resistors (108, 109) is supplied to the gate of a first FET (107) that is interposed between two series-connected built-in batteries (103, 104). When the voltage at a predetermined level or above is supplied from the external power source (101), the first FET (107) is turned off, a second FET (110), which is provided between the built-in batteries (103, 104) and a load (113), is also turned off, and the voltage is supplied to the load (113) only from the external power source (101).

Abstract: An apparatus contains a main electrical supply and an additional electrical supply for supplying additional electrical current in response to a change in an output load supplied by the main electrical supply. A differential measuring device senses a change in the load, or output of the main supply, and provides an indication to the additional electrical supply to supply additional current to the load. The additional electric supply contains a capacitor connected to a voltage source having a higher voltage output than the main electrical supply, and a current generator.

Abstract: A lightning detector system which includes a radio frequency (RF) detector assembly which receives input from an antenna and a line sensor in order to sense signatures of compromising events such as lightning strikes or transient line events caused by power grid loss, transformer breakdown, switching surges or load induced events. A central processing unit (CPU) isolates the equipment from the power grid and simultaneously causes AC current to be supplied to the equipment only from storage cells. The CPU and detection devices are continually powered by power from the storage cells rather than directly from the AC power grid. The system also incorporates a timer or counter device, such that the system will convert back to AC power from the grid if no subsequent triggering event occurs within a preset time period.

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: A hybrid standby power system for producing regulated DC electrical power, a method of producing such power and a telecommunications installation that employs either the system or the method. In one embodiment, the system includes: (1) a primary power input, couplable to a primary power source, that accepts primary electrical power subject to interruption, (2) a standby power input, couplable to a standby power source, that accepts unregulated standby electrical power and (3) a power converter, couplable to at least one of the primary and standby power inputs, including a rectifier that rectifies at least one of the primary and standby electrical power to provide unregulated DC electrical power and a DC--DC converter that converts the unregulated DC electrical power into the regulated DC electrical power.

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: 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: A self-biased power isolator system is disclosed that provides a fault tolerant power system without the need for auxiliary power. Enhancement-mode MOSFET 120 includes a drain coupled to a first node, a source coupled to a second node, and a gate. Amplifier 50 includes inputs for comparing the voltages from the first and second nodes and an output coupled to the gate of MOSFET 120 by which amplifier 50 controls the state of enhancement-mode MOSFET 120. Amplifier 50 further includes a positive power input coupled to the second node and a negative power input coupled to ground. In one embodiment, the first node is operable to be coupled to a power supply 10 and the second node is operable to be coupled to a load 18. A further embodiment allows the architecture to be replicated, each coupled at the second node to provide an N+1 fault tolerant power system.

Abstract: A digital voltage detector uses a running average to detect utility service disturbances in real time. An isolation transformer taps the main electrical AC power supply line and provides an analog voltage waveform to a system controller. The analog waveform is sampled digitally in real time, and the samples are squared to create respective instantaneous squared voltage values. A running average is kept of the instantaneous squared voltage values for a preselected period of time, preferably one half-cycle for the main power supply waveform. The running average is compared to a preselected under-voltage threshold value and a preselected over-voltage threshold value, and a disturbance detection signal is generated if the running average violates either threshold value. The disturbance detection signal is preferably used to activate a standby electrical AC power supply, and contemporaneously to disable the main electric AC power supply.

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

Abstract: A printed circuit board includes an edge connector operable to be coupled to an expansion bus. An integrated circuit is mounted on the printed circuit board and is coupled to the edge connector. The integrated circuit is operable to snoop memory operations on the expansion bus and cause selected memory data to be stored in a memory on the printed circuit board. A first power conductor extends across a first portion of the printed circuit board and is coupled to the integrated circuit. A second power conductor extends across a second portion of the printed circuit board and is also coupled to the integrated circuit. The circuit board also includes a decoupling unit connected between the first power conductor and the second power conductor. The decoupling unit causes disconnect of the first power conductor from the second power conductor during times in which voltage within the first power conductor is less than voltage within the second power conductor.