Abstract: A control system and method for controlling operation of a group of linear solenoids, which in turn control operation of an electrical load such as a solenoid or actuator, that exhibits increased responsiveness to a change in the target linear solenoid load current. A microcomputer cyclically generates and outputs pulse-width-modulated drive signals based on acquired drive data to establish clock periods. A switch connected between the microcomputer and the target load switchably connects the target load to a power source based on the drive data to selectively drive the target load. A feedback loop between the target load and the microcomputer provides actual target load drive data to the microcomputer, and the microcomputer adjusts the drive signals at a rate of not more than two times per cycle based on the actual drive data to converge the actual drive data to a calculated target load drive value.

Abstract: The battery pack according to the present invention is to avoid any trouble or the like of the primary or secondary battery inside the battery pack with a simple mechanical construction when a load is intermittently connected between the external terminals of the battery pack. For this end, the battery pack includes at least the battery cell and a protection circuit for shutting off overcurrent discharge and features in the provision of shut-off holding means and releasing means. The shut-off holding means maintains discharge shut-off condition after abnormal discharge shut-off by shorting or connecting a low resistance between the external plus terminal and the external minus terminal from outside of the battery pack. The releasing means releases the shut-off condition of the shut-off holding means when a predetermined voltage is applied between the external plus terminal and the external minus terminal.

Abstract: A fully protected H-bridge for a d-c motor consists of two high side MOSFETs and a control and logic IC on a first conductive heat sink all within a first package and two discrete low side MOSFETs. The entire bridge is controlled by the IC. Shoot thru protection is provided for each leg, and a PMW soft start sequence is provided through the control of the low side MOSFETs, programed by an external, chargeable RC circuit. Input signals to the high side MOSFETs select the operation modes. Protective circuits are provided for short circuit current and over current conditions. Sleep mode and braking/non braking control is also provided.

Abstract: An over-voltage protected integrated circuit is provided, which includes a discharge node, an input-output pad, a signal trace, which is coupled to the input-output pad, and a pair of back-to-back diodes, which is coupled between the first signal trace and the discharge node.

Abstract: The present invention is directed to a carrying case with an integrated power supply system for providing power to multiple electronic devices from a single power source. In addition to allowing quick access and storage of various electronic devices, the carrying case also allows the individual electronic devices to be easily connected to the power source and eliminates the need to carry multiple charging cords. In certain embodiments, the power supply system further includes an additional battery or other power source, which increases the runtime of connected electronic devices and reduces the need to carry additional individual batteries for the individual devices. With different connectors on the input to the power system, different AC or DC power sources may be utilized. Different connectors can also be used to provide power to different electronic devices.

Abstract: A monitoring system includes a power source, a power bus coupled to said power source, a plurality of power taps coupled to said power bus, each of said power taps having a ride-through capacitor operatively coupled thereto to provide power during brief interruptions in the power supply to said power bus by said power source.

Abstract: There is described a method for controlling an electric motor comprising an operating relay having relay windings with respective first and second relay contacts and a control means, which motor via current conductors is connected to said relay and a power source wherein an operator by using said control means controls the application of current to the motor armature or rotor and field coil(s) or field magnet(s), monitoring devices are provided which sense indicating parameters that are compared with respective corresponding reference values in a safety function unit in order to determine whether the contacts of the operating relay are mistakenly in the on position, and if one of the contacts is the on position, ensures the switching on of at least the other one of the relay contacts so that the current application to the motor is interrupted and the motor stops.

Abstract: A digital electric power inverter comprising: a CPU, a PWM driving circuit, a PWM converting circuit, a rectifying circuit, an AC driving circuit, a DC/AC inverting circuit, an overload detecting circuit and an alarm circuit, the power inverter is characterized by that: the entire circuitry of the electric power inverter is designed to be controlled by the CPU that can accurately control these circuits to get an ability of high driving outputting.

Abstract: An integrated transient voltage surge suppression system and automatic power transfer switch which includes a framework, an automatic transfer switch mounted to the framework, the automatic transfer switch being configured for electrical connection to a primary source of electrical power, a secondary source of electrical power, and a recipient electrical power load, the automatic transfer switch being configured to normally route primary electrical power from the primary source of electrical power to the recipient electrical power load, the automatic transfer switch being further configured to switch upon the occurrence of a predetermined switch condition such that the automatic power switch alternately routes secondary electrical power from the secondary source of electrical power to the recipient power load; and a transient voltage surge suppression device mounted to the framework and electrically positioned between the automatic transfer switch and the recipient electrical power load.

Abstract: A circuit for applying power to mixed mode integrated circuits in a predefined sequence. The circuit includes a first circuit powered by a first voltage and a second circuit powered by a second voltage that is less than the first voltage and having the second voltage coupled to the first circuit. The circuit for applying power to mixed mode integrated circuits includes[[,]] a modified [[IO]] I/O cell of the second circuit. The modified [[IO]] I/O cell has a driver transistor including a back gate terminal, a gate terminal that is driven by the second circuit, a source drain terminal that is coupled to a first circuit signal, and a drain source terminal that is coupled to the second power supply voltage. The circuit for applying power to mixed mode integrated circuits further includes[[,]] a controller circuit coupled to the first voltage and the second voltage supplied as controller circuit inputs.

Abstract: A data processing system power supply selection device. The system power supply selector circuit can include a first make-without-break power supply selector module having a power supply input, at least one controlling power supply input, and a system power rail output substantially continuously coupled to said at least a first power supply input.

Abstract: An undervoltage tripping device for a multipolar low-voltage switching device is described. The tripping device contains an electromagnetic tripping mechanism for effectuating a tripping of the multipolar low-voltage switching device given a drop below a predeterminable voltage limit value. The tripping mechanism has a magnetic circuit with a spring-loaded armature and a trip coil including a number of winding portions corresponding to a number of phases of a multiphase power supply circuit. A rectifier bridge is powered by the multiphase power supply circuit. The rectifier bridge has a number of rectifier branches corresponding to the number of the phases of the multiphase power supply circuit. The rectifier bridge is connected to the tripping mechanism and the rectifier branches jointly power the tripping mechanism. The tripping mechanism effectuates an all-pole tripping of the low-voltage switching device given a failure of one of the phases of the multiphase power supply circuit.

Abstract: An analog or digital circuit that senses both low and high input voltage and operates to disconnect both line and neutral electrical power connections to a protected device when abnormally low or high voltages are received from a single- or multi-phase power source, and reconnects the protected device when input power has stabilized. The sensing circuit and power supply is functional with voltages up to at least 240 Vac. The nominal 120 Vac circuit is designed to withstand a 6 kilovolt surge without damage. The apparatus does not disconnect the ground line during an out-of-tolerance voltage condition.

Abstract: The present invention is a method of data storage using a phase-change memory element operating within its amorphous phase. The element stores at least one bit of data upon the application of a pulse that resets the element to one of at least a first resistance state and a second resistance state. Since the threshold voltage of a memory element varies linearly with its programmed resistance, the stored data can be read by the application of one or more discriminating voltages to the element. The current flowing through the element is limited to prevent a phase change when an applied discriminating voltage is greater than the threshold voltage. When the applied discriminating voltage is less than the threshold voltage, current flowing through the memory element is not limited. Based upon these current outputs, the resistance state of the element is determined.

Abstract: The invention refers to a charge/discharge protection circuit for a rechargeable battery which is protected by a fusible link, where the rechargeable battery comprises a control logic which opens or closes a load switch depending on the magnitude of the battery voltage, the voltage on the charge/discharge terminals of the protection circuit and the charge/discharge current. The protection circuit is designed so that the electric strength needs to match only the actual maximum battery voltage, thus requiring little real estate on an IC chip and also allowing most components to be integrated.

Abstract: A state controller of a data transfer processing circuit switches an operation of an A-device or a B-device between a host operation and a peripheral operation by state transition. A power supply switch circuit connects a power supply circuit with a VBUS line based on transition of the state controller. A power supply switching circuit of a power supply control circuit connects the VBUS line or the power supply circuit with the data transfer processing circuit based on a switching signal. The switching signal is generated based on an output signal of a switch circuit or a control signal from the state controller.

Abstract: Described are a system and method of testing connectivity between a main power supply and a standby power supply. The system includes a processor, a main power supply, and a standby power supply. The processor issues a command to the standby power supply to provide dc power to main power supply. The standby power supply switches from providing ac power to providing dc power to the main power supply in response to the command. The main power supply, in response to receiving dc power from the standby power supply, provides a communication that operates to indicate to the processor that the main power supply is receiving dc power from the standby power supply in response to the command.

Abstract: A switching device includes a working circuit, to which an operating voltage can be or is applied to which has at least one electronic switching element. This switching element includes at least one control terminal for applying a switching signal and is switched off or switched on depending on the switching signal. At least one electronic protection element is for protecting the switching element in its switched state from excessive Joule losses in the event of danger, especially in the event of an overload or a short circuit. The protection element bears the predominant part of the operating voltage that is released at the working circuit.

Abstract: Apparatus and methods for controlling a startup signal during a brownout. The invention controls the startup of a signal during the brownout using a monitor circuit and a control circuit. The startup signal is used in conjunction with a soft start feature to regulate power. The monitor circuit is configured for monitoring an input signal to the circuit and for providing a control signal in response to a change in the voltage level of the input signal. The control circuit is configured for receiving the control signal from the monitor circuit to control the startup signal during the brownout. The control circuit may control the startup signal with a transistor by electrically grounding the startup signal such that a capacitor may discharge during the brownout. The control circuit may prevent undesirable triggering of over-current protection circuitry within the regulator.

Abstract: The invention refers to a charge/discharge protection circuit for a rechargeable battery, where the protection circuit is integrated on a single chip, including the fusible link, the load current switch and the short-circuit switch. This is achieved by dividing the functions of the fusible link, the load current switch, and the short-circuit switch into in parallel arranged T-sections, each of which is designed for only a fraction of the nominal load so that each of the easily integrated fuse segments carry only the respective fraction of the nominal current. It is important that the entire protection circuit or its control logic will not be destroyed before through an unduly high over-voltage, in which case the sequential melting of the fuse segments would no longer be guaranteed. This is handled by a semiconductor switch which short-circuits the over-voltage immediately.

Abstract: A method and system determines the status of an external power supply connection to an information handling system. A subsystem manager of the information handling system compares an external power source identification signal and a power available signal to determine whether external power is available, unavailable or faulty. For instance, an information handling system configured as a portable computer receives external power from an AC/DC converter along with an identification signal for the converter. A state machine running on the portable computer system's Super I/O compares the identification signal and a power available signal from an internal charger to determine state of the external power source and indicate the state to a user.

Abstract: A circuit board includes a power switch operable so as to generate a trigger signal upon actuation, a card slot adapted for connecting with a video card, and a controller coupled electrically to the power switch and the card slot. The controller detects connection of the video card to the card slot and further detects operating voltage of the video card. The controller inhibits the power switch from generating the trigger signal upon detection that the operating voltage of the video card that is connected to the card slot is higher than a predetermined voltage.

Abstract: A power supply protection circuit for stopping a power supply to electrical equipments in case a normal power voltage is not outputted from a direct current power supply and an excess voltage or a reduced voltage is outputted. The power supply protection circuit according to the present invention is constituted of a power source line 2 for supplying a direct current power, via relay contacts 3a and 3b of a relay, to a electrical equipment 15, a first circuit 10 for detecting an excess voltage and a reduced voltage, a second circuit 20, and a relay operation circuit 25. In the first circuit 10, when a first excess voltage-detecting element 14 detects an excess voltage, a first semiconductor-switching element 12 becomes unconductive, and when first excess voltage detecting element 14 does not detect an excess voltage, a first semiconductor-switching element 12 becomes conductive.

Abstract: A motherboard is protected from burning or other damage caused by installation of card of a higher voltage than that for which the motherboard is designed, such as the installation of an AGP 2× graphics card in a motherboard designed for an AGP 4× graphics card. In the AGP example, a detection circuit determines whether the installed card is an AGP 2× or an AGP 4× graphics card. First and second power controlling circuits that control delivery of the DC power to the motherboard are either opened or closed based on whether and what type of card is installed. A switch may also be provided to control the passing of DC power through the first and second power controlling circuits. An alert unit, such as a light or buzzer, may also be provided to indicate the installation of a higher voltage card.

Abstract: An apparatus for isolating electrical loads during a power supply transfer interruption event, including an electrical circuit interposed between an electrical power source and a load which has a voltage detector for continuously detecting voltage supplied to the load from the power source, comparing the detected voltage against a predetermined desired voltage and outputting a signal indicative of an out-of-limits voltage condition from the power source to the load, an interrupt switch for receiving the output from the voltage detector and interrupting the supply of power to the load during an interval of no more than 1 cycle of the power supply, and a reset switch for restoring the power supply to the load.

Abstract: A digital electric power inverter comprising: a CPU, a PWM driving circuit, a PWM converting circuit, a rectifying circuit, an AC driving circuit, a DC/AC inverting circuit, a plurality of detecting circuits and an alarm circuit, the power inverter is characterized by that: the entire circuitry thereof is designed to be controlled by the CPU that can accurately control these circuits to endue the power inverter with an intact and multi-selection protecting function, thus render the parts thereof to develop their largest effects.

Abstract: Briefly, in accordance with one embodiment of the invention, an integrated circuit includes: a stress-follower circuit configuration. The stress-follower circuit of the configuration is coupled to a pad of the integrated circuit. The stress-follower circuit configuration is coupled so as to reduce the voltage stress on the gate of a transistor in a transistor stack so that in operation the transistor in the stack tolerates an operating voltage approximately 1.5 volts above its nominal voltage. The transistor stack is also coupled to the pad.

Abstract: The present invention provides in one embodiment a method of transferring power throughout a vehicle system. Voltage measurements from a capacitor bank are received. These measurements are compared with a threshold voltage. A determination is made if the measurements are less than the threshold voltage. Instructions are transmitted to a battery to supply power to a plurality of coils of an integrated starter generator (ISG) motor. The plurality of coils are analyzed to determine if the plurality of coils are energized. Power is transmitted from the plurality of coils to the capacitor bank, if the plurality of coils are energized.

Abstract: The invention relates to an apparatus (1) for protection of electronic circuits with a decentralized power supply (PS1, PS2). One object of the invention is to avoid damage to other loads (PN1, PN2) which are still intact when a short circuit occurs in one load (PN1, PN2) in the circuit. The apparatus (1) comprises a number of loads (PN1, PN2) which are supplied in a decentralized manner. One monitoring device (PSUP1, PSUP2) in each case monitors a respective one of the load supply voltages (P1, P2) and ensures primary-side fault disconnection of all the power supplies (PS1, PS2) if a threshold value is undershot.

Abstract: The present invention reduces the capacity of the AC-DC converter for the peak load and realizes low price and reduction in the volume of the power unit. The apparatus built-in backup power supply has the peak cut function for sharing a part of the load current at the time of peak load from the secondary battery. The two-way DC-DC converter 5 and the secondary battery 4 are installed on the DC output side of the AC-DC converter 3 and a current larger than a predetermined peak cut level is discharged from the secondary battery 4 at the time of peak load. Further, when the load is less than the predetermined cut level, the secondary battery 4 is charged from the AC-DC converter 3 via the two-way DC-DC converter 5. Furthermore, a most suitable peak cut level according to the SOC of the secondary battery and load pattern is automatically set and dynamically changed.

Abstract: A combined current and voltage sensor includes: a combined sensor shell; a current sensor located in the combined sensor shell, the current sensor disposed proximate to said first load strap; and a first voltage sensor located in the combined sensor shell, the first voltage sensor disposed proximate to the first load strap. A circuit breaker includes: a first load strap in electrical communication with an electronic trip unit; a breaker in electrical communication with the electronic trip unit; a current sensor disposed at the first load strap; and a first voltage sensor disposed proximate the current sensor.

Abstract: What is described here is a power supply unit for plasma systems such as plasma processing or coating devices, wherein electric arcs or disruptive breakdown may occur, which originate from an electrode in particular, comprising a d.c. voltage or direct-current source whose output terminals are connected via an inductive resistor and a power switch to the electrodes of the plasma system, and possibly a circuit for detecting electric arcs or disruptive breakdown, that operates the switch upon occurrence of an electric arc or disruptive breakdown, in such a way that electrical energy producing a plasma will no longer be applied to the electrodes. The invention is characterised by the provisions that the inductive resistor(s) is (are) each connected to a recovery diode and that the switch is a series switch.

Abstract: Aspects of failure detection of an isolation device in a power supply of a redundant power supply system are described. The aspects include an isolation device coupled to a voltage input line of a power supply. A comparator coupled to the isolation device provides a predictive failure analysis (PFA) signal when the isolation device fails.

Abstract: A power circuit is provided so that a charge can be normally driven even during replacement of a first battery. This power circuit comprises: first and second batteries for driving a charge; a first battery voltage detection means; a first switch for controlling a second battery power supply path based on an output of the voltage detection means; an overcharge prevention means for preventing an overcharge for the secondary battery caused by the first battery; and a switch controlled by an output of the overcharge prevention means.

Abstract: A method for testing and safeguarding the availability of a networked system which is assigned to a system carrier, wherein a multiplicity of subscribers exchange data via a bus-type network which is comprised of one or more bus lines. Specific voltage levels are applied to the bus line or the lines by the appropriate subscribers. By virtue of this, as a minimum, at least individual subscribers transmit data. The bus line or the lines is/are monitored by the at least one receiving subscriber for an overshoot or undershoot of voltage levels. Due to this, the data is evaluated in at least one receiving subscriber with the aid of voltage levels. During operation of the system, signals present on the bus-type network are discriminated, tested or measured with respect to at least one signal criterion by individual subscribers under conditions defined in a network-wide manner for all subscribers.

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

Abstract: A power supply system includes: a high voltage power supply; a main power supply wire; a step down circuit inputting a power having a high voltage and outputting a power having a lowered voltage; a sub-power supply wire; a voltage sensor for sensing a voltage of the power outputted from the step down circuit; a sub-switching element disposed on the sub-power supply wire; and a controller for controlling the sub-switching element. The controller turns off the sub-switching element, when the voltage sensed with the voltage sensor is equal to or higher than a first predetermined voltage defined lower than the lowered voltage. Moreover, the controller drives the sub-switching element in duty control for stepping down the power having the high voltage to the power having the lowered voltage outputted from the step down circuit, when the voltage sensed with the voltage sensor is lower than the first predetermined voltage.

Abstract: A circuit including a power supply plane, a ground supply plane, and a signal source that generates reference voltage signals and a first signal. The signal source includes a driver adapted to generate a first signal to the receiver, the first signal having a present and a previous voltage levels. The signal source also includes a low reference voltage generator and a high reference voltage generator, each producing a low reference voltage signal and a high reference voltage signal, respectively, from a low reference output and a high reference output, respectively. The high reference output and the low reference output are coupled to the ground plane and the power supply plane, respectively. The high reference voltage generator and the low reference generator are capable of communicating the high reference voltage signal and the low reference voltage signal to the receiver.

Abstract: A device in a computer system which can prevent the chip coupled to a 4× video card expansion slot from damage and the damage is caused by plugging a 2× video card into the 4× video card expansion slot. When the type of the plugged video card is 2×, the device can lower the voltage of the electric current that inputted to the VCC3 contacts of the 4× expansion slot to below 1.65 volt and keep the chip safe. If the type of the plugged video card is 4×, the device will not change the voltage of the electric current which flows to the VCC3 contacts of the 4× expansion slot, the 4× video card can therefore normally run.

Abstract: An apparatus for decreasing speed of an inverter driven inertial load within a time period for use with a dynamic brake across a DC link including a controller for controlling the inverter to regulate the power returned to the brake such that, when a brake command is received, the power is increased during a power-up period while motor deceleration begins and up to a constant power level after which the constant power level is maintained by increasing torque such that the dynamic brake is fully used during the majority of a braking cycle and a method to accomplish the same.

Abstract: The present invention relates to an improved electrical power strip which will automatically energize and de-energize one or more devices which are plugged into the strip, upon receiving an electrical signal from the primary device, without the need for manual actuation of a switch on the electrical strip or an under monitor system by the user. This system senses the primary status of the power supply through a low voltage power tap connector which is plugged in any appropriate socket of the primary device (which may be a personal computer). The output signal triggers a synchronous transfer switch or relay which enables power to secondary devices (which may be a monitor, printer, scanner, sub woofer, modem, etc.), permitting them to be synchronously turned on or off depending on the computer system status (ON or OFF).

Abstract: A charge/discharge protection circuit with n parallel load current switches and a control logic for the latter, which in an over-voltage event disconnects the battery from the charge/discharge terminals through sequentially controlled melting of integrated fusible links, can be placed on a smaller and therefore more economical chip, if the control logic (6) in an over-voltage event, simultaneously closes all load current switches (10 [1:n]), then following sequentially opens a first number of the load current switches, and at the same time closes the switch segment (12 [1:(m−1)]) of a short-circuit switch array associated with the respective load current switch, so that the former associated fusible links (11 [1:(m−1)]) melt sequentially; after the opening of this first number of load current switches the latter closes again and at the same time the remaining number (10 [m:n]) of still closed load current switches opens, as well as continues to sequentially

Abstract: Apparatus for supplying power to communication devices operating within a Local Area Network (LAN) over LAN cabling, the communication devices including one or more powered devices adapted to receive power over the LAN cabling, the apparatus including a power supply which is adapted to receive power from an unregulated source and to provide therefrom regulated power. The apparatus further includes power distribution and control circuitry, which is adapted to identify the powered devices on the LAN, to receive the regulated power and to generate therefrom respective output voltages for supply to the powered devices. The apparatus is housed in a chassis which retains the power supply and the power distribution and control circuitry as a single module.

Abstract: The protection circuit for a power supply unit comprises a switching stage, at which at least two output voltages to be monitored are connected, these voltages being isolated from one another by means of resistors. Arranged here in the connection path of the output voltages is a diode, which turns on and thereby triggers the switching stage in the event of a fault, when there is a drop in one of the output voltages. In this way, the switching stage provides information which acts on a control loop of the power supply unit, so that the power supply unit switches off. The protection circuit also includes a passive network with a resistor and a capacitor, which prescribes a time constant, after which the protection circuit permits renewed starting of the power supply unit. The switching stage may be realized, for example, by a transistor stage, which provides the information signal for the event of a fault for the power supply unit when turning on occurs.

Abstract: The protection circuit for a switch has an energy-storage means, which is connected to a control input of the switch and which is charged with a delay via resistance means when a control voltage is present and is discharged via switching means when the control voltage is low or absent, and has a switching stage which is connected to a supply voltage, is switched on when a specific threshold voltage is present across the energy-storage means and in this way reduces the supply voltage. In one exemplary embodiment, when the switching stage is switched on, the charge which is dissipated from the supply voltage is at least partially routed to the energy-storage means via a diode which is connected in parallel with the said energy-storage means, so that the phase during which the switching stage is switched on is lengthened and the energy-storage means, in this case a capacitor, is completely discharged.

Abstract: A power source apparatus with a saving in wiring, large noise immunity and an additional function is achieved by connecting AC input bus lines (Vin+), (Vin−), DC output bus lines (Vo+), (Vo−) and a current balance signal bus line (CB) for connecting first, second, third power source units 1, 2, 3 through connectors to form a module power source and connecting an additional function unit 4 for adding a predetermined additional function to the module power source using the bus lines to this module power source through a connector.

Abstract: Switching circuits including DC:DC converters of various topologies are provided with a soft-start mechanism that ensures safe start-up operation. The mechanism causes the converter switches to be driven such that on-impedance is increased during at least a portion of the time the switches are turned on. Increased on-impedance condition is invoked during power-up, and/or no-load or light-load condition. The increased on-impedance temporarily reduces output voltage and/or drive current provided by the converter.

Abstract: An integrated circuit including a transistor having a first electrode coupled to an output bond pad and a second electrode coupled to a reference potential, such as ground bond pad. A degeneration device is coupled between the second electrode and the reference potential. A diode is coupled between the second electrode of the transistor and the reference potential with the anode of the diode coupled to the second electrode reference potential and the cathode of the diode coupled to the reference potential for an NPN transistor.

Abstract: A method for protecting an electrical device includes monitoring a line voltage to detect a high voltage condition such that the voltage is above a predetermined voltage range, and monitoring the line voltage to detect a low voltage condition such that the voltage is below the predetermined range. The method also includes electrically isolating the electrical device such that the electrical device does not receive electricity when at least one of a high voltage condition and a low voltage condition is detected.

Abstract: A lamp ballast for energizing a lamp has short circuit protection. The lamp ballast contains a transformer that provides an output voltage to the lamp. The transformer has a primary winding, a secondary winding, and a third sense winding. The third sense winding has an output that provides an indication of transformer output voltage. A reference voltage circuit creates a reference voltage that provides an indication of a non-short circuited lamp ballast condition. A comparator compares the reference voltage and the output of the third sense winding to provide an indication if the third sense winding output is below the reference. This indicates if there is a short in the output of the lamp ballast. The secondary is wound on multiple sections of a bobbin with one section being a low voltage section. The sense winding is wound under the secondary in the bobbin secondary low voltage section.