Abstract: A protection circuit includes a switch circuit, a sample circuit, a comparison circuit, and a relay circuit. The switch circuit is connected between a hard disk power supply and a hard disk to control whether to output power from the hard disk power supply to the hard disk. The sample circuit samples the voltage being supplied to the hard disk, the comparison circuit receives the sampled voltage, compares the sampled voltage to a reference voltage, and controls the switch circuit to be turned on or off accordingly. The relay circuit is connected between a system power supply and an enable terminal of the comparison circuit. The relay circuit outputs a high level signal to turn on the switch circuit when the system power supply is being supplied and the hard disk power supply is not being supplied to the hard disk.

Abstract: During charging of a cell module in which a plurality of cells are connected in series, a voltage is applied in forward polarity to a switch element even when a current interrupting switch provided to the cell module is open, thereby shorting an anti-fuse element, and the switch element is thereby opened.

Abstract: Methods, systems, and apparatus for determining whether an accessory includes particular circuitry. A host device may measure a first voltage and a second voltage received from an accessory, where the voltages are provide through the accessory from a power source. Before measuring the second voltage, the host device may send an instruction to the accessory instructing the accessory to alter an impedance of the power path between the power source and the host device, and the host device may draw at least a threshold amount of current from the power source via the accessory. The host device may then determine whether the accessory includes particular circuitry based on the relationship between the first voltage and the second voltage.

Abstract: A semiconductor device may be protected from over-voltages via a comparator-controlled, high-current FET coupled to the semiconductor device output and between circuit devices that carry high voltages. A three-terminal, N-channel field effect transistor (FET) may have its source coupled to the output of the semiconductor device to be protected from over voltage. The FET drain may be connected to the load to be driven by the semiconductor device. A transistor, or other voltage comparator, may be configured and connected in order to compare the voltage on the FET drain to a Vmax reference voltage. When a voltage on the FET drain exceeds Vmax, the comparator output may shut down the FET, thereby isolating the semiconductor device, which is connected to the FET source, from the overvoltage on the FET drain.

Abstract: This document discusses methods and apparatus for preventing or reducing sub-threshold pass gate leakage. In an example, an apparatus can include a pass gate configured to electrically couple a first node with a second node in a first state and to electrically isolate the first node from the second node in a second state, control logic configured to control the pass gate, wherein the control logic includes a supply rail, and an over-voltage circuit configured to compare voltages received at a plurality of input nodes and to couple an output to an input node a highest voltage. In an example, the output of over-voltage circuit can be selectively coupled to the supply rail.

Abstract: A protection circuit that is used with a power supply that produces charging power, and a storage battery for which normal operation is conditional upon a terminal voltage being less than or equal to a maximum voltage, including: a first switch disposed to a first path that electrically connects the storage battery and the power supply; a second path that electrically connects the storage battery and a load; a voltage detection circuit that detects a terminal voltage of the storage battery; an over-charge detection circuit that monitors the storage battery terminal voltage and controls the first switch to turn off when the terminal voltage is detected to exceed the maximum voltage; and a control circuit that controls the monitoring operation interval of the over-charge detection circuit according to the terminal voltage of the storage battery detected by the voltage detection circuit.

Abstract: A circuit for protecting an electric load from overvoltages has an n-channel MOSFET (metal oxide semiconductor field-effect transistor) (T1) and a means for producing a reference voltage in order to achieve the most effective overvoltage protection possible by means of the cheapest and most compact circuit possible, wherein the means for producing a reference voltage is connected to the gate of the MOSFET (T1), wherein a supply voltage is applied to the circuit on the input side and wherein the gate is supplied with a voltage greater than the supply voltage using an auxiliary voltage source in such a way that the MOSFET (T1) is turned on.

Abstract: An electronic device may include a connector port that accommodates reversible connector plugs. The connector port may include protection circuitry that protects other components in the electronic device from undesired power supply voltages. The protection circuitry may form a first branch and a second branch opposite to the first branch. The protection circuitry may receive control signals from power polarity detection circuitry. The power polarity detection circuitry may detect the presence of power supply voltages at the first branch and the second branch. In response to detecting the presence of a power supply voltage at a given branch, the power polarity detection circuitry may disable a power supply signal path through the opposite branch and enable a power supply signal path through the given branch.

Abstract: A switched mode power supply includes a transformer and an integrated circuit regulator. The integrated circuit regulator is coupled to the transformer and includes switching regulator logic, a counter, and a switching transistor. The regulator logic generates a switching signal in response to the feedback signal. The counter receives the feedback signal, where the feedback signal periodically cycles between a first state and a second state when the switched mode power supply operates normally. An output of the counter indicates an auto-restart mode of the regulator in response to the feedback signal remaining in the first state for a predetermined count due to a fault condition. The switching transistor is coupled to be turned on and off in response to the switching signal when the output of the counter does not indicate the auto-restart mode and is disabled when the output of the counter indicates the auto-restart mode.

Abstract: An arrangement for controllably disconnecting a utility power service from a load includes a utility meter housing, a switch and a processing circuit. The utility meter housing includes metrology circuitry configured to generate metering information regarding electrical power provided to the load. The switch is configured to controllably interrupt a connection between the utility power service and the load. The switch has an open state and a closed state. The processing circuit is configured to determine whether a line voltage varies from an expected value by more than a predetermined amount over a predetermined amount of time. The processing circuit is further configured to cause a change in state of the switch based on the determination.

Abstract: Provided is a protective semiconductor device detecting a disconnection reliably with secondary cells including for each cell: cell-connecting terminals; a first resistance detecting the voltage of each cell; a comparator detecting whether or not the voltage of each cell is in the reference voltage range; a series circuit composed of a second resistance and a first switch element, and including a control circuit controlling ON/OFF of the switch element, wherein the first switch element connects the second resistance to the connecting terminals by turning ON, while disconnecting it by turning OFF, the control circuit maintains a disconnection test signal ON, while turning ON the plurality of first switch elements sequentially and detecting the disconnection between the cells and the connecting terminals based on the output signal from the comparator corresponding to the first switch element turned ON.

Abstract: An integrated circuit device comprising at least one analogue to digital converter. The at least one ADC comprises at least one input operably coupled to at least one external contact of the integrated circuit device. The integrated circuit device further comprises detection circuitry comprising at least one detection module. The at least one detection module being arranged to receive at a first input thereof an indication of a voltage level at the at least one input of the at least one ADC, compare the received indication to a threshold value, and if the received indication exceeds the threshold value, output an indication that an excessive voltage state at the at least one input of the at least one ADC has been detected.

Abstract: A voltage balancing unit for a symmetric monopole high voltage direct current (HVDC) transmission line interconnecting two voltage source converters (VSCs), the transmission line including first arresters having a first switching impulse protective level (SIPL) is provided. The voltage balancing unit includes a pair of second arresters having a second SIPL which is less than the first SIPL, and a switching device being arranged for temporarily connecting, in the event of a voltage unbalance on the transmission line, the first arresters between either pole and ground. A voltage unbalance on the transmission line may be removed by temporarily connecting second arresters, with a significantly lower SIPL than the first arresters, for limiting the pole voltage to a level close to the normal voltage. Further, a method of voltage balancing is provided. Voltage unbalances may arise as a consequence of lightning induced earth faults.

Abstract: A protection method is executed by an electronic device that is powered by a supply voltage of a power source. The protection method includes steps of: storing a power-off threshold voltage; detecting the supply voltage of the power source to generate a detecting voltage; determining whether the detecting voltage is equal to the power-off threshold voltage; beginning to count for a predetermined period of time when the detecting voltage is equal to the power-off threshold voltage and acquiring the detecting voltage during the predetermined period of time; determining whether each acquired detecting voltage is smaller than the power-off threshold voltage; and generating a first control signal when one of the acquired detecting voltages is larger than or is equal to the power-off threshold voltage; wherein the first control signal controls a processor of the electronic device to stop performing a power-off procedure.

Abstract: The invention relates to a multi-staged overvoltage protection circuit, in particular for information-technology systems, comprising at least one coarse protection element and at least one fine protection element, wherein the at least one fine protection element can be activated by a triggering device depending on a threshold. According to the invention, the applied operating voltage is led to an evaluation device, which generates a reference voltage. Also provided is an evaluation unit, firstly for checking to see whether the current operating voltage is above the reference voltage, secondly for checking to see whether the voltage excess exceeds a previously determined level, and thirdly for establishing whether the rate of change of the operating voltage is greater than another previously determined value so that a transient overvoltage exists, wherein the triggering device then receives an activation signal from the evaluation device.

Abstract: Systems and methods of diagnosing a condition of a reverse-voltage protection switch in an electric system. The electric system includes a power source, an electric load, and a reverse-voltage protection switch in a series-type configuration. The electric system further includes a ground switch configured to selectively connect the source terminal of the reverse-voltage protection circuit to ground. The terminals of the reverse-voltage protection circuit are disconnected from the power source. The ground switch is closed to connect one terminal of the reverse-voltage protection switch to ground. A bias voltage is applied to the other terminal of the reverse-voltage protection switch and the reverse-voltage protection switch is opened. An improper short-circuit condition across the reverse-voltage protection switch is detected when the voltage at the biased terminal of the reverse-voltage protection switch is less than a threshold when the reverse-voltage protection switch is opened.

Abstract: There are disclosed a method and apparatus for detecting a fault of a battery pack and a power relay assembly. An apparatus for detecting a fault of a battery pack including a plurality of cells includes a pack voltage measurement unit for measuring a voltage of the battery pack, a cell voltage measurement unit for measuring a plurality of cell voltage for the plurality of cells, and a control unit for determining whether there is a fault at the battery pack based on the voltage of the battery pack and the plurality of cell voltages. A battery pack and a load connected to the battery pack can be protected by detecting whether there is a fault at the battery.

Abstract: A disclosed battery protecting circuit for protecting a secondary battery including at least first and second cells connected in series includes a first terminal connected on a high potential side of the first cell; a second terminal connected on a low potential side of the first cell and a high potential side of the second cell; a third terminal connected on a low potential side of the second cell; a charge abnormality detecting circuit detecting abnormality of the charged state of the secondary battery; a shifting circuit shifting electric potential of the second terminal on a side of the first terminal or a third terminal when a disconnection occurs between the secondary battery and the second terminal; a disconnection detecting circuit detecting the disconnection based on the electric potential of the second terminal; and a latching circuit retaining a result detected by the disconnection detecting circuit.

Abstract: The disclosure relates to a process of configuring a standalone self-supplied numeric controlled relay for providing phase and earth over current protection to electrical systems by accurate current measurement. The arrangement for current measurement with control algorithms is provided for power control by providing amplified and conditioned current for optimization between the current to power an electronic circuit and the fidelity of a measured current waveform so that they both are at the acceptable levels at the same time. This disclosure describes the current sensing and associated algorithm for power control in a truly self-powered relay.

Abstract: In some embodiments, an overcurrent protection circuit is configured to operate in accordance with operation modes including a first operation mode in which when the power supply circuit is activated, the capacitor is charged until the terminal voltage reaches a first voltage, a second operation mode in which depending on a time period in which a current flowing through an output transistor of the power supply circuit exceeds a predetermined value, the capacitor is charged so that the terminal voltage increases from the first voltage toward a second voltage, and the power supply circuit is shut down when the terminal voltage reaches the second voltage, and a third operation mode in which when the power supply circuit is shut down, the capacitor is discharged until the terminal voltage reaches a third voltage, and the shutdown of the power supply circuit is released when the terminal voltage reaches the third voltage.

Abstract: Provided is an over-voltage protection device for a resonant wireless power transmission device. The over-voltage protection device includes an amplifier for amplifying a transmission signal, a resonance signal generator for generating a wireless resonance signal according to the transmission signal amplified by the amplifier, a voltage detector for sensing a voltage of the wireless resonance signal generated by the resonance signal generator, and a controller for monitoring the voltage detected by the voltage detector to determine whether the voltage repetitively increases and decreases with periodicity when the voltage is greater than a reference voltage and controlling the amplifier to decrease an output of the transmission device by a value according to a result of the determination.

Abstract: A battery pack including a battery and a battery protection circuit is disclosed. In one aspect, the battery protection circuit comprises a protective device configured to inhibit a flow of current between an electrode of the circuit and the battery when activated. The battery protection circuit further comprises a primary protection circuit and a secondary protection circuit. The primary protection circuit is configured to generate a control signal for control the protective device when detecting an abnormal voltage in a unit cell of the battery. The secondary protection circuit is configured to activate the protective device, either when receiving the control signal from the primary protection circuit or when detecting an abnormal voltage in a unit cell of the battery.

Abstract: A protective circuit for an arrangement includes a multiplicity of individual cells in a rechargeable battery pack. A predefined number of individual cells are connected in series in a cell row and at least two cell rows are mutually parallel, and at least one cell connector situated between the individual cells at a location of one cell row is electrically connected via a compensation line to the cell connector situated at an identical location of the parallel cell row, and the potential of the cell connector connected to the compensation line at one location of one cell row and the potential of the cell connector electrically connected to the compensation line at the same location of the parallel cell row are detected and the detected potentials are fed to an evaluation unit.

Abstract: A data cable between two electronic devices includes a first interface comprising a first metal shell and a ground end; and a second interface connected to another electronic device comprising a second metal shell, a ground end and an identification end. The data cable includes a detection circuit detecting voltage difference between the first metal shell and the ground end, and the detection circuit comprises an output end connected to the identification end of the second interface. An electronic device using the data cable detects any current leakage in an external electronic device. When the host has current leakage, the electronic device cuts power from the host and prevents data exchange, preventing damage or loss.

Abstract: A current sensor includes a magnetic balance sensor and a switching circuit. The magnetic balance sensor includes a feedback coil which is disposed near a magnetic sensor element varying in characteristics due to application of an induction field caused by measurement current and which produces a canceling magnetic field canceling the induction field. The switching circuit switches between magnetic proportional detection and magnetic balance detection. The magnetic proportional detection is configured to output a voltage difference as a sensor output. The magnetic balance detection is configured to output, as a sensor output, a value corresponding to current flowing through the feedback coil when a balanced state in which the induction field and the canceling magnetic field cancel each other out is reached after the feedback coil is energized by the voltage difference.

Abstract: The power source apparatus enables each battery pack to be charged with power supplied from an external charging power supply, and allows power stored in each battery pack to be output externally. Each battery pack is provided with battery pack fault output terminals to send battery pack error signals to other battery packs or to the protection unit when a malfunction occurs. The protection unit is provided with protection unit input-output terminals to connect with battery pack fault output terminals, and a protection circuit capable of cutting-off battery pack current. When a battery pack malfunction occurs, a battery pack error signal is output from the battery pack fault output terminals to the protection unit input-output terminals. When the protection unit detects a battery pack error signal, the protection circuit cuts-off current.

Abstract: Provided is a power supply integrated circuit including an overheat protection circuit with high detection accuracy. The overheat protection circuit includes: a current generation circuit including: a first metal oxide semiconductor (MOS) transistor including a gate terminal and a drain terminal that are connected to each other, the first MOS transistor operating in a weak inversion region; a second MOS transistor including a gate terminal connected to the gate terminal of the first MOS transistor, the second MOS transistor having the same conductivity type as the first MOS transistor and operating in a weak inversion region; and a first resistive element connected to a source terminal of the second MOS transistor; and a comparator for comparing a reference voltage having positive temperature characteristics and a temperature voltage having negative temperature characteristics, which are obtained based on a current generated by the current generation circuit.

Abstract: A protection circuit that protects a load charged by a power supply. The protection circuit includes a reference voltage set circuit, a sampling circuit, a switch, and a comparator. The reference voltage set circuit provides a reference voltage. The sampling circuit is electrically connected to the power supply and provides a sampling voltage based on a charge voltage output from the power supply to the load. The switch is electrically connected between the power supply and the load. The comparator includes a non-inverting input terminal electrically connected to the reference voltage set circuit, an inverting input terminal electrically connected to the sampling circuit, and an output terminal electrically connected to the switch. The comparator compares the sampling voltage with the reference voltage, and controls the switch to turn on or off according to the comparison.

Abstract: A switching mode power supply (SMPS) including a surge protection unit that is connected to a protection pin of a pulse width modulation (PWM) controller to cut off a power supply of the SMPS when a voltage that is applied to the protection pin exceeds a predetermined threshold voltage, where the surge protection unit blocks an external surge voltage lower than a surge protection capacity of the surge protection unit for blocking a surge voltage input from outside thereof, and, when the output voltage of the SMPS is not within the predetermined range, the surge protection unit applies a voltage obtained by subtracting the surge protection capacity of the surge protection unit from a predetermined feedback voltage output from a feedback unit to the protection pin, and where the surge protection capacity is set higher than the predetermined threshold voltage of the protection pin.

Abstract: Apparatuses and methods for protecting electronic circuits are disclosed. In one embodiment, an apparatus for providing protection from transient signals comprises an integrated circuit, a pad on a surface of the integrated circuit, and a configurable protection circuit within the integrated circuit. The configurable protection circuit is electrically connected to the pad. The configurable protection circuit comprises a plurality of subcircuits arranged in a cascade, and selection of one or more of the plurality of the subcircuits for operation determines at least one of a holding voltage or a trigger voltage of the configurable protection circuit.

Abstract: A protection circuit includes a switch circuit, a sample circuit, a comparison circuit, and a relay circuit. The switch circuit is connected between a hard disk power supply and a hard disk to control whether to output power from the hard disk power supply to the hard disk. The sample circuit samples the voltage being supplied to the hard disk, the comparison circuit receives the sampled voltage, compares the sampled voltage to a reference voltage, and controls the switch circuit to be turned on or off accordingly. The relay circuit is connected between a system power supply and an enable terminal of the comparison circuit. The relay circuit outputs a high level signal to turn on the switch circuit when the system power supply is being supplied and the hard disk power supply is not being supplied to the hard disk.

Abstract: A device and method for detecting a short circuit in an electrical component during a start-up routine. In an embodiment, a device may have a problematic display having a short circuit that may result in damage to other components of the device if the device were allowed to fully startup during a normal start-up routine. Thus, power supplied to the panel may be initiated in stages so as to monitor any current that may be flowing through the panel, which in turn, may be indicative of a short circuit in the panel. If enough “leakage” current is detected through the panel during this staged startup routine, then a short-circuit detection circuit may interrupt the startup routine and lock out the operation of the device until the detected short circuit in the panel can be addressed.

Abstract: A temperature detection method for a semiconductor device and a power conversion apparatus are disclosed. A temperature detection device is used to detect the temperature for thermal protection of a power semiconductor device. The temperature detection device is placed in the proximity of a component having the power semiconductor device packaged therein, and either an emitter terminal or a collector terminal of the power semiconductor device. Since the temperature detection device is mounted on a circuit board, it does not require insulation from a cooling fin on which the power semiconductor device is mounted and lead wires can be eliminated.

Abstract: A method for detecting the state of a load device which can be connected to a switching connection, wherein the switching connection can be coupled to, and decoupled from, a predefined switching potential. A voltage drop across the switching connection is used as a basis for detecting whether the load device is connected to the switching connection, the load device is not connected to the switching connection or there is a short circuit between the switching connection and a first or a second switching potential. An additional current source is connected to the switching connection at the same time as the switching connection is decoupled from the predefined switching potential.

Abstract: An overvoltage protection circuit protects a portable electronic device against overvoltage. The overvoltage protection circuit includes an input unit for receiving an input voltage supplied by a voltage source; a voltage-divider module for dividing the input voltage and outputting a divided voltage; a voltage-regulator module for comparing a comparison voltage with the divided voltage and generating a first control signal; a first switch unit being controllably switched by the first control signal to a short-circuit state or an open-circuit state and generating a second control signal; and a second switch unit being controllably switched by the second control signal to a circuit state reverse to that of the first switch unit, and stopping supplying the input voltage to the portable electronic device when the input voltage is no less than a rated voltage of the portable electronic device. Therefore, a temperature-independent overvoltage protection can be achieved.

Abstract: An overvoltage protection circuit and a portable electronic device having the same are introduced. The overvoltage protection circuit provides overvoltage protection when an input voltage exceeds a rated voltage tolerable by an internal circuit unit in the portable electronic device. A reference voltage and a partial voltage are generated from the input voltage through a voltage limiting unit and voltage dividing module, respectively, and conveyed to a comparing module for comparison. Comparison of the reference voltage and the partial voltage is followed by generation of a switch signal whereby a switch unit determines whether to apply the input voltage to the internal circuit unit. The voltage dividing module sets the maximum rated voltage tolerable by the internal circuit unit and enables the overvoltage protection circuit to give overvoltage protection to the portable electronic device regardless of temperature.

Abstract: An isolated type power supply includes a transformer, and a power switch and a current sense resistor serially connected to a primary coil of the transformer, and a protection apparatus and method monitor a control signal which is used to switch the power switch in normal operation, and trigger a signal to stop the power from switching when the control signal becomes greater than a threshold. This protection apparatus and method can more quickly detect short circuit of the current sense resistor, and prevent the isolated type power supply from overcurrent impact.

Abstract: Disclosed herein is a wireless power transmission system, including: a transmission unit generating and transmitting power for charging a battery; a reception unit receiving the transmitted power and charging the battery with power; and a transmission control unit detecting a charging status of the battery by using the transmitted power, and, if the charging status of the battery is in a damage section due to reflective power, controlling the transmission unit to transmit power lower than power of a normal operation, whereby damage of transmission and reception devices due to a reflective wave can be minimized.

Abstract: An electronic system is disclosed, which includes a connector unit to communicate data with a host system, an electronic circuit to store the data, and a switch to convey the data to and from the electronic circuit via the connector unit. The switch includes a negative voltage protection unit coupled to the connector unit, and a transistor switch coupled to the negative voltage protection unit, the connector unit, and the electronic circuit. The negative voltage protection unit forces the transistor switch off if a negative voltage is detected.

Abstract: A method of detecting the presence of an unsafe line condition at a power metering device is disclosed. The method comprises the steps of determining if a disconnect switch is in the open position, and measuring a first voltage at a first load contact. The method measures a second voltage at a second load contact and determines if the first voltage is greater than a first voltage threshold or less than a second voltage threshold. The method further determines if the second voltage is greater than the first voltage threshold or less than the second voltage threshold. The method indicates that an unsafe condition exists if either the first voltage is greater than the first voltage threshold, or first voltage is less than the second voltage threshold or the second voltage is greater than the first voltage threshold or the second voltage is less than the second voltage threshold, when the disconnect switch is in the open position.

Abstract: An arc fault detector comprises a current transformer (CT) having a primary winding and a secondary winding (W1), the primary winding being formed by at least one conductor (L) of an AC or DC supply circuit. The inductance of the CT is selected so that the CT has a lower frequency operating point (LFOP) of at least 10 KHz. The detector also comprises circuitry (10, 12, SW) for disconnecting the supply if the voltage induced in the secondary winding meets predetermined criteria as to magnitude and duration.

Abstract: A battery system includes a battery and a battery protection apparatus. The battery protection apparatus protects the battery from over-discharge. The battery protection apparatus includes a voltage controlled switch, a start switch, and a voltage detecting unit. The voltage controlled switch establishes an electrical connection between the battery and the load. The start switch turns on the voltage controlled switch when actuated. The voltage detecting unit detects a battery voltage of the battery and generates a detecting voltage according to the battery voltage. The voltage controlled switch is turned off when the detecting voltage is lower than a predetermined value.

Abstract: A power supply circuit includes an energy-consuming component including an input terminal, an input over-voltage protection circuit connected to the input terminal, and a feed back circuit. The feedback circuit is connected to the input over-voltage protection circuit and the input terminal of the energy-consuming component. The feedback circuit monitors the voltage on the input terminal, compares the voltage on the input terminal with a reference voltage, and turns off the input over-voltage protection circuit to cut off voltage provided to the input terminal of the energy-consuming component when the voltage on the input terminal is larger than the reference voltage.

Abstract: A protective monitoring circuit includes a protective circuit to detect at least one of overcharging, overdischarging, and overcurrent of a chargeable secondary battery to control whether to turn on or off a control transistor to protect the secondary battery, and a secondary-battery monitoring circuit, having a reduced size and having a breakdown voltage lower than a battery voltage of the secondary battery, to detect a status of the secondary battery, wherein the protective circuit generates a voltage that is commensurate with an output voltage of the secondary battery and that is within a predetermined tolerance voltage range of the secondary-battery monitoring circuit, and the secondary-battery monitoring circuit generates a detection value responsive to the generated voltage supplied from the protective circuit, the detection value being indicative of the output voltage of the secondary battery.

Abstract: A protection circuit includes an electronic switch and a comparator. The comparator includes a positive input connected to a first power supply, a negative input connected to an output power supply, and an output connected to a first terminal of the electronic switch through a first resistor. A second terminal of the electronic switch is connected to a device. A third terminal of the electronic switch is connected to the output power supply. When a voltage on the positive input is greater than a voltage on the negative input, the comparator outputs a high level signal to turn on the electronic switch, the output power supply powers the device. When the voltage on the positive input is less than the voltage on the negative input, the comparator outputs a low level signal to turn off the electronic switch, the output power supply does not power the device.

Abstract: An overvoltage protecting unit and an overcurrent protecting unit protect a power device from an overvoltage and an overcurrent using a comparator having hysteresis. An overtemperature protecting unit protects the power device from an overtemperature using a thermistor having a resistance that changes as a temperature of the thermistor changes.

Abstract: A service line safety monitor which may be configured as a separate module or incorporated into an EVSE is adapted to monitor the connection with the service line to determine whether there is a defect in the connection. The module preferably employs a current transformer to determine a no-load and a load applied to the EVSE. Comparisons are made to determine whether there is a power loss. In the event of a power loss beyond a safe limit, the monitor disconnects the EVSE from the service line. A warning indicator is also employed.

Abstract: The aim of the invention is to reduce the frequency change of a electric network in fault situations so that there is no need for protection operations during relatively short imbalances between electricity production and demand thereof. The aim is achieved by means of an apparatus, system and method for electric power supply according to main claims for directing electric power to the electric motor (7). The apparatus according to the invention monitors the frequency of the network (1). In case the frequency of the network changes sufficiently, the apparatus reacts by changing the amount of electric power directed to the electric motor (7). The electric supply network (1) is provided with an opportunity to change the amount of produced electric energy in a controlled way so that the electric supply network is continuously in operation.

Abstract: An electric connection box 10 comprises an FET 32 for connection with a power supply B, a substrate side conduction path 18 connected with the FET 32 and connecting the FET 32 with a load L, a diode element D connected with the substrate side conduction path 18 electrically and to transfer heat and having a PN junction, and a CPU 19 for judging whether the voltage drop value between the input/output terminals 25 and 26 of the diode element D is larger than a threshold or not and delivering an off-command signal to the FET 32 if a judgment is made that the voltage drop value is smaller than the threshold.

Abstract: A bidirectional switch device, has: a bidirectional switch having a HEMT; and a control circuit which, during a first condition, applies a first voltage lower than a threshold voltage across a gate and one terminal among a source and a drain of the HEMT to turn off a first current path from the other terminal among the source and the drain to the one terminal, and during a second condition, applies a second voltage lower than the threshold voltage across the other terminal and the gate to turn off a second current path from the one terminal to the other terminal, and further during a third condition, applies a third voltage higher than the threshold voltage across the source and the gate and across the drain and the gate of the HEMT to turn on the first and second current paths.