Abstract: Switching contacts of a switching device are provided to ensure optimum service life. An optimum switching point, in terms of the load of one of the switching contacts, is determined depending on a current path that is measured during the switching process and the switching point is shifted by a delay time from switching operation to switching operation. The optimal switching point is preferably determined by self-calibration of the switching device.

Abstract: Terminals (11, 13) for electrical connection respectively have front end portions (11b, 13b) to be joined to a wiring board (20) with solder and base end portions (11a, 13a) drawn outside from a cover (7) made of heat-expanding material. In order for the base end portions to absorb stress countering the external force received from the cover subjected to thermal expansion due to the heat generated by an electromagnetic coil (5) by the deflection deformation of the intermediate portions (11c, 13c) of the terminals positioned closer to the cover than the wiring board 20 with the relay device mounted on the wiring board, the terminals are formed with a predetermined length of L? in the extending direction of the terminals so that the length required for necessary flexibility is secured for the intermediate portions.

Abstract: An overcurrent limitation circuit for use in a direct current stabilization electric power supply circuit controls and drives an output transistor to output a constant voltage in accordance with a difference between a reference voltage and a voltage proportional to the output voltage. The overcurrent limitation circuit includes a proportional output current generating device for generating a current proportional to a current flowing through the output transistor, a current/voltage-converting device for converting an output current flowing from the proportional output current generating device into a voltage, and a switching device configured to supply the current/voltage converting device with the output current from the proportional output current generating device when the output voltage is higher than a prescribed level, and interrupts the supplying when the output voltage is lower than the prescribed level.

Abstract: In one embodiment, an overvoltage protection circuit is disclosed for decoupling a voltage source available at a Subscriber Line Interface circuit (SLIC) from a subscriber loop line conductor when the voltage source is shorted to the conductor in a non-ringing condition. In another embodiment, a multi-point protection apparatus is provided for protecting a SLIC against transients having different levels.

Abstract: An ESD protection circuit with whole-chip ESD protection. A plurality of ESD protection devices, apart from an ESD detection circuit, can be MOS transistors connected between the input/output pads and the VDD/VSS lines or a power rail clamp circuit between the VDD and VSS lines. The ESD detection circuit is connected between the VDD and VSS lines. When an ESD event occurs and an ESD current is bypassed to the power line, the ESD detection circuit generates a plurality of enabling signals to simultaneously enable the ESD protection devices, which provides a plurality of discharge paths to bypass the ESD current.

Abstract: An apparatus and method for providing electrostatic discharge protection. An exemplary micro tube spark gap type electrostatic discharge protection device comprises first and second separated spark electrodes hat form a spark gap therebetween. A high frequency noncoupled starter circuit is provided that comprises first and second high voltage electrodes disposed adjacent to the spark gap, and coupled to a high frequency voltage source. The high frequency voltage source generates a high frequency voltage that passes from the high voltage electrodes through the spark gap. The high frequency voltage (electric field) supplied by the voltage source falls just short of ionizing the gap, but provides energy to start a discharge. Once ionization occurs, the high frequency voltage is shut off, allowing for maximal energy loss. This results in a voltage versus time characteristic having a decreased ionization voltage and an increased power loss level after the high frequency voltage shuts off.

Abstract: A method of protecting a section of a three phase power line uses superimposed current components in the power line to enable a local relay to detect operation of remote circuit breakers of remote relays in response to a fault on at least one phase of the power line. Line signal transducers output line condition signals indicative of voltage and/or current in the line near the circuit breaker, and a signal processor in the local relay processes the line condition signals to selectively produce a fault signal for opening its circuit breaker after taking account of remote circuit breaker operation.

Abstract: An on-chip thermal sensing circuit is disclosed. The thermal sensing circuit including a detection circuit located on an integrated circuit (IC) for detecting a local temperature of the IC. The output of the thermal sensor has a frequency that is directly related to the local temperature. The detection circuit has an associated time constant that is used to produce the frequency.

Abstract: Metal oxide varistors (MOVs) are employed in surge protection devices, such as overvoltage protection devices, between signal lines and ground to reduce the capacitance and the capacitive imbalance introduced by the overvoltage protector, thereby improving higher frequency transmissions, such as xDSL communications, over a twisted-pair telecommunications network. The MOVs can be stacked electrically in series to reduce the capacitance of each MOV and to reduce the variability, tolerance or spread of the capacitance between MOVs. Asymmetrical MOVs with electrodes having different surface areas can also be used to reduce capacitance and to reduce capacitive imbalance between MOVs. Furthermore, Asymmetrical MOVs, as well as MOVs with electrodes having the same surface area, can be stacked electrically in series. Such series stacked, asymmetrical, and series stacked asymmetrical MOVs can be used in parallel with a gas discharge tube to form, for example, a station protector for use at a customer premises.

Abstract: The inventive spark arrester comprises an odd number of series-connected spark units forming a chain, with each spark units comprising at least one discharge gap. In order to increase the reliability of protection of electric installation components having a flat voltage—time characteristic by ensuring a low discharge level and a fast response of the arrester, the output of each even spark unit is connected via a resistor to a clamp connecting the arrester to the protected components subjected to a high potential, while the output of each odd spark unit, except the last one, is connected via another resistor to another clamp connecting the arrester to the protected components subjected to a low potential. Preferred embodiments of the arrester promote a generation of a long surface discharge along a surface of tubular body made of a solid dielectric, said body being common for all spark units constituting the arrester.

Abstract: Protection circuitry (100) for protecting an integrated circuit against an ESD pulse is provided. The protection circuitry (100) includes a discharge circuitry (101) on a substrate (106) that discharges an ESD pulse to the integrated circuit to ground (104a). The protection circuitry (100) also includes a drive circuitry (102) that uses a portion of the ESD pulse voltage to bias the substrate (106) using a first guard ring (110) in the substrate (106), which surrounds the discharge circuitry (101) and drive circuitry (102). The protection circuitry (100) further includes a second guard ring (120) in substrate (106), which surrounds the first guard ring (110) and connects to Vss/ground potential (104c), thereby providing uniformity of the substrate bias.

Abstract: A current detection circuit applicable to a switching circuit using switching transistors to supply a prescribed load current to a load, comprises a sample-hold capacitor for temporarily holding a terminal voltage of the switching transistor that is turned on, and a switch that is inserted between the switching transistor and sample-hold capacitor and is controlled to be turned on in synchronization with the ON-timing of the switching transistor, wherein charged voltage of the sample-hold capacitor is detected as a detection voltage. An overcurrent detection circuit is constituted in such a way that the switching transistor is compulsorily turned off when the detection voltage exceeds reference voltage. The switching circuit may correspond to a pulse-width modulation (PWM) amplifier using a pair of a PMOS transistor and an NMOS transistor that are alternately turned on or off.

Abstract: A surge counter/detector apparatus includes current sensors communicating with power lines to sense a surge condition. A trigger circuit communicates with the current sensors and outputs a first signal in response to the sensed surge condition. The trigger circuit is reset and enabled by a second signal in order to enable subsequent output of the first signal. A processor detects the first signal from the trigger circuit and responsively increments and displays a count value at a display. The processor provides the second signal having a first state to reset the trigger circuit and a second state to enable the trigger circuit. The processor includes a timer to vary a time between (a) detecting the first signal, and (b) resetting and enabling the trigger circuit.

Abstract: An apparatus for sensing and measuring the HV surge arrester current includes two toroidal current transformers arranged coaxially with respect to the earth wire of the surge arrester, elements for sensing the current signals emitted by the transformers and for converting the current signals in digital signals, and elements for transmitting the digital signals to an information network and analog state signals by relay activation. The two toroidal current instrument transformers are associated, respectively, one to elements for sensing the normal leakage current, and the other to elements for sensing the impulsive current, the latter comprising a circuit (TRIGGER) discriminating between “switching” and “lightning” signals, in which the basis for discrimination is a signal duration threshold, of about 35 ?s.

Abstract: A fault detector sensor includes a current transformer, with two multi-turn windings each formed around a portion of the core, with one winding adjacent to each of the hot and neutral wires of the power line being protected. Both windings are connected in series in a way which reinforces arc fault noise generated by arc faults involving the line and neutral, but which causes signal reduction for noise signals from the line and neutral, or either, to ground. The windings and core are selected to self resonate at a frequency that excludes power line carrier frequencies but which includes arc fault frequencies. The core optionally has a third winding, forming a grounded neutral transformer, or ground fault detector. Instead of a third winding, one of the arc fault sensing windings can act as a dual function sensor.

Abstract: A trip unit for a circuit interrupter includes a power supply, a plurality of input terminals and a plurality of output terminals. A heater conductor is electrically connected between each pair of the input and output terminals. The heater conductor is adapted to generate heat responsive to current flowing through the conductor. A diode is disposed proximate each of the conductors for heating thereby. The diodes are electrically interconnected with the power supply and are adapted to provide a forward voltage representative of the temperature of the corresponding conductor. Another diode is electrically interconnected with the power supply and is adapted to provide a forward voltage representative of ambient temperature. A thermal trip circuit generates a trip signal for the circuit interrupter responsive to the forward voltage of the diodes.

Abstract: The circuit of the invention provides protection for both a spur circuit and the network while allowing other spurs on the network to continue operation and is applicable to any type of fieldbus network including both FF and ASi type networks. A control circuit monitors a current limiter coupled to each spur circuit. If the spur circuit goes into an overcurrent condition for a preset period of time, the control circuit turns it off. After a second period of time has elapsed, the control circuit turns the current limiter back on permitting current to flow in the spur once again while continuing to monitor the current limiter.

Abstract: An apparatus for power source protection with automatic latch-off is provided for use in an electronic apparatus. The electronic apparatus includes a power supply and a main functional circuit, such as a notebook computer. The power supply is coupled to the main functional circuit via an electronic switching device, so as to power the main functional circuit via a power source terminal of the electronic switching device. The apparatus for power source protection with automatic latch-off includes a low-voltage-triggered latch-off device and a low-voltage-triggered responding device. The low-voltage-triggered latch-off device is coupled to the electronic switching device, so as to control the on or off state of the electronic switching device. The low-voltage-triggered responding device is coupled to the power source terminal and the low-voltage-triggered latch-off device.

Abstract: Briefly, in accordance with one embodiment of the invention, an integrated circuit comprises a charge protection device that is reverse body biased when the integrated circuit is in normal operation.

Abstract: A thyristor provides overcurrent protection to a low impedance load, such as a transformer, by adding a resistance in series with the transformer winding. As overcurrents attempt to pass through the transformer winding, a sufficient voltage is generated in the transformer so that a thyristor connected thereacross is triggered into conduction. A resistance formed between the thyristor gate and cathode establishes the threshold of current that can pass through the transformer winding before the thyristor is triggered. When triggered into conduction, the thyristor shunts the current and the transformer is thus protected.