Disclosed is a leakage current measuring device for a grid protection system protecting a power distribution or transmission grid from damage in case of a power surge, the grid protection system including a disconnector device and a surge arrester connected in series along a grounding path, the grounding path connecting a phase of a power distribution or transmission grid through the surge arrester and the disconnector device to ground, the disconnector device being configured for being activated in case of an overload condition, thereby disconnecting the surge arrester. The leakage current measuring device includes a leakage current sensor for measuring a leakage current I.sub.L flowing along the grounding path, the leakage current I.sub.L being indicative of the electrical connection status of the disconnector device. The electrical connection status is one of an activated and an inactivated status of the disconnector device.

The disclosed embodiments relate to method and/or device which is effective at cancelling or altering electrical signals or pulses, generated by, for example, digital electronic systems and components, that are induced, reflected or otherwise made present on the mains power supply conductors and/or the earthing or grounding conductor (if present.) The disclosed embodiments cancel these electrical signals thereby providing an effective means of preventing the exfiltration of various data from a computing or similar system by means of power line emissions. The disclosed embodiments may perform this subjugation by: altering the shape of the fundamental current and voltage waveforms and also altering and diminishing any non-fundamental frequency waveforms to a point where they are no longer measurable or detectable; and preventing the communication via inductive coupling of any electrical signals on mains current onto the grounding path or vice versa.

The present disclosure provides an electrostatic discharge protection circuit, a chip including a first pad and a second pad. The electrostatic discharge protection circuit includes a trigger unit and a discharge transistor. The trigger unit is connected between the first pad and the second pad, provided with a trigger terminal, and configured to generate a trigger signal when there is an electrostatic pulse on the first pad. The first pad is connected to a first voltage, the second pad is connected to a second voltage, and the first voltage is greater than the second voltage. The discharge transistor has a first terminal connected to the first pad, and a second terminal connected to the second pad, and discharges an electrostatic charge to the second pad when triggered by the trigger signal.

An apparatus includes a first diode and a second diode connected in series between a first voltage terminal and a second voltage terminal, a switch connected between the first voltage terminal and the second voltage terminal, and a clamping threshold circuit connected between a common node of the first diode and the second diode, and a gate of the switch, wherein the clamping threshold circuit is configured such that in response to a voltage surge applied to the common node of the first diode and the second diode, the switch is turned on once the voltage surge is greater than a predetermined threshold.

A system-in-package includes a function circuit and a protection circuit that protects the function circuit by preventing an instantaneous transient voltage from being applied to the function circuit. Here, the protection circuit includes a TVS diode and a capacitor. The TVS diode includes an anode that receives a ground voltage and a cathode that is connected to a first external connection terminal. The capacitor includes a first terminal that is connected to a second external connection terminal electrically separated from the first external connection terminal and a second terminal that receives the ground voltage.

A clamping circuit employs a filter comprising two series branches of surge arresting circuits to clamp voltage spikes on equipment in series with a power transmission line. Clamping of these voltage spikes protects insulators, semiconductors, and other sensitive components within the series equipment from transient grid events. By using a predetermined frequency to control the response, the filter does not interfere with normal operation of the power system nor the operation of a power flow control module series-coupled to the transmission line through the filter. The clamping circuit employs hysteresis and imposes a shared voltage ratio between the two circuit branches, the ratio depending on frequency and voltage of the transient asserted on the transmission line, in order to provide a very sharp protection response to events within the target frequency range.

The present invention discloses parallel, series and hybrid ESD protection circuits. A preferred parallel ESD protection circuit comprises a plurality of ESD devices connected in parallel, with each comprising a resistor and an OTS component connected in series. A preferred series ESD protection circuit comprises a plurality of ESD devices connected in series, wherein the OTS components in all ESD devices are disposed on a same level. A preferred hybrid ESD protections circuit comprises ESD devices connected in parallel, as well as in series.

An apparatus includes a surge protection device, a current sensor configured to sense a current through the surge protection device, and a surge discriminator circuit coupled to the current sensor and configured to discriminate among a plurality of surge levels for the surge protective device responsive to the sensed current. The current sensor may include a current transformer configured to generate a secondary current responsive to the sensed current and the surge discriminator circuit may be configured to discriminate among a plurality of surge levels responsive to the generated secondary current.

Embodiments of an ESD protection device are described. In an embodiment, an ESD protection device includes a first voltage rail electrically connected to a first node, a second voltage rail electrically connected to a second node, and ESD cells connected between the first and second voltage rails and configured to shunt current in response to an ESD pulse received between the first and second nodes. Each of the ESD cells includes clamp circuits electrically connected to the second voltage rail, ballast resistors connected between the first voltage rail and the clamp circuits, where at least some of the ballast resistors are electrically connected to a third voltage rail, a driver circuit connected between the second and third voltage rails and configured to generate a driver signal, and an output stage configured to generate an output signal in response to the driver signal.

A protection circuit including a detection circuit, a current discharge element, a first transistor, and a second transistor is provided. The detection circuit is coupled between a first pad and a second pad to detect ESD events. In response to an ESD event, the detection circuit sets the detection signal to a predetermined level. The current discharge element is coupled between the first and second pads. In response to the detection signal being at the predetermined level, the current discharge element is turned on so that the ESD current passes through the current discharge element. The first transistor is coupled between a core circuit and the second pad. The second transistor is coupled between the first transistor and the second pad. In response to the detection signal being at the predetermined level, the second transistor is turned on to turn off the first transistor.