A power and control device (1) for medium voltage applications characterized in that it comprises a power and control unit (2) having a first feeding port (21) electrically coupleable with electric power supply means (60), a first control device (3) operatively coupled to said first feeding port, said first control device being adapted to prevent the electrical feeding of said power and control unit through said first feeding port, when the operating temperature of said power and control device is lower than a first threshold value (TH1) indicative of a minimum operating temperature provided for said power and control unit.

To provide a semiconductor device for driving an electric load to be divided into a plurality of opening/closing devices so that when an abnormality exists in any one of the division devices, that division device can be removed and replaced by an auxiliary device. Each of a plurality of opening/closing circuit units has an upper-side opening/closing device and a lower-side opening/closing device; while load driving is stopped, there is monitored the potential of the connection point between the upper and lower opening/closing devices at a time when any one of the opening/closing devices is closed or both of them are opened, and it is determined whether there exists short-circuit abnormality or disconnection abnormality in each of the opening/closing devices. When abnormality exists, the upper and lower opening/closing devices are removed and the auxiliary circuit is made effective.

The present disclosure provides a short-circuit protection apparatus and method. The short-circuit protection apparatus includes a current detection circuit, a control circuit, and a voltage detection circuit. The current detection circuit detects an output current of an output circuit and outputs a current detection signal when the detected current is greater than a preset current. The control circuit receives the current detection signal and controls the output circuit to be turned off The voltage detection circuit detects an output voltage of the output circuit. When the output voltage is not in the preset voltage range, the output voltage is detected continuously When the output voltage is in the preset voltage range, the control circuit receives the voltage detection signal for controlling the output circuit.

In order both to accommodate instantaneous current as well as overcurrent protection in accordance with the load, an overcurrent protection circuit has: a threshold value generation unit that, in accordance with a threshold value control signal, switches between setting an overcurrent detection threshold value to a first set value ( Iref) and a second set value ( Iset) lower than the first set value; an overcurrent detection unit that compares a sense signal in accordance with the current being monitored and the overcurrent detection value and generates an overcurrent protection signal; a reference value generation unit that generates a reference value ( Iset) in accordance with the seconds set value; a comparison unit that compares the sense signal and the reference value, and generates a comparison signal; and a threshold value control unit that monitors the comparison signal, and generates a threshold value control signal.

A semiconductor device, overvoltage detection structure is described that includes a current path including a Zener diode connected in series with a fuse. The Zener diode is configured to conduct a current in response to an overvoltage condition at a semiconductor device and the fuse is configured to permanently break the current path of the overvoltage detection structure in response to the Zener diode conducting the current.

When a temperature is less than a first threshold, a protection circuit unit executes a normal operation by a pulse width modulation. When the temperature is greater than or equal to the first threshold and is less than a second threshold, the protection circuit unit executes a first heat dissipation suppressing operation that suppresses a self-heating of a switching element. When the temperature is greater than or equal to the second threshold, the protection circuit unit executes a full off operation that terminates the switching element. When the temperature is decreased to be less than the first threshold and to be greater than or equal to a third threshold after the temperature becomes greater than or equal to the second threshold, the protection circuit unit executes a second heat dissipation suppressing operation that suppresses a heat dissipated due to an energization of the switching element.

A system for controlling the connection of an inverter to a load center. In one aspect, the system cooperatively connects an inverter supply to a load center. When the inverter supply is connected to the load center, the system unbonds the ground conductor of the inverter supply from the neutral conductor of the inverter supply. When the inverter supply is not connected to the load center, or is disconnected from the load center, the system bonds the ground conductor of the inverter supply to the neutral conductor of the inverter supply. The bonding and unbonding may be done by monitoring circuitry that drives a switch, or by an electro-mechanical switch integrating into a plug and that operates without monitoring circuitry.

A test signal is applied from a continuity test source to a photovoltaic (PV) panel string, to test electrical continuity in the PV panel string and between the PV panel string and an inverter that is coupled to the PV panel string. If the test signal is detected at a PV panel disconnect switch that is separate from the continuity test source and switchably couples one or more Direct Current (DC) PV panels in the PV panel string, then the PV panel disconnect switch is controlled to connect the one or more DC PV panels in the PV panel string. Otherwise, the PV panel disconnect switch is controlled to disconnect the one or more DC PV panels from the PV panel string. The test signal could be, for example, an Alternating Current (AC) signal tuned to a PV installation that includes the PV panel string and the inverter.

A method for a power system having a string of a plurality of power sources connected across a power device includes connecting a plurality of safe voltage units having safety switches connected respectively across each of the power sources. The method includes sensing a plurality of parameters of the power sources, and monitoring for a signal transmitted from the power device. Each of the safety switches is activated to be OFF responsive to detecting the signal within a predetermined time period. Upon not detecting the signal from the power device within the predetermined time period, a safe mode of operation of the power system is entered in which the voltages of each of the power sources is reduced to a voltage level less than a predetermined voltage level by turning the safety switches ON.

An example apparatus includes: a transistor having a source, a drain, and a gate; first voltage clamp circuitry having a first terminal, a second terminal, and a third terminal, the first terminal of the first voltage clamp circuitry coupled to the source of the transistor, the second terminal of the first voltage clamp circuitry coupled to the gate of the transistor; second voltage clamp circuitry having a first terminal, a second terminal, a third terminal, and a fourth terminal, the first terminal of the second voltage clamp circuitry coupled to the drain of the transistor, the second terminal of the second voltage clamp circuitry coupled to the gate of the transistor, the third terminal of the second voltage clamp circuitry coupled to the source of the transistor; and clamp control circuitry having a first terminal, a second terminal, a third terminal, and a fourth terminal.