An example switch device includes a switching element to connect/disconnect a current path from a power supply terminal to a ground terminal via a load, and an overcurrent protection circuit to limit output current flowing in the switching element to be an overcurrent limit value or less. When an output short circuit of the load is detected, the overcurrent protection circuit decreases the overcurrent limit value to be lower as a power supply voltage is higher. The overcurrent protection circuit includes a reference current generation portion that includes: a differential amplifier portion, an upper side current generation portion arranged to generate a predetermined an upper side current, a lower side current generation portion arranged to generate a lower side current, and a difference current generation portion arranged to output a difference current based on the lower side current and the upper side current, as the reference current.

An intelligent power module includes a power switch, a freewheeling device, and a controller circuit incorporating a gate drive circuit and one or more power switch protection circuits. In one embodiment, the power switch is an insulated gate bipolar transistor (IGBT) device, the freewheeling device is a PN junction diode, and the controller circuit is implemented as a semiconductor integrated circuit (IC). The power module implements protection functions for the power switching device where the protection circuits are formed on the controller circuit IC and co-packaged with the power switch. In some embodiments, the control circuit in the power module includes an active soft-start circuit which is activated to realize soft-start of the power switch. In other embodiments, the control circuit in the power module includes an active turn-on pulse control circuit to detect for abnormal system input signal pulse events and block system undesired input pulses.

An intelligent power module includes a power switch, a freewheeling device, and a controller circuit incorporating a gate drive circuit and one or more power switch protection circuits. In one embodiment, the power switch is an insulated gate bipolar transistor (IGBT) device, the freewheeling device is a PN junction diode, and the controller circuit is implemented as a semiconductor integrated circuit (IC). The power module implements protection functions for the power switching device where the protection circuits are formed on the controller circuit IC and co-packaged with the power switch. In some embodiments, the control circuit in the power module includes an active soft-start circuit which is activated to realize soft-start of the power switch. In other embodiments, the control circuit in the power module includes an active turn-on pulse control circuit to detect for abnormal system input signal pulse events and block system undesired input pulses.

A control device, such as a smart thermostat, employs solid state relays as switches to activate and deactivate systems controlled by the device. By measuring the current flow through the power buses to one or more of the solid state relays of the control device, potentially damaging over current conditions can be distinguished from permissible transient over-current conditions and the control device can deactivate any solid state relays which would be damaged while allowing solid state relays which are experiencing allowable transients to remain operating. In the case of a severe over current condition, a current monitoring device can issue a fault signal, triggering an interrupt condition which will cause a processor in the controller to shut down the affected solid state relays very quickly.

An operating method is used for a compressor of a refrigerating machine, where the compressor includes an electric motor- and a power supply device configured to modulate a supply voltage and/or current and/or frequency for driving an electric motor. The method includes (a) setting a stator resistance calibration value and at least one threshold value for a control parameter, the threshold value being correlated to the calibration value; (b) injecting, continuously during operation of the electric motor, a disturbance signal into the electric motor (c) detecting a resulting voltage signal and a resulting current signal, corresponding to the perturbation signal; (d) associating with the control parameter a value calculated as a function of the resulting voltage signal and a resulting current signal; and (e) regulating or interrupting the supply voltage and/or current and/or frequency depending on the control parameter with respect to the at least one threshold value.

A method for monitoring, metering and improving system parameters, including leakage sensitivity and response over a time period in an electrical panel for a single phase system, or a 3-phase system comprising phase lines X, Y and Z, wherein the system reaction and accuracy are critical to a decision to disconnect the line with the malfunction before operation of the leakage breaker to cut off power. Set parameter 1: a leakage threshold in mA that can be changed in system setup mode. Set parameter 2: Allowable deviation in mA for alert; and set parameter 3: Maximum deviation in mA to disconnect currents. Set parameter N for the time to include in an average calculation.

A controller for driving a power switch incorporates a protection circuit to protect the power switch from fault conditions, such as over-voltage conditions or power surge events. The protection circuit includes a fault detection circuit and a protection gate drive circuit. The fault detection circuit is configured to monitor the voltage across the power switch and to generate a fault detection indicator signal and the protection gate drive circuit is configured to generate a gate drive signal to turn on the power switch in response to a detected fault condition. In particular, the protection gate drive circuit generates a gate drive signal that has a slow assertion transition and is clamped at a given gate voltage value. In this manner, the protection circuit implements active clamping of the gate terminal of the power switch and safe handling of the power switch during over-voltage events.

An electronic control system includes first through third measurement units that measure current, temperature and current or temperature, respectively. An electronic control device controls an operation of a power semiconductor element by using measurement results of the first through third measurement units. At least a part of the power semiconductor element incorporates the first and second measurement units, and the electronic control device estimates temperature from a measured value of the current. Whether the first measurement unit, the second measurement unit, and the third measurement unit are normal or abnormal on a basis of a measured value of the first measurement unit is determined, and an abnormality is determined of at least one of the power semiconductor element and a wire harness through which an output current of the power semiconductor element flows according to a measurement result of the measurement unit determined to be normal.

A temperature sensing tape is provided and can include an insulating support structure and at least one temperature sensing element disposed on the insulating support structure wherein the at least one temperature sensing element can be formed from a single polymer mixture that includes two or more polymers, and wherein each of the two or more polymers can have a respective, different crystallinity point.

A temperature sensing tape is provided and can include an insulating support structure and at least one temperature sensing element disposed on the insulating support structure wherein the at least one temperature sensing element can be formed from a single polymer mixture that includes two or more polymers, and wherein each of the two or more polymers can have a respective, different crystallinity point.