Non-ideal diodes have a non-zero resistance across a PN junction when the junction is forward biased. When a diode comprising a power supply has a voltage drop across the junction that exceeds a predetermined threshold, the threshold-exceeding voltage drop trips a comparator, the output of which controls a switch between a power supply and a load.

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.

A controller includes a tracking regulator having a reference voltage input and a voltage output and configured to regulate the voltage output to the reference voltage input. The controller is configured to, in response to a short to ground of the voltage output, electrically couple the reference voltage input to the voltage output.

Techniques are disclosed relating to electrical safety systems that may be useful, for example, in electromagnetic geophysical prospecting. Electromagnetic streamer systems often include a number of electrical loads in series that are powered by a constant-current power supply unit. Known techniques for detecting electrical faults have various drawbacks in such an arrangement. Embodiments of this disclosure may be used to mitigate some or all of such drawbacks.

Techniques are disclosed relating to electrical safety systems that may be useful, for example, in electromagnetic geophysical prospecting. Electromagnetic streamer systems often include a number of electrical loads in series that are powered by a constant-current power supply unit. Known techniques for detecting electrical faults have various drawbacks in such an arrangement. Embodiments of this disclosure may be used to mitigate some or all of such drawbacks.

A protection circuit includes a first sensor connecting path having a first overcurrent protection element and connecting one of terminals of a first temperature sensor to a sensor input circuit; a second sensor connecting path having a second overcurrent protection element and connecting one of terminals of a second temperature sensor to the sensor input circuit; a rectifying element connecting the first sensor connecting path, whose normal voltage is higher than a reference voltage line, to the reference voltage line in a section between the first overcurrent protection element and the sensor input circuit; and an overvoltage protection element connecting the second sensor connecting path, whose normal voltage is higher than the reference voltage line, to the reference voltage line in a section between the second overcurrent protection element and the sensor input circuit.

A protection circuit includes a first sensor connecting path having a first overcurrent protection element and connecting one of terminals of a first temperature sensor to a sensor input circuit; a second sensor connecting path having a second overcurrent protection element and connecting one of terminals of a second temperature sensor to the sensor input circuit; a rectifying element connecting the first sensor connecting path, whose normal voltage is higher than a reference voltage line, to the reference voltage line in a section between the first overcurrent protection element and the sensor input circuit; and an overvoltage protection element connecting the second sensor connecting path, whose normal voltage is higher than the reference voltage line, to the reference voltage line in a section between the second overcurrent protection element and the sensor input circuit.

An embodiment electronic circuit includes an electronic switch comprising a load path, and a control circuit configured to drive the electronic switch and configured to operate in one of a first operation mode and a test mode. The control circuit comprises a test mode input and is configured to operate in the test mode based on a test signal received at the test mode input. The control circuit in the first operation mode is configured to generate a first protection signal based on a current-time-characteristic of a load current of the electronic switch and drive the electronic switch based on the first protection signal.

A circuit and a method for shutdown of automatic ignition controls upon valve relay failures. One or more embodiments describe a method including controlling a power supply to a valve by a valve drive circuit, the valve drive circuit comprising a first relay coil and a second relay coil. The method also includes controlling the valve drive circuit by checking the first relay coil and the second relay coil and issue a drive signal to the first relay coil and the second relay coil. The method further includes protecting from accidental supply of power by a protection switch based on the drive signal issued by the controller.

A circuit and a method for shutdown of automatic ignition controls upon valve relay failures. One or more embodiments describe a method including controlling a power supply to a valve by a valve drive circuit, the valve drive circuit comprising a first relay coil and a second relay coil. The method also includes controlling the valve drive circuit by checking the first relay coil and the second relay coil and issue a drive signal to the first relay coil and the second relay coil. The method further includes protecting from accidental supply of power by a protection switch based on the drive signal issued by the controller.