FIELD

Embodiments relate to the field of protection devices, an in particular, to current-limiting circuits.

BACKGROUND

Current-limiting circuits are known for protecting various equipment and devices. In some applications, such as the protection of instrumentation systems, large voltage transients take place during normal operation, as well as long-term exposure to high voltage levels. With respect to these and other considerations, the present embodiments are provided.

BRIEF SUMMARY

One embodiment of the present disclosure may be implemented as a device that includes enhancement mode devices (field effect transistors) and bipolar transistor devices, generating a novel voltage-current operation curve. This operation curve makes this device particularly advantageous for protecting instrumentation systems that are intended to experience large voltage transients and long-term exposure to voltages that would normally damage measurement equipment. The current limiting devices of the present embodiments are designed to have a large impedance value prior to a “turn-on” voltage, while quickly transitioning to a low-impedance. When the conducted current exceeds a setpoint or a high-voltage event occurs, the current limiting device further transitions to a “cutoff” region, which transition resumes the initial high-impedance state. In a further embodiment the threshold current may be set using internal components, while a further embodiment allows the current setpoint to be set by external components. The current limiting devices has of the present disclosure may also be designed to allow for series scaling and parallel scaling. The present embodiments have applications for measurement systems as a protected signal measurement path. Further applications of embodiment of the present disclosure include use as an active current limiter for low-power line-connected power supplies. In further embodiments, the present embodiments may be used in combination with overvoltage protection devices to create more comprehensive electronic network protection systems.

