A power supply circuit includes an internal power source that receives power supply from an external power source, an abnormality detection circuit that receives power supply from the internal power source to detect abnormalities of the external power source, a protection target circuit that receives the power supply from the external power source, and a protection function unit that restricts electric power supplied to the protection target circuit to a predetermined range, when the abnormality detection circuit detects the abnormalities.

A power supply circuit includes an internal power source that receives power supply from an external power source, an abnormality detection circuit that receives power supply from the internal power source to detect abnormalities of the external power source, a protection target circuit that receives the power supply from the external power source, and a protection function unit that restricts electric power supplied to the protection target circuit to a predetermined range, when the abnormality detection circuit detects the abnormalities.

A safety module for a field-bus system comprising a switch-on unit, a control unit, a supply input provided to feed supply power, a first supply output provided to relay secured supply power to a consumer, a first switching element to electrically connect or disconnect the supply input and the first supply output, and a supply module to provide an operating power via an operating-power-supply line for operating the control unit. The control unit is connected to the first switching element to secure the supply power being relayed via the first supply output by actuating the first switching element. The supply module is electrically connected to the supply input and to a field-bus-power input. The field-bus-power input is provided to feed a field-bus power into the safety module for operating the switch-on unit. The supply module is provided to generate the operating power either from the supply power or field-bus power.

A two-terminal electronic fuse device involves two switches, four diodes, switch control circuitry, and a storage capacitor, connected in a particular topology. When AC current flows through the fuse, a charging current charges the storage capacitor. Energy stored in the storage capacitor is then used to power the switch control circuitry. If the voltage on the storage capacitor drops, then the switches are opened briefly and at the correct time. Opening the switches allows the charging current to flow. By opening the switches and charging the storage capacitor only at times of low current flow through the fuse, the disturbance of load current flowing through the fuse is minimized. If an overload current condition is detected, then the fuse has tripped and first and second switches are opened. If the capacitor does not need charging and there is no overload condition, then the switches remain closed.

A two-terminal electronic fuse device involves two switches, four diodes, switch control circuitry, and a storage capacitor, connected in a particular topology. When AC current flows through the fuse, a charging current charges the storage capacitor. Energy stored in the storage capacitor is then used to power the switch control circuitry. If the voltage on the storage capacitor drops, then the switches are opened briefly and at the correct time. Opening the switches allows the charging current to flow. By opening the switches and charging the storage capacitor only at times of low current flow through the fuse, the disturbance of load current flowing through the fuse is minimized. If an overload current condition is detected, then the fuse has tripped and first and second switches are opened. If the capacitor does not need charging and there is no overload condition, then the switches remain closed.

A power conversion circuit is provided. The power conversion circuit includes a bridge circuit connected between power input terminals, a drive circuit supplied with power from a DC power source via the power input terminals, a boost circuit for, when the DC power source is reversely connected, starting up and supplying power to a control circuit, and a reverse voltage detection circuit for detecting a reverse voltage generated when the DC power source is reversely connected.

The present disclosure relates a method of detecting an electrical disturbance by a DC component in a digital protective relay, which includes acquiring a sample value by sampling an input signal at a regular cycle, detecting the electrical disturbance based on a difference between a sampled first sample value and a second sample value after the first sample value, and when the electrical disturbance is detected, detecting the DC component based on a difference between the second sample value and a third sample value after the second sample value and a difference between the third sample value and a fourth sample value after the third sample value.

Embodiments of the present disclosure relate to managing power provided to a semiconductor circuit to prevent undervoltage conditions. A measured voltage value describing a measured supply voltage at a first subcircuit of a semiconductor circuit can be received, the measured voltage value having a first resolution. A selected metric indicative of a supply voltage present at the first subcircuit can be received, the selected metric having a second resolution higher than the first resolution. The selected metric is calibrated to obtain a calibrated metric when a transition of the measured voltage value occurs.

A monitoring unit for monitoring a circuit breaker includes a safety module; programmable computation modules; an electrical power supply management system to switch, according to the level of electrical power received from electrical power supply sources and according to a predefined power supply program, between an active power supply mode in which the safety module and at least a portion of the computation modules are supplied with power, and a safety power supply mode in which the safety module is supplied with power and the computation modules are not supplied with power.

A monitoring unit for monitoring a circuit breaker includes a safety module; programmable computation modules; an electrical power supply management system to switch, according to the level of electrical power received from electrical power supply sources and according to a predefined power supply program, between an active power supply mode in which the safety module and at least a portion of the computation modules are supplied with power, and a safety power supply mode in which the safety module is supplied with power and the computation modules are not supplied with power.