A DC power supply may use an input supply surge protection circuit that may be robust against positive and negative power surges. DC power may be provided through a first unidirectional circuit component such as a diode or selectively controlled MOSFET coupled in parallel with a transient voltage suppressor or Zener diode. The first unidirectional circuit component may have a first voltage rating and the transient voltage suppressor or Zener diode may have a second voltage rating lower than the first voltage rating. This may allow current to flow backward over the transient voltage suppressor or Zener diode to protect the first unidirectional circuit component from exposure to voltage beyond the first voltage rating in a power surge.

A reverse polarity protection device includes a protection unit, a detection unit, and a control unit electrically connected between a power supply device and a load device. The detection unit is electrically connected to the power supply device for detecting the polarity of an output signal of the power supply device, and the control unit is electrically connected to the detection unit and the protection unit. The detection unit outputs a detection signal to the control unit according to a detection result of the polarity of the output signal. If the detection signal shows that the polarity of the output signal is reverse, the control unit will control the protection unit to form an open circuit between the power supply device and load device to stop transmitting the output signal of the power supply device to the load device and achieve a reverse polarity protection effect of the load device.

An input/output (I/O) interface includes a resistance-to-current (R/I) converter; an internal resistor; first, second, and third current sources; first and second diodes; and a comparator. The R/I converter is coupled to an I/O pin and generates an output current based on an external resistance at the I/O pin during an analog operating mode. The internal resistor is coupled to the I/O pin and to ground. The first current source is coupled to the R/I converter circuit. The first diode is coupled to the R/I converter and to the I/O pin. The second current source is coupled to the R/I converter and the first diode and to ground. The second diode is coupled to the I/O pin and to the third current source. The comparator has inputs coupled to the I/O pin and to a reference voltage, and outputs a control signal indicative of a digital operating mode.

A reverse-flow prevention circuit includes: an n-channel metal-oxide semiconductor having an anode terminal, a cathode terminal, and a control terminal; a reference voltage node; an output voltage node; a first rectifier element, a second rectifier element, and a third rectifier element; a secondary-side winding of a transformer having a center tap terminal; a voltage regulator having an input terminal, an output terminal, and a reference voltage terminal; and a transistor having a high-voltage terminal, a low-voltage terminal, and a control terminal.

An electricity backfeed protection assembly is beneficially installed between a main circuit breaker panel of a structure or dwelling, and a utility meter measuring electricity delivered to the structure or dwelling by a utility provider or other primary power source. The electricity backfeed protection assembly includes a contactor having a coil. A contact protector device is electrically connected to the coil of the contactor. The electrical backfeed protection assembly automatically prevents electricity from a secondary power source (including, without limitation, a portable generator) from backfeeding into supply lines of a primary power source (such as utility lines or equipment).

A host electronic device may be coupled to an accessory electronic device. The host device and the accessory device may be connected via power supply lines and user data lines. If the host and accessory devices are improperly connected or if the accessory device is exposed to an incorrect voltage environment, the internal circuitry on the accessory device can be damaged. The accessory device may therefore include a reverse voltage protection circuit that can help prevent a large amount of current from inadvertently flowing into the accessory device. The protection circuit may include a low-side-enabled reverse current protection switch coupled between the external and internal ground terminals and also a single low-drop switch coupled to each of the user data lines. The low-drop switch will be activated whenever the voltage at the external ground terminal exceeds the voltage at the data line to help deactivate low-side-enabled reverse current protection switch.

A control system and method for sectionalizing switches and pulse-testing interrupter/reclosers in a distribution grid feeder which enables fault location, isolation and service restoration without requiring an external communications infrastructure to pass information between the switches. The method includes switches entering an armed state when they experience a high fault current during an initial fault event. Then, when the interrupter/recloser runs its test pulse sequence, any armed switch counts all test pulses as fault pulses, while non-armed switches count the test pulses as load pulses. Switches open to isolate the fault based on threshold values of fault pulse count and load pulse count. When an initially active interrupter/recloser completes its test pulse sequence, another interrupter/recloser begins its sequence, and all switches reconfigure their threshold values based on the new interrupter/recloser. Interrupter/reclosers after the initial device use a fast close-open event if necessary to arm some switches for proper fault-count opening.

A load drive circuit includes a power source terminal (“PST”), a power source and a load terminal connecting a load to the power source. A semiconductor switch connects the PST to the load terminal. A control circuit includes an output terminal for opening/closing the semiconductor switch. A freewheeling circuit includes a freewheeling diode and a protection switch blocks a current from the power source to the semiconductor switch when the power source is connected in a reverse manner. A first terminal connects the control circuit to a first fixed potential and a second terminal connects an anode of the freewheeling diode to a second fixed potential. A connection circuit includes a connection switch connecting the output terminal and the first terminal. The connection circuit connects the output terminal to the first terminal when a rise in a potential difference between the first terminal and the second terminal is detected.

A supply module includes an electrical control input and an electrical supply input as well as an electrical control output and an electrical supply output, as well as a control line arranged between the control input and the control output, which is designed for the transmission of control information, wherein at least one supply line group is assigned to the electrical supply input, which group includes a supply feed line and a supply outlet line, which are each extended between the electrical supply input and the electrical supply output, and which includes a switching module which is coupled to the control line and which has a feed switch arranged in the supply feed line, wherein a consumer output is formed for an electrical supply of an external consumer and is connected via an output feed line to the supply feed line and via an output drain line to the supply outlet line, the output feed line being connected between feed switch and the electrical supply output.

A power regulator includes an input capacitor connected between a first voltage bus and an intermediate point, an output capacitor connected between a second voltage bus and the intermediate point, a plurality of switches and an inductor connected between the input capacitor and the output capacitor, wherein a source of one switch of the plurality of switches is connected to the intermediate point and a protection device connected between the intermediate point and a third voltage bus.