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 system includes a current transformer including: a primary coil, and a secondary coil including at least two taps; a tap selection circuit; a current measurement apparatus configured to produce an indication of an amount of current flowing in the secondary coil; a power supply electrically connected to a first one of the taps, the power supply configured to receive electrical power from the first one of the taps; and a controller coupled to the power supply and the current measurement apparatus, the controller configured to receive electrical power from the power supply and to control the tap selection circuit based on the indication of an amount of current in the secondary coil.

A winding unit for connecting to a high-voltage grid or network includes a winding embedded in a solid insulating body and a first main connection terminal connected to a first winding end of the winding and disposed on a first support formed on the insulating body. A second main connection terminal is connected to a second winding end of the winding. The winding has partial windings and taps for adjusting the number of windings of the partial windings connected in series. Outgoing lines extending in the insulating body connect the taps to a tap connection terminal accessible from the outside. The tap connection terminals are formed on the support in order to encapsulate the higher voltage in a resin block over the entire periphery by using a shielding cage.

In described examples, a first transistor has: a drain coupled to a source of a depletion-mode transistor; a source coupled to a first voltage node; and a gate coupled to a control node. A second transistor has: a drain coupled to a gate of the depletion-mode transistor; a source coupled to the first voltage node; and a gate coupled through at least one first logic device to an input node. A third transistor has: a drain coupled to the gate of the depletion-mode transistor; a source coupled to a second voltage node; and a gate coupled through at least one second logic device to the input node.

In described examples, a first transistor has: a drain coupled to a source of a depletion-mode transistor; a source coupled to a first voltage node; and a gate coupled to a control node. A second transistor has: a drain coupled to a gate of the depletion-mode transistor; a source coupled to the first voltage node; and a gate coupled through at least one first logic device to an input node. A third transistor has: a drain coupled to the gate of the depletion-mode transistor; a source coupled to a second voltage node; and a gate coupled through at least one second logic device to the input node.

Techniques for enabling multi-pack and component connectivity detection are provided. In some configurations, individual PCMs can test the connectivity between components of a device without the need to operate the components. For example, PCMs configured in accordance with the present disclosure can test the connectivity between a motherboard, a display circuit, a camera, and a number of battery packs without the need to operate the motherboard, display circuit, camera, etc. In some configurations, conductors that are part of cables and connectors used to connect the components can be used to determine the state of one or more connections. When a signal that runs through the conductors meets one or more criteria, the PCMs of a device cause a predetermined delay prior to enabling one or more components. By testing the connectivity between components before each component transitions to an operational state, other problems caused by faulty connections can be mitigated.

Provided herein is a power distribution system comprising a main power bus, sub-buses coupled to the main power bus, and a controller. The sub-buses provide power to electrical components of a vehicle. Each of the sub-buses includes an electrically programmable fuse in series with a relay. The controller is configured to detect a fault in a sub-bus of the sub-buses, determine a fault type associated with the fault, and in response to determining the fault type, generate a command to cause the relay to change a relay state.

A fault point locating device which estimates a fault point in an electric power system, is provided with: a variation range calculating means which obtains a range of variation of sensor values and a range of variation of an impedance of the electric power system, on the basis of the sensor values, which include measured voltage values and measured current values before and after the fault and which are measured using sensors installed in the electric power system, sensor errors representing error ranges of the sensors in relation to the sensor value measurements, said impedance, and an impedance variation parameter for determining the range of variation of the impedance; a combination creating means which creates combinations of values that the sensor values and the impedance value could attain; and a fault point locating means which calculates a fault point range representing distances from the sensors to the fault point.

In some examples, a device includes a memory configured to store a pre-warning threshold level for a parameter of a power switch. The device also includes a logic circuit configured to receive a signal from a controller and set the pre-warning threshold level in response to receiving the signal from the controller. The logic circuit is also configured to determine that a magnitude of the parameter of the power switch does not satisfy the pre-warning threshold level. The logic circuit is further configured to output an alert to the controller in response to determining that the magnitude of the parameter does not satisfy the pre-warning threshold level.

In some examples, a device includes a memory configured to store a pre-warning threshold level for a parameter of a power switch. The device also includes a logic circuit configured to receive a signal from a controller and set the pre-warning threshold level in response to receiving the signal from the controller. The logic circuit is also configured to determine that a magnitude of the parameter of the power switch does not satisfy the pre-warning threshold level. The logic circuit is further configured to output an alert to the controller in response to determining that the magnitude of the parameter does not satisfy the pre-warning threshold level.