A serial bus buffer circuit includes a master input-output terminal, a slave input-output terminal, a switched resistor circuit, and a switch control circuit. The switched resistor circuit is configured to provide a low impedance connection between the master input-output terminal and the slave input-output terminal. The switch control circuit is coupled to the switched resistor circuit, and is configured to enable the low impedance connection based on voltage at the master input-output terminal and voltage at the slave input-output terminal.

In a circuit breaker arrangement, this disclosure describes a method and circuit design enables a current transformer to be used to detect ground faults in circuit breakers (such as a main-tie-main circuit breakers) that have been designed to receive signals from Rogowski coils.

An electrical device includes a first terminal structured to electrically connect to a power source; a second terminal structured to electrically connect to a load; a voltage sensor electrically connected to a point between the first and second terminals and being structured to sense a voltage at the point between the first and second terminals; a switch electrically connected between the first terminal and the second terminal; and a control unit structured to detect a power quality event in the power flowing between the first and second terminals based on the sensed voltage and to control a state of the switch based on the detected power quality event.

Methods, systems, and apparatus for circuit breakers with integrated safety, control, monitoring, and protection features. In one aspect, a circuit breaker includes, an input and an output, a switch coupled between the input and the output, a sensor configured to measure the current flowing from the input to the output, and a control system coupled to the sensor and the switch, wherein the control system is configured to perform operations including comparing a rate of change of the current measured by the sensor to a threshold rate of change of current, determining that the rate of change of the current measured by the sensor exceeds the threshold rate of change of current for at least a predetermined period of time, and as a consequence of determining that the rate of change of current exceeds the threshold rate of change, opening the switch, thereby disconnecting the input from the output.

Methods, systems, and devices for protecting a wireless power transfer system. One aspect features a sensor network for a wireless power transfer system. The sensor network includes a differential voltage sensing circuit and a current sensing circuit. The differential voltage sensing circuit is arranged within a wireless power transfer system to measure a rate of change of a voltage difference between portions of an impedance matching network and generate a first signal representing the rate of change of the voltage difference. The current sensing circuit is coupled to the differential voltage sensing circuit and configured to calculate, based on the first signal, a current through a resonator coil coupled to the wireless power transfer system.

Methods, systems, and devices for protecting a wireless power transfer system. One aspect features a sensor network for a wireless power transfer system. The sensor network includes a differential voltage sensing circuit and a current sensing circuit. The differential voltage sensing circuit is arranged within a wireless power transfer system to measure a rate of change of a voltage difference between portions of an impedance matching network and generate a first signal representing the rate of change of the voltage difference. The current sensing circuit is coupled to the differential voltage sensing circuit and configured to calculate, based on the first signal, a current through a resonator coil coupled to the wireless power transfer system.

In described examples, a power interface subsystem includes power transistors, each having: a conduction path coupled between a battery terminal and an accessory terminal; and a control terminal. A differential amplifier has: a first input coupled to the battery terminal; a second input coupled to the accessory terminal; and an output node. An offset voltage source is coupled to cause an offset of a selected polarity at one of the inputs to the differential amplifier. The offset has a first polarity in a first operating mode and a second polarity in a second operating mode. Gate control circuitry is coupled to apply a control level at the control terminal(s) of selected one(s) of the power transistors responsive to a voltage at the output node, and to apply an off-state control level to the control terminal(s) of unselected one(s) of the power transistors.

A wireless electric vehicle charging system comprises base-side equipment for generating a magnetic field and vehicle-side equipment for receiving energy via the magnetic field to supply power to a vehicle-driving battery. Monitoring circuitry monitors one or more of voltage, current, or phase associated with the base-side equipment and halts generation of the magnetic field in response to a change in the voltage, current, or phase associated with the operation of the base-side equipment that indicates a fault condition at the vehicle-side equipment, which may include a loss of power or disconnection of a battery. Based on detection of the change, the monitoring circuitry can halt generation of the magnetic field to prevent damage at the vehicle-side equipment.

A circuit including a source, a load, and an isolation circuit for controllably isolating the load from the source. The isolation circuit is disposed between the source and the load. The isolation circuit includes at least one insulated-gate bipolar transistor (IGBT) and at least one gate turn-off thyristor (GTO) in parallel with the insulated-gate bipolar transistor. When no fault condition exists, the GTO is configured to be ON to couple the load to the source. When a fault condition exists, the at least one IGBT is configured to turn ON. After the at least one IGBT turns ON, the at least one GTO is configured to turn OFF. After a predetermined amount of time, reflecting the post fabrication alteration to the GTO's minority carrier lifetime (e.g. electron irradiation), after the at least one GTO turns OFF, the at least one IGBT is configured to turn OFF. Alternatively, the circuit is used as an inverter switch, where at the command to turn ON is supplied, the at least one IGBT is turned ON, followed by the at least one SGTO. When commanded to turn OFF the at least one SGTO is turned OFF followed by the at least one IGBT. This alternative configuration allows the robust, controllable switching speeds of IGBTs and the superior conduction efficiency of SGTOs. The two configurations mentioned above utilize a wide range of SGTO performance, thus the ability to control the SGTOs turn-off speed by reducing its minority carrier lifetime after the device is processed is of large importance. The efficiency of all uses of the circuit can be optimized with the judicious selection of SGTO minority carrier lifetime and the ratio of active area between the SGTO and IGBT devices. In all cases there is a balance between the time the circuit can achieve hard turn-off without current commutation, the conduction efficiency of the circuit and the maximum amount of controllable current. In all cases both the conduction efficiency of the circuit is higher than an IGBT-only based circuit, and the switching performance is higher than a GTO-only based circuit.

A circuit including a source, a load, and an isolation circuit for controllably isolating the load from the source. The isolation circuit is disposed between the source and the load. The isolation circuit includes at least one insulated-gate bipolar transistor (IGBT) and at least one gate turn-off thyristor (GTO) in parallel with the insulated-gate bipolar transistor. When no fault condition exists, the GTO is configured to be ON to couple the load to the source. When a fault condition exists, the at least one IGBT is configured to turn ON. After the at least one IGBT turns ON, the at least one GTO is configured to turn OFF. After a predetermined amount of time, reflecting the post fabrication alteration to the GTO's minority carrier lifetime (e.g. electron irradiation), after the at least one GTO turns OFF, the at least one IGBT is configured to turn OFF. Alternatively, the circuit is used as an inverter switch, where at the command to turn ON is supplied, the at least one IGBT is turned ON, followed by the at least one SGTO. When commanded to turn OFF the at least one SGTO is turned OFF followed by the at least one IGBT. This alternative configuration allows the robust, controllable switching speeds of IGBTs and the superior conduction efficiency of SGTOs. The two configurations mentioned above utilize a wide range of SGTO performance, thus the ability to control the SGTOs turn-off speed by reducing its minority carrier lifetime after the device is processed is of large importance. The efficiency of all uses of the circuit can be optimized with the judicious selection of SGTO minority carrier lifetime and the ratio of active area between the SGTO and IGBT devices. In all cases there is a balance between the time the circuit can achieve hard turn-off without current commutation, the conduction efficiency of the circuit and the maximum amount of controllable current. In all cases both the conduction efficiency of the circuit is higher than an IGBT-only based circuit, and the switching performance is higher than a GTO-only based circuit.