A device includes a controllable current source connected between a first node and a first terminal coupled to a cathode of a controllable diode. A capacitor is connected between the first node and a second terminal coupled to an anode of the controllable diode. A first switch is connected between the first node and a third terminal coupled to a gate of the controllable diode. A second switch is connected between the second and third terminals. A first diode is connected between the third terminal and the second terminal, an anode of the first diode being preferably coupled to the third terminal.

An AC switch (1) includes a first thyristor (T1), a second thyristor (T2), a third thyristor (T3), and a fourth thyristor (T4). The first thyristor (T1) has an anode connected to an AC power source (2), and a cathode connected to a load (3). The second thyristor (T2) is connected in antiparallel to the first thyristor (T1). The third thyristor (T3) has an anode connected to the AC power source (2), and a cathode connected to the load (3). The fourth thyristor (T4) is connected in antiparallel to the third thyristor (T3). A current detector (5) detects the AC current supplied from the AC power source (2) to the load (3). A controller (6) causes the first thyristor (T1) and the third thyristor (T3) to conduct alternately and causes the second thyristor (T2) and the fourth thyristor (T4) to conduct alternately, for each one-cycle period of the AC current, in accordance with the detection value from the current detector (5).

A switching module includes a determiner to open a first bidirectional switch and close a second bidirectional switch from a first time point over a testing period to determine that the first bidirectional switch has a short circuit failure when a differential absolute value of voltage values detected by voltmeters is equal to a preset voltage threshold value or less, and to open the first bidirectional switch and close the second bidirectional switch from a second time point after a period of n+½ times, where n is a positive integer, the set cycle from the first time point elapses, over a testing period to determine that the first bidirectional switch has a short circuit failure when a differential absolute value of the voltage values detected by the voltmeters is equal to the voltage threshold value or less.

A control system includes a control unit. When turning a bidirectional switch element ON, the control unit controls the bidirectional switch element to cause a time lag between a first timing and a second timing. The first timing is a timing when a voltage equal to or higher than a threshold voltage is applied to one gate electrode selected from a first gate electrode and a second gate electrode. The one gate electrode is associated with one source electrode selected from a first source electrode and a second source electrode and having a lower potential than the other source electrode. The second timing is a timing when a voltage equal to or higher than a threshold voltage is applied to the other gate electrode associated with the other source electrode having a higher potential than the one source electrode.

A solid-state switch, comprising at least one switch controller. At least one switch having a first terminal coupled to a power source, a second terminal coupled to the power source and a control terminal coupled to the switch controller and configured to selectively conduct and block current flow from the first terminal to the second terminal. At least one power converter coupled to the first terminal and the second terminal and configured to convert power from the power source from a first voltage level to a second voltage level and to provide power at the second voltage level to the switch controller.

In a method for controlling a direct current switch having first and second semiconductor switches capable of being switched off, the first and second semiconductor switches are arranged between first and second terminals to enable conduction of a current with a first polarity through the first semiconductor switch and conduction of the current with a second polarity that is opposite to the first polarity through the second semiconductor switch. One of the first and second semiconductor switches is switched off as a function of a current measurement value.

Disclosed is a rapid short-circuit protection circuit of charger at output end. With the short-circuit protection circuit adopted at an output end of a battery charger, MOS switch transistors in a battery power supply circuit may not burn out when an output end VOUT of the battery charger is short-circuited, and thus a good short-circuit protection effect is rendered.

A photocoupler of an embodiment includes a packaging member, a first and a second MOSFET, a semiconductor light receiving element, a semiconductor light emitting element, a first wiring part, and a sealing resin layer. The input terminal includes a first and a second lead. The output terminal includes a third and a fourth lead. The first conductive region includes a signal input part and a bend part. The fourth conductive region includes a signal input part and a bend part. The semiconductor light receiving element is joined to the first and second MOSFETs astride a gap part. The semiconductor light emitting element is joined onto a light receiving region. The first wiring part connects the source electrode of the first MOSFET and the source electrode of the second MOSFET.

An AC-AC power converter, such as a motor soft starter, includes an input connectable to an AC source with a disconnect switch, an output connectable to an AC load, and phase lines connecting the input and output to transmit power. In-line solid-state switching blocks are connected between line terminals and load terminals of the AC source and AC load, respectively, such that each phase line includes a solid-state switching block connected thereto. Free-wheeling solid-state switching blocks are connected to the load terminals at one end and together at a common connection at another end, such that each phase line includes a free-wheeling solid-state switching block connected thereto. Each of the in-line and free-wheeling solid-state switching blocks comprises a bi-directional switching block that selectively controls current and withstands voltage in both directions. The switching blocks also provide soft-starter functions, variable speed control, and integrated circuit breaker protection capability.

A power device can include a first conductive terminal, a second conductive terminal, a power overlay having a conductive backplane and solid state switches, and a controller module configured to selectively operate the solid state switches to enable conductive communication between the first conductive terminal and the second conductive terminal.