In the field of gate drivers there is provided a regulated voltage source (10; 10A, 10B), for a gate driver (200; 300) of a switching device (18) having a gate terminal (26) via which the switching device (18) can at least be turned on. The regulated voltage source (10; 10A, 10B) comprises an input terminal (12) via which the regulated voltage source (10; 10A, 10B) in use receives current. The regulated voltage source (10; 10A, 10B) also includes first and second connection terminals (22, 24) via at least one of which the regulated voltage source (10; 10A, 10B) in use applies a voltage (V) to a gate terminal (26) of a switching device (18). In addition the regulated voltage source (10; 10A, 10B) includes a regulated energy storage stage (28) which is electrically connected between the input and output terminals (12, 22, 24) and which includes a primary energy storage device (30; 30A, 30B) connected in parallel with a storage limiter (34) to limit the amount of energy stored in the primary energy storage device (30; 30A, 30B). Between the primary energy storage device (30; 30A, 30B) and the storage limiter (34) lies an energy retainer (46) to prevent the escape of energy from the primary energy storage device (30; 30A, 30B) via the storage limiter (34). The regulated voltage source (10; 10A, 10B) further includes a freewheel diode (50) that is arranged in parallel with the energy storage stage (28) and a secondary energy storage device (52; 52A, 52B) which is arranged in parallel with each of the freewheel diode (50) and the energy storage stage (28).

In the field of gate drivers there is provided a regulated voltage source (10; 10A, 10B), for a gate driver (200; 300) of a switching device (18) having a gate terminal (26) via which the switching device (18) can at least be turned on. The regulated voltage source (10; 10A, 10B) comprises an input terminal (12) via which the regulated voltage source (10; 10A, 10B) in use receives current. The regulated voltage source (10; 10A, 10B) also includes first and second connection terminals (22, 24) via at least one of which the regulated voltage source (10; 10A, 10B) in use applies a voltage (V) to a gate terminal (26) of a switching device (18). In addition the regulated voltage source (10; 10A, 10B) includes a regulated energy storage stage (28) which is electrically connected between the input and output terminals (12, 22, 24) and which includes a primary energy storage device (30; 30A, 30B) connected in parallel with a storage limiter (34) to limit the amount of energy stored in the primary energy storage device (30; 30A, 30B). Between the primary energy storage device (30; 30A, 30B) and the storage limiter (34) lies an energy retainer (46) to prevent the escape of energy from the primary energy storage device (30; 30A, 30B) via the storage limiter (34). The regulated voltage source (10; 10A, 10B) further includes a freewheel diode (50) that is arranged in parallel with the energy storage stage (28) and a secondary energy storage device (52; 52A, 52B) which is arranged in parallel with each of the freewheel diode (50) and the energy storage stage (28).

A semiconductor relay device includes a conversion circuit configured to receive an input signal from outside and pass a first current to a first node based on the input signal. A zener diode has an anode coupled to a second node and a cathode coupled to the first node. A resistor is coupled between the second node and a third node. A number n of diodes are serially coupled. A thyristor has an anode coupled to the first node, a cathode coupled to the second node, and a control terminal coupled to the third node. A transistor has a gate coupled to the first node. An anode of a diode at a first end of the n diodes is coupled to the first node, and a cathode of a diode at a second end of the n diodes is coupled to a third node.

A semiconductor relay device includes a conversion circuit configured to receive an input signal from outside and pass a first current to a first node based on the input signal. A zener diode has an anode coupled to a second node and a cathode coupled to the first node. A resistor is coupled between the second node and a third node. A number n of diodes are serially coupled. A thyristor has an anode coupled to the first node, a cathode coupled to the second node, and a control terminal coupled to the third node. A transistor has a gate coupled to the first node. An anode of a diode at a first end of the n diodes is coupled to the first node, and a cathode of a diode at a second end of the n diodes is coupled to a third node.

A semiconductor relay device includes a conversion circuit configured to receive an input signal from outside and pass a first current to a first node based on the input signal. A zener diode has an anode coupled to a second node and a cathode coupled to the first node. A resistor is coupled between the second node and a third node. A number n of diodes are serially coupled. A thyristor has an anode coupled to the first node, a cathode coupled to the second node, and a control terminal coupled to the third node. A transistor has a gate coupled to the first node. An anode of a diode at a first end of the n diodes is coupled to the first node, and a cathode of a diode at a second end of the n diodes is coupled to a third node.

A semiconductor relay device includes a conversion circuit configured to receive an input signal from outside and pass a first current to a first node based on the input signal. A zener diode has an anode coupled to a second node and a cathode coupled to the first node. A resistor is coupled between the second node and a third node. A number n of diodes are serially coupled. A thyristor has an anode coupled to the first node, a cathode coupled to the second node, and a control terminal coupled to the third node. A transistor has a gate coupled to the first node. An anode of a diode at a first end of the n diodes is coupled to the first node, and a cathode of a diode at a second end of the n diodes is coupled to a third node.

A switch device includes first and second switch units that are coupled respectively to first and second output terminals. Each of the first and second switch units includes a plurality of diodes and at least one semiconductor-controlled rectifier (SCR), where at least one of the diodes and one of the at least one SCR cooperatively permit a current to flow therethrough to a corresponding one of the first and second output terminals when each thereof operates in an ON state, and where at least one of the diodes and one of the at least one SCR cooperatively permit a current to flow therethrough from a corresponding one of the first and second output terminals when each thereof operates in an ON state.

A switch device includes first and second switch units that are coupled respectively to first and second output terminals. Each of the first and second switch units includes a plurality of diodes and at least one semiconductor-controlled rectifier (SCR), where at least one of the diodes and one of the at least one SCR cooperatively permit a current to flow therethrough to a corresponding one of the first and second output terminals when each thereof operates in an ON state, and where at least one of the diodes and one of the at least one SCR cooperatively permit a current to flow therethrough from a corresponding one of the first and second output terminals when each thereof operates in an ON state.

A defibrillator disclosed in the present application including at least: a high voltage capacitor charged through a battery power source; a ladder bridge circuit connected to one end of the high voltage capacitor; a control unit for controlling an on/off operation of switching elements constituting the ladder bridge circuit, wherein the ladder bridge circuit comprises: a first circuit unit and a second circuit unit, one ends of which are connected to one end of the high voltage capacitor and which are connected in parallel to each other; and a third circuit unit connected in series to the other ends of the first circuit unit and the second circuit unit.

A switching device (28) comprising a primary switching block (30) including at least one semiconductor switch (34); and a switching control unit (32) to control the switching of the or each semiconductor switch (34). The switching device further includes a crowbar circuit (46) comprising a crowbar switch (56) switchable to selectively allow current to flow through the crowbar switch (56) in order to bypass the or each switching module; and a secondary switching block including a switching element (58) connected across a control electrode and a cathode of the crowbar switch (56). The switching element (58) is in communication with the switching control unit (32) to receive, in use, a control signal (66) generated by the switching control unit (32) when the primary switching block (30) is operating within predefined operating parameters.