A semiconductor switch device suitable for a.c. power control

Claim 2

A semiconductor switch device including a thyristor structure having a first and second four-layer semiconductor switch components formed in the same body of semiconductor material, and a first gate connection, wnerein there is provided a third four-layer semiconductor switch component in the same body so as to be electrically coupled to the first and second components, and an end terminal of the third component being electrically separate from corresponding terminals of the first and second components to provide a second gate connection for the device.

Claim 3

A device according to Claim 1 in which the body of semiconductor material comprises a first layer of a I irst conductivity type and a second layer overlying the first layer and of a second conductivity type opposite to the first conductivity type, the first component having a first region of the second conductivity type in the first layer and forming the gate of the device and a second region of the first conductivity type in the first region, the second component having a third region of the second conductivity type in the first layer and a fourth region opposite the third region, of the first conductivity type in the second layer, there being provided a connection joining the second and third regions forming a first main terminal of the device and metallization connecting a surface of the second layer opposite the first region to the fourth region, the metallization forming a second main terminal of the device.

Claim 4

A device according to Claim 2 wherein the third component has a fifth region of the second conductivity type in the first layer and a sixth region of the first conductivity type in the fifth region, the second gate connection being connected to the sixth region, and the metallization also being connected to the surface of the second layer opposite the fifth region.

Claim 5

A device according to Claim 2 wherein the third component has a fifth region of the second conductivity type in the first layer and a sixth region of the first conductivity type in the second layer opposite the fifth region, the second gate connection being connected to the fifth region and the metallization being additionally connected to the sixth region.

Claim 6

A device according to Claim 2 wherein the third component has a fifth region of the second conductivity type in the first layer and a sixth region of the first conductivity type in the second layer opposite the fifth region, the second gate connection being connected to the sixth region, and the fifth region being connected to the second and third regions.

Claim 7

A device according to Claim 3 or 5 wherein the first and fifth regions are joined to form a single region.

Claim 8

A device according to Claim 3, 4, 5 or 6 including at least one further region of the second conductivity type, but of low impurity concentration, in the first layer in which further region the first, third and fifth regions are formed.

Claim 9

A semiconductor switch device comprising three four-layer semiconductor switch components laterally positioned with respect to each other and extending from one major face to the other in the same body of semiconductor material, the body including a first layer of a first conductivity type extending to the major face, a second layer of a second conductivity type, opposite to the first conductivity type, extending from the first layer to the other major face, first, second and third regions of the second conductivity type formed in the first major face, first and second regions of the first conductivity type respectively formed in the first and second regions of the second conductivity and extending to the first major face,'and a third region of the first conductivity type formed in the other major face opposite the third region of the second conductivity type formed in the one major face, the first regions and adjacent parts of the first and second layers forming a first of the semiconductor switch components, the second regions and adjacent parts of the first and second layers forming a second of the semiconductor switch components, and the third regions and the parts of the first and second layers between them forming a third of the semiconductor switch components, the second regions being sufficiently close to the first and third regions for there to be sufficient d.c. coupling between the first and second components and between the second and third components for one of the components to be able to switch the other, a first main terminal being formed by an ohmic connection from the first region of the first conductivity type to the third region of the second conductivity type, a second main terminal being formed by an ohmic connection from the third region of the first conductivity type to parts of the other face of the body opposite the first and second regions, a first gate connection to the first region of the second conductivity type and a second gate connection to the second region of the first conductivity type.

Claim 10

A semiconductor switch device comprising three four-layer semiconductor switch components laterally positioned with respect to each other and extending from one major face to the other in the same body of semiconductor material, the body including a first layer of a first conductivity type extending to the major face, a second layer of a second conductivity type, opposite to the first conductivity type, extending from the first layer to the other major face, first, second and third regions of the second conductivity type formed in the first major face, first and second regions of the first conductivity type respectively formed in the first and second regions of the second conductivity and extending to the first major face,'and a third region of the first conductivity type formed in the other major face opposite the third region of the second conductivity type formed in the one major face, the first regions and adjacent parts of the first and second layers forming a first of the semiconductor switch components, the second regions and adjacent parts of the first and second layers forming a second of the semiconductor switch components, and the third regions and the parts of the first and second layers between them forming a third of the semiconductor switch components, the second regions being sufficiently close to the first and third regions for there to be sufficient d.c. coupling between the first and second components and between the second and third components for one of the components to be able to switch the other, a first main terminal being formed by an ohmic connection from the first region of the first conductivity type to the third region of the second conductivity type, a second main terminal being formed by an ohmic connection from the third region of the first conductivity type to parts of the other face of the body opposite the first and second regions, a first gate connection to the first region of the second conductivity type and a second gate connection to the second region of the first conductivity type.

Claim 11

A device according to Claim 8, wherein the first and second regions of the second conductivity type are joined to form a single region.

Claim 12

A device according to Claim 8 or 9 including at least one further region of the second conductivity type, but of low impurity concentration, in the first layer, in which further region the first, second and third regions of the second conductivity type are formed.

Claim 16

A semiconductor switch device substantially as described herein with reference to Figure 1 or Figure 2 of the accompanying drawings or modified as herein described.

Claim 17

A semiconductor switch device substantially as described herein with reference to Figure 1 or Figure 2 of the accompanying drawings or modified as herein described.

Claim 18

An integrated circuit incorporating a device according to any preceding claim.

Claim 19

A circuit according to Claim 15 including means for deriving from an a.c. supply when connected to the circuit a direct voltage suitable for application to the second gate connection of the device.

Claim 20

A circuit according to Claim 16 including means for applying to the first gate connection of the device an alternating voltage in phase with an a.c. supply when connected to the circuit, and a semiconductor control switch connected from the first gate connection to a conductor on which the direct voltage is established, a control gate connection for the circuit being connected to a control electrode of the semiconductor control switch.

Claim 21

A circuit according to Claim 17, wherein the semiconductor control switch is a thyristor.

Claim 22

A circuit according to Claim 18, including a second thyristor connecting the gate connection of the first mentioned thyristor to the conductor on which the direct voltage is established, the second thyristor being arranged to draw a predetermined current from the gate connection when the voltage on the gate connection differs by more than a predetermined amount from the voltage on the conductor on which the direct voltage is established.

Claim 23

A circuit according to Claim 17, wherein the semiconductor control switch is a bipolar semiconductor bistable circuit.

Claim 24

An integrated circuit substantially as described herein with reference to-Figure 3 or 4 of the accompanying drawings of modified as herein described.

Claim 25

An integrated circuit substantially as described herein with reference to-Figure 3 or 4 of the accompanying drawings of modified as herein described.

Claim 26

A circuit arrangement including an integrated circuit according to any of Claims 16 to 21, a capacitor connected to the integrated circuit to store the direct voltage, a load connected in series with the integrated circuit from one a.c. supply conductor to another, and means connected to the integrated circuit for providing a signal to control the a.c. power applied to the load.

Claim 27

A circuit arrangement substantially as described herein with reference to any of Figures 5 to 8 of the accompanying drawings.

Claim 28

A circuit arrangement substantially as described herein with reference to any of Figures 5 to 8 of the accompanying drawings.