Signal transmission circuit

1 . A signal transmission circuit for transmitting an insulation signal, comprising:

a multilayer substrate including a plurality of layers that are always connected to one another; and

a pattern transformer disposed on the multilayer substrate,

wherein the pattern transformer includes

a primary winding having a wound printed pattern wiring provided in each of a first plane region and a second plane region of the multilayer substrate, and

a secondary winding disposed at a different position from the primary winding in a layer direction and having a wound printed pattern wiring provided in each of the first plane region and the second plane region of the multilayer substrate,

wherein the primary winding and the secondary winding are electromagnetically coupled, and

wherein the primary winding and the secondary winding are configured such that a current flows clockwise through one of the wound printed pattern wiring provided in the first plane region or the wound printed pattern wiring provided in the second plane region while a current flows counterclockwise through the other one of the wound printed pattern wiring provided in the first plane region or the wound printed pattern wiring provided in the second plane region,

wherein the plurality of layers includes: a first pattern layer with the printed pattern wiring of the secondary winding; a second pattern layer with the printed pattern wiring of the secondary winding formed on one side of the first pattern layer; a third pattern layer with the printed pattern wiring of the primary winding formed on one side of the second pattern layer; a fourth pattern layer with the printed pattern wiring of the primary winding formed on one side of the third pattern layer;

a first insulating layer disposed between the first pattern layer and the second pattern layer; a second insulating layer disposed between the second pattern layer and the third pattern layer; and a third insulating layer disposed between the third pattern layer and the fourth pattern layer, and

wherein the first insulating layer and the third insulating layer are provided with connection portions, including a first connection portion disposed in the first plane region and a second connection portion disposed in the second plane region, for connecting the printed pattern wirings adjacent to each other in the layer direction;

wherein the printed pattern wiring of the primary winding is formed in the third pattern layer and the fourth pattern layer, and wherein the printed pattern wiring of the primary winding includes: a first winding portion which is, starting from a positive end, wound clockwise and spirally inward around the first connection portion of the third insulating layer and extending to be connected to the first connection portion, in the first plane region of the fourth pattern layer; a second winding portion which is connected to the first winding portion via the first connection portion and, starting from the first connection portion in the third pattern layer, wound clockwise and spirally outward around the first connection portion, in the first plane region of the third pattern layer; a third winding portion which is connected to a negative end of the second winding portion, and, starting from the negative end of the second winding portion, wound counterclockwise and spirally inward around the second connection portion and extending to be connected to the second connection portion, in the second plane region of the third pattern layer; and a fourth winding portion which is connected to the third winding portion via the second connection portion and, starting from the second connection portion in the fourth pattern layer, wound counterclockwise and spirally outward around the second connection portion, and connected to a negative end, in the second plane region of the fourth pattern layer,

wherein the printed pattern wiring of the secondary winding is formed in the first pattern layer and the second pattern layer, and wherein the printed pattern wiring of the secondary winding includes: a fifth winding portion which is, starting from a positive end, wound clockwise and spirally inward around the second connection portion of the first insulating layer and extending to be connected to the second connection portion, in the second plane region of the first pattern layer; a sixth winding portion which is connected to the fifth winding portion via the second connection portion and, starting from the second connection portion in the second pattern layer, wound clockwise and spirally outward around the second connection portion, in the second plane region of the second pattern layer; a seventh winding portion which is connected to a negative end of the sixth winding portion, and, starting from the negative end of the sixth winding portion, wound counterclockwise and spirally inward around the first connection portion and extending to be connected to the first connection portion, in the first plane region of the second pattern layer; and an eighth winding portion which is connected to the seventh winding portion via the first connection portion and, starting from the first connection portion in the first pattern layer, wound counterclockwise and spirally outward around the first connection portion, and connected to a negative end, in the first plane region of the first pattern layer.

2 . The signal transmission circuit according to claim 1 ,

wherein the primary winding is configured such that a current flows clockwise through the wound printed pattern wiring provided in the first plane region while a current flows counterclockwise through the wound printed pattern wiring provided in the second plane region, and

wherein the secondary winding is configured such that a current flows counterclockwise through the wound printed pattern wiring provided in the first plane region while a current flows clockwise through the wound printed pattern wiring provided in the second plane region.

3 . The signal transmission circuit according to claim 1 ,

wherein one secondary-side end of the pattern transformer is connected to one end of a coil,

wherein another end of the coil is connected to one end of a first capacitor,

wherein another end of the first capacitor is connected to another secondary-side end of the pattern transformer, and

wherein the coil and the first capacitor form a resonance circuit which resonates with an AC signal output from a secondary side of the pattern transformer.