An isolator includes a substrate; a first planar coil provided above the substrate and along a surface of the substrate; a first insulating portion on the first planar coil; a second planar coil on the first insulating portion; and a metal layer above the first insulating portion. The first planar coil, the second planar coil, and the metal layer are arranged in a first direction perpendicular to the surface of the substrate. The first planar coil and the second planar coil each having a center and an outer perimeter in a second direction along the surface of the substrate. A distance in the second direction from the center of the first planar coil to the outer perimeter of the first planar coil is less than a distance in the second direction from the center of the second planar coil to the outer perimeter of the second planar coil.

Disclosed herein is a differential mode filter that includes first and second terminal electrodes provided on a first flange part of a core, and first and second wires wound around a winding core part of the core in an opposite direction to each other and connected respectively to the first and second terminal electrodes. The first and second wires cross each other on the winding core part to form a plurality of crossing portions that include first, second, and third crossing portions that are first, second, and third occurrences counting from the one end of the first and second wires, respectively. A first crossing angle between the first and second wires at the first crossing portion is larger than at least one of second and third crossing angles between the first and second wires at the second and third portions, respectively.

In order to transfer a signal for driving a high-side semiconductor power switch, a signal transfer device includes a transmitting circuit, a receiving circuit, and an insulating transformer provided between the transmitting circuit and the receiving circuit. In the insulating transformer, a secondary side of a set transformer part and a secondary side of a reset transformer part are magnetically coupled. The magnetic coupling direction is formed so that a secondary-side terminal of the transformer part and a secondary-side terminal of the transformer part can have polarities reverse to each other. Thus, it is possible to provide a signal transfer device for transferring a signal through an insulating transformer, in which occurrence of common-mode noise can be suppressed and a countermeasure circuit against the noise can be simplified.

In order to transfer a signal for driving a high-side semiconductor power switch, a signal transfer device includes a transmitting circuit, a receiving circuit, and an insulating transformer provided between the transmitting circuit and the receiving circuit. In the insulating transformer, a secondary side of a set transformer part and a secondary side of a reset transformer part are magnetically coupled. The magnetic coupling direction is formed so that a secondary-side terminal of the transformer part and a secondary-side terminal of the transformer part can have polarities reverse to each other. Thus, it is possible to provide a signal transfer device for transferring a signal through an insulating transformer, in which occurrence of common-mode noise can be suppressed and a countermeasure circuit against the noise can be simplified.

A semiconductor device has a semiconductor substrate, a first insulating layer, a first inductor, a second insulating layer, a second inductor, a pad and an annular wiring. The first insulating layer is formed on the semiconductor substrate. The first inductor is directly formed on the first insulating layer. The second insulating layer is formed on the first insulating layer such that the second insulating layer covers the first inductor. The second inductor is directly formed on the second insulating layer such that the second inductor faces the first inductor. The pad is directly formed on the second insulating layer. The pad is electrically connected with the second inductor. The annular wiring is electrically connected with the pad. The annular wiring is spaced apart from the second inductor. The annular wiring surrounds the second inductor without forming a vertex in plan view.

An electronic switching system and device comprising driver circuits for power transistors are disclosed, with particular application for MOSFET driven, normally-on gallium nitride (GaN) power transistors. Preferably, a low power, high speed CMOS driver circuit with an integrated low voltage, lateral MOSFET driver is series coupled, in a hybrid cascode arrangement, to a high voltage GaN HEMT and provides for improved control of noise and voltage transients. Monitoring and control functions, including latching and clamping, are based on monitoring of V.sub.cc conditions for shut-down and start-up conditioning to enable safer operation, particularly for high voltage and high current switching. Preferred embodiments also provide isolated, self-powered, high speed driver devices, with reduced input losses.

A semiconductor device has a semiconductor substrate, a first insulating layer, a first inductor, a second insulating layer, a second inductor, a pad and an annular wiring. The first insulating layer is formed on the semiconductor substrate. The first inductor is directly formed on the first insulating layer. The second insulating layer is formed on the first insulating layer such that the second insulating layer covers the first inductor. The second inductor is directly formed on the second insulating layer such that the second inductor faces the first inductor. The pad is directly formed on the second insulating layer. The pad is electrically connected with the second inductor. The annular wiring is electrically connected with the pad. The annular wiring is spaced apart from the second inductor. The annular wiring surrounds the second inductor without forming a vertex in plan view.

A pulse receiving circuit constituting a signal transmission device includes a first pulse detector that receives a differential input between a first reception pulse signal, i.e. an internal signal at a secondary winding of a first transformer and a second reception pulse signal, i.e. an internal signal at a secondary winding of a second transformer; a second pulse detector that receives the differential input between the first reception pulse signal and the second reception pulse signal with input polarity reversed to that of the first pulse detector; and a logic unit that generates a reception pulse signal based on output signals of the first and second pulse detectors, respectively.

An Isolating Transmission Line Transformer (ITLT) for use in a data communications system is provided, the transformer comprising: a substantially planar substrate formed of electrically insulative material having opposed first and second surfaces; a first port formed of two separate terminals provided at one part of the substrate; a second port formed of two separate terminals provided at a second part of the substrate; a first conductor connected in series to the first port and arranged as a single loop; a second conductor which is electrically isolated from the first conductor and connected in series to the second port, the second conductor being arranged as a single loop in a substantially opposite orientation to the first conductor; wherein the first and second ports and at least part of the first and second conductors are provided on the substrate surface(s); and a core arranged between the first and second ports to cover the majority of the first and second conductors.

An Isolating Transmission Line Transformer (ITLT) for use in a data communications system is provided, the transformer comprising: a substantially planar substrate formed of electrically insulative material having opposed first and second surfaces; a first port formed of two separate terminals provided at one part of the substrate; a second port formed of two separate terminals provided at a second part of the substrate; a first conductor connected in series to the first port and arranged as a single loop; a second conductor which is electrically isolated from the first conductor and connected in series to the second port, the second conductor being arranged as a single loop in a substantially opposite orientation to the first conductor; wherein the first and second ports and at least part of the first and second conductors are provided on the substrate surface(s); and a core arranged between the first and second ports to cover the majority of the first and second conductors.