US 12,651,691 B2Granted

Voltage-isolated integrated circuit packages with planar transformers

AssigneeAllegro MicroSystems, LLC

InventorWilliam P. Taylor

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Abstract

Aspects of the present disclosure include systems, structures, circuits, and methods providing planar transformers and planar transformer structures. The planar transformers and transformer structures can include first and second core layers of soft ferromagnetic material on opposite sides of an electrical substrate. First and second coils can be configured as conductive traces disposed on the opposite sides of the substrate. The first and second soft ferromagnetic layers are in contact in a contact region. One or more holes are disposed in either or both of the soft ferromagnetic layers and contain soft ferromagnetic material to reduce reluctance of the transformer structure. The planar transformer can be included in integrated circuit (chip) packages or modules. The packages and modules may include various types of circuits; in some examples, chip packages or modules may include a gate driver or other high voltage circuit.

Claims21

Dependent claims

A planar transformer comprising:

a first substrate portion having a first plurality of conductive traces forming a first coil;
a second substrate portion having a second plurality of conductive traces forming a second coil, wherein the second substrate portion is substantially parallel with and spaced apart from the first substrate portion, wherein the transformer comprises the first and second coils;
a first core layer disposed over a first surface of the first substrate portion, wherein the first core layer comprises a soft ferromagnetic material;
a second core layer disposed over a second surface of the second substrate portion, wherein the second core layer comprises a soft ferromagnetic material;
wherein a first contact portion of the first core layer is in contact with a second contact portion of the second core layer at a contact region between the first and second substrate portions;
a first insulating layer disposed between the first surface of the first substrate portion and the first core layer;
a second insulating layer disposed between the second surface of the second substrate portion and the second core layer;
one or more through holes disposed in the first or second core layer, wherein the one or more through holes comprise a soft ferromagnetic material to connect the first core layer to the second core layer, wherein connections to the respective first and second coils are galvanically isolated from each other;
and
a post disposed between the first and second core layers and between the first and second substrate portions, wherein the post comprises a soft ferromagnetic material wherein the first and second coils are magnetically coupled by the first and second core layers, the post, and the soft ferromagnetic material of the holes to provide a magnetic path to channel flux created by the currents flowing in the first and second coils of the transformer.

7 more elements

A method of making a planar transformer structure, the method comprising:

providing first and second substrate portions, wherein the second substrate portion is substantially parallel with and spaced apart from the first substrate portion;
providing first and second coils to the first and second substrate portions, respectively;
providing a first core layer, having soft ferromagnetic material, over a first surface of the first substrate portion, covering a portion of the first coil;
providing a second core layer, having soft ferromagnetic material, over a second surface of the second substrate portion, covering a portion of the second coil, wherein the transformer comprises the first and second coils;
causing the first core layer to contact the second core layer at a contact region;
forming a first insulating layer in between the first surface of the first substrate portion and the first core layer;
forming a second insulating layer disposes between the second surface of the second substrate portion and the second core layer;
forming one or more holes in the first or second core layer at the contact region;
introducing soft ferromagnetic material into the one or more holes, wherein the soft ferromagnetic material connects the first core layer to the second core layer;
and
providing a post disposed between the first and second core layers and between the first and second substrate portions, wherein the post comprises a soft ferromagnetic material wherein the first and second coils are magnetically coupled by the first and second core layers, the post, and the soft ferromagnetic material of the holes to provide a magnetic path to channel flux created by the currents flowing in the first and second coils of the transformer.

8 more elements

Dependencies are inferred from the claim text.