General Electric Company

Martin Marietta Corporation

Alexander J Yerman

Khai D Ngo

Waseem A Roshen

Constantine A Neugebauer

James A Loughran

Robert Louis Steigerwald

Victor A Temple

Sayed-Amr A El-Hamamsy

Charles S Korman

Rayette Ann Fisher

Richard O Carlson

James G McMullen

Marshall D Ketchum

A transformer having a very low, predetermined leakage inductance includes an elongate dielectric laminate having two surfaces. A primary winding having a pattern conformal to the configuration of the laminate is disposed on one surface and extends substantially the length of the laminate. The laminate has at least one secondary winding disposed on its other surface. The laminate is rolled with a dielectric layer about a cylinder, and the primary and secondary windings are patterned such that the primary and secondary windings comprise interleaved winding layers with the dielectric layer disposed between each of the winding layers. The rolled laminate, dielectric layer, and windings are contained within a cylindrical magnetic pot core. The result is a transformer having tightly interleaved primary and secondary windings and, therefore, a very low leakage inductance. In addition, the distance between adjacent primary and secondary turns is fixed by the thickness of the dielectric layer; hence, the leakage inductance is highly predictable.

Very low leakage inductance, single-laminate transformer

A multi-pole magnetic component, such as an inductor, includes z-folded conductive film windings and a core having a plurality of pairs of spaced apart core posts extending between a base plate and a top plate of the core. The core includes an air gap that is distributed substantially evenly along the flux path. Magnetic flux flows through the core posts in a series manner so as to have an opposite flux direction in adjacent poles. Preferably, the air gap is determined such that the ratio of the distance between each adjacent core post and the distance between the base and top plates results in magnetic fields that are substantially tangential to the surface of the conductive film winding. Furthermore, the core posts are preferably shaped to have a larger cross sectional area at the base portion of the posts than at the top portion thereof. Alternatively, the core posts are attached to the bottom plate and are inserted into suitably shaped cut-out portions of the top plate. In either case, the air gap between each core post and the respective core plate is smaller around the center of the core post than at the outer edges thereof. As a result, flux is concentrated near the center of the core posts, thereby reducing fringing fields which, in turn, minimizes high-frequency winding losses.

High-frequency, low-profile inductor

A high-frequency, low-profile transformer having at least one pair of magnetic poles includes a primary winding having a z-folded, continuous primary conductive film with a generally serpentine configuration disposed on a primary dielectric membrane and further includes a z-folded, continuous secondary winding constructed from a plurality of secondary conductive film portions disposed on a secondary dielectric membrane. Each of the secondary conductive film portions is configured to form a single continuous path enclosing each of the magnetic poles in such manner that each path encloses one pole of each pair of the magnetic poles of each adjacent layer of the secondary winding. Each path thus continues along a respective fold of the winding stack. The secondary winding layers are interleaved with the primary winding layers and electrically connected together. In one preferred embodiment, the transformer has two pairs of magnetic poles, and each path formed by each secondary conductive film has a shape characterized as two generally ovoid portions connected together at a relatively wide midportion. Low-resistance conductive bridges are used to electrically connect the secondary conductive film portions together along alternate folds of the winding stack.

Z-foldable secondary winding for a low-profile, multi-pole transformer

A transformer having a barrel winding comprised of flat conductive film conductors is provided with a repeatable winding configuration by employing a dielectric metal laminate as the winding material and by patterning both primary and secondary windings on the same dielectric membrane, thereby fixing the relative positions of the primary winding and secondary winding terminals and conductors.

Barrel-wound conductive film transformer

A resonant converter, including a transformer for separating a high-voltage (primary) side from a relatively low-voltage (secondary) side, has at least one synchronous rectifier and an auxiliary sense winding coupled to the gate thereof. The input capacitances of the synchronous rectifiers are reflected to the primary side and the secondary side by the square of the ratio of the number of auxiliary sense winding turns to the number of primary and

Gate drive for synchronous rectifiers in resonant converters

A high-frequency transformer is constructed from a flexible circuit comprising a primary conductive film winding and one or more secondary conductive film windings disposed on a single dielectric membrane. The flexible circuit is folded to form a stack of primary winding layers interleaved with secondary winding layers and then inserted into a mangetic cup core. The flexible circuit is preferably patterned photolithographically.

Method of fabricating a high-frequency transformer

A folded conductive film winding transformer provides a plurality of poles and enables increased turns ratios or power handling capacity in structures which must meet severe height limitations.

Low-profile multi-pole conductive film transformer

A conductive film magnetic component such as an inductor or transformer includes a conductive film winding having a generally serpentine configuration when disposed in a plane. This film is folded to form a stack of layers with each 'layer' comprising part of a winding turn and with successive 'layers' connected at the folds via the continuous conductive film. The conductive film may be self-supporting and coated with a dielectric layer or may be disposed on a dielectric membrane. The film and membrane are preferably patterned photolithographically.

Method of making conductive film magnetic components

A package for a two-switching-device half bridge circuit comprises an insulating substrate having first, second and third external power terminals along with control terminals bonded to the substrate. The power terminals are configured to provide a straight-through-the package current path from the first external power terminal to the second or common external power terminal and from the second or common external power terminal to the third external power terminal. The control terminals are preferably Kelvin terminal pairs in order to minimize feedback from the power current paths to the control circuits. The power devices are preferably bonded to the first external power terminal and the second external power terminal, respectively, with their connections respectively to the second power terminal and third power terminal substantially identical in order to provide power current paths through the package having substantially identical electrical and thermal impedances. This half bridge package is appropriate for use in high performance, high frequency, half bridge circuits.

Half bridge device package, packaged devices and circuits

Conductive film magnetic components

A high-frequency transformer is constructed from a flexible circuit comprising a primary conductive film winding and one or more secondary conductive film windings disposed on a single dielectric membrane. The flexible circuit is folded to form a stack of primary winding layers interleaved with secondary winding layers and then inserted into a magnetic cup core. The flexible circuit is preferably patterned photolithographically.

High-frequency transformer

A semiconductor hermetic package for semiconductor device comprises base, sidewall and cover members. Signals can be coupled between the enclosed devices and external devices by coupling means including conductive regions disposed in and through the package. Light pipes or conductive tracks and paths extending through the package can be used to couple the signals. A portion of the package can function as a grading resistance.

Hermetic semiconductor enclosure

An additive process allowing discretionary interconnection of only the acceptable devices on a semiconductor wafer includes screen printing a polyimide layer over the wafer to form vias over all of the device contact pads on the wafer while coating the remainder of the wafer. The devices are then individually tested through the vias and, when a device is determined to be unacceptable according to predetermined specifications, the vias above that device are filled with polyimide. A layer of metal is next deposited over the entire wafer by evaporation and makes electrical contact with only the acceptable devices since the unacceptable devices have been blocked off. The metal layer is thereafter patterned to leave an interconnection pattern wherein only the acceptable devices on the wafer are electrically connected.

Screenable power chip mosaics, a method for fabricating large power

An impermeable encapsulation system for integrated circuit chips utilizes a polyimide-siloxane block copolymer as an undercoat applied to the chip surface and an impermeable outer coat comprised either of a non-reactive metal, such as titanium, tantalum or aluminum, or an amorphous semiconductor material comprising silicon-boron. All of these materials may be effectively applied at temperatures sufficiently low to avoid damaging the chip.

Impermeable encapsulation system for integrated circuits

A method for fabricating a composite semiconductor from a plurality of substantially identical individual semiconductor devices formed on a common semiconductor wafer includes testing the devices on the wafer to generate a positional mapping of acceptable and non-acceptable devices, dividing the wafer into a plurality of areas of arbitrary size, connecting corresponding contact pads on only the acceptable devices within a given area to each other via common conductive paths which are supported on a dielectric film covering the pads, the film having appropriately located holes filled with conductive material to electrically couple the common conductive paths and the underlying contact pads of only the acceptable devices. The devices within a given area are intercoupled in a manner to form an operational array; single or multiple arrays may be coupled together to form a composite package having common external contacts and heat sink supports.

Growing community of inventors

Scotia, NY, United States of America

Alexander J Yerman