Method of making square toroid transformer for hybrid integrated circuit

• US 4,847,986 A
• Filed: 09/30/1988
• Issued: 07/18/1989
• Est. Priority Date: 07/02/1986
• Status: Expired due to Term

• Current Assignee: Burr-Brown Corporation (Texas Instruments, Inc.)
• Original Assignee: Burr-Brown Corporation (Texas Instruments, Inc.)
• Inventors: Meinel, Walter B.
• Primary Examiner(s): Kozma, Thomas J.
• Application Number:
  US07/252,188
• Time in Patent Office: 291 Days
• Field of Search: 29/602.1, 29/606, 336/65, 336/200, 336/183, 336/184, 336/223, 336/221, 336/225
• US Class Current: 29/606
• CPC Class Codes: H01F 17/0033 with the coil helically wound around a magnetic core
• CPC Class Codes: H01F 17/062 Toroidal core with turns of coil around it
• CPC Class Codes: H01F 2027/2814 with only part of the coil or of the winding in the printed circuit board, e.g. the remaining coil or winding sections can be made of wires or sheets
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01F 30/16 Toroidal transformers
• CPC Class Codes: H01G 4/012 Form of non-self-supporting electrodes
• CPC Class Codes: H01G 4/38 Multiple capacitors, i.e. structural combinations of fixed capacitors
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 23/642 Capacitive arrangements H01L23/49589, H01L23/645, H01L23/647, H01L23/66 take precedence; capacitive effects between wiring layers on the semiconductor body H01L23/5222
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 25/165 Containers
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01014 Silicon [Si]
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01057 Lanthanum [La]
• CPC Class Codes: H01L 2924/01063 Europium [Eu]
• CPC Class Codes: H01L 2924/01068 Erbium [Er]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 2924/30107 : Inductance
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H05K 1/0306 : Inorganic insulating substrates, e.g. ceramic, glass
• CPC Class Codes: H05K 1/162 : incorporating printed capacitors
• CPC Class Codes: H05K 2201/09236 : Parallel layout
• CPC Class Codes: H05K 2201/10946 : Leads attached onto leadless component after manufacturing the component
• CPC Class Codes: Y10T 29/4902 : Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49073 : by assembling coil and core

Abstract

A square toroid transformer is assembled on a ceramic hybrid integrated circuit substrate. The primary and secondary windings of the transformer are provided on opposite arms of a square toroid ferrite core by providing first and second groups of spaced, parallel metal conductors on the surface of the ceramic substrate and adherent thereto, and an insulative layer over the first and second groups of conductors, leaving their respective end portions exposed. The square toroid ferrite core, coated with dielectric material, is attached to the insulative layer. Wire bonds in planes perpendicular to the longitudinal axes of the opposite arms each are wire bonded, respectively, to an inner end of one of the metal conductors and an outer end of an adjacent one. A large number of turns for both the primary winding and the secondary winding are achieved, resulting in high primary and secondary winding and inductances, while maintaining a uniform separation and high breakdown voltage between the primary and secondary wirings.

Claims

1. A method of making and operating a hybrid integrated circuit transformer, comprising the steps of:

(a) providing first and second groups of parallel metal strip conductors on a non-conductive substrate, each strip conductor having an inner end and an outer end;

(b) forming a layer of dielectric material on intermediate portions of each of the strip conductors between the inner outer ends thereof, the inner and outer ends extending beyond the layer of dielectric material;

(c) adhesively attaching a unitary rectangular magnetic core coated with dilectric material and having first, second, third, and fourth arms, the first and third arms being parallel and the second and fourth arms being parallel, the first group of strip conductors being under the first arm and the second group of strip conductors being under the third arm;

(d) forming a first group of bonding wire conductors looping over the first arm and each having first and second ends wire bonded to an outer end of a strip conductor of the first group and an inner end of an adjacent strip conductor of the first group, respectively, and also forming a second group of bondoing wire conductors looping over the third arm and each having first and second ends wire bonded to an outer end of a strip conductor of the second group and an inner end of an adjacent strip conductor of the second group, respectively; and

(e) producing a voltage difference between adjacent loops of the first and second groups of up to approximately 1,500 volts, whereby electrical arcing between the adjacent loops is avoided without application of parylene insulative coating to the hybrid integrated circuit transformer.