Prosecution Insights
Last updated: August 16, 2026
Application No. 18/600,226

A CO-PLANAR TRANSFORMER AND WINDING CONFIGURATION

Non-Final OA §103
Filed
Mar 08, 2024
Priority
Mar 10, 2023 — provisional 63/451,444
Examiner
LEWIS, MONICA
Art Unit
2838
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Mcmaster University
OA Round
2 (Non-Final)
32%
Grant Probability
At Risk
2-3
OA Rounds
10m
Est. Remaining
49%
With Interview

Examiner Intelligence

Grants only 32% of cases
32%
Career Allowance Rate
19 granted / 60 resolved
-36.3% vs TC avg
Strong +17% interview lift
Without
With
+17.1%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
17 currently pending
Career history
77
Total Applications
across all art units

Statute-Specific Performance

§101
2.7%
-37.3% vs TC avg
§103
59.8%
+19.8% vs TC avg
§102
23.4%
-16.6% vs TC avg
§112
12.0%
-28.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 60 resolved cases

Office Action

§103
DETAILED ACTION This action is in response to the amendment filed on 4/15/2026. Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Specification The title of the invention is not descriptive. A new title is required that is clearly indicative of the invention to which the claims are directed. Response to Arguments Applicant’s arguments have been fully considered and are persuasive. Therefore, the rejection has been withdrawn and a new ground(s) of rejection is made. Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claim(s) 1, 8-9, 11-12 is/are rejected under 35 U.S.C. 103 as being unpatentable over US Doc. No. US20220399153A1 (hereinafter Mukherjee) in view of US Doc. No. US 20130293336 A1 (hereinafter Lo) Regarding claim 1, Mukherjee discloses a co-planar transformer [e.g. Fig. 1A, element 115] comprising:- a printed circuit board comprising a plurality of primary windings and a plurality of secondary windings [e.g. Fig. 3, elements 320]; paragraph 0039, “Windings are formed using conductive traces on several different layers of a PCB to produce an isolated output”] , - wherein a number of the plurality of primary windings is equal to a number of the plurality of secondary windings [e.g. Fig. 5, elements 505 & 515]; - wherein the plurality of primary windings and the plurality of secondary windings are provided on the printed circuit board [e.g. paragraph 0039, “Windings are formed using conductive traces on several different layers of a PCB to produce an isolated output”]; and - wherein the plurality of primary windings and the plurality of secondary windings are in an interleaving configuration [e.g. paragraph 0039, “ the windings 320 are interleaved throughout the PCB layers”]. Mukherjee fails to disclose wherein the interleaving is provided horizontally across the printed circuit board Lo teaches wherein the interleaving is provided horizontally across the printed circuit board [e.g. Fig. 1, elements 108 & 110]. It would be obvious to someone having ordinary skill in the art, before the effective filing date, to modify Mukherjee to further include wherein the interleaving is provided horizontally across the printed circuit board as taught by Lo to improve transformer efficiency. Regarding claim 8, Mukherjee a dual-active bridge converter [e.g. Fig. 1, element 110] comprising:- a primary circuit [e.g. Fig. 1, the circuit of 4 switches on the side of the transformer with element 105] coupled to an input voltage [e.g. Fig. 1, element 105], - a secondary circuit coupled to an output voltage [e.g. Fig. 1, elements 140]; - a co-planar transformer isolating the primary circuit from the secondary circuit [e.g. Fig. 1, element 115]; - the co-planar transformer comprising: - a printed circuit board comprising a plurality of primary windings and a plurality of secondary windings [e.g. Fig. 3, elements 320]; paragraph 0039, “Windings are formed using conductive traces on several different layers of a PCB to produce an isolated output”]; - wherein a number of the plurality of primary windings is equal to a number of the plurality of secondary windings [e.g. Fig. 5, elements 505 & 510]; - wherein the plurality of primary windings and the plurality of secondary windings are provided on the printed circuit board [e.g. paragraph 0039, “Windings are formed using conductive traces on several different layers of a PCB to produce an isolated output”]; and - wherein the plurality of primary windings and the plurality of secondary windings are in an interleaving configuration [e.g. paragraph 0039, “ the windings 320 are interleaved throughout the PCB layers”]. Mukherjee fails to disclose wherein the interleaving is provided horizontally across the printed circuit board Lo teaches wherein the interleaving is provided horizontally across the printed circuit board [e.g. Fig. 1, elements 108 & 110]. It would be obvious to someone having ordinary skill in the art, before the effective filing date, to modify Mukherjee to further include wherein the interleaving is provided horizontally across the printed circuit board as taught by Lo to improve transformer efficiency. Regarding claim 9, Mukherjee discloses the dual-active bridge converter of claim 8, wherein the primary circuit comprises four input bridge switches [e.g. Fig. 1, first 4 switches connected directly to element 105], and the plurality of primary windings comprising a corresponding primary voltage and a primary current [e.g. abstract, “Various embodiments of the present disclosure relate to power conversion using a planar transformer assembly”]. Regarding claim 11, Mukherjee discloses the dual-active bridge converter of claim 9, wherein the secondary circuit further comprises four output bridge circuits [e.g. Fig. 1, 4 switches in element 125], and the plurality of secondary windings comprising a corresponding secondary voltage and a secondary current [e.g. abstract, “Various embodiments of the present disclosure relate to power conversion using a planar transformer assembly”]. Regarding claim 12, Mukherjee discloses the dual-active bridge converter of claim 11, further comprising an output capacitor [e.g. Fig. 1, element 120] in parallel to the four output bridge switches [e.g. Fig. 1, 4 switches in element 125]. Claim(s) 2 is/are rejected under 35 U.S.C. 103 as being unpatentable over US Doc. No. US20220399153A1 (hereinafter Mukherjee) in view of US Doc. No. US 20130293336 A1 (hereinafter Lo) and US Doc. No. US8310329B1 (hereinafter Herbert). Regarding claim 2, Mukherjee discloses the co-planar transformer of claim 1, wherein:- the printed circuit board is a two-layer board [e.g. Fig. 5, elements 520 & 525] connected by vias [e.g. paragraph 0006, “Each primary and secondary winding is interleaved on layers of a printed circuit board using one or more vias providing electrical connections within the layers of the printed circuit board”]. Mukherjee fails to disclose the plurality of the primary windings and the plurality of the secondary windings is duplicated on the two layers of the printed circuit board; and - each of the plurality of primary and secondary windings on a top layer of the two-layer board is connected in parallel to a corresponding winding on a bottom layer of the two-layer board through a corresponding via. Herbert teaches the plurality of the primary windings [e.g. Fig. 9, elements 65] and the plurality of the secondary windings [e.g. Fig. 9, element 64] is duplicated on the two layers of the printed circuit board [e.g. Fig. 9, element 63]; and - each of the plurality of primary and secondary windings on a top layer of the two-layer board [e.g. Fig. 9, top elements 64 & 65] is connected in parallel [e.g. paragraph 0088, “As a generality, alternate layers of the winding are connected in parallel”]to a corresponding winding on a bottom layer of the two-layer board [e.g. Fig. 9, bottom elements 64 & 65]. It would be obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Mukherjee to incorporate the teachings of Herbert to duplicate the winding on both layers to reduce construction costs and height. Claim(s) 3-4 is/are rejected under 35 U.S.C. 103 as being unpatentable over US Doc. No. US20220399153A1 (hereinafter Mukherjee) in view of US Doc. No. US 20130293336 A1 (hereinafter Lo) and CN Doc. No. CN114864239A (hereinafter Zhang). Regarding claim 3, Mukherjee fails to disclose the co-planar transformer of claim 1, further comprising:- two printed circuit boards; and - wherein the plurality of primary windings of each of a first and a second printed circuit board of the two printed circuit boards are connected in series. Zhang teaches the co-planar transformer of claim 1, further comprising:- two printed circuit boards [e.g. abstract, “The planar transformer comprises a first PCB, a second PCB”]; and - wherein the plurality of primary windings of each of a first and a second printed circuit board of the two printed circuit boards are connected in series [e.g. paragraph 0040, “In the embodiment of the present application, the first primary winding is connected in series with the second primary winding”]. It would be obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Mukherjee to incorporate the teachings of Herbert to reduce leakage inductance and improve the performance of the transformer. Regarding claim 4, Mukherjee fails to disclose the co-planar transformer of claim 3:- wherein the plurality of secondary windings of each of the first and the second printed circuit boards are connected in parallel. Zhang teaches the co-planar transformer of claim 3:- wherein the plurality of secondary windings of each of the first and the second printed circuit boards are connected in parallel [e.g. paragraph 0040, “the first secondary winding is connected in parallel with the second secondary winding”]. It would be obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Mukherjee to incorporate the teachings of Zhang to reduce leakage inductance and improve the performance of the transformer. Claim(s) 5 is/are rejected under 35 U.S.C. 103 as being unpatentable over US Doc. No. US20220399153A1 (hereinafter Mukherjee) in view of US Doc. No. US 20130293336 A1 (hereinafter Lo), CN Doc. No. CN114864239A (hereinafter Zhang) and JP Document ID JP2012026780A (hereinafter Kenichi) . Regarding claim 5, Mukherjee fails to disclose the co-planar transformer of claim 3, wherein: - the plurality of primary windings of each of the first and second printed circuit boards are connected through soldered copper rods. Kenichi teaches the co-planar transformer of claim 3, wherein: - the plurality of primary windings of each of the first and second printed circuit boards are connected through soldered copper rods [e.g. paragraph 0063, “By soldering from the tip part of the winding end, the solder soaks and penetrates both the surface of each of the metal wires (copper wires) composing the litz wire, stranded wire or parallel wire and the surface of the terminal metal fitting (copper or copper alloy)”]. It would be obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Mukherjee to incorporate the teachings of Kenichi to use copper as the connecting material to improve the conductivity of the connecting material. Claim(s) 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over US Doc. No. US20220399153A1 (hereinafter Mukherjee) in view of US Doc. No. US 20130293336 A1 (hereinafter Lo), CN Doc. No. CN114864239A (hereinafter Zhang) and TW Document ID. TW200915361A (hereinafter Siessegger). Regarding claim 6, Mukherjee fails to disclose the co-planar transformer of claim 4, wherein:- the plurality of secondary windings of each of the first and second printed circuit boards are connected through connection rods inserted through parallel pads for each secondary winding on each board. Siessegger teaches the co-planar transformer of claim 4, wherein:- the plurality of secondary windings [e.g. paragraph 22, “The main circuit board and the sub-circuit board are respectively provided with windings (not shown) forming the conductor rails, and each winding forms the front-stage winding and the secondary winding of the flat transformer”] of each of the first and second printed circuit boards [e.g. Fig. 1, elements 4 & 6] are connected through connection rods [e.g. Fig. 1, elements 22] inserted through parallel pads [e.g. Fig. 1, element 20] for each secondary winding on each board. It would be obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Mukherjee to incorporate the teachings of Siessegger to minimize size. Claim(s) 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over US Doc. No. US20220399153A1 (hereinafter Mukherjee) in view of US Doc. No. US 20130293336 A1 (hereinafter Lo) and DE Document ID. DE 102018005043 A1 (hereinafter Gossen). Regarding claim 7, Mukherjee discloses the co-planar transformer of claim 1, further comprising:- three stacks of printed circuit boards, wherein each stack comprises six printed circuit boards connected in parallel to each other; and - the three stacks are connected in series to each other. Mukherjee fails to disclose wherein each stack comprises a six printed circuit boards connected in parallel to each other. Gossen teaches wherein each stack comprises a six printed circuit boards connected in parallel to each other [e.g. paragraph 0029, “In other words, at least three circuit boards form a stack. Even more than three circuit boards, e.g. For example, four or six printed circuit boards as part of the planar transformer are conceivable. The windings of the additional circuit board(s) are connected either in series or in parallel to the windings of the first and second circuit boards”]. It would be obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Mukherjee to incorporate the teachings of Gossen to improve modularity and adjustability of the transformation ratio. Claim(s) 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over US Doc. No. US20220399153A1 (hereinafter Mukherjee) in view of US Doc. No. US 20130293336 A1 (hereinafter Lo) and WO2020170783A1 (hereinafter Nishizaka). Regarding claim 10, Mukherjee fails to disclose an input capacitor in parallel to the four input bridge switches. Nishizaka teaches an input capacitor [e.g. Fig. 1 element 103] in parallel to the four input bridge switches [e.g. Fig. 1, elements 111-114]. It would be obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Mukherjee to incorporate the teachings of Nishizaka to decrease size and increase power density of the transformer. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to JARED RAYMOND HAUSMAN whose telephone number is (571)272-6139. The examiner can normally be reached M-F. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Monica Lewis can be reached at 5712721838. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /MONICA LEWIS/Supervisory Patent Examiner, Art Unit 2838 /JARED RAYMOND HAUSMAN/Examiner, Art Unit 2838
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Prosecution Timeline

Mar 08, 2024
Application Filed
Jan 15, 2026
Non-Final Rejection mailed — §103
Apr 15, 2026
Response Filed
Jul 07, 2026
Non-Final Rejection mailed — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

2-3
Expected OA Rounds
32%
Grant Probability
49%
With Interview (+17.1%)
3y 3m (~10m remaining)
Median Time to Grant
Moderate
PTA Risk
Based on 60 resolved cases by this examiner. Grant probability derived from career allowance rate.

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