Prosecution Insights
Last updated: April 19, 2026
Application No. 18/726,032

DC-DC CONVERTER OF POWER CONVERSION SYSTEM

Non-Final OA §103
Filed
Jul 01, 2024
Examiner
CHOI, SEUNG HO
Art Unit
2838
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Ls Electric Co. Ltd.
OA Round
1 (Non-Final)
100%
Grant Probability
Favorable
1-2
OA Rounds
2y 7m
To Grant
0%
With Interview

Examiner Intelligence

Grants 100% — above average
100%
Career Allow Rate
1 granted / 1 resolved
+32.0% vs TC avg
Minimal -100% lift
Without
With
+-100.0%
Interview Lift
resolved cases with interview
Typical timeline
2y 7m
Avg Prosecution
12 currently pending
Career history
13
Total Applications
across all art units

Statute-Specific Performance

§103
100.0%
+60.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1 resolved cases

Office Action

§103
DETAILED ACTION This Office action is in response to the application filed on 01 July 2024. 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 . Priority Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55. Specification The disclosure is objected to because of the following informalities: In paragraph [37], “the controller 7 may control a plurality of switches of the DC-DC converter 10 individually to perform” provides an informality. I suggest a change from converter 10 to converter 1. In paragraph [65], “twelfth switches S11 and S12 are connected in series. is connected in series.” provides the informality. In paragraph [69], “the ninth switch S9 is turned off before both the ninth switch S9 and the tenth switch S10 are turned off,” provides the informality. 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. Claims 1, 5, and 6 are rejected under 35 U.S.C. 103 as being unpatentable over Hong Sung Su et. al (KR-101935452-B1; hereafter “Hong”) in view of Bae Sun Ho et. al (KR-20210009936-A; hereafter “Bae”). -Regarding claim 1; Hong discloses: A DC-DC converter (Fig. 6a) comprising: a first stage converter (Fig. 6a; 100)second stage converter (Fig. 6a; 200) connected to an output of the first stage converter (Fig. 6a; 100), Bae discloses; PNG media_image1.png 722 910 media_image1.png Greyscale A DC-DC converter comprising: a first stage converter (Fig. 4) configured to step up or step down an input voltage (Fig. 4; Vin) and output (Fig. 4; Vo) the stepped up or stepped down input voltage; and a first to fourth switches (Fig. 4; S1,S2,S3,S4) connected in series; fifth to eighth switches(Fig. 4; S5,S6,S7,S8) connected in series; a first capacitor (Fig. 4; 21) connected in parallel to a series connection of the first and second switches; a second capacitor (Fig. 4; 23) connected in parallel to a series connection of the third and fourth switches; a third capacitor (Fig. 4; 22) connected in parallel to a series connection of the fifth and sixth switches; a fourth capacitor (Fig. 4; 24) connected in parallel to a series connection of the seventh and eighth switches; a first inductor(Fig. 4; L1) electrically connected to a first node (Fig. 4; A) between the first and second switches and a second node (Fig. 4; B) between the fifth and sixth switches; and a second inductor(Fig. 4; L2) electrically connected to a third node(Fig. 4; C) between the third and fourth switches and a fourth node(Fig. 4; D) between the seventh and eighth switches. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device described in Hong such that a commonly used step up/down converter in power transform described in Bae is applied to the DC-DC converter of power conversion system as the first stage converter. Doing so allows for operating with high operating efficiency regardless of specific voltage conditions and high voltage circuit to be configured with a low voltage switching element. -Regarding claim 5: Bae discloses: The DC-DC converter of claim 1, wherein the first inductor and the second inductor are coupled to each other to form a coupled inductor (Fig. 4; z shaped line between two inductors L1 and L2). -Regarding claim 6: Bae discloses: The DC-DC converter of claim 1, wherein the first stage converter (Fig. 4) is configured such that a plurality of first converters (Fig. 7; wherein three first stage converters) each including the first to eighth switches, the first to fourth capacitors, and the first and second inductors are connected in parallel. Claim(s) [ 2, 3, and 7 ] is/are rejected under 35 U.S.C. 103 as being unpatentable over Hong Sung Su et. al (KR-101935452-B1; hereafter “Hong”) as applied to claim above Bae Sun Ho et. al (KR-20210009936-A; hereafter “Bae”), and further in view of Alfred Rufer et. al (2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe) DOI: 10.1109/EPE.2015.7309167; hereafter “Alfred”). -Regarding claim 2: The combination of Hong and Bae does not disclose the details of the second stage converter. Alfred discloses: PNG media_image2.png 530 835 media_image2.png Greyscale The DC-DC converter of claim 1, wherein the second stage converter (Fig. 5a) includes: a transformer (Fig. 5a; red circle); ninth to twelfth switches (Fig. 5a; black arrows, T1, T2, T3, T4) disposed on a primary side of the transformer; and thirteenth to sixteenth switches (Fig. 5a; red arrows, which indicate diodes only without transistors) disposed on a secondary side of the transformer. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device described in Hong such that a commonly used step up/down converter in power transform described in Bae, and an NPC half-bridge for a higher operating voltage described in Alfred are applied to the DC-DC converter of power conversion system as the first stage converter, and the second stage converter each. Doing so allows for operating with high operating efficiency regardless of specific voltage conditions and high voltage circuit to be configured with a low voltage switching element. -Regarding claim 3: Alfred discloses: The DC-DC converter of claim 2, wherein the second stage converter includes: a first diode (Fig. 5a; Dp) connected between the ninth switch (Fig. 5a; T1) and the tenth switch (Fig. 5a; T2); and a second diode (Fig. 5a; Dn) connected between the eleventh switch (Fig. 5a; T3) and the twelfth switch (Fig. 5a; T4). -Regarding claim 7: Alfred discloses: The DC-DC converter of claim 6, wherein the second stage converter (Fig. 5a) is configured such that a plurality of second converters (Fig. 6a, wherein two second stage converters) each including the transformer and the ninth to sixteenth switches (diodes only without transistors in 13th to 16th switches) are connected in parallel at inputs thereof and connected in series at outputs thereof. Allowable Subject Matter Claim 4 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim. The following is a statement of reasons for the indication of allowable subject matter: -with respect to claim 4: the prior arts in Bae, Hong, and Alfred disclose the claimed invention in basic claims but do not further disclose about the switch operation which is in complementary manner. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Any inquiry concerning this communication or earlier communications from the examiner should be directed to SEUNG HO CHOI whose telephone number is (571)272-8188. The examiner can normally be reached Monday-Thursday, 7:30 AM - 5:30 PM ET. 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, Crystal Hammond can be reached at 571-270-1682. 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. /SEUNG HO CHOI/Examiner, Art Unit 2838 /CRYSTAL L HAMMOND/Supervisory Primary Examiner, Art Unit 2838
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Prosecution Timeline

Jul 01, 2024
Application Filed
Mar 03, 2026
Non-Final Rejection — §103 (current)

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Prosecution Projections

1-2
Expected OA Rounds
100%
Grant Probability
0%
With Interview (-100.0%)
2y 7m
Median Time to Grant
Low
PTA Risk
Based on 1 resolved cases by this examiner. Grant probability derived from career allow rate.

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