DETAILED ACTION
This Office action is in response to the application filed on 17 June 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.
Response to argument
Applicant's arguments filed on 26 June 2026, with respect to the rejection of claim 1 have been fully considered but they are not persuasive. In response to applicant’s argument,
“First, in rejecting claim 1, the Examiner alleges that the capacitors Cresl, Cres2 in
Roberto corresponds to the claimed capacitor (Office Action page 5). However, in the circuit disclosed by Roberto, the DC voltage bias of the two resonant capacitors Cresl and Cres2 is Vin/2, i.e., <vcres>=Vin/2 (see Fig. 2 and page 1228, left column, section II of Roberto). In contrast, in the present application, the DC voltage bias of the resonant capacitor during operation is 0, i.e., <vcres>=0 (see paragraph [0017] of the publication).”, it is noted that argument about the capacitor DC bias voltages is arguing a limitation from the spec (form paragraph 7.37.08).
“Second, the voltage conversion range in Roberto's circuit and the current application are mathematically different. The ratio of the input voltage to the output voltage of Roberto's patented circuit is ….…….In contrast, for the claimed circuit, the ratio of the input voltage to the output voltage is …………where n=Nl/N2, Nl is the number of primary turns of the transformer, and N2 is the number of secondary turns of the transformer, both being positive integers. Because n is a natural number such as 1, 2, 3, ... etc., the claimed circuit can achieve transformation ratios such as 3:1, 4:1, ... etc. Conversely, Roberto's circuit can only achieve transformation ratios such as 6: 1, 8: 1, ... etc. Thus, the claimed circuit can be used to design a 4: 1 bus converter, but Roberto's circuit cannot achieve a 4: 1 voltage transformation ratio. The 4: 1 bus converter is widely used in the power supply field for GPU power boards and has huge application potential. Therefore, compared with the claimed circuit, Roberto's circuit has clear application limitations.”, it is noted that argument about the voltage conversion ratio range is again arguing limitation from the spec.
“Third, the Examiner alleges that it would have been obvious to modify Roberto's
device by deleting one of the LC series resonant converters from the transformer and connecting the primary winding in the manner described by Jin (Office Action page 8). In Jin's circuit, both the proximal power conversion unit and the distal power conversion unit are formed by four power switches connected in series. This is a prerequisite for Jin's circuit to work; otherwise, a short-circuit phenomenon would occur, all power switches would be damaged, and the circuit would not operate normally. Jin's circuit requires two additional resonant capacitors, Crl and Cr2 for operation. Crl is placed between points A and C of the proximal power conversion unit, and Cr2 is placed between points D and F of the distal power conversion unit (see Fig. 4 of Jin reproduced below). The two resonant capacitors serve a voltage-withstanding function. Otherwise, the circuit would not operate normally. In contrast, in the present application, both the proximal and distal power conversion units are formed by three power switches connected in series. If only the apparatus described by Roberto is modified, i.e., one LC series resonant converter is deleted from the transformer and the primary winding is connected in the manner described by Jin, the resulting circuit
would fail to work. The prerequisite for operation is to change it to four power switches in series and to add two resonant capacitors Crl and Cr2 for voltage withstanding. One of ordinary skill in the art would recognize that simply changing the transformer connection in Roberto to match Jin would not change Roberto's voltage conversion range, nor would it eliminate the DC bias from Roberto's flying capacitor architecture, which is a necessity for Roberto's hybrid switched-capacitor topology to enable zero-voltage switching (ZVS) operation for all MOSFETs and maintain high efficiency over the resonant frequency (see page 1290, right column section III of Roberto). Because the proposed combination
would disrupt the intrinsic operating principles of the references and render them
unsatisfactory for their intended purposes, one of ordinary skill in the art would have no motivation to combine them under MPEP § 2143.01.”, it is noted that argument about combination of references has a couple points to respond to: one could be bodily incorporation (FP 7.37.02), i.e. they are arguing you have to add 4 transistors in each leg when combining Roberto+Jin but that was not the modification you proposed. Two, their allegation that the modified system would be inoperable is simply attorney argument presented without evidence. MPEP 716.01(c). Third, it seems again they are saying that the proposed combination would not teach the limitations they pointed to from the spec about the DC bias of the capacitors and the # of switches in each leg (4 vs 3).
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 1-8 are rejected under 35 U.S.C. 103 as being unpatentable over Roberto Rizzolatti et. al (2021 IEEE Applied Power Electronics Conference and Exposition (APEC), DOI: 10.1109/APEC42165.2021.9487136; hereafter “Roberto”) in view of Da Jin et. al (US2023/0238173A1; hereafter “Jin”).
-Regarding claim 1;
Roberto discloses:
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A power conversion system (Fig. 2), comprising a positive input interface (Fig. 2; red arrow a), a negative input interface (Fig. 2; red arrow b), a positive output interface(Fig. 2; red arrow c), a negative output interface(Fig. 2; red arrow d), a resonant capacitor (Fig. 2; Cres1, Cres2) .a transformer(Fig. 2; green arrow), and a proximal power conversion unit (Fig. 2; Q1, Q2, and Q3) and a distal power conversion unit (Fig. 2; Q4, Q5, and Q6) connected in parallel between the positive input interface and the negative input interface, wherein an input capacitor(Fig. 2; Vin), is arranged between the positive input interface and the negative input interface, an output capacitor (Fig. 2; Vout) is arranged between the positive output interface and the negative output interface, the proximal power conversion unit comprises a proximal first power switch (Fig. 2;Q1) ,a proximal second power switch(Fig. 2;Q2), and a proximal third power switch(Fig. 2;Q3) connected in series, the distal power conversion unit comprises a distal first power switch(Fig. 2;Q4), a distal second power switch(Fig. 2;Q5), and a distal third power switch(Fig. 2;Q6) connected in series, the transformer comprises a primary winding(Fig. 2;N1) and two secondary windings(Fig. 2;N2), the two secondary windings have a same number of turns, after the resonant capacitor C and the primary winding are connected in series (Fig. 2; Cres1 and N1), undotted terminal of the secondary winding of the transformer is connected to a dotted terminal of the secondary winding of the transformer (Fig. 2; com), a dotted terminal of the secondary winding of the transformer is connected between the proximal second power switch and the proximal third power switch (Fig. 2; Vx), and an undotted terminal of the secondary winding of the transformer is connected between the distal second power switch and the distal third power switch (Fig.2; Vy ), a positive output port is connected to a connection line between the two secondary windings (Fig. 2; com) and, a negative output port is connected to a negative input port through a wire (Fig. 2; bottom line), and a ground wire is further connected to the wire between the negative output port and the negative input port (Fig. 2; ground point).
However, Roberto does not teach “one end is connected between the proximal first power switch and the proximal second power switch of the proximal power conversion unit, and the other end is connected between the distal first power switch and the distal second power switch of the distal power conversion unit; a dotted terminal of the primary winding of the transformer is located between the distal first power switch and the distal second power switch,”.
Roberto added the second LC series resonant converter to the transformer and connected the primary winding to a different node (between 2nd and 3rd switches). Roberto also discloses the identical results (Fig. 3) as the claimed invention (compare Fig. 7 in the claimed invention with Fig.3 in Roberto’s paper).
Jin discloses:
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one end is connected (above Fig; point E) between the proximal first power switch (above Fig; M6) and the proximal second power switch (above Fig; M7) of the proximal power conversion unit, and the other end is connected (above Fig; point B) between the distal first power switch(above Fig; M2) and the distal second power switch (above Fig; M3) of the distal power conversion unit; a dotted terminal of the primary winding of the transformer is located between the distal first power switch and the distal second power switch(above Fig; point B),
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 Roberto such that one of the LC series resonant converters is deleted from the transformer and the primary winding is connected as described in Jin. Doing so allows for providing a desirable level of a flexible voltage transformation ratio in the power conversion system.
-Regarding claim 2;
Roberto discloses:
The power conversion system according to claim 1, wherein the proximal first power switch, the distal second power switch and the proximal third power switch are controlled by a control signal I (Fig. 2; ɸa) to be turned on or off at the same time, the distal first power switch, the proximal second power switch, and the distal third power switch are controlled by a control signal II(Fig. 2; ɸb) to be turned on or off at the same time, and phases of the control signal I and the control signal II are offset from each other by 180 degrees (Fig. 3; operation waveform).
-Regarding claim 3;
Roberto discloses:
The power conversion system according to claim 2, wherein the proximal first power switch, the proximal second power switch, the distal first power switch, and the distal second power switch each are a Si MOSFET (Introduction part), a GaN HEMT, or a SiC MOSFET (Introduction part).
-Regarding claim 4;
Roberto discloses:
The power conversion system according to claim 2, wherein the proximal third power switch and the distal third power switch each are a Si MOSFET (Introduction part), a GaN HEMT, a SiC MOSFET (Introduction part), or a diode.
-Regarding claim 5;
Roberto discloses:
The power conversion system according to claim 1. wherein the primary winding and the two secondary windings are wound around a same magnetic core column (Fig. 2; N1 and N2).
-Regarding claim 6;
Roberto discloses:
The power conversion system according to claim 2, wherein the primary winding and the two secondary windings are wound around a same magnetic core column (Fig. 2; N1 and N2).
-Regarding claim 7;
Roberto discloses:
The power conversion system according to claim 3, wherein the primary winding and the two secondary windings are wound around a same magnetic core column (Fig. 2; N1 and N2).
-Regarding claim 8;
Roberto discloses:
The power conversion system according to claim 4, wherein the primary winding and the two secondary windings are wound around a same magnetic core column (Fig. 2; N1 and N2).
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. The reference (Cheng Li, A Comparative Study of Hybrid DC-DC Converters by Indirect Power) reviews and classifies hybrid converters from the perspective of the power processed by their components.
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.
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/SEUNG HO CHOI/Examiner, Art Unit 2838
/CRYSTAL L HAMMOND/Supervisory Primary Examiner, Art Unit 2838
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