DETAILED ACTION
This office action is in response to the amendment filed on 04/02/2026.
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 .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 03/07/2024, 03/17/2024, 04/12/2024 and 10/14/2024 has been considered by the examiner.
Specification
The lengthy specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant’s cooperation is requested in correcting any errors of which applicant may become aware in the specification.
Claim Interpretation
In re to claims 13-15, 17-20, 22 and 27-28 method claims are rejected based on the following case law, note that under MPEP 2112.02, the principles of inherency, if a prior art device, in its normal and usual operation, would necessarily perform the method claimed, then the method claimed will be considered to be anticipated by the prior art device. When the prior art device is the same as a device described in the specification for carrying out the claimed method, it can be assumed the device inherently performs the claimed process. In re King, 801 F.2d 1324, 231 USPQ 136 (Fed Cir. 1986). Therefore the previous rejections based on the apparatus will not be repeated.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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) 1-3, 13-15, 25 and 27 is/are rejected under 35 U.S.C. 103 as being unpatentable over Stuler et al. US 2015/0263629 in view of Yang et al. US 2022/0271676.
Regarding Claims 1 and 13, Stuler teaches (Figures 1-8) a controller (112) for an asymmetrical half-bridge converter (at fig. 1) with a primary winding (126), the controller comprising: a first switch driver (at 236) configured to drive a first switch (114) of the asymmetrical half-bridge converter and a secondary winding formed on a secondary side (128 and 130); a second switch driver (at 236) configured to drive a second switch (116) of the asymmetrical half-bridge converter; and a control logic (at 200 without 236) coupled to the first switch driver and the second switch driver, wherein during a first switching period and a second switching period (switching cycles), the control logic is configured to: control the first switch driver to turn on the first switch for a first ON duration (see fig. 7, 724) for the primary winding to store energy (during on time of 114); control the first switch driver and the second switch driver to turn off the first switch and the second switch for a first OFF duration after the first ON duration (deadtime after 726); control the second switch driver to turn on the second switch for a second ON duration after the first OFF duration (fig. 7 tun on of 708 after 726) for transferring the energy stored in the primary winding to the secondary winding (during the on time of 116); and control the first switch driver and the second switch driver to turn off the first switch and the second switch for a second OFF duration after the second ON duration (deadtime of 708 after turn off); wherein during the first switching period, the control logic determines a discharge period (turn on time of the low switch) according to the feedback voltage (Fig. 2 with 202); and wherein during the second switching period (at 318 in figure 3), the control logic adjusts a length of the second ON duration to a fixed ratio (1/Y, par. 36) of the discharge period, the fixed ratio is less than 1 (with step 322 and operation until step 334, see par. 36 and 45-46 ). (For Example: Par. 27, 34-38 and 41-46)
Stuler does not teach an auxiliary winding formed on a primary side of the asymmetrical half-bridge converter, the auxiliary winding generating a feedback voltage.
Yang teaches (Figure 3) an auxiliary winding (NA) formed on a primary side of the asymmetrical half-bridge converter (300), the auxiliary winding generating a feedback voltage (Vaux). (For Example: Par. 42-43)
It would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention to modify the circuit of Stuler to include an auxiliary winding formed on a primary side of the asymmetrical half-bridge converter, the auxiliary winding generating a feedback voltage as taught by Yang to improve the isolation between the feedback signal, the primary and secondary side.
Regarding Claims 2 and 14, Stuler teaches (Figures 1-8) wherein the fixed ratio is between 0.75 and 0.95 (1/Y, par. 36). (Examiner’s Note: Y can take any value than can make the statement true)
Regarding Claims 3 and 15, Stuler teaches (Figures 1-8) a converter.
Stuler does not teach wherein during the second switching period, a first knee point is generated in the feedback voltage corresponding to an end of the second ON duration, and a second knee point is generated in the feedback voltage corresponding to an end of the discharge period; and during the second switching period, the second OFF duration is ended at the second knee point of the feedback voltage.
Yang teaches (Figures 3-5) wherein during the second switching period (Figure 5), a first knee point is generated in the feedback voltage corresponding to an end of the second ON duration (t3, fig. 5), and a second knee point (t4, fig. 4) is generated in the feedback voltage corresponding to an end of the discharge period; and during the second switching period, the second OFF duration is ended at the second knee point of the feedback voltage (T4, fig. 5). (For Example: Par. 55-56)
It would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention to modify the circuit of Stuler to include wherein during the second switching period, a first knee point is generated in the feedback voltage corresponding to an end of the second ON duration, and a second knee point is generated in the feedback voltage corresponding to an end of the discharge period; and during the second switching period, the second OFF duration is ended at the second knee point of the feedback voltage, as taught by Yang to improve the power efficiency for different load operations.
Regarding Claims 25 and 27, Stuler teaches (Figures 1-8) wherein the control logic (at fig. 2) is configured to: control the second switch driver (at 236) to turn on the second switch (at 708) for a third ON duration after the second OFF duration (turn on before 730 in Fig. 7); and control the first switch driver and the second switch driver (at 236) to turn off the first switch and the second switch (114 and 116) for a third OFF duration (dead time at 730) after the third ON duration (Fig. 7). (For Example: Par. 27, 34-38 and 41)
Claim(s) 5 and 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Stuler et al. US 2015/0263629 in view of Yang et al. US 2022/0271676 and Liu US 20240305207.
Regarding Claims 5 and 17, Stuler teaches (Figures 1-8) wherein during a third switching period when the asymmetrical half-bridge converter is in a heavy loading mode (Fig. 7, is normal operation), the control logic is configured to: control the first switch driver (at 236) to turn on (with 706) the first switch for a fourth ON duration (731); control the first switch driver and the second switch driver (at 236) to turn off the first switch and the second switch for a fourth OFF duration after the fourth ON duration (dead time after 731); control the second switch driver to turn on the second switch (708) for a fifth ON duration after the fourth OFF duration (at 728); control the first switch driver and the second switch driver to turn off the first switch and the second switch for a fifth OFF duration after the fifth ON duration (dead time after 728).
Stuler does not teach if an end of a switching period duration is earlier than an end of the discharge period in the second switching period, during the third switching period, configure a length of the fifth ON duration to exceed a length of the discharge period.
Liu teaches (Figure 6) if an end of a switching period duration (duration of switching cycle determined by the switches, fig. 6) is earlier than an end of the discharge period in the second switching period (with IR and IS in figure 6), during the third switching period, configure a length of the fifth ON duration to exceed a length of the discharge period (TD2 of T13 is longer than TD2 of T13, fig. 6). (For Example: Par. 56-66)
It would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention to modify the circuit of Stuler to include if an end of a switching period duration is earlier than an end of the discharge period in the second switching period, during the third switching period, configure a length of the fifth ON duration to exceed a length of the discharge period, as taught by Yang to improve the isolation between the feedback signal, the primary and secondary side.
Claim(s) 6, 18, 26 and 28 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yang 2021/0408921 in view of Shen US 2016/0020699.
Regarding Claims 6 and 18, Yang teaches (Figures 1-3) a controller for an asymmetrical half-bridge converter (100 for fig. 1), the asymmetrical half-bridge converter comprising an auxiliary winding (Na) formed on a primary side of the asymmetrical half-bridge converter, the auxiliary winding generating a feedback voltage (Vaux), the controller comprising: a first switch driver (102) configured to drive a first switch (30) of the asymmetrical half-bridge converter; a second switch driver (103) configured to drive a second switch (40) of the asymmetrical half-bridge converter; and a control logic (Fig. 1b except 102-103) coupled to the first switch driver and the second switch driver, wherein during a first switching period and a second switching period (switching cycles in light mode) and when the asymmetrical half-bridge converter is in a light-loading mode (Fig. 3, par. 36), the control logic is configured to: control the first switch driver (102) to turn on the first switch for a first ON duration (Sh, fig. 3); control the first switch driver and the second switch driver (102-103) to turn off the first switch and the second switch for a first OFF duration after the first ON duration (dead time after SH is off); control the second switch driver (103) to turn on the second switch for a second ON duration after the first OFF duration (SL high); control the first switch driver and the second switch driver (102-103) to turn off the first switch and the second switch for a second OFF duration after the second ON duration (dead time when SL is turned off); wherein the control logic is configured to terminate the second OFF duration when the feedback voltage (VNa) approaches one of resonant peaks after an end of the second ON duration (Figure 3 during Tdly one of the VV peaks). (For Example: Par. 32-39)
Yang does not teach wherein during the first switching period, the control logic determines a discharge period according to the feedback voltage and counts peaks of the feedback voltage to generate a count value; and wherein during the second switching period, based on the count value, the discharge period, and the switching period duration, the control logic selects one of the resonant peaks of the feedback voltage following an end of a switching period duration to terminate the second OFF duration.
Shen teaches (Figures 9-12) wherein during the first switching period (switching cycle), the control logic (Fig. 9) determines a discharge period according to the feedback voltage (e.g. Tdis) and counts peaks of the feedback voltage to generate a count value (with 302, par. 61-65); and wherein during the second switching period, based on the count value, the discharge period, and the switching period duration, the control logic selects one of the resonant peaks of the feedback voltage following an end of a switching period duration to terminate the second OFF duration (see fig. 10 with PTsvl and Tend and Fig. 11 with steps 305-324). (For Example: Par. 51-65)
It would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention to modify the circuit of Yang to include wherein during the first switching period, the control logic determines a discharge period according to the feedback voltage and counts peaks of the feedback voltage to generate a count value; and wherein during the second switching period, based on the count value, the discharge period, and the switching period duration, the control logic selects one of the resonant peaks of the feedback voltage following an end of a switching period duration to terminate the second OFF duration, as taught by Shen to reduce the occurrence of intolerable audible noise.
Regarding Claims 26 and 28, Yang teaches (Figures 1-3) wherein the control logic (100) is configured to: control the second switch driver (103) to turn on the second switch (40) for a third ON duration after the second OFF duration (Fig. 3, PSSW); and control the first switch driver and the second switch driver (102-103) to turn off the first switch and the second switch (30-40) for a third OFF duration (TRH) after the third ON duration (Fig. 3). (For Example: Par. 32-39)
Claim(s) 10 and 22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yang US 20210408921 in view of Shen US 2016/0020699 and further in view of Liu US 20240305207.
Regarding Claims 10 and 22, Yang teaches (Figures 1-3) during a third switching period and when the asymmetrical half-bridge converter is in a heavy loading mode (Fig. 2 operation), the control logic is configured to: control the first switch driver (103) to turn on the first switch for a fourth ON duration (SH on); control the first switch driver and the second switch driver (102-103) to turn off the first switch and the second switch for a fourth OFF duration after the fourth ON duration (TRL); control the second switch driver (103) to turn on the second switch for a fifth ON duration after the fourth OFF duration (SL High); and control the first switch driver and the second switch driver to turn off the first switch and the second switch for a fifth OFF duration after the fifth ON duration (TRH); wherein during the second switching period, the control logic determines a discharge period according to the feedback voltage (discharge of the IM current, Figure 2, VNA is high).
Yang does not teach wherein in the third switching period, the control logic controls the fifth ON duration to be longer than the discharge period; and wherein in the third switching period, the fifth ON duration is used to assist the first switch in performing zero-voltage switching.
Liu teaches (Figure 6) wherein in the third switching period (Fig. 6), the control logic (at 30) controls the fifth ON duration to be longer than the discharge period (TD2 of t17-t18); and wherein in the third switching period, the fifth ON duration is used to assist the first switch in performing zero-voltage switching (par. 64, ZVS for the QH switch). (For Example: Par. 56-66)
It would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention to modify the circuit of Stuler to include if an end of a switching period duration is earlier than an end of the discharge period in the second switching period, during the third switching period, configure a length of the fifth ON duration to exceed a length of the discharge period, as taught by Yang to improve the isolation between the feedback signal, the primary and secondary side.
Allowable Subject Matter
Claims 8 and 20 are 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 and any intervening claims.
Reasons for Indicating Allowable Subject Matter
The following is an examiner’s statement of reasons for indicating Allowable Subject Matter:
Claims 8 and 20; prior art of record fails to disclose either by itself or in combination: “…the control logic determines a discharge period according to the feedback voltage during the first switching period, and ends the second ON duration and starts the second OFF duration before the discharge period ends in the second switching period; and during the second switching period, a second knee point is generated in the feedback voltage when the discharge period ends, and the second OFF duration is ended and the third ON duration is started according to the second knee point..”
These features taken alone or in combination are neither disclosed nor suggested by the prior art of record.
Response to Arguments
Applicant's arguments filed 04/02/2026 have been fully considered but they are not persuasive.
Applicant argued that “In other words, the energy-storing on-time duration ultimately produced in Step 324 of Stuler is restored to a value equal to the prior on-time (i.e., a 100% ratio), rather 5 than being adjusted to a fixed ratio less than 1 of the energy-storing period. The ratio 1/Y in Step 322 serves only as an intermediate threshold check and does not function as the final adjustment ratio for the pulse width. The resulting present on-time in Stuler is equal to the previous on-time period. The present on-time disclosed in Stuler is (1) not a fraction of previous on-time period, and also (2) not a discharge period for transferring the 10 energy stored in the primary winding to the secondary winding”. However, Stuler teaches in figure 8 and par. 46 “The operation illustrated here corresponds to the steps 320-324 of FIG. 3 and steps 418-422 of FIG. 4.” Figure 8 reproduce below. As can be see clearly from the bottom figure when the system when the feedback signal decreases (814) and the on time comparator (812) goes high and low and then remains high (at 820) the on time (808) of the second switch 116 which would be the second on time (after 808) is reduce from its previous on time due to the behavior of signals 812 and 814. Therefore, the second on time is reduce from a 1.5 factor of the maximum switching frequency to the normal switching frequency and since the switching one time of the switch 116 is reduce from the previous one (as shown in fig. 8) said switching frequency is reduce by a factor less than one.
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Applicant argued that “Applicant respectfully submits that Shen fails to disclose or suggest the limitations of amended Claim 6 because Shen is directed to a Quasi-Resonant (QR) converter operating with a single power switch (e.g., Switch 34 in Shen's FIG. 1). In contrast, the amended Claim 6 specifically requires an asymmetrical half-bridge (AHB) converter that operates using first and second switches.” However, the features of an AHB converter are not teach by the Shen reference, the Yang reference is the reference used to teach said limitations. Plus, the Shen reference teaches on par. 49 that the invention is not limited to QR converters.
Applicant argued that “Specifically, Shen does not disclose using a count value and a discharge period from a first switching period to select a resonant peak in a second switching period to terminate a second OFF duration of the second switch.” In response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., a second OFF duration of the second switch) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993).
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to GUSTAVO A ROSARIO-BENITEZ whose telephone number is (571)270-7888. The examiner can normally be reached M-F 9AM-5PM.
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/GUSTAVO A ROSARIO-BENITEZ/Primary Examiner, Art Unit 2838
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