DETAILED ACTION
The instant action is in response to application 5 December 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 .
Specification
The title is not descriptive. Examiner suggests Discontinuous Conduction Mode for Active Clamp Flyback Converter.
The abstract is objected for the following informalities: Though it is understood what is meant, “configured to” has the potential of being read as legal language per MPEP 2181 (I). Legal language is not permitted in the abstract per MPEP 608.01(b) (C).
The 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.
Drawings
The drawings are objected to under 37 CFR 1.83(a). The drawings must show every feature of the invention specified in the claims. Therefore, the “comparison result of a voltage difference between a drain and a source for the main power transistor and a preset voltage value” must be shown or the feature(s) canceled from the claim(s). No new matter should be entered.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Priority
Acknowledgment is made of applicant's claim for foreign priority based on an application filed in China on 27 May 2022.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-19 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph.
As to claim 1, the portion of the specification seeking protection is unclear. Also auxiliary power transistors would usually be attached to the aux winding. It is generally indefinite to go against common nomenclature (MPEP 2173.05(a)). In this particular case, it is unclear whether the auxiliary power transistor refers to the other switch in the half bridge or the synchronous rectifier shown in Fig. 10 in item 115. For the purposes of examination, it will be assumed the main power transistor is Q1 and the auxiliary is Q2, since this appears to be suggested by Figure 12. Q3, which one of ordinary skill would generally regard as the auxiliary transistor, will be assumed to be descried as the switching transistor in claims 3/4.
Claim 5 has a similar problem with the synchronous rectifier correlating to the switching transistor rather than the auxiliary switch.
Claim 9 also has similar problems as described above. It shall be interpreted as described above with the switching transistor either referring to the transistor connected to the auxiliary winding or the synchronous rectifier.
Claims 2-4, 6-8, 10-19 depend directly or indirectly from a rejected claim and are, therefore, also rejected under 35 USC 112(b) , or 35 U.S.C. 112 (pre-AIA ) second paragraph for the reasons set above.
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 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.
For method claims, 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 will inherently perform 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. (The claims have been condensed.)
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
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 of this title, 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 1-4, 12, 14, 18 (as best understood) are rejected under 35 U.S.C. 103 as being unpatentable over Fahlenkemp (US 20200112257) in view of Liu (US 20050174811) and Yan (US 20220399879).
As to claim 1, Fahlenkemp discloses a control circuit of a power supply module, , the power supply module comprises an active clamp flyback converter circuit, an auxiliary winding, and a rectifier circuit, the active clamp flyback converter circuit comprises a main power transistor, an auxiliary power transistor, and a transformer, the auxiliary winding is coupled to the transformer, the active clamp flyback converter circuit operates in a discontinuous conduction mode (¶36 “discontinuous conduction mode”),
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Though Fahlenkemp teaches much of the same invention he does not explicitly disclose and the auxiliary winding supplies power to the control circuit through the rectifier circuit; or control the main power transistor to be turned on based on a comparison result of a voltage difference between a drain and a source of the main power transistor and a preset voltage value.
Liu teaches and the auxiliary winding supplies power to the control circuit through the rectifier circuit (Liu, Fig. 3,Va, D1, C1, S, La, D2, X2).
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 above to use auxiliary control power to eliminate the need for an additional control power supply.
Yan teaches control the main power transistor to be turned on based on a comparison result of a voltage difference between a drain and a source of the main power transistor and a preset voltage value (Fig. 1C).
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 above to use comparison conduction as disclosed in Yan to prevent voltage spikes across the transistor.
As to claim 2, Fahlenkemp in view of Liu and Yan teaches wherein the control circuit is configured to: control, based on a comparison result of the voltage difference between the drain and the source of the main power transistor and a sum of [[the]] an input voltage and a primary- side winding coupling voltage, the rectifier circuit to start discharging to the transformer for the preset duration (this appears to be taught by Fig. 4 of Fahlenkemp).
As to claim 3, Fahlen kemp in view of Liu and Yang teaches wherein the rectifier circuit comprises a switching transistor and a capacitor, a drain of the switching transistor is connected to one terminal of the auxiliary winding, a source of the switching transistor is connected to one terminal of the capacitor, and the other terminal of the capacitor is connected to the other terminal of the auxiliary winding (Liu, Fig. 3).
As to claim 4, Fahlen kemp in view of Liu and Yang teaches wherein the control circuit controls the switching transistor to be turned on, and the capacitor discharges to the transformer through the auxiliary winding; and the control circuit controls the switching transistor to be turned off, and the capacitor stops discharging to the transformer (Liu, Fig. 3).
As to claim 12, Fahlen kemp in view of Yang teaches electronic device comprises an auxiliary winding, the auxiliary winding is coupled to the transformer,
Liu teaches the auxiliary winding supplies power to the control circuit through the rectifier circuit, a drain of the switching transistor is connected to one terminal of the auxiliary winding, a source of the switching transistor is connected to one terminal of the capacitor, and the other terminal of the auxiliary winding is connected to the other terminal of the capacitor; and when the control circuit controls the switching transistor to be turned on, the rectifier circuit discharges to the transformer through the auxiliary winding (Fig. 3).
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 above to use auxiliary control power to eliminate the need for an additional control power supply.
As to claim 18, Fahlen kemp in view of Liu and Yang makes obvious wherein the input voltage is an alternating- current voltage. Though they teach a DC voltage, using rectifiers is old and well known and therefore not patentable (See MPEP 2144.03). The expected advantage would be to use utility power.
Claims 5-11,13-17, 19, (as best understood) are rejected under 35 U.S.C. 103 as being unpatentable over Fahlenkemp (US 20200112257) in view of Yan (US 20220399879).
As to claim 5, Fahlenkemp teaches A control circuit of a power supply module, wherein and comprises an active clamp flyback converter circuit and a rectifier circuit, the active clamp flyback converter circuit comprises a main power transistor, an auxiliary power transistor, and a transformer, the transformer comprises a primary-side winding and a secondary-side winding, the active clamp flyback converter circuit operates in a discontinuous conduction mode, and the secondary-side winding supplies power to [[the]] a load through the rectifier circuit; and the control circuit is configured to: after the auxiliary power transistor is turned off and before the main power transistor is turned on, control the rectifier circuit to discharge to the transformer through the secondary-side winding for preset duration; and after the rectifier circuit stops discharging to the transformer (this is similar to claim 1 above, but specifying the secondary side rectifier rather than the primary side rectifier) ,
Yan teaches control the main power transistor to be turned on based on a comparison result of a voltage difference between a drain and a source of the main power transistor and a preset voltage value (Fig. 1C).
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 above to use comparison conduction as disclosed in Yan to prevent voltage spikes across the transistor.
As to claim 6, Fahlenkemp in view of Yan teaches wherein the control circuit is configured to: control, based on a comparison result of the voltage difference between the drain and the source of the main power transistor and a sum of an input voltage and a primary- side winding coupling voltage, the rectifier circuit to start discharging to the transformer for the preset duration (this appears to be taught by Fig. 4 of Fahlenkemp).
As to claim 7, Fahlenkemp in view of Yan makes obvious wherein the rectifier circuit comprises a switching transistor and a capacitor, a drain of the switching transistor is connected to one terminal of the secondary-side winding, a source of the switching transistor is connected to one terminal of the capacitor, and the other terminal of the capacitor is connected to the other terminal of the secondary-side winding. Though not explicitly taught, Substituting the diodes for switches meets the limitation, which is old and well known in the art (See MPEP §2143.03 and (US 5774350 Fig. 1/2 and Col. 2, lines 20-35, US 5672992 Figs. 12/15 and Col. 7 lines 1-10, US 4016476, Fig. 13A/A5A and Col. 8 liens 24-35). The advantage of using diodes is a simpler control circuit. The advantage of using switches is a smaller conduction drop across the conducting semiconductor. Therefore, one of ordinary skill would use switches instead of diodes to reduce conduction losses.
As to claim 8, Fahlenkemp in view of Yan makes obvious wherein the control circuit controls the switching transistor to be turned on, and the capacitor discharges to the transformer through the secondary-side winding; and the control circuit controls the switching transistor to be turned off, and the capacitor stops discharging to the transformer (see explanation of claim 7, this would occur by substituting the diode for the transformer).
As to claim 9, Fahlenkemp in view of Yan teaches An electronic device, comprising: an active clamp flyback converter circuit, configured to receive an input voltage, wherein the active clamp flyback converter circuit comprises a main power transistor, an auxiliary power transistor, and a transformer, and the active clamp flyback converter circuit operates in a discontinuous conduction mode; a rectifier circuit, configured to receive power supplied by the transformer; and a control circuit, configured to: after the auxiliary power transistor is turned off and before the main power transistor is turned on, control the rectifier circuit to discharge to the transformer for preset duration; and after the rectifier circuit stops discharging to the transformer, control the main power transistor to be turned on based on a comparison result of a voltage difference between a drain and a source of the main power transistor and a preset voltage value (this is similar to claim 5 above, the main difference is the converter itself is clamed. The combination and motivation is similar to claim 5 above).
As to claim 10, Fahlenkemp in view of Yan teaches wherein the control circuit is configured to: control, based on a comparison result of the voltage difference between the drain and the source of the main power transistor and a sum of an input voltage and a primary- side winding coupling voltage, the rectifier circuit to start discharging to the transformer for the preset duration (this appears to be taught by Fig. 4 of Fahlenkemp).
As to claim 11, this is obvious as described in claim 7 above.
As to claim 13, this is similar to claim 8 above, but further specifies a load, which Fahlenkamp specifies in ¶6.
As to claim 14, Fahlenkemp in view of Yan teaches wherein within a period of the discontinuous conduction mode, the control circuit is configured to: control the main power transistor to be turned on and the auxiliary power transistor to be turned off, and control the main power transistor to be turned off after the main power transistor is turned on for a period of time; and after the main power transistor is turned off for a period of time, control the auxiliary power transistor to be turned on and the main power transistor to be turned off, and after the auxiliary power transistor is turned on for a period of time, control the auxiliary power transistor to be turned off (Fig. 4).
As to claims 15, 17, 19 this similar to claim 18 above, and is obvious for similar reasons.
As to claim 16, Fahlenkamp specifies a load in ¶6.
Conclusion
Examiner has cited particular column, paragraph, and line numbers in the references applied to the claims above for the convenience of the applicant. Although the specified citations are representative of the teachings of the art and are applied to specific limitations within the individual claim, other passages and figures may apply as well. It is respectfully requested from the applicant in preparing responses, to fully consider the references in their entirety as potentially teaching all or part of the claimed invention, as well as the context of the passage as taught by the prior art or disclosed by the Examiner. In the case of amending the claimed invention, Applicant is respectfully requested to indicate the portion(s) of the specification which dictate(s) the structure relied on for proper interpretation and also to verify and ascertain the metes and bounds of the claimed invention.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to PETER M NOVAK whose telephone number is (571)270-1375. The examiner can normally be reached on 9AM-5PM,Monday through Thursday, EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Crystal Hammond can be reached on 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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/PETER M NOVAK/ Primary Examiner, Art Unit 2839
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