Ex Parte 7714558 et al

Patent Trial and Appeal BoardMay 28, 2014

95001625 (P.T.A.B. May. 28, 2014)

UNITED STATES PATENT AND TRADEMARKOFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 95/001,625 05/19/2011 7714558 6160 67394 7590 05/28/2014 Perkins Coie LLP - Monolithic Power Systems P.O. BOX 1247 SEATTLE, WA 98111-1247 EXAMINER TIBBITS, PIA FLORENCE ART UNIT PAPER NUMBER 3992 MAIL DATE DELIVERY MODE 05/28/2014 PAPER Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE _____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ______________ SILERGY TECHNOLOGY, INC., Third Party Requester and Appellant v. MONOLITHIC POWER SYSTEMS, INC., Patent Owner and Respondent ______________ Appeal 2014-004230 Reexamination Control No. 95/001,625 United States Patent 7,714,558 B2 Technology Center 3900 ______________ Before JOHN C. MARTIN, KARL D. EASTHOM, and KEVIN F. TURNER, Administrative Patent Judges. MARTIN, Administrative Patent Judge. NEW DECISION ON APPEAL UNDER 37 C.F.R. § 41.77(f) Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 2 This New Decision on Appeal Under 37 C.F.R. § 41.77(f) is in response to the Examiner’s “Determination Under 37 C.F.R. § 41.77(d),” which was mailed on February 19, 2013 (hereinafter “Examiner’s § 41.77(d) Determination”). The Examiner therein determined that the September 21, 2012, amendments to claims 1-10 have written description support under 35 U.S.C. § 112, first paragraph, and are sufficient to overcome the new ground of rejection of original claims 1-10 of Patent 7,714,558 B2 (“’558 patent”) under 35 U.S.C. § 102 for anticipation by MAX796.1 Examiner’s § 41.77(d) Determination at 3, para. 10, and at 5, para. 17. This ground of rejection was entered and discussed at pages 2 and 35-47 of the Board’s August 27, 2012, Decision on Appeal in Appeal 2012-008582 (“Initial Decision”). We AFFIRM the Examiner’s § 41.77(d) Determination and accordingly are modifying the Initial Decision by withdrawing the rejection of claims 1-10 for anticipation by MAX796. I. DISCUSSION The Initial Decision (i) affirmed the Examiner’s decision not to adopt Requester’s proposed rejections of original claims 1-10 under 35 U.S.C. 1 MAXIM, Step-Down Controllers with Synchronous Rectifier for CPU Power (MAX796/MAX797/MAX799) (Nov. 1997). Exhibit E to Detailed Request for Inter Partes Reexamination of U.S. Patent 7,714,558 (hereinafter “Request”), filed May 19, 2011. Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 3 § 102 for anticipation by each of Schwartz,2 Yang,3 and LTC34124 (Initial Decision 17, 22, 28) and (ii) reversed the Examiner’s decision not to adopt the proposed rejection of claims 1-10 under 35 U.S.C. § 102 for anticipation by MAX796. Id. at 2 and 35-47. The Initial Decision designated this reversal as a new ground of rejection pursuant to 37 C.F.R. § 41.77(b) and noted that Patent Owner is entitled to respond by either reopening prosecution (e.g., amending the rejected claims) or requesting rehearing. Id. at 2 and 47-48. Figure 1 of the ’558 patent is reproduced below. 2 Peter Hamlin Schwartz & Zhong Yuan Ren, U.S. Patent 5,808,455, which issued on September 15, 1998. Request Ex. B. 3 Jian Yang, Analysis and Evaluation of Over Current Protection for DC to DC PWM Converters, The 4th International Power Electronics and Motion Control Conference, 149-53 (Aug. 14-16, 2004). Request Ex. C. 4 Linear Technology, LT3412, 2.5A, 4MHz, Monolithic Synchronous Step- Down Regulator (2002). Request Ex. D. Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 4 Figure 1 illustrates an embodiment of a DC-DC voltage regulator output 100 that includes: (a) “high and low supply transistors” 120 and 140 (recited in claim 1 as “a high side pass device and a low side pass device”), which are connected between a power rail 130 and ground 150; (b) an inductive load 110; and (c) a capacitor 160. ’558 patent 4:2-11. Power is supplied (i.e., current is sourced) to inductive load 110 through power transistor 120 from power supply 130. Id. at 4:8-10. Current can be sunk from inductive load 110 through power transistor 140 to ground 150. Id. at 4:10-11. By modulating these two pass devices, the inductor will build up energy and discharge it into the capacitor at respective charge and discharge rates. Id. at 3:21-24. Figure 5 of the ’558 patent is reproduced below. Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 5 Figure 5 illustrates an embodiment of the current overload protection apparatus for the DC-DC voltage regulator output depicted in Figure 1. Id. at 2:35-37. Flip-flop 520 controls transistor 120 and also (through inverter 525) transistor 140. Id. at 5:19-20. Flip-flop 520 is controlled by circuitry that includes three comparators: (i) a comparator 515, which is connected to a sense resistor 505 for sensing the current though high side pass transistor 120; (ii) a Schmitt-trigger comparator 540, which is responsive to the output signal of comparator 515 and (via a transistor 550) a reference voltage Vilimit+X; and (iii) a comparator 530, which is connected to a sense resistor 510 for sensing the current through low side pass transistor 140. Id. at 5:27- 40. These comparators control the state of flip-flop 520 as follows: Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 6 [W]hen current through sense resistor 505 causes a voltage exceeding the bias voltage of transistor 550, comparator 540 can set (or reset) the flip-flop 520. This allows for turning off supply of current to load 110. Similarly, when current has decayed sufficiently, this may be sensed through comparator 530, using sense resistor 510 and the output node coupled to load 110, for example. Thus, comparator 530 may reset (or set) flip-flop 520, allowing normal operation to continue. Id. at 5:32-40. Neither of original independent claims 1 and 6, which read as follows, specifically recites a comparator: 1. A method implemented on a DC/DC switch mode voltage regulator with a high side pass device and a low side pass device, the method comprising: detecting an over current condition over a current limit on the high side pass [device]; and if the over current condition is detected, locking out the high side pass device and turning on the low side pass device until an undercurrent condition under a second current limit located on the low side pass device is reached, wherein once said second current limit is reached on the low side pass device, the high side pass device can be turned back on such that the states of said high side pass device and low side pass device are interdependent and cannot be controlled independently. 6. A DC/DC switch mode voltage regulator with a high side pass device and a low side pass device comprising: means for detecting an over current condition over a current limit on the high side pass device; and Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 7 if the over current condition is detected, means for locking out the high side pass device and turning on the low side pass device until an undercurrent condition under a second current limit located on the low side pass device is reached, wherein once said second current limit is reached on the low side pass device, the high side pass device can be turned back on such that the states of said high side pass device and low side pass device are interdependent and cannot be controlled independently. ’558 patent cols. 6-8. The only original claim that recites a comparator is dependent claim 7, which reads as follows: 7. The apparatus of claim 6, wherein the means for detecting includes a sense element and a finite current level comparator to determine an over current condition. Id. at col. 8. The Initial Decision, when discussing (at pages 41-45 and 47) Requester’s proposed rejection of claims 1-10 for anticipation by MAX796, agreed with Requester that the both of the recited “over current condition” and “undercurrent condition” are detected by Schmitt trigger comparator 103 in Figure 3, which is annotated to include reference numerals 101-03 in Requester’s Appeal Brief and reproduced below.5 5 Appellant’s Brief, filed October 17, 2011, at 7. Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 8 As indicated in the caption, Figure 3 of MAX796 illustrates a pulse-width- modulating (PWM) controller block diagram. Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 9 Patent Owner responded to the Board’s new ground of rejection by amending original claims 1, 6, and 7 and adding new dependent claims 11- 14.6 Specifically, each of independent claims 1 and 6 was amended to recite, inter alia, two comparators for detecting the recited “over current condition” and “undercurrent condition,” respectively: 1. (Currently Amended) A method implemented on a DC/DC switch mode voltage regulator with a high side pass device and a low side pass device, the method comprising: detecting an over current condition over a current limit on the high side pass device, wherein the over current condition over the current limit on the high side pass device is detected by the combination of a first resistor coupled in series with the high side pass device, a first comparator coupled in parallel with the first resistor, and a Schmitt-triggered comparator having a first input terminal coupled to an output of the first comparator; and if the over current condition is detected, locking out the high side pass device and turning on the low side pass device until an undercurrent condition under a second current limit located on the low side pass device is reached, wherein the undercurrent condition is detected by the combination of a sense resistor coupled in series with the low side pass 6 Respondent’s Response to the Decision on Appeal, filed September 21, 2012, at 2-5 (hereinafter “Amendment”). Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 10 device and a second comparator coupled to the sense resistor, and wherein once said second current limit is reached on the low side pass device, the high side pass device can be turned back on such that the states of said high side pass device and low side pass device are interdependent and cannot be controlled independently. 6. (Currently Amended) A DC/DC switch mode voltage regulator with a high side pass device and a low side pass device comprising: means including a Schmitt-triggered comparator for detecting an over current condition over a current limit on the high side pass device, and if the over current condition is detected, means for locking out the high side pass device and turning on the low side pass device until an undercurrent condition under a second current limit located on the low side pass device is reached; and means including a first comparator for detecting the undercurrent condition under the second current limit located on the low side pass device; wherein once said second current limit is reached on the low side pass device, the high side pass device can be turned back on such that the states of said high side pass device and low side pass device are interdependent and cannot be controlled independently. Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 11 Amendment 2-3. The Amendment provides the following explanation of how the new language in claims 1 and 6 reads on Figure 5 of the ’558 patent: 1) New limitations in claim 1: i. “a first resistor coupled in series with the high side pass device” in claim 1 is shown as sense resistor 505; ii. “a first comparator coupled in parallel with the first resistor” in claim 1 is shown as comparator 515; iii. “a Schmitt-triggered comparator” in claim 1 is shown as Schmitt-triggered comparator 540; iv. “a sense resistor coupled in series with the low side pass device” in claim 1 is shown as sense resistor 510; and v. “a second comparator coupled to the sense resistor” in claim 1 is shown as comparator 530. 2) New limitations in claim 6: i. “means including a Schmitt-triggered comparator for detecting an over current condition” in claim 6 is shown as Schmitt-triggered comparator 540; and ii. “means including a first comparator for detecting the undercurrent condition” in claim 6 is shown as comparator 530. Id. at 8-9. Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 12 Requester did not file any comments (as authorized by 37 C.F.R. § 41.77(c)) in response to the Amendment. In a December 7, 2012, Order Remanding Inter Partes Reexamination Under 37 C.F.R. § 41.77(d) to the Examiner, the Board stated (at page 2): We have reviewed the proposed amendments and find that their effect is to narrow the scope of the subject matter recited in the rejected claims without broadening the claims in any respect. We are therefore satisfied that the amendments constitute a proper “amendment of the claims so rejected” under 37 C.F.R. § 41.77(b). Accordingly, all of the proposed amendments and Patent Owner’s accompanying comments are ENTERED for consideration by the Examiner pursuant to this remand under 37 C.F.R. § 41.77(d). The Examiner’s § 41.77(d) Determination states (at 3, para. 10) that “the specification has sufficient 35 U.S.C. § 112 1st paragraph support for the Sept 2012 Claim Amendments” and (at 5, para. 17) that “the Sept 2012 Claim Amendments have overcome the 2012 Board[’s] New Grounds of Rejection.”7 We affirm this determination by the Examiner and accordingly hereby modify the Initial Decision by withdrawing the new ground of rejection of claims 1-10 under 35 U.S.C. § 102 for anticipation by MAX796. Initial Decision 2 and 35-47. 7 An Action Closing Prosecution that erroneously had been mailed (on January 23, 2013) was withdrawn at page 2, paragraph 6 of the Examiner’s (Continued on next page.) Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 13 II. DECISION The Examiner’s § 41.77(d) Determination (i.e., that the Amendment has overcome the rejection of claims 1-10 for anticipation by MAX796) is affirmed. The Initial Decision (i.e., the August 27, 2012, Decision on Appeal in Appeal 2013-008582) is modified by withdrawing the new ground of rejection of claims 1-10 under 35 U.S.C. § 102 for anticipation by MAX796. Initial Decision 2 and 35-47. The Initial Decision is unchanged in all other respects. See 37 C.F.R. § 41.77(f) (“The new decision is deemed to incorporate the earlier decision, except for those portions specifically withdrawn.”). In the event neither party files a request for rehearing within the time provided in 37 C.F.R. § 41.79 and this decision becomes final and appealable under 37 C.F.R. § 41.81, a party seeking judicial review must timely serve notice on the Director of the United States Patent and Trademark Office. See 37 C.F.R. §§ 90.1 and 1.983. AFFIRMED peb § 41.77(d) Determination. Appeal 2014-004230 Reexamination Control 95/001,625 Patent 7,714,558 B2 14 For Patent Owner: PERKINS COIE LLP - MONOLITHIC POWER SYSTEMS P.O. BOX 1247 SEATTLE, WA 98111-1247 For Third Party Requester: HAYNES AND BOONE, LLP (3RD PTY REQ) IP SECTION 2323 VICTORY AVE., SUITE 700 DALLAS, TX 75219