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 .
Claim Rejections - 35 USC § 102
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.
Claims 1-4 and 8-11 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Günay et al.("IC Random Number Generator Exploiting Two Simultaneous Metastable Events of Tetrahedral Oscillator"), hereinafter Günay.
Regarding claim 1, Günay discloses an electronic circuit for Random Number Generation (RNG) (Abstract), comprising: multiple inverters connected to one another in a ring and configured to generate an oscillating signal (Section II, paragraph 1); A contention-current generator, which is connected to a node at which an output of an inverter of the ring drives an input of a subsequent inverter of the ring with a drive current, the contention-current generator comprising at least a buffer configured to drive the node, at least while a voltage at the node transitions between opposite logic states, with a contention current that opposes the drive current and is weaker than the drive current (Figure 2, ring is Inverters 1-4, contention source is Inverters 5-6); and digitization circuitry, which is configured to generate a sequence of random numbers by sampling the oscillating signal generated in the ring (Section II, paragraph 1).
Regarding claim 2, Günay discloses the contention-current generator in claim 1 comprises a bus holder (Figure 2, Inverters 5-6).
Regarding claim 3, Günay discloses the input of the buffer of the contention-current generator in claim 1 is driven by an output of a downstream inverter of the ring (Figure 2, Inverter 5 as the buffer).
Regarding claim 4, Günay discloses wherein the downstream inverter in claim 3 is the subsequent inverter in the ring (Figure 2, Inverter 4 as the downstream inverter).
Regarding claims 8-11, they are method claims corresponding to apparatus claims 1-4, respectively. They are rejected for the same reasons.
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 5-6 and 12-13 are rejected under 35 U.S.C. 103 as being unpatentable over Günay in view of Smith et al. (“Analysis and Design of a Tetrahedral Oscillator”), hereinafter Smith.
Regarding claim 5, Günay discloses the circuit as recited in claim 1 but fails to explicitly disclose that the contention-current source’s drive strength is weaker than the ring oscillator.
However, Smith discloses the buffer in the contention-current generator has a weaker drive strength than the inverter generating the drive current (Section III A, paragraph 4).
Günay and Smith are considered analogous art because they are in the same field of ring oscillators. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the application to modify the design of the circuit of Günay with the limitations disclosed by Smith so the ring oscillator will oscillate at a higher frequency (Section III B, paragraph 6).
Regarding claim 6, Smith discloses the contention current from claim 1 is weaker than the drive current by no more than a predefined ratio (Section III A, paragraph 4).
Regarding claims 12 and 13, they are method claims corresponding to apparatus claims 5 and 6, respectively. They are rejected for the same reasons.
Claims 7 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Günay in view of Lee et al. (US 9,356,582), hereinafter Lee.
Regarding claim 7, Günay discloses the circuit as recited in claim 1 but fails to disclose the calibration circuit.
Lee discloses a calibration circuit (Abstract), which is configured to calibrate one or both of (i) the inverter of the ring (Column 2, lines 54-56) and (ii) the buffer in the contention-current generator, so as to ascertain that the contention current is weaker than the drive current by no more than a predefined ratio.
Günay and Lee are considered analogous because they are both in the field of ring oscillators. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the application modify the circuit disclosed by Günay to incorporate the calibration circuit disclosed by Lee to reduce the variation brought on by the circuit manufacturing process, optimize the performance of the manufacturing process, and allow the design to be made by multiple manufacturers. (Column 2, lines 59-65).
Regarding claim 14, it is a method claim corresponding to apparatus claim 7, and is rejected for the same reason.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Dally et al. (US 6,617,936) discloses a ring oscillator with additional cross-coupling inverters. Golic (US 8,150,900) discloses a random number generator with switches to change the entropy level and uses XOR gates as part of the output-to-input feedback loop. Pankratz et al. ("Multiloop High-Power-Supply-Rejection Quadrature Ring Oscillator") discloses a ring oscillator with contention inverters and a calibration circuit used for clock generators. Liu et al. ("A Low-Cost Low-Power Ring Oscillator-Based Truly Random Number Generator for Encryption on Smart Cards") discloses a random number generator comprising a ring oscillator with bus holders as to increase jitter. Böffgen et al. (DE 102014219795A1) discloses a ring oscillator with switches that can increase or decrease the circuit's entropy. Diamant et al. (US 9,774,317) discloses a random number generator using tristate buffers instead of inverters as a source of increasing entropy.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Matthew Strapp whose telephone number is (571)272-9343. The examiner can normally be reached Monday-Friday 8:00 AM-4:00 PM.
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, Andrew Caldwell can be reached at (571)272-3702. 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.
/M.S./
Matthew StrappExaminer, Art Unit 2182
(571) 272-9343
/ANDREW CALDWELL/Supervisory Patent Examiner, Art Unit 2182