DETAILED ACTION
This Office action is in response to the application filed on 22 March 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 .
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
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.
Claim(s) 1, 4, 8, and 14 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Billingsley et al. (US 2011/0102052; “Billingsley”).
In re claim 1 and 14, Billingsley discloses an inrush current protection system (shown at various levels of detail in Figs. 3, 4, 13 and 14) and the method of its operation (the method, expressed as the functional operation of the device, will be apparent given Billingsley’s teaching of the functional limitations as cited below), comprising:
a first power terminal (Fig. 13: Lin) and a second power terminal (Fig. 13: Nin), configured to be coupled with a power source (Abstract: “an input conductor connected to an AC power supply”);
a third power terminal (Fig. 13: Lout) and a fourth power terminal (Fig. 13: Nout), configured to be coupled with a load (Abstract: “an output conductor connected to a load”), and wherein the fourth power terminal is coupled with the second power terminal (Fig. 13: Nout coupled to Nin via 220, K1; or in the simplified Fig. 4: output neutral terminal is directly connected to the input neutral terminal);
a sequence of devices coupled in series between the first power terminal and the third power terminal, in any order, including:
(a) an inrush-protection device (Figs. 3, 13: R28; Fig. 4: R38);
a first controlled switch (Figs. 3, 14: 34; Figs. 4, 13: K2) with two switch terminals (as shown) and a first control terminal (see, e.g., the connection from relay control circuit 38 to relay 34 as shown in Figs. 3 and 14), wherein the first controlled switch is coupled in parallel with the inrush-protection device (see Figs. 3, 4, 13, 14); and
a control circuit (see the various control circuitries shown in Fig. 13, which are also shown in greater detail across Figs. 5-6 and 8-12) coupled with the first power terminal, the second power terminal, and the first control terminal (see detail Fig. 11: connection to Lin, Nin, and the control terminal via the output hybrid switch control signal), and wherein the control circuit is configured to:
continually determine if a supply voltage is within an acceptable range and no swell is present (see [0055] and [0059]: the under- and over-voltage detection circuits set an acceptable range of the input, and it is understood from the background of the specification, e.g., [0003, [0011], that this further entails detection of a swell);
upon determining that the supply voltage is within the acceptable range and that no swell is present, start a first wait timer and wait until the first wait timer has timed out (see [0112]: “If the line voltage is acceptable … microcontroller 110 executes an on-cycle routine by … setting the relay control signal after a delay of several cycles”; the delay of several cycles corresponds to starting the first wait timer and waiting until it has timed out); and
after the first wait timer has timed out, assert the first control terminal to close the first controlled switch and bypass the inrush-protection device (id.).
In re claim 4, Billingsley discloses wherein the inrush-protection device includes a resistor (Figs. 3, 13: R28; Fig. 4: R38).
In re claim 8, Billingsley discloses wherein the first controlled switch switches off within 20 milliseconds after the first control terminal has been de-asserted (see [0007], indicating example response times of the relay coil in the range of 2-8 ms).
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.
Claim(s) 3 is rejected under 35 U.S.C. 103 as being unpatentable over Billingsley in view of Divan (US 2008/0247106; “Divan”).
In re claim 3, Billingsley discloses the invention according to claim 1 as explained above. Furthermore, it is noteworthy that Billingsley teaches at [0008] an example in which the protection system is used to power capacitive loads in the form of charging of capacitors in connected DC equipment. Nonetheless, Billingsley does not specifically disclose the sequence of devices further including: (b) a rectifier, which comprises at least one of a diode, a half-bridge rectifier, a full-bridge rectifier, a synchronous rectifier, or a partially synchronous rectifier.
It would have been a matter of common sense to a person of ordinary skill in the relevant arts that in order for the protection system in Billingsley to supply DC load equipment from the AC input line source, a rectifier would be a necessity. Such a solution is shown in Divan at Fig. 2, showing a protection system including a rectifier (236) including a diode full-bridge rectifier circuit (239) for the purpose of converting the protected AC input power into output DC power to serve the DC load.
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the system of Billingsley by incorporating, in the sequence of devices, a diode full-bridge rectifier as shown by Divan in order to supply DC load equipment from the AC line source.
Claim(s) 5-6 are rejected under 35 U.S.C. 103 as being unpatentable over Billingsley in view of Wissing (US 2020/0076185; “Wissing”).
In re claims 5-6, Billingsley discloses the invention according to claim 1 as explained above, but does not further disclose wherein the inrush-protection device includes a temperature-dependent resistor (a thermistor), wherein the thermistor has a negative temperature coefficient.
Whereas Wissing discloses the use of a negative temperature coefficient (NTC) thermistor as an inrush current limiting element in a protection system (see Fig. 3, comprising NTC thermistor R3 and see [0050]). Wissing teaches that NTC thermistors enable inrush current limiting to be performed at low cost and without elaborate circuitry ([0012]).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the system of Billingsley by using an NTC thermistor as the inrush protection device, as shown by Wissing, for the purpose of providing the inrush current limiting functionality at low cost and without elaborate circuitry.
Claim(s) 7 and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Billingsley.
In re claim 7, Billingsley discloses wherein the first controlled switch (Figs. 3, 14: 34; Figs. 4, 13: K2) includes a relay (see, e.g., [0037]). Billingsley does not explicitly disclose that the switch has an ON resistance of less than 2 ohms.
However, the purpose of the hybride switch device disclosed in Billingsley is that the triac 36 is used for fast, zero voltage switching on/off, while the more conductive relay 34 is used to conduct the full load current once turned on (see Abstract, [0035], [0041]). Billingsley indicates at [0035] that the full load current is 15 A, at which the triac would cause a voltage drop of 1 V and associated power loss of 15 W. Applying Ohm’s Law, this indicates that the triac has a channel resistance of about 67 mΩ.
As cited above, the relay 36 is used to bypass the triac and conduct the full load current because it has a lower resistance and thus causes less power loss. Thus, the person of ordinary skill in the art would understand that the implication of Billingsley’s disclosure is to use a relay having a resistance of less than the 67 mΩ of the triac, which would easily satisfy the claimed requirement of “less than 2 ohms”.
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the system of Billingsley by ensuring the relay has an ON resistance of less than 2 ohms, and more specifically less than the approximate 67 mΩ of the triac, in order to realize the stated purpose of lower power consumption and lower heat generation when the relay conducts the full load current.
In re claim 10, Billingsley discloses the invention according to claim 1 as explained above, but does not explicitly disclose that the first wait timer times out after at least four milliseconds (4 ms). However, at [0112] Billingsley indicates a delay time of “several cycles” before turning on the relay. Based on the overall disclosure of Billingsley, “cycle” is understood to refer to a length of the line cycle of the AC input source—e.g., at [0014] the term appears in the context of a “line voltage half cycle”.
In order for the protection system in Billingsley to be used in connection to standard utility/grid power in most places around the world, including North America, Europe, etc., the AC line frequency would be 50Hz or 60Hz. In either of these cases, the length of a single line cycle would be between about 17 ms and 20 ms (by calculating the cycle length or period as the reciprocal of the frequency), meaning that a delay of several line cycles would necessarily be greater than the claimed range of “at least four milliseconds (4 ms)”.
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the system of Billingsley such that the first wait timer times out after a delay of several cycles lasting at least four milliseconds (4 ms), in order for the system to be connected to standard AC grid power as the input source.
Allowable Subject Matter
Claims 2, 9, 11-13 and 15-20 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.
The following is a statement of reasons for the indication of allowable subject matter:
With respect to claim 2, the closest prior art in Billingsley, applied above in the rejection of independent claim 1, does not disclose the additional feature of opening the first controlled switch and stopping and resetting the first wait timer upon determining that the supply voltage is not within the acceptable range or that a swell is present, as recited in claim 2. That is, the first wait timer is the “delay of several cycles” referred to in [0112] of Billingsley, and no mention is made of stopping or resetting the timer.
Claims 15 and 16 both recite substantially similar content to claim 2, only written in the form of method steps instead of a functional operation of the device. As such, claims 15 and 16 would be allowable for substantially similar reasons as explained above for claim 2.
With respect to claim 9, the closest prior art in Billingsley, applied above in the rejection of independent claim 1, does not disclose the additional feature, wherein the first controlled switch switches off within 5 microseconds after the first control terminal has been de-asserted. That is, Billingsley explicitly teaches that the first controlled switch is a relay, which takes an unpredictable and essentially random amount of time to turn off, on the order to 2-8 ms (see Billingsley at [0007]).
With respect to claims 11-13, the closest prior art in Billingsley, applied above in the rejection of independent claim 1, does not disclose the additional features wherein the control circuit is further configured to: before waiting for the first wait timer to time out, close the second controlled switch; detect if a surge occurs; and upon detecting that a surge occurs, open the first controlled switch and stop and reset the first wait timer, as recited in claim 11.
With respect to claims 17-20, the closest prior art in Billingsley, applied above in the rejection of independent claim 1, does not disclose the additional features (1c) upon determining that the sufficient supply voltage is present and no swell is present, and before starting the first wait timer, closing the second controlled switch; and (1f) determining if a surge is present, and upon determining that a surge is present, returning to (1d), as recited in claim 17.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
US Patent 11,070,045 discloses an electrical protective device for low-voltage direct current (LVDC) network having a controller that on start-up first closes a mechanical relay in a ground line, waits a first delay, then closes a bipolar transistor to allow current to flow through a positive supply line, then turns on a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) connected in parallel with the bipolar transistor once an output voltage reaches a minimum target.
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/FRED E FINCH III/Primary Examiner, Art Unit 2838