DETAILED ACTION
1. This Office Action is responsive to claims filed for App. 18/997,044 on May 3, 2025. Claims 20-39 are pending.
America Invents Act
2. The present application is being examined under the pre-AIA first to invent provisions.
Information Disclosure Statement
3. The information disclosure statement (IDS) submitted on January 18, 2025 was filed. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Claim Rejections - 35 USC § 102
4. 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.
5. Claims 20-26 and 29-36 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Howard et al. ( US 2020/0059229 A1 ).
Howard teaches in Claim 20:
A method of programming a state of a phase change material (PCM) switch stack, the PCM switch stack comprising a plurality of PCM switches arranged in a stacked configuration ( Figure 1, [0022] discloses designs 3 which include arrays of phase-change material (PCM) radio frequency (RF) switches. Figure 3 shows stacked aspects of PCM switches 6. Furthermore, Figure 8A, [0051] discloses additional details of the switches 6a-6c and [0058] discloses a circuit 59 which can include these switches ), each PCM switch comprising a heater ( Figure 8A, [0055] discloses heating elements 9a-9c, corresponding to each switch ), the method comprising driving the plurality of PCM switches in separate time intervals, one or more PCM switches at a time. ( [0056] discloses turning the switch, for example, 6a, ON and OFF. [0057] discloses a similar process for switch 6b, etc and this is an example of driving the switches in separate time intervals, one or more switch at a time )
Howard teaches in Claim 21:
The method of claim 20, further comprising transitioning each of the plurality of PCM switches between an ON state and an OFF state by applying a respective electrical pulse profile to the heater of that PCM switch during the corresponding time interval. ( Figure 5A/5B, [0079] discloses providing electrical pulses to the heater contacts of switches 6a-6c at the interpreted time intervals to turn ON and subsequently OFF )
Howard teaches in Claim 22:
The method of claim 21, wherein the electrical pulse profile for transitioning to the OFF state comprises a first electrical pulse having a higher power and shorter pulse width, and the electrical pulse profile for transitioning the switch to the ON state comprises a second electrical pulse having a lower power and longer pulse width. ( Figure 8B, [0065] discloses pulses for turning OFF the switches, namely 57a-57c as well as pulses for turning ON the switches, namely 58a-58c. Please note the amplitudes and [0053] discloses selecting the width and other values in a variety of designs )
Howard teaches in Claim 23:
The method of claim 22, further comprising providing a reference clock input to a logic and control circuit that generates the separate time intervals, and selecting the pulse widths of the first and second electrical pulses by counting respective clock cycles from the reference clock input using the logic and control circuit. ( Figure 8B, [0076] discloses total cycle, including t0 to t8. Please note the timings for the ON and OFF states of each switch. Respectfully, it is clear these are clock signals applied from a timing controller or some kind of logic and control circuit. [0091] discloses details on the ASIC 5, etc. )
Howard teaches in Claim 24:
The method of claim 23, wherein the logic and control circuit is integrated on the same chip as the plurality of PCM switches and is configured to receive a digital control input indicating whether each PCM switch is to be placed in the ON state or the OFF state. ( Figure 8A, [0091] discloses ASIC 5, switches 6 are integrated on the same chip as a circuitry for programming and testing )
Howard teaches in Claim 25:
The method of claim 20, wherein driving the plurality of PCM switches in separate time intervals comprises generating staggered control pulses using a plurality of driver circuits, each driver circuit corresponding to one of the plurality of PCM switches, wherein each control pulse enables the corresponding driver circuit while disabling driver circuits for all other PCM switches. ( As disclosed in Claim 20, each switch is driven separately and Figure 5A/5B discloses turning each switch on using control pulses, using the circuitry shown in Figure 8A. When one switch is ON, the other switches are OFF, i.e. staggered and disabled )
Howard teaches in Claim 26:
The method of claim 25, wherein each driver circuit is configured to generate an electrical pulse for placing the corresponding PCM switch in the ON state or the OFF state, the method further comprising supplying a first bias voltage to the driver circuit for generating the pulse for the OFF state, and a second bias voltage, lower than the first, for generating the pulse for the ON state. ( Figure 8B, [0065] discloses pulses for turning OFF the switches, namely 57a-57c as well as pulses for turning ON the switches, namely 58a-58c. Please note the amplitudes )
Howard teaches in Claim 29:
The method of claim 25, wherein each PCM switch is integrated with its corresponding driver circuit and the logic and control circuit in a single monolithic integrated circuit chip. ( Figure 8A, [0091] discloses ASIC 5, switches 6 are integrated on the same chip as a circuitry for programming and testing )
Howard teaches in Claim 30:
The method of claim 29, wherein each driver circuit includes a first transistor stack configured to drive the heater for the OFF state and a second transistor stack configured to drive the heater for the ON state, each transistor stack being activated in a non-overlapping time interval within the separate time intervals. ( Figure 8A, [0031] disclose the heating element 9a-9c which is controlled by transistors turning on and off. Please note the two sides of 12a-12c each with the ON and OFF controlling )
Howard teaches in Claim 31:
A system for programming a state of a phase change material (PCM) switch stack, the system comprising:
a plurality of PCM switches arranged in a stacked configuration ( Figure 1, [0022] discloses designs 3 which include arrays of phase-change material (PCM) radio frequency (RF) switches. Figure 3 shows stacked aspects of PCM switches 6. Furthermore, Figure 8A, [0051] discloses additional details of the switches 6a-6c and [0058] discloses a circuit 59 which can include these switches ), each PCM switch comprising a heater ( Figure 8A, [0055] discloses heating elements 9a-9c, corresponding to each switch ) and a volume of phase-change material coupled to the heater ( Figure 8A, [0028] disclose the materials in each switch for providing the phase change capability );
a plurality of driver circuits, each driver circuit coupled to one of the PCM switches ( Figure 8A shows a plurality of driver circuits connected to 12a-12c ); and
a logic and control circuit coupled to the driver circuits ( [0091] discloses details on the ASIC 5, etc. ),
wherein the logic and control circuit is configured to activate the plurality of PCM switches in separate time intervals, one PCM switch at a time, by providing control pulses to the respective driver circuits to transition each PCM switch between an ON state and an OFF state. ( [0056] discloses turning the switch, for example, 6a, ON and OFF. [0057] discloses a similar process for switch 6b, etc and this is an example of driving the switches in separate time intervals, one or more switch at a time )
Howard teaches in Claim 32:
The system of claim 31, wherein each PCM switch and corresponding driver circuit is integrated on the same chip. ( Figure 8A, [0091] discloses ASIC 5, switches 6 are integrated on the same chip as a circuitry for programming and testing )
Howard teaches in Claim 33:
The system of claim 31, wherein each driver circuit is configured to provide, responsive to the control pulses: a first electrical pulse profile having a lower power and longer pulse width to transition a corresponding PCM switch into the ON state; and a second electrical pulse profile having a higher power and shorter pulse width to transition the corresponding PCM switch into the OFF state. ( Figure 8B, [0065] discloses pulses for turning OFF the switches, namely 57a-57c as well as pulses for turning ON the switches, namely 58a-58c. Please note the amplitudes )
Howard teaches in Claim 34:
The system of claim 33, wherein the logic and control circuit comprises at least one programmable counter and receives a reference clock, the at least one programmable counter being configured to determine the pulse width of each electrical pulse profile by counting cycles of a reference clock. ( [0024], [0053] discloses details of the programmable pulses, such as amplitudes, widths and periods. Please note this is shown in Figures 5A/5B based on clock signals )
Howard teaches in Claim 35:
The system of claim 31, further comprising a serial interface configured to supply digital control signals to the logic and control circuit indicating whether each PCM switch is to be driven to the ON or OFF state. ( [0053] discloses digitally programmable pulsers 38 and 39 and being able to select pulse aspects )
Howard teaches in Claim 36:
The system of claim 31, wherein the control pulses include a control pulse for the ON state and a control pulse for the OFF state, and wherein each driver circuit comprises:
a first transistor stack configured to receive the control pulse for the ON state; and a second transistor stack configured to receive the control pulse for the OFF state, each transistor stack being arranged in series with at least one load device transistor. ( Figure 8A, [0031] disclose the heating element 9a-9c which is controlled by transistors turning on and off. Please note the two sides of 12a-12c each with the ON and OFF controlling. Please note various transistors in series, such as 46a-46c )
Claim Rejections - 35 USC § 103
6. The following is a quotation of pre-AIA 35 U.S.C. 103(a) which forms the basis for all obviousness rejections set forth in this Office action:
(a) A patent may not be obtained though the invention is not identically disclosed or described as set forth in section 102, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. Patentability shall not be negated by the manner in which the invention was made.
7. The factual inquiries for establishing a background for determining obviousness under pre-AIA 35 U.S.C. 103(a) are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
8. Claims 27, 29 and 37-39 are rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Howard et al. ( US 2020/0059229 A1 ), as applied to Claims 20 and 31, further in view of Sforzin et al. ( US 2023/0207004 A1 ).
As per Claim 27:
Howard does not explicitly teach of “using a current mirror to establish a reference current for the electrical pulses applied to the heater of each PCM switch.”
However, the use of current mirrors is well known in the art. To emphasize, in the same field of endeavor, phase change material designs, Sforzin teaches of a system for a memory cell, ( Sforzin, Figure 3, [0047] ). Notably, Sforzin teaches of using a current mirror circuit 310 to provide electric potentials to the control circuit 320. [0060] teaches the control circuit 320 has amplifiers, transistors, for controlling the phase change material, detailed in [0034]. As combined, the use of a current mirror can be used before akin circuitry shown in Howard’s Figure 8A.
Therefore, it would have been obvious to one of ordinary skill in the art, at the effective filed date of the invention, to implement the current mirror, as taught by Sforzin, with the motivation that the mirror can increase an accuracy of the current of the memory cell, ( Sforzin, [0057] ). This can allow for more precise changes in the PCM.
Sforzin teaches in Claim 28:
The method of claim 27, wherein establishing the reference current comprises applying a feedback circuit including an operational amplifier, a reference resistor matched to the heater, and at least one transistor arranged to mirror a set current to each driver circuit corresponding to a PCM switch. ( Sforzin, Figure 3, [0062] discloses a feedback circuit 330 with multiple operational amplifiers. Also, please note the cell resistor 405 which is connected to an output branch of the mirror circuit. [0034] discloses various resistance states for the specific potentials of the phase change material. Furthermore, please note the combination with Howard’s circuit for the switches )
As per Claim 37:
Howard does not explicitly teach of “a feedback circuit including an operational amplifier and a reference resistor, arranged to generate a reference current; and a current mirror coupled to the feedback circuit and the plurality of driver circuits, the current mirror configured to mirror the reference current into each driver circuit, wherein the reference current is selected such that process, temperature, and supply voltage variations are mitigated.”
However, the use of current mirrors is well known in the art. To emphasize, in the same field of endeavor, phase change material designs, Sforzin teaches of a system for a memory cell, ( Sforzin, Figure 3, [0047] ). Notably, Sforzin teaches of using a current mirror circuit 310 to provide electric potentials to the control circuit 320. [0060] teaches the control circuit 320 has amplifiers, transistors, for controlling the phase change material, detailed in [0034]. As combined, the use of a current mirror can be used before akin circuitry shown in Howard’s Figure 8A. Sforzin teaches of increasing the accuracy using the mirror (read as mitigating variations). Furthermore, Sforzin, Figure 3, [0062] discloses a feedback circuit 330 with multiple operational amplifiers. Also, please note the cell resistor 405 which is connected to an output branch of the mirror circuit. [0034] discloses various resistance states for the specific potentials of the phase change material. Furthermore, please note the combination with Howard’s circuit for the switches.
Therefore, it would have been obvious to one of ordinary skill in the art, at the effective filed date of the invention, to implement the current mirror, as taught by Sforzin, with the motivation that the mirror can increase an accuracy of the current of the memory cell, ( Sforzin, [0057] ). This can allow for more precise changes in the PCM.
Howard teaches in Claim 38:
The system of claim 37, wherein the current mirror in each driver circuit is arranged to generate two different currents based on the reference current: a first current corresponding to the ON state and a second current corresponding to the OFF state. ( Sforzin, Figure 3, [0062] discloses a feedback circuit 330 with multiple operational amplifiers, similar to Howard. [0034] discloses various resistance states for the specific potentials of the phase change material. Furthermore, please note the combination with Howard’s circuit for the switches, such as controlling the ON and OFF states using the current mirror )
Sforzin and Howard teach in Claim 39:
The system of claim 33, wherein each heater comprises a heater resistor, and wherein the first and second pulse profiles produce different thermal power through said heater resistor to effect the desired ON or OFF state of the phase change material. ( Please note the cell resistor 405 which is connected to an output branch of the mirror circuit. [0034] discloses various resistance states for the specific potentials of the phase change material (read as a heater resistor). Furthermore, please note the combination with Howard’s circuit for the switches as well )
Conclusion
9. Any inquiry concerning this communication or earlier communications from the examiner should be directed to DENNIS P JOSEPH whose telephone number is (571)270-1459. The examiner can normally be reached Monday - Friday 5:30 - 3:30 EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Amr Awad can be reached at 571-272-7764. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/DENNIS P JOSEPH/Primary Examiner, Art Unit 2621
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