DETAILED ACTION
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 .
Response to Amendment
The Amendments, filed on 04/27/2026, have been received and made of record. In response to the most recent Office Action, dated 02/09/2026, claims 1, 5-8, 12, 14, and 16-18 have been amended, and claims 4 and 11 have been cancelled.
Currently Claims 1-3, 5-10 and 12-20 are pending.
Response to Arguments
Applicant’s Amendments, filed on 04/27/2026, have been entered and fully considered. The Applicant has amended Independent Claims 1 and 8 to incorporate limitations of now cancelled claims 4 and 11, respectively. In light of the amendments, the Applicant has presented a set of arguments pointing out their rational of how the prior art references, Maxim Integrated (“24V Input, 500mA Buck Regulator with Dual-Input Power MUX – MAX77756 Data Sheet”) in view of Von Novak (US 2019/0103766 A1), made of record in the most recent Office Action do not teach the currently recited claim limitations. Applicant's arguments have been fully considered but they are not persuasive. Applicant has also submitted arguments pointing out their rational of how the prior art reference made of record in the most recent Office Action do not teach the claim limitations recited in independent claim 15. Applicant’s arguments have been fully considered but they are not persuasive. Below the Examiner has provided the response to each of the points raised by the Applicant in the submitted remarks.
The first argument raised by the Applicant has been reproduced below for purposes of clarity and is found on pages 10-11 of the submitted remarks.
Respectfully, Applicant submits that Von Novak does not teach "monitor[ing] at least one of an output current or an output voltage of the power stage to determine when to switch to the higher voltage value and the lower voltage value." The Office cites to Figures 6A-7A of Von Novak to teach these claim elements. OA pg. 13. Von Novak describes "the input switches 660 and the output switches 665 are controlled by a controller (e.g., PMIC 625) implementing a control algorithm configured to enhance efficiency of the power conversion of power conversion circuit 600." "For example, if three voltage sources provide 3, 6, and 9 volts, respectively, and the output terminal is configured to carry 5 volts, the 6 volt voltage source would be used to generate the voltage for the output terminal. Accordingly, the input switch 660 associated with the 6 volt voltage source may be opened and closed, and the output switch 665 associated with the terminal may be closed to provide the desired voltage of 5 V."
These portions of Von Novak do not teach monitoring the output current/voltage to then determine how to switch the inputs. Instead, Von Novak describes selecting or configuring the desired output voltage and then setting the input and output switches to efficiently provide the output voltage. The PMIC 625 in Von Novak does not monitor the actual current/voltage at the output and then use that to select the input. For at least this reason, Applicant submits the combination of references does not render claim 1 obvious.
The Examiner respectfully disagrees as the argument presented considers only selected portions of Von Novak and does not consider the reference as a whole or the combined teachings of Maxim Integrated and Von Novak. Von Novak in Paragraph 0035 highlights a controller coupled to a sensor that may be a voltage and/or current sensing circuit. Von Novak further states that the sensor may measure electrical parameters including “input voltage, output voltage, output current and etc” and that the controller adjusts how an output voltage is supplied to components of an electronic device. Therefore, Von Novak does teach monitoring at least one of an output voltage or an output current using the sensed parameters. Furthermore, in Paragraph 0059, Von Novak teaches that the controller controls the input switches and the output switches use a control algorithm configured to enhance power-conversion efficiency. Paragraph 0063 shows that the control may select among different voltage sources based on the sensed parameters that include a desired output voltage and a desired output current. Paragraph 0064 highlights that source selections decision accounts for changing loads. Accordingly, Von Novak teaches that the disclosure is not limited to selecting an input source based on state and programmed output voltage values rather Von Novak teaches sensing output voltage and output current, accounting for changing load conditions and changing the selected voltage source to pick the correct source to be outputted thus leading to an improved efficiency of the system.
The second argument raised by the Applicant has been reproduced below for purposes of clarity and is found on pages 11-12 of the submitted remarks.
Further, even assuming arguendo that the Von Novak does teach the recited claim elements, Applicant submits "the claimed combination cannot change the principle of operation of the primary reference or render the reference inoperable for its intended purpose. See MPEP § 2143.01, subsection VI." In this case, the whole point of the dual- input power MUX in Maxim Integrated is to "select[] the higher voltage from two different input sources to power the step-down converter." pg. 1. Maxim Integrated further explains "[t]he integrated dual-input power MUX automatically selects the higher of two different voltage sources to power the buck converter." Pg. 15. That is, "[t]he MUX connects the higher of V1N1 or V1N2 to SUP to power the buck. Only the higher voltage input channel is on. The selection logic has switchover hysteresis to avoid chattering. The off channel must be 200mV higher than the on channel to cause a switchover. Switchover is automatic and can happen any time while the buck is enabled." Id.
Applicant submits it would change the principle of operation to instead rely on monitoring the output of the power stage to determine when to switch the inputs. Maxim Integrated clearly indicates that it must monitor the inputs to determine which has the higher voltage and then switch to that input. Monitoring the outputs would not enable Maxim Integrated to determine which of the inputs has the greatest voltage. Put differently, knowledge regarding the output does not tell the circuit in Maxim integrated which input currently has the greatest voltage. Thus, the combination proposed by the Office would render Maxim Integrated inoperable for its intended purpose. For at least this reason, Applicant submits the combination of references does not render claim 1 obvious.
The Examiner respectfully disagrees and would like to start off by pointing out that one cannot show non-obviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Furthermore, the test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981). Although Maxim Integrated teaches a selecting the higher available input, Von Novak teaches selecting among available input sources according to load and efficiency considerations. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Maxim Integrated’s source selection control with the source selection control disclosed by Von Novak. The advantage of this design is that it allows for the selection of the input voltage based on the output or load conditions which avoids the use of a higher input voltage when a lower input voltage can more efficiently satisfy the load demand. This proposed modification amounts to the predictable use of Von Novak’s known efficiency-based source selection control. Each component would continue to perform its recognized function as the MUX switches would still select an input source and the buck power stage would continue to operate based on the selected input voltage.
The third argument raised by the Applicant is in reference to independent claims 8 and 15 and has been reproduced below for purposes of clarity and is found on page 12 of the submitted remarks.
Independent claim 8 is amended to recite "the PWM controller is configured to monitor at least one of an output current or an output voltage of the power stage to determine when to switch to the first mode and the second mode" and is allowable for similar reasons as stated above.
Independent claim 15 recites "monitoring an output of a power stage in a voltage regulator", "in response to the output of the power stage falling below a threshold, enabling a first mode where the power stage uses a first input voltage to perform PWM", and "in response to the output of the power stage being above the threshold, enabling a second mode where the power stage uses a second input voltage to perform PWM." As discussed above, the combination of references does not teach or suggest monitoring an output of a power stage in order to switch the inputs power sources to the power stage.
The Examiner respectfully disagrees for the reasons provided in the rebuttal above.
Based on the reasoning provided above the rejection made under 35 U.S.C. 103 is maintained and made final.
Claim Rejections
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 (i.e., changing from AIA to pre-AIA ) 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.
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 1-3, 8-10, 15-16 and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over Maxim Integrated (“24V Input, 500mA Buck Regulator with Dual-Input Power MUX – MAX77756 Data Sheet”) in view of Von Novak (US 2019/0103766 A1).
Regarding claim 1, Maxim Integrated teaches a voltage regulator (Page 14 Functional Diagram has been annotated as Annotated Figure 1A below for purposes of clarity; Annotated Figure 1A), comprising: a pulse width modulation (PWM) controller (Annotated Figure 1A Component SC; Figure 1 on Page 16 shows Component SC in detail which comprises a PWM comparator to generate the control signals; Page 15 Right Column explains that the controller is a PWM based controller); and a power stage (Annotated Figure 1A Component PS) configured to receive a PWM signal from the PWM controller (Annotated Figure 1A Component SC outputs signals to control Components Q1 and Q2; Figure 1 shows that Components Q1 and Q2 receive a PWM signal) in order to step-down an input voltage (Annotated Figure 1A Component Buck within Component SC is a step down converter; Annotated Figure 1A Component DC Input 1 or DC Input 2), wherein the power stage includes at least one switch (Annotated Figure 1A Component SU) for changing the input voltage (Annotated Figure 1A Component SU changes the input voltage between DC input 1 and DC input 2 based on which switch between Components S1 and S2 is active) from a lower voltage value to a higher voltage value used when performing PWM using the PWM signal (Page 15 Left Column “The MUX connects the higher of VIN1 or VIN2 to SUP to power the buck. Only the higher voltage input channel is on. The lower voltage input channel is off”; This passage shows that the higher input voltage is used as the input voltage for Components Q1 and Q2 which are controlled by a PWM signal), wherein the PWM controller is configured to monitor at least one of an output current or an output voltage of the power stage to perform PWM in a first mode having the higher voltage (Page 15 Left Column “The MUX connects the higher of VIN1 or VIN2 to SUP to power the buck. Only the higher voltage input channel is on. The lower voltage input channel is off”; This passage shows that the higher input voltage is used by the buck converter; Annotated Figure 1A Component SC is seen in detail in Figure 1 of Page 16; Figure 1 shows that the output voltage OUT/FB is monitored against a threshold or reference; Figure 1 also shows that the current going to the output at node LX is monitored for peaks and valleys).
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Maxim Integrated does not teach changing the input voltage from a higher voltage value to a lower voltage value; wherein the monitored at least one of an output current or an output voltage of the power stage to determine when to switch to a first mode with the higher voltage and when to switch to a second mode with the lower voltage.
Von Novak teaches a multiple input single inductor power converter (Figure 6A), comprising: at least one switch supply unit (Figure 6A Component 660) comprising a first switch coupled to a first input voltage (Figure 6A Component 660 Middle Switch) that provides a higher voltage value (Figure 6A Component WP PP is the voltage connected with the middle switch; FIG. 7 is an example of an output of a decision matrix for PMIC 625 where a voltage source (e.g., wireless power (WP) coil, WP post pre-regulator (PP), or Battery) is selected based on the desired output voltage (e.g., 1.1V, 1.8V, 3.3V, 3.6V, or 5V) and the input voltage provided by the different voltage sources; Figure 7 shows that WP PP is set to a voltage value of 5V in the first row); a second switch coupled to a second input voltage (Figure 6A Component 660 Top Switch) that provides a lower voltage value (Figure 7A Component WP coil is the voltage connected with the top switch; Figure 7 shows WP coil is set to a voltage of 2.5 V in the first row which makes it lower than the voltage of Component WP PP); a control unit (Paragraph 0059 “the input switches 660 and the output switches 665 are controlled by a controller (e.g., PMIC 625) implementing a control algorithm configured to enhance efficiency of the power conversion of power conversion circuit 600”) configured to change the input voltage to the lower voltage from the higher voltage (Figure 7 top row shows that when the output voltage required is 1.1V-1.8V WP coil is connected and not WP PP) or the higher voltage to the lower voltage based on the output voltage demand of the load (Figure 7 top row shows that when the output voltage required is 3.3V-5V then WP PP is connected; Paragraphs 0057-0064 highlights that the voltage is selected based on efficiency and the load demands), wherein the controller is configured to monitor the output voltage to determine when to switch to a first mode with the higher voltage and when to switch a second mode with the lower voltage (Paragraph 0064 “an output of a decision matrix for PMIC 625 where a voltage source (e.g., wireless power (WP) coil, WP post pre-regulator (PP), or Battery) is selected based on the desired output voltage (e.g., 1.1V, 1.8V, 3.3V, 3.6V, or 5V) and the input voltage provided by the different voltage sources”).
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 teachings of Maxim Integrated to incorporate a control scheme of selecting a lower voltage source or a higher voltage source based on load conditions as taught by Von Novak. The advantage of this design is that the buck converter can be utilized more efficiently instead of trying to step down a higher voltage in situations where a light load operation is needed thus reducing switching loss and enhancing the efficiency of the overall system.
Regarding claim 2, Maxim Integrated and Von Novak teach all the limitations of claim 1. Maxim Integrated further teaches wherein the at least one switch (Annotated Figure 1A Component SU) comprises a first switch (Annotated Figure 1A Component S1) coupled to a first input voltage (Annotated Figure 1A Component DC Input 1) that provides the higher voltage value (Annotated Figure 1A Component S1 being connected would indicate it is the higher voltage; Page 15 Left Column “The MUX connects the higher of VIN1 or VIN2 to SUP to power the buck. Only the higher voltage input channel is on. The lower voltage input channel is off”) and a second switch (Annotated Figure 1A Component S2) coupled to a second input voltage (Annotated Figure 1A Component DC Input 2) that provides the lower voltage value (Annotated Figure 1A Component S2 being disconnected would indicate a lower voltage; Page 15 Left Column “The MUX connects the higher of VIN1 or VIN2 to SUP to power the buck. Only the higher voltage input channel is on. The lower voltage input channel is off”).
Regarding claim 3, Maxim Integrated and Von Novak teach all the limitations of claim 2. Maxim Integrated further teaches wherein the power stage (Annotated Figure 1A Component PS) further comprises: a third switch coupled to both the first and second switches (Annotated Figure 1A Component Q1 is connected to both Components S1 and S2), wherein the third switch is controlled based on the PWM signal to perform PWM (Annotated Figure 1A Component Q1 is controlled by the step down control unit shown in Figure 1 of Page 16 which shows a PWM comparator is used to generate PWM signals to control Q1 and Q2 with a PWM control scheme) using the higher voltage value (Page 15 Left Column “The MUX connects the higher of VIN1 or VIN2 to SUP to power the buck. Only the higher voltage input channel is on. The lower voltage input channel is off”; This passage shows that the higher input voltage is used by the buck converter).
Maxim Integrated does not teach using the lower voltage value.
Von Novak teaches a multiple input single inductor power converter (Figure 6A), comprising: at least one switch supply unit (Figure 6A Component 660) comprising a first switch coupled to a first input voltage (Figure 6A Component 660 Middle Switch) that provides a higher voltage value (Figure 6A Component WP PP is the voltage connected with the middle switch; FIG. 7 is an example of an output of a decision matrix for PMIC 625 where a voltage source (e.g., wireless power (WP) coil, WP post pre-regulator (PP), or Battery) is selected based on the desired output voltage (e.g., 1.1V, 1.8V, 3.3V, 3.6V, or 5V) and the input voltage provided by the different voltage sources; Figure 7 shows that WP PP is set to a voltage value of 5V in the first row); a second switch coupled to a second input voltage (Figure 6A Component 660 Top Switch) that provides a lower voltage value (Figure 7A Component WP coil is the voltage connected with the top switch; Figure 7 shows WP coil is set to a voltage of 2.5 V in the first row which makes it lower than the voltage of Component WP PP); a control unit (Paragraph 0059 “the input switches 660 and the output switches 665 are controlled by a controller (e.g., PMIC 625) implementing a control algorithm configured to enhance efficiency of the power conversion of power conversion circuit 600”) configured to change the input voltage to the lower voltage from the higher voltage (Figure 7 top row shows that when the output voltage required is 1.1V-1.8V WP coil is connected and not WP PP) or the higher voltage to the lower voltage based on the output voltage demand of the load (Figure 7 top row shows that when the output voltage required is 3.3V-5V then WP PP is connected; Paragraphs 0057-0064 highlights that the voltage is selected based on efficiency and the load demands), wherein the voltage selected whether that be the higher one or the lower one is used by a power converter (Figure 6A Component 650 is operated with the inductor as a converter and uses the input voltage that is selected for conversion; Paragraphs 0059, 0062 and 0065).
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 teachings of Maxim Integrated to incorporate a control scheme of selecting a lower voltage source or a higher voltage source based on load conditions as taught by Von Novak. The advantage of this design is that the buck converter can be utilized more efficiently instead of trying to step down a higher voltage in situations where a light load operation is needed thus reducing switching loss and enhancing the efficiency of the overall system.
Regarding claim 8, Maxim Integrated teaches an integrated circuit (IC) (Page 14 Functional Diagram has been annotated as Annotated Figure 1A above for purposes of clarity; Annotated Figure 1A), comprising: a voltage regulator (Annotated Figure 1A Components SC+PS), comprising: a power stage (Annotated Figure 1A Component PS); and a pulse width modulation (PWM) controller configured to have the power stage perform PWM based on an input voltage (Annotated Figure 1A Component SC; Figure 1 on Page 16 shows Component SC in detail which comprises a PWM comparator to generate the control signals; Page 15 Right Column explains that the controller is a PWM based controller); a secondary controller (Annotated Figure 1A Component Power Mux Select Logic) configured to switch (Annotated Figure 1A Components S1 and S2 are selected to be ON and switched) between a first mode where the power stage uses a first input voltage (Annotated Figure 1A Component DC Input 1) to perform PWM (Annotated Figure 1A Component SU changes the input voltage between DC input 1 and DC input 2 based on which switch between Components S1 and S2 is active; Page 15 Left Column “The MUX connects the higher of VIN1 or VIN2 to SUP to power the buck. Only the higher voltage input channel is on. The lower voltage input channel is off”; This passage highlights that if DC input 1 is higher than DC input 1 and S1 are used) and a second mode where the power stage uses a second, different input voltage (Annotated Figure 1A Component DC input 2) to perform PWM (Page 15 Left Column “The MUX connects the higher of VIN1 or VIN2 to SUP to power the buck. Only the higher voltage input channel is on. The lower voltage input channel is off”; This passage highlights that if DC input 2 is higher than DC input 2 and S2 are used; DC input 2 is a different input voltage as it comes from a different source); wherein the PWM controller is configured to monitor at least one of an output current or an output voltage of the power stage to perform PWM (Page 15 Left Column “The MUX connects the higher of VIN1 or VIN2 to SUP to power the buck. Only the higher voltage input channel is on. The lower voltage input channel is off”; This passage shows that the higher input voltage is used by the buck converter; Annotated Figure 1A Component SC is seen in detail in Figure 1 of Page 16; Figure 1 shows that the output voltage OUT/FB is monitored against a threshold or reference; Figure 1 also shows that the current going to the output at node LX is monitored for peaks and valleys).
Maxim Integrated does not teach wherein a singular controller is used for both the converter and the selection of the input voltage source; wherein the monitored at least one of an output current or an output voltage of the power stage to determines when to switch to the first mode or the second mode.
Von Novak teaches a multiple input single inductor power converter (Figure 6A), comprising: at least one switch supply unit (Figure 6A Component 660) comprising a first switch coupled to a first input voltage (Figure 6A Component 660 Middle Switch) that provides a higher voltage value (Figure 6A Component WP PP is the voltage connected with the middle switch; FIG. 7 is an example of an output of a decision matrix for PMIC 625 where a voltage source (e.g., wireless power (WP) coil, WP post pre-regulator (PP), or Battery) is selected based on the desired output voltage (e.g., 1.1V, 1.8V, 3.3V, 3.6V, or 5V) and the input voltage provided by the different voltage sources; Figure 7 shows that WP PP is set to a voltage value of 5V in the first row); a second switch coupled to a second input voltage (Figure 6A Component 660 Top Switch) that provides a lower voltage value (Figure 7A Component WP coil is the voltage connected with the top switch; Figure 7 shows WP coil is set to a voltage of 2.5 V in the first row which makes it lower than the voltage of Component WP PP); a control unit (Paragraph 0059 “the input switches 660 and the output switches 665 are controlled by a controller (e.g., PMIC 625) implementing a control algorithm configured to enhance efficiency of the power conversion of power conversion circuit 600”) configured to change the input voltage to the lower voltage from the higher voltage (Figure 7 top row shows that when the output voltage required is 1.1V-1.8V WP coil is connected and not WP PP) or the higher voltage to the lower voltage based on the output voltage demand of the load (Figure 7 top row shows that when the output voltage required is 3.3V-5V then WP PP is connected; Paragraphs 0057-0064 highlights that the voltage is selected based on efficiency and the load demands), wherein the controller is configured to monitor the output voltage to determine when to switch to a first mode with the higher voltage and when to switch a second mode with the lower voltage (Paragraph 0064 “an output of a decision matrix for PMIC 625 where a voltage source (e.g., wireless power (WP) coil, WP post pre-regulator (PP), or Battery) is selected based on the desired output voltage (e.g., 1.1V, 1.8V, 3.3V, 3.6V, or 5V) and the input voltage provided by the different voltage sources”).
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 teachings of Maxim Integrated to incorporate a control scheme of selecting a lower voltage source or a higher voltage source based on load conditions as taught by Von Novak. The advantage of this design is that the buck converter can be utilized more efficiently instead of trying to step down a higher voltage in situations where a light load operation is needed thus reducing switching loss and enhancing the efficiency of the overall system.
Regarding claim 9, Maxim Integrated and Von Novak teach all the limitations of claim 8. Maxim Integrated further teaches wherein the power stage comprises a first switch coupled to the first input voltage (Annotated Figure 1A Component S1) and a second switch coupled to the second, different input voltage (Annotated Figure 1A Component S2).
Regarding claim 10, Maxim Integrated and Von Novak teach all the limitations of claim 9. Maxim Integrated further teaches wherein the power stage further comprises: a third switch coupled to both the first and second switches (Annotated Figure 1A Component Q1), wherein the third switch is controlled based on a PWM signal received from the PWM controller to perform PWM using one of the first input voltage or the second, different input voltage (Annotated Figure 1A Component Q1 is controlled by Component Step Down Control which produces a PWM signal to control switches Q1 and Q2; Component Buck uses which ever input voltage is selected).
Regarding claim 15, Maxim Integrated teaches a method (Page 14 Functional Diagram has been annotated as Annotated Figure 1A above for purposes of clarity; Annotated Figure 1A) comprising: monitoring an output (Annotated Figure 1A Component SC; Figure 1 on Page 16 shows Component SC in detail; Figure 1 shows that OUT/FB voltage parameters are monitored; Figure 1 also shows that Current Valleys and Peaks are also monitored) of a power stage (Annotated Figure 1A Component PS) in a voltage regulator (Annotated Figure 1A Component SC+PS) and comparing them to a threshold (Figure 1 Component OUT/FB is compared with a reference voltage; Component Ilx is compared with a valley reference and a peak reference); in response to a first input voltage being higher, enabling a first mode where the power stage uses a first input voltage (Annotated Figure 1A Component SU changes the input voltage between DC input 1 and DC input 2 based on which switch between Components S1 and S2 is active; Page 15 Left Column “The MUX connects the higher of VIN1 or VIN2 to SUP to power the buck. Only the higher voltage input channel is on. The lower voltage input channel is off”; This passage shows that the higher input voltage is used as the input voltage for Components Q1 and Q2 which are controlled by a PWM signal) to perform PWM (Figure 1 shows that the controller possesses a PWM signal comparator to generate a PWM signal to control switches Q1 and Q2 based on the input voltage provided); and in response to a second input voltage being higher, enabling a second mode where the power stage uses a second input voltage (Page 15 Left Column “The MUX connects the higher of VIN1 or VIN2 to SUP to power the buck. Only the higher voltage input channel is on. The lower voltage input channel is off”; This passage shows that the higher input voltage is used as the input voltage for Components Q1 and Q2 which are controlled by a PWM signal thus if DC input 2 was higher it would be selected) to perform PWM (Figure 1 shows that the controller possesses a PWM signal comparator to generate a PWM signal to control switches Q1 and Q2 based on the input voltage provided).
Maxim Integrated does not teach enabling a first input voltage in response to the output of the power stage falling below a threshold and enabling a second input voltage in response to the output of the power stage being above the threshold.
Von Novak teaches a multiple input single inductor power converter (Figure 6A), comprising: at least one switch supply unit (Figure 6A Component 660) comprising a first switch coupled to a first input voltage (Figure 6A Component 660 Middle Switch) that provides a higher voltage value (Figure 6A Component WP PP is the voltage connected with the middle switch; FIG. 7 is an example of an output of a decision matrix for PMIC 625 where a voltage source (e.g., wireless power (WP) coil, WP post pre-regulator (PP), or Battery) is selected based on the desired output voltage (e.g., 1.1V, 1.8V, 3.3V, 3.6V, or 5V) and the input voltage provided by the different voltage sources; Figure 7 shows that WP PP is set to a voltage value of 5V in the first row); a second switch coupled to a second input voltage (Figure 6A Component 660 Top Switch) that provides a lower voltage value (Figure 7A Component WP coil is the voltage connected with the top switch; Figure 7 shows WP coil is set to a voltage of 2.5 V in the first row which makes it lower than the voltage of Component WP PP); a control unit (Paragraph 0059 “the input switches 660 and the output switches 665 are controlled by a controller (e.g., PMIC 625) implementing a control algorithm configured to enhance efficiency of the power conversion of power conversion circuit 600”) configured to change the input voltage to the lower voltage from the higher voltage (Figure 7 top row shows that when the output voltage required is 1.1V-1.8V WP coil is connected and not WP PP) or the higher voltage to the lower voltage based on load demands or output voltage thresholds (Figure 7 top row shows that when the output voltage required is 3.3V-5V then WP PP is connected; Paragraphs 0057-0064 highlights that the voltage is selected based on efficiency and the load demands; Paragraph 0065 highlights that voltage thresholds can be used; Paragraph 0065 “to select a voltage source that supplies an input voltage slightly below the desired output voltage (e.g., by a first threshold) and boost the voltage than select a voltage source that supplies an input voltage further above the desired output voltage (e.g., by a second threshold) and buck the voltage. F”).
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 teachings of Maxim Integrated to incorporate a control scheme of selecting a lower voltage source or a higher voltage source based on load conditions as taught by Von Novak. The advantage of this design is that the buck converter can be utilized more efficiently instead of trying to step down a higher voltage in situations where a light load operation is needed thus reducing switching loss and enhancing the efficiency of the overall system.
Regarding claim 16, Maxim Integrated and Von Novak teach all the limitations of claim 15. Maxim Integrated further teaches wherein monitoring the output of the power stage (Annotated Figure 1A Component SC; Figure 1 on Page 16 shows Component SC in detail) comprises monitoring both an output current (Figure 1 Component ILX is the current going to the output at node LX) and an output voltage (Figure 1 Component OUT/FB is the output voltage feedback) of the power stage to determine whether the output current and the output voltage are below respective current and voltage thresholds that include the threshold (Figure 1 Component ILX is compared with a peak reference at ILIM and a valley reference at the bottom comparator; OUT/FB is compared with a reference voltage).
Regarding claim 19, Maxim Integrated and Von Novak teach all the limitations of claim 15. Maxim Integrated further teaches wherein enabling the first mode comprises: turning on a first switch to couple the first input voltage (Annotated Figure 1A Component S1) to a second switch that performs PWM (Annotated Figure 1A Component Q1); and turning off a third switch coupled to the second input voltage (Annotated Figure 1A Component S2; Page 15 Left Column “The MUX connects the higher of VIN1 or VIN2 to SUP to power the buck. Only the higher voltage input channel is on. The lower voltage input channel is off”).
Regarding claim 20, Maxim Integrated and Von Novak teach all the limitations of claim 19. Maxim Integrated further teaches wherein enabling the second mode comprises: turning on the third switch to couple the second input voltage (Annotated Figure 1A Component S2) to the second switch that performs PWM (Annotated Figure 1A Component Q1); and turning off the first switch coupled to the first input voltage (Annotated Figure 1A Component S1; Page 15 Left Column “The MUX connects the higher of VIN1 or VIN2 to SUP to power the buck. Only the higher voltage input channel is on. The lower voltage input channel is off”).
Allowable Subject Matter
Claims 5-7, 12-14 and 17-18 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.
Regarding claim 5, none of the prior art, made of record, singularly or in combinations, teaches or fairly suggests wherein the first mode is a continuous current mode (CCM), wherein a different duty cycle is used to perform PWM in the first mode than in the second mode. Claim 6 depends upon claim 5.
Regarding claim 7, none of the prior art, made of record, singularly or in combinations, teaches or fairly suggests wherein the PWM controller is configured to switch to the second mode only after the output current and the output voltage of the power stage have both been below a current threshold and a voltage threshold, respectively, for a predefined time period.
Regarding claim 12, none of the prior art, made of record, singularly or in combinations, teaches or fairly suggests wherein the first mode is a CCM, wherein a different duty cycle is used to perform PWM in the first mode than in the second mode. Claims 13 depends upon claim 12.
Regarding claim 14, none of the prior art, made of record, singularly or in combinations, teaches or fairly suggests wherein the PWM controller is configured to switch to the second mode only after the output current and the output voltage of the power stage have both been below a current threshold and a voltage threshold, respectively, for a predefined time period.
Regarding claim 17, none of the prior art, made of record, singularly or in combinations, teaches or fairly suggests wherein the first mode is enabled only when the output current and the output voltage are both below the respective current and voltage thresholds. Claim 18 depends upon claim 17.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Shahzeb K. Ahmad whose telephone number is (571)272-0978. The examiner can normally be reached Monday - Friday 8 A.M. to 5 P.M..
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, Thienvu V. Tran can be reached at 571-270-1276. 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.
/Shahzeb K Ahmad/Examiner, Art Unit 2838
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