Power supply circuit design support device, power supply circuit design support method, and program for power supply circuit design support

Abstract

To determine the optimal resistance for designing a power supply circuit that outputs desired voltage.SOLUTION: A power supply circuit design support device according to the present invention is provided with: output voltage calculation means 3 that calculates output voltage that is output in time series from the start up of a power supply circuit including a power supply IC and a feedback resistance externally connected to the power supply IC, by using a numerical formula created by the value of feedback voltage and the value of the feedback resistance in the power supply circuit; curve generation means 4 that, on the basis of the time-series output voltage calculated by the output voltage calculation means 3, obtains a temporal change curve of the output voltage; display means that displays an image; and display control means 5 that displays, on the display means, a graph based on the temporal change curve obtained by the curve generation means 4.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power supply circuit design support device, a power supply circuit design support method, and a power supply circuit design support program. [Background technology]

[0002] When designing a power supply circuit, one of the important factors that designers must consider is the decision on feedback resistors. Generally, two feedback resistors are used in a power supply circuit. However, because there are a huge number of different resistors available from each manufacturer on the market, there are also a huge number of combinations of two resistors. Furthermore, the task of deciding the optimal resistor combination to design a power supply circuit that outputs the desired voltage can be very time-consuming, especially for young engineers with little experience. Furthermore, this task can lead to mistakes, such as overlooking the optimal combination.

[0003] Patent Document 1 discloses a method for manufacturing a semiconductor device. In this method, a template having a representation of a separate circuit block and an equation relating the performance parameters of the circuit block to the electrical parameters of the components of the circuit block is selected from a library. In addition, desired values ​​of the performance parameters of the circuit block are selected, and the desired values ​​of the performance parameters are substituted into the equation to configure the design of the semiconductor device, and the equation is solved for the electrical parameters. In this way, values ​​of the electrical parameters to realize the desired values ​​of the performance parameters are calculated, and the semiconductor device operates based on the design.

[0004] Patent Document 2 discloses a method for supporting power supply circuit design by flexibly responding to changes in the selection criteria for the circuit system. In this method, the circuit system, judgment factors, element ranges, and weighting values ​​input in the steps of inputting the circuit system of the switching power supply, inputting the judgment factors, inputting the element range, and inputting the weighting values ​​for the element range are stored in a database in a hierarchical structure. Furthermore, in this method, by inputting electrical specifications, a plurality of judgment factors and their values ​​are extracted from the specifications, and a range for the judgment factors is specified by referring to the information in the database from the extracted judgment factor and value pair, and a weighting value for circuit selection that matches the judgment factor and range is extracted from the database. Then, based on the weighting value for each extracted judgment factor, a switching power supply circuit system that is most suitable for the specifications is selected and displayed.

[0005] Patent Document 3 discloses a power supply voltage adjustment circuit. ext The output voltage V out A feedback resistor R is disposed between resistor R1 and ground resistor R2, which constitute a mechanism on the external power supply circuit side having a feedback function to output fb1 and the output voltage V out and a D / A conversion circuit having a variable resistor disposed within the SoC3 that receives the supply of an internal power supply voltage VDD based on the above.

[0006] Then, the resistance values ​​of the variable resistors RDAC and IDAC are changed to obtain the output voltage V out In particular, it has a bandgap reference circuit that generates a BGR voltage VBGR, and calculates control data that changes the resistance values ​​RDAC and IDAC of the variable resistors using the BGR voltage VBGR when SoC3 is in an idle state and the BGR voltage VBGR when SoC3 is in an active state.

[0007] Other works relating to the design of power supply circuits include those described in Patent Documents 4, 5, 6 and 7. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2002-157289 A [Patent Document 2] JP 2007-102638 A [Patent Document 3] JP 2023-113320 A [Patent Document 4] JP 2009-199338 A [Patent Document 5] JP 2005-189930 A [Patent Document 6] Japanese Patent Application Publication No. 11-39373 [Patent Document 7] Japanese Patent Application Publication No. 10-187786 Summary of the Invention [Problem to be solved by the invention]

[0009] As mentioned above, there are many inventions related to circuit design and power supply circuit design, but there are almost none that can be used relatively easily by those with low levels of expertise. Also, although each IC manufacturer may provide optimization tools for their own products, the tools are limited to circuits that use ICs provided by the manufacturer. In actual circuit design, power supply ICs from multiple manufacturers are often used, and in such cases it is necessary to learn how to use multiple tools, which is quite a lot of work. In this situation, there is a demand for a versatile power supply circuit design optimization tool that is not tied to an IC manufacturer, in order to improve the efficiency of power supply circuit design.

[0010] The present invention has been made in consideration of the above-mentioned current situation, and an object of the present invention is to provide a power supply circuit design support device, a power supply circuit design support method, and a power supply circuit design support program that are useful in determining the optimum resistance for designing a power supply circuit that outputs a desired voltage. [Means for solving the problem]

[0011] The power supply circuit design support device according to the present invention is characterized by comprising: output voltage calculation means for calculating an output voltage to be output in a time series from a rise in a power supply circuit including a power supply IC and a feedback resistor externally connected to the power supply IC, using a formula created from a feedback voltage value of the power supply circuit and a value of the feedback resistor; curve generation means for obtaining a time-varying curve of the output voltage based on the time-varying output voltage calculated by the output voltage calculation means; display means for displaying an image; and display control means for displaying on the display means a graph based on the time-varying curve obtained by the curve generation means.

[0012] In the power supply circuit design support device according to the present invention, the output voltage calculation means calculates the output voltage as V out and the feedback voltage is V fb If the feedback resistor on the power supply side is R1 and the feedback resistor on the ground side is R2, then the following formula (1) is obtained: V out =V fb ×{(R1 / R2)+1} (Formula 1) It is characterized by determining the output voltage.

[0013] The power supply circuit design support device according to the present invention is characterized in that it comprises a multiple candidate processing control means for determining a plurality of feedback resistance values ​​based on the given feedback resistance value, calculating a plurality of corresponding output voltage candidates based on the plurality of feedback resistance values, generating a plurality of output voltage change curves over time based on the plurality of output voltage candidates, and controlling the display of a graph based on the generated plurality of output voltage change curves over time.

[0014] In the power supply circuit design support device of the present invention, the multiple candidate processing control means is provided with upper and lower limit values ​​for the feedback resistance, and determines at least one value between the upper and lower limit values ​​to obtain at least three feedback resistance values.

[0015] The power supply circuit design support device according to the present invention is characterized in that it comprises a number increasing means for increasing the number of feedback resistance values ​​that are the basis for calculating a plurality of output voltage candidates based on a given accuracy of feedback resistance and supplying the increased number to the multiple candidate processing control means.

[0016] The power supply circuit design support device according to the present invention is characterized in that it comprises a database of temperature change data relating to temperature changes in resistance value, and when the temperature of the environment in which the power supply circuit is used is given, it refers to the database based on the given temperature, changes the value of the feedback resistance given to the multiple candidate processing control means, and notifies the multiple candidate processing control means of this changed value to cause processing based on this value. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a configuration diagram of a design support device for a power supply circuit according to an embodiment of the present invention, which is configured using a computer. [Diagram 2] FIG. 2 is a diagram showing each unit stored in an external storage device of the power supply circuit design support apparatus according to the embodiment of the present invention. [Diagram 3] FIG. 4 is a diagram showing a display example when inputting a part name in the design support device for a power supply circuit according to the embodiment of the present invention. [Figure 4] 4 is a flowchart showing an operation of the design support device for a power supply circuit according to the embodiment of the present invention. [Diagram 5] 4 is a flowchart showing an operation of the design support device for a power supply circuit according to the embodiment of the present invention. [Figure 6] 5A to 5C are explanatory diagrams illustrating a graph creation process by the power supply circuit design support device according to the embodiment of the present invention. [Figure 7]A graph showing the change in output voltage in the region around the time the power supply IC starts up. [Figure 8] FIG. 4 is a graph showing output voltages for five different combinations of feedback resistors obtained by the power supply circuit design support device according to the embodiment of the present invention. [Figure 9] FIG. 9 is an enlarged view of a main portion of the display screen of FIG. 8. [Figure 10] FIG. 13 is a graph showing output voltages for five combinations of upper limit values ​​of feedback resistors, calculated by the power supply circuit design support device according to the embodiment of the present invention. [Figure 11] FIG. 13 is a graph showing output voltages obtained by combining upper-limit intermediate values ​​of five feedback resistors using the power supply circuit design support device according to the embodiment of the present invention. [Figure 12] FIG. 13 is a graph showing output voltages obtained by combining the median values ​​of five feedback resistors using the power supply circuit design support device according to the embodiment of the present invention. [Figure 13] FIG. 13 is a graph showing output voltages obtained by combining five intermediate values ​​on the lower limit side of feedback resistances, obtained by the power supply circuit design support device according to the embodiment of the present invention. [Figure 14] FIG. 13 is a graph showing output voltages for five combinations of lower limit values ​​of feedback resistances, calculated by the power supply circuit design support device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of a power supply circuit design support device, a power supply circuit design support method, and a power supply circuit design support program according to the present invention will be described with reference to the accompanying drawings. In each drawing, the same components are given the same reference numerals and duplicated explanations will be omitted. As shown in FIG. 1, the power supply circuit design support device according to the present invention can be configured using a computer.

[0019] That is, a CPU 10 configures a power supply circuit design support device using programs and data in a main memory 11. An external storage interface 13, an input interface 14, a display interface 15, and a communication interface 16 are connected to the CPU 10 via a bus 12.

[0020] An external storage device 23 is connected to the external memory interface 13. The external storage device 23 stores programs and data for the operation of this power supply circuit design support device, which can be read out and used by the CPU 10 as appropriate into the main memory 11. For this reason, the external storage device 23 stores programs for realizing the output voltage calculation means 3, curve generation means 4, display control means 5, multiple candidate processing control means 6, number increasing means 7, and temperature change response means 8 shown in FIG.

[0021] The output voltage calculation means 3 calculates the output voltage that is output in time series from the rising edge of a power supply circuit including a power supply IC and a feedback resistor externally connected to the power supply IC, using a formula created from the value of the feedback voltage of the power supply circuit and the value of the feedback resistor.

[0022] The curve generating means 4 obtains a curve of change in the output voltage over time based on the time-series output voltage calculated by the output voltage calculating means 3. The display control means 5 displays a graph based on the curve of change over time obtained by the curve generating means 4 on the display device 25 of Fig. 1 which is a display means.

[0023] The output voltage calculation means 3 calculates the output voltage as V out and the feedback voltage is V fb If the feedback resistor on the power supply side is R1 and the feedback resistor on the ground side is R2, then the following formula (1) is obtained: V out =V fb ×{(R1 / R2)+1} (Formula 1) Find the output voltage.

[0024] The multiple candidate processing control means 6 is provided with a feedback resistance value, and determines multiple feedback resistance values ​​based on this value, calculates multiple corresponding output voltage candidates based on the multiple feedback resistance values, generates time-varying curves of multiple output voltages based on the multiple output voltage candidates, and controls the display of a graph based on the generated time-varying curves of the multiple output voltages.

[0025] The multiple candidate processing control means 6 is given an upper limit value and a lower limit value of the feedback resistance, and obtains at least one value between the upper limit value and the lower limit value to obtain at least three feedback resistance values. Here, the means 6 obtains the intermediate value between the upper limit value and the lower limit value (median intermediate value), the intermediate value between the upper limit value and the median intermediate value (upper limit intermediate value), and the intermediate value between the lower limit value and the median intermediate value (lower limit intermediate value), to obtain five feedback resistance values ​​including the upper limit value and the lower limit value.

[0026] The number increasing means 7 is provided with the accuracy of the feedback resistance, and increases the number of feedback resistance values ​​that are the basis for calculating a plurality of output voltage candidates based on this accuracy, and supplies the increased number to the multiple candidate processing control means 6.

[0027] The temperature change response means 8 is provided with a database of temperature change data relating to temperature changes in resistance value, and when the temperature of the environment in which the power supply circuit is used is given, the temperature change response means 8 refers to the database based on the given temperature, changes the value of the feedback resistance given to the multiple candidate processing control means 6, and notifies the multiple candidate processing control means 6 of this changed value, causing it to perform processing based on this value.

[0028] Returning to Fig. 1, the explanation will be continued. An input device 24 such as a keyboard or a touch panel, and a pointing device 22 such as a mouse are connected to the input interface 14. A display device 25 having a screen such as an LCD is connected to the display interface 15, and the display device 25 realizes a display means. The communication interface 16 is configured so as to be connectable via a network to a supply site of performance and characteristic data of the power supply ICs of each manufacturer, and the performance and characteristic data of the power supply ICs of each manufacturer is stored in an external storage device 23 as shown in Fig. 2, and is used for generating a time series curve, etc.

[0029] The external storage device 23 stores a database of circuit diagram data for the power supply circuit to be designed, and the circuit diagram can be called up by inputting the "part name," which is the identification information for each part, and displayed on the display device 25. Figure 3 shows an example of the display on the power supply circuit design device when "DCDC general-purpose" is input as the "part name" from the input device 24.

[0030] In this embodiment, the programs of the processes executed by the above-mentioned means shown in the flowcharts of Figs. 4 and 5 are stored in the external storage device 23, and the operations are performed based on these programs. out The value of the feedback voltage V fb The value is input (S12).

[0031] Furthermore, the value (range) of the feedback resistor (R1 or R2) is input (S13). Here, the CPU 10 detects whether the resistance value of the feedback resistor R1 has been input as the multiple candidate processing control means 6 (S14). If the resistance value of the feedback resistor R1 has been input and the process branches to YES in step S14, the upper limit, lower limit, median, upper limit side median, and lower limit side median of the feedback resistor R1 are calculated (S15). On the other hand, if the resistance value of the feedback resistor R2 has been input and the process branches to NO in step S14, the upper limit, lower limit, median, upper limit side median, and lower limit side median of the feedback resistor R2 are calculated (S16).

[0032] Next, it is detected whether the accuracy of the resistance value must be taken into consideration (S17). That is, as shown in the display example of FIG. 3, when the check box of "Resistance Accuracy" is checked by inputting the accuracy value, the process branches to YES in this step S17, and the output voltage V is adjusted by taking into consideration the change in resistance value due to the accuracy of the resistor. out The calculation formula is changed (S18).

[0033] Here, as mentioned above, the output voltage V out is calculated using (Equation 1), but if the "resistor accuracy" is 0.1%, the maximum output voltage V out MAX is V out MAX=V fb ×{(R1·1.001 / R2·0.999)+1}···(Formula 2) and the minimum output voltage V out MIN is V out MIN=V fb ×{(R1·0.999 / R2·1.001)+1}···(Formula 3) It becomes.

[0034] The above can be illustrated as shown in Figure 6. V obtained from (Equation 1) out On the other hand, the upper V out V below MAX out In this way, when step S18 is completed or when the process branches to NO in step S17, the process proceeds to step S19, where it is determined whether or not temperature changes must be taken into consideration (S19). That is, as shown in the example display of FIG. 3, when a process is performed in which a temperature value in the operating state is input in the "operating temperature" box, for example, and the check box is turned ON, the process branches to YES in this step S19, and the output voltage V is adjusted to take temperature changes into consideration. out The calculation formula is changed (S20).

[0035] Generally, the resistance temperature coefficient can be positive or negative depending on the temperature. In this embodiment, a database of resistance temperature coefficients of each manufacturer is prepared, and this is used to change the calculation formula. In this embodiment, the operating temperature is 25 degrees, and the resistance temperature coefficient is set to a maximum of 1.01 times the resistance value and a minimum of 0.99 times.

[0036] Then, the maximum output voltage including temperature V out MAX_SM is V out MAX_SM=V fb ×{(R1·1.001·1.01 / R2·0.999·0.99)+1}···(Formula 4) and the minimum output voltage V out MIN_SM is V out MIN=V fb ×{(R1·0.999·0.99 / R2·1.001·1.01)+1}···(Formula 5) It becomes.

[0037] In this way, when step S20 is completed or when step S19 branches to NO, the process proceeds to step S21 to detect whether processing corresponding to the resistance value of R1 has already been performed. If the result is YES in this step S21, five resistance values ​​of R2 are calculated, a formula is obtained similarly to R1, and the results are displayed (S22). On the other hand, if the result is NO in the above step S21, five resistance values ​​of R1 are calculated, a formula is obtained similarly to R2, and the results are displayed (S23). As mentioned above, in step S11, the desired output voltage V out The value of the feedback voltage V fb In step S22 and S23, the other feedback resistor R2 (or R3) is calculated from the five feedback resistors R1 (or R2) obtained by inputting the value of R1 (or R2) and the value (range) of R1 (or R2) in step S13.

[0038] In the above, the upper limit, lower limit, central median, upper limit side median, and lower limit side median of the feedback resistor R1 and the upper limit, lower limit, central median, upper limit side median, and lower limit side median of the feedback resistor R2 are finally obtained. out is obtained and displayed as shown in FIG. 8. Here, V obtained by (Equation 4) and (Equation 5) out is a value at a certain point in time. Usually, the power supply IC gradually changes from start-up to a value that can be calculated by (Equation 1). For example, a characteristic curve as shown in FIG. 7 is shown. Each manufacturer provides time-series data corresponding to such characteristic curves from the supply site as performance and characteristic data of the power supply IC, so as described above, this is obtained from the network via the communication interface 16 and stored in the external storage device 23 as shown in FIG. 2. Then, based on the time-series data corresponding to the characteristic curve in FIG. 7, X(t) is calculated and stored so that the output voltage at each time t can be obtained by multiplying (Equation 1) by X(t). When (Equation 4) and (Equation 5) are found, the time series data is calculated using {(Equation 4)·X(t)} to obtain the upper side of the graph, and the time series data is calculated using {(Equation 5)·X(t)} to obtain the lower side of the graph, and an image is obtained in which five graphs are superimposed, with the upper limit, lower limit, central intermediate value, upper limit intermediate value, and lower limit intermediate value of the feedback resistance R1 and resistance R2 as shown in Figure 7, which have a voltage value range at each time, and displayed. Note that the characteristic curve in Figure 7 is created by setting several (R1 / R2)s and calculating the feedback voltage V for each of these (R1 / R2). fb A number of different values ​​are prepared, each varying in steps.

[0039] In this embodiment, the area indicated by circle B in Fig. 8 can be selected by the pointing device 22 or the like, and this portion can be enlarged and displayed as shown in Fig. 9. Furthermore, by giving an instruction from the input device 24, an image of a graph can be obtained in which the upper limit, lower limit, central intermediate value, upper limit side intermediate value, and lower limit side intermediate value of the feedback resistance R1 and resistance R2 are each independently displayed, and each of these can be displayed as shown in the five diagrams from Fig. 10 to Fig. 14.

[0040] As described in the present embodiment, by using the device, method, or program of the embodiment, five combinations of feedback resistors for outputting a desired output voltage can be instantly obtained without manual calculation. In addition, it is possible to display the output voltage for each of the five combinations of feedback resistors in a graph, allowing the user to intuitively select the optimal output result by visual inspection. In addition, it is possible to reflect the output voltage variation due to the accuracy of the resistors and the output voltage fluctuation due to the environmental temperature in the calculation results as necessary, which is useful for designing a power supply circuit. It goes without saying that these five combinations are merely examples. [Explanation of symbols]

[0041] 3. Output voltage calculation method 4 Curve generation means 5 Display control means 6 Multiple candidate processing control means 7. Ways to increase quantity 8. Measures to deal with temperature changes 10 CPU 11 Main Memory 12 Bus 13 External memory interface 14 Input Interface 15 Display Interface 16 Communication Interface 22 Pointing Device 23 External storage device 24 Input Devices 25 Display device

Claims

1. an output voltage calculation means for calculating an output voltage outputted in time series from a rise in a power supply circuit including a power supply IC and a feedback resistor externally connected to the power supply IC, using a formula created by a feedback voltage value of the power supply circuit and a value of the feedback resistor; a curve generating means for obtaining a curve of change in the output voltage over time based on the time series output voltage calculated by the output voltage calculating means; A display means for displaying an image; a display control means for displaying on the display means a graph based on the time-varying curve obtained by the curve generating means; A power supply circuit design support device comprising:

2. The output voltage calculation means calculates the output voltage as V out and the feedback voltage is V fb If the feedback resistor on the power supply side is R1 and the feedback resistor on the ground side is R2, then the following (Equation 1) is obtained: V out = V fb ×{(R1 / R2) + 1}... (Equation 1) 2. The power supply circuit design support device according to claim 1, wherein an output voltage is calculated.

3. a multiple candidate processing control means for controlling a plurality of candidate values ​​to be calculated based on a given feedback resistance value, a plurality of output voltage candidates corresponding to the plurality of feedback resistance values, a generation of a plurality of output voltage change curves over time based on the plurality of output voltage candidates, and a display of a graph based on the generated plurality of output voltage change curves over time; 3. The power supply circuit design support device according to claim 1, further comprising:

4. 4. The power supply circuit design support device according to claim 3, wherein the multiple candidate processing control means is provided with upper and lower limit values ​​for a feedback resistance, and determines at least one value between the upper and lower limit values ​​to obtain at least three feedback resistance values.

5. a number increasing means for increasing the number of feedback resistor values ​​on which a plurality of output voltage candidates are calculated based on the accuracy of the feedback resistor, and supplying the increased number to the plurality of candidate processing control means; 4. The power supply circuit design support device according to claim 3, further comprising:

6. a temperature change response means which includes a database of temperature change data relating to temperature changes in resistance value, and when a temperature of an environment in which the power supply circuit is used is given, changes the value of the feedback resistance given to the multiple candidate processing control means by referring to the database based on the given temperature, and notifies the multiple candidate processing control means of this changed value to cause the multiple candidate processing control means to perform processing based on this value; 4. The power supply circuit design support device according to claim 3, further comprising:

7. an output voltage calculation step of calculating an output voltage that is output in time series from a rise in a power supply circuit including a power supply IC and a feedback resistor externally connected to the power supply IC, using a formula created by a feedback voltage value of the power supply circuit and a value of the feedback resistor; a curve generating step of obtaining a time-varying curve of the output voltage based on the time-series output voltage calculated in the output voltage calculating step; a display control step of displaying a graph based on the time-varying curve obtained in the curve generating step on a display means for displaying an image; A power supply circuit design support method comprising:

8. The output voltage calculation step calculates the output voltage as V out and the feedback voltage is V fb If the feedback resistor on the power supply side is R1 and the feedback resistor on the ground side is R2, then the following (Equation 1) is obtained: V out = V fb ×{(R1 / R2) + 1} ···· (Equation 1) 8. The method for supporting design of a power supply circuit according to claim 7, further comprising the step of determining an output voltage.

9. a multiple candidate processing control step of determining a feedback resistance value based on the feedback resistance value, calculating multiple output voltage candidates corresponding to the multiple feedback resistance values, generating multiple output voltage change curves over time based on the multiple output voltage candidates, and controlling display of a graph based on the generated multiple output voltage change curves over time; 9. The power supply circuit design support method according to claim 7, further comprising:

10. 10. The power supply circuit design support method according to claim 9, wherein the multiple candidate processing control step is configured to obtain at least three feedback resistance values ​​by determining at least one value between an upper limit value and a lower limit value given for the feedback resistance.

11. a number increasing step in which, given a feedback resistor accuracy, the number of feedback resistor values ​​on which a plurality of output voltage candidates are calculated is increased based on this accuracy, and the number is supplied to the plurality of candidate processing control step; 10. The power supply circuit design support method according to claim 9, further comprising:

12. a temperature change response step including a database of temperature change data relating to temperature changes in resistance value, and when a temperature of an environment in which the power supply circuit is used is given, changing the value of the feedback resistance given to the multiple candidate processing control step based on the given temperature by referring to the database, and notifying the multiple candidate processing control step of the changed value to cause processing based on this value to be performed; 10. The power supply circuit design support method according to claim 9, further comprising:

13. Computer, an output voltage calculation means for calculating an output voltage outputted in time series from a rise in a power supply circuit including a power supply IC and a feedback resistor externally connected to the power supply IC, using a formula created by a feedback voltage value of the power supply circuit and a value of the feedback resistor; a curve generating means for obtaining a curve of change in the output voltage over time based on the time series output voltage calculated by the output voltage calculating means; a display control means for displaying a graph based on the time-varying curve obtained by the curve generating means on a display device for displaying images; A power supply circuit design support program that functions as a

14. The computer is used as the output voltage calculation means to calculate the output voltage V out and the feedback voltage is V fb If the feedback resistor on the power supply side is R1 and the feedback resistor on the ground side is R2, then the following (Equation 1) is obtained: V out = V fb ×{(R1 / R2) + 1} ···· (Equation 1) 14. The power supply circuit design support program according to claim 13, characterized in that the program is made to function so as to obtain an output voltage.

15. The computer, a multiple candidate processing control means for controlling a plurality of candidate values ​​to be calculated based on a given feedback resistance value, a plurality of output voltage candidates corresponding to the plurality of feedback resistance values, a generation of a plurality of output voltage change curves over time based on the plurality of output voltage candidates, and a display of a graph based on the generated plurality of output voltage change curves over time; 15. The power supply circuit design support program according to claim 13, wherein the power supply circuit design support program functions as follows:

16. 16. The power supply circuit design support program according to claim 15, characterized in that the computer is caused to function as the multiple candidate processing control means such that an upper limit value and a lower limit value of a feedback resistance are given, and at least one value is obtained between the upper limit value and the lower limit value to obtain at least three feedback resistance values.

17. The computer, a number increasing means for increasing the number of feedback resistor values ​​on which a plurality of output voltage candidates are calculated based on the accuracy of the feedback resistor, and supplying the increased number to the computer functioning as the multiple candidate processing control means; 16. The power supply circuit design support program according to claim 15, wherein the power supply circuit design support program functions as follows:

18. The computer, a temperature change response means which includes a database of temperature change data relating to temperature changes in resistance value, and when a temperature of an environment in which the power supply circuit is used is given, refers to the database based on the given temperature, changes the value of the feedback resistance given to the computer functioning as the multiple candidate processing control means, and notifies the computer functioning as the multiple candidate processing control means of this changed value, causing the computer to perform processing based on this value; 16. The power supply circuit design support program according to claim 15, wherein the power supply circuit design support program functions as follows:

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