A voltage regulating circuit and method

Abstract

The application discloses a voltage regulating circuit and method, and relates to the technical field of testing. The circuit comprises a plurality of single boards to be tested and a voltage regulating sub-circuit electrically connected with the single boards to be tested. The voltage regulating sub-circuit comprises a main controller, a first voltage regulating unit and a second voltage regulating unit connected with the main controller respectively. The main controller completes voltage regulation of the plurality of single boards to be tested by controlling the first voltage regulating unit or the second voltage regulating unit. The mapping relationship between the output value of a first digital-analog converter and the output voltage of a switching power supply can be determined for the first single board to be tested through the first voltage regulating unit and the second voltage regulating unit. The voltage regulation of the plurality of single boards to be tested does not need to be performed separately, the consistency of the output voltage of the switching power supply of different test single boards is improved, and the test time cost is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of testing technology, and more particularly to a voltage regulation circuit and method. Background Technology

[0002] When testing chip performance, it is usually necessary to cover the PVT scenario, which means that the chip's performance can meet the design specifications within any specified range of process, voltage, and temperature. In the voltage testing scenario, in addition to testing typical voltage values, some modules of the chip need to be tested in stepwise voltage increments of 5 mV to 10 mV within the operating voltage range.

[0003] Currently, the mainstream power supply design schemes for single-board computers in the industry are all composed of switching power supplies. When it is necessary to adjust the output voltage, an external voltage is used to adjust the voltage of the FB feedback pin of the switching power supply to achieve the purpose of adjusting the output voltage.

[0004] Due to the characteristics of the components, the feedback resistors R1, R2, R3, FB and the output value of DAC1 all have unavoidable component errors. In scenarios with a large sample size of test boards, the maximum error of the output voltage VOUT value of the switching power supply when different test boards input the same DAC1 value is about ±100mV to 200mV. The consistency of the output voltage VOUT value adjusted by the same DAC1 is extremely poor.

[0005] Therefore, when testing the next board, testers cannot use the mapping relationship between the DAC1 value and the VOUT value of the first board. They need to test the mapping relationship between the DAC1 value and the VOUT value of each test board separately. This greatly increases the testing cost and prolongs the testing time when the sample size of the test boards is large. Summary of the Invention

[0006] The purpose of this invention is to provide a voltage regulation circuit and method to solve the problem of high testing costs and extended testing time when the sample size of a single board is large.

[0007] In a first aspect, the present invention provides a voltage regulating circuit, the circuit comprising: Multiple circuit boards under test, and a voltage regulating sub-circuit electrically connected to the circuit boards under test; The voltage regulating sub-circuit includes a main controller, and a first voltage regulating unit and a second voltage regulating unit respectively connected to the main controller; The main controller adjusts the voltage of multiple test boards by controlling the first voltage regulating unit or the second voltage regulating unit.

[0008] With the above technical solution, the voltage regulation circuit provided in this application embodiment includes: multiple test boards and a voltage regulation sub-circuit electrically connected to the test boards; the voltage regulation sub-circuit includes a main controller and a first voltage regulation unit and a second voltage regulation unit respectively connected to the main controller; the main controller completes voltage regulation of the multiple test boards by controlling the first voltage regulation unit or the second voltage regulation unit, and the mapping relationship between the output value of the first digital-to-analog converter and the output voltage of the switching power supply can be determined for the first test board through the first voltage regulation unit and the second voltage regulation unit, without the need to individually regulate the voltage of multiple test boards, improving the consistency of the output voltage of the switching power supply of different test boards, and greatly reducing the test time cost.

[0009] In one possible implementation, each of the boards under test includes a switching power supply, an inductor, a first resistor, a second resistor, and a corresponding chip under test; The switching pin of the switching power supply is connected to one end of the inductor, and the other end of the inductor is connected to the first resistor and the chip under test, respectively. The feedback pin of the switching power supply is connected to the other end of the first resistor and the second resistor; the first resistor and the second resistor are connected in series, the other end of the second resistor is grounded, and the connection point of the first resistor and the inductor is connected to the voltage output terminal. The first voltage regulating unit is connected to the feedback pin after the first resistor and the second resistor; the second voltage regulating unit is connected between the voltage output terminal and the chip under test.

[0010] In one possible implementation, the first voltage regulating unit includes a first digital-to-analog converter, a third resistor, and a fourth switch; Wherein, one end of the first digital-to-analog converter is connected to the main controller, and the other end is connected to one end of the third resistor; the other end of the third resistor is connected to one end of the fourth switch, and the other end of the fourth switch is connected to the node of the first resistor, the second resistor and the feedback pin of the switching power supply.

[0011] In one possible implementation, the main controller loads the output voltage of the first digital-to-analog converter onto the feedback pin of the switching power supply, thereby changing the output voltage of the switching power supply.

[0012] In one possible implementation, the second voltage regulating unit includes an operational amplifier, a comparator, a second digital-to-analog converter, an analog-to-digital converter, a general-purpose input / output module, a fourth resistor, a first switch, a second switch, and a third switch; In this configuration, one end of the second digital-to-analog converter (DAC) is connected to the main controller, and the other end of the DAC is connected to the inverting input of the comparator; one end of the second switch is connected to the non-inverting input of the comparator, and the other end of the second switch is connected to one end of the first switch; the other end of the first switch is connected to one end of the DAC, and the other end of the DAC is connected to the main controller; the output of the comparator is connected to one end of the general-purpose input / output module, and the other end of the general-purpose input / output module is connected to the main controller. The other end of the second switch and one end of the first switch are respectively connected to the output terminal and the inverting input terminal of the operational amplifier; the non-inverting input terminal of the operational amplifier is connected to one end of the fourth resistor, the other end of the fourth resistor is connected to one end of the third switch, and the other end of the third switch is connected to the voltage output terminal and the chip under test.

[0013] In a second aspect, the present invention also provides a voltage regulation method for regulating the voltage of any of the voltage regulation circuits described in the first aspect, the method comprising: The main controller adjusts the voltage of multiple test boards by controlling the first voltage regulating unit or the second voltage regulating unit.

[0014] In one possible implementation, the main controller controls the first voltage regulating unit or the second voltage regulating unit to regulate the voltage of multiple boards under test, including: When testing the first of the multiple test boards, the main controller controls the third and fourth switches to open the first channel, while simultaneously controlling the first switch to close and the second switch to open. The main controller outputs voltage point by point through the first digital-to-analog converter according to the preset voltage adjustment step size from small to large. The main controller collects the voltage at the output terminal of the operational amplifier point by point through the analog-to-digital converter, records and saves the voltage one by one, and generates a mapping relationship between the output value of the first digital-to-analog converter and the output voltage of the switching power supply.

[0015] In one possible implementation, after the controller acquires the voltage at the output terminal of the operational amplifier point by point through the analog-to-digital converter, records and saves the voltage in a one-to-one correspondence, and generates a mapping relationship between the output value of the first digital-to-analog converter and the output voltage of the switching power supply, the method further includes: When testing the second of the multiple test boards, the main controller controls the third and fourth switches to open the second channel, while simultaneously controlling the first switch to open and the second switch to close. The main controller uses the second digital-to-analog converter as the reference voltage for the inverting input of the comparator, and outputs the first digital-to-analog converter value corresponding to the test voltage value according to the mapping relationship between the output value of the first digital-to-analog converter of the first test board and the output voltage of the switching power supply.

[0016] In one possible implementation, after the first digital-to-analog conversion value corresponding to the output voltage value to be tested, the following is further included: The main controller detects the output voltage value of the comparator in real time through the general-purpose input / output module; When the output voltage is low, the output voltage of the first digital-to-analog converter is gradually reduced according to the mapping relationship between the output value of the first digital-to-analog converter of the first board under test and the output voltage of the switching power supply, until the general-purpose input / output module detects an interrupt signal. The output voltage of the first digital-to-analog converter when the corresponding interrupt signal is generated is retained until the voltage under test is switched.

[0017] In one possible implementation, after the main controller detects the output voltage value of the comparator in real time through the general-purpose input / output module, the method further includes: When the output voltage is high, the output voltage of the first digital-to-analog converter is gradually increased according to the mapping relationship between the output value of the first digital-to-analog converter of the first board under test and the output voltage of the switching power supply, until the general-purpose input / output module detects an interrupt signal. The output voltage of the first digital-to-analog converter when the corresponding interrupt signal is generated is retained until the voltage under test is switched.

[0018] The beneficial effects of the voltage regulation method provided in the second aspect are the same as those of the voltage regulation circuit described in the first aspect or any possible implementation of the first aspect, and will not be repeated here. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the circuit structure of a voltage regulating circuit provided in an embodiment of this application is shown; Figure 2 A schematic flowchart of a voltage regulation method provided in an embodiment of this application is shown; Figure 3 A schematic flowchart of another voltage regulation method provided in an embodiment of this application is shown.

[0020] Figure label: 10 - Board under test; 20 - Voltage regulation sub-circuit; 201 - Main controller; 202 - First voltage regulation unit; 203 - Second voltage regulation unit; 101 - Switching power supply; L1 - Inductor; R1 - First resistor; R2 - Second resistor; 102 - Chip under test; SW - Switch pin; FB - Feedback pin; DAC1 - First digital-to-analog converter; S4 - Fourth switch; U1 - Operational amplifier; U2 - Comparator; DAC2 - Second digital-to-analog converter; ADC - Analog-to-digital converter; GPIO - General purpose input / output module; R4 - Fourth resistor; S1 - First switch; S2 - Second switch; S3 - Third switch. Detailed Implementation

[0021] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0022] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0023] In this invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0024] Figure 1A schematic diagram of the circuit structure of a voltage regulating circuit provided in an embodiment of this application is shown, as follows: Figure 1 As shown, the circuit includes: Multiple test boards 10, and a voltage regulating sub-circuit 20 electrically connected to the test boards; The voltage regulating sub-circuit 20 includes a main controller 201, and a first voltage regulating unit 202 and a second voltage regulating unit 203 respectively connected to the main controller 201; The main controller 201 controls the first voltage regulating unit 202 or the second voltage regulating unit 203 to regulate the voltage of the multiple test boards 10.

[0025] The voltage regulation circuit provided in this application includes: multiple boards under test (BUTs) and a voltage regulation sub-circuit electrically connected to the BUTs; the voltage regulation sub-circuit includes a main controller and a first voltage regulation unit and a second voltage regulation unit respectively connected to the main controller; the main controller completes voltage regulation of the multiple BUTs by controlling the first voltage regulation unit or the second voltage regulation unit, and the mapping relationship between the output value of the first digital-to-analog converter and the output voltage of the switching power supply can be determined for the first BUT by the first voltage regulation unit and the second voltage regulation unit, without the need to individually regulate the voltage of multiple BUTs, thereby improving the consistency of the output voltage of the switching power supply of different test boards and greatly reducing the test time cost.

[0026] Optional, see Figure 1 Each of the test boards 10 includes a switching power supply 101, an inductor L1, a first resistor R1, a second resistor R2, and a corresponding test chip 102. The switching pin SW of the switching power supply 101 is connected to one end of the inductor L1, and the other end of the inductor L1 is connected to the first resistor R1 and the chip under test 102 respectively. The feedback pin FB of the switching power supply 101 is connected to the other end of the first resistor R1 and the second resistor R2; the first resistor R1 and the second resistor R2 are connected in series, the other end of the second resistor R2 is grounded, and the connection point of the first resistor R1 and the inductor L1 is connected to the voltage output terminal Vout. The first voltage regulating unit 202 is connected to the feedback pin FB at a position after the first resistor R1 and the second resistor R2; the second voltage regulating unit 203 is connected between the voltage output terminal Vout and the chip under test 102.

[0027] Optional, see Figure 1 The first voltage regulation unit 202 includes a first digital-to-analog converter DAC1, a third resistor R3, and a fourth switch S4; Wherein, one end of the first digital-to-analog converter DAC1 is connected to the main controller 201, and the other end is connected to one end of the third resistor R3; the other end of the third resistor R3 is connected to one end of the fourth switch S4, and the other end of the fourth switch S4 is connected to the node of the first resistor R1, the second resistor R2 and the feedback pin FB of the switching power supply 101.

[0028] Optionally, the main controller loads the output voltage of the first digital-to-analog converter onto the feedback pin of the switching power supply to change the output voltage of the switching power supply.

[0029] Optional, see Figure 1 The second voltage regulation unit 203 includes an operational amplifier U1, a comparator U2, a second digital-to-analog converter DAC2, an analog-to-digital converter ADC, a general-purpose input / output module GPIO, a fourth resistor R4, a first switch S1, a second switch S2, and a third switch S3; In this configuration, one end of the second digital-to-analog converter DAC2 is connected to the main controller 201, and the other end of the second digital-to-analog converter DAC2 is connected to the inverting input of the comparator U2; one end of the second switch S2 is connected to the non-inverting input of the comparator U2, and the other end of the second switch S2 is connected to one end of the first switch S1; the other end of the first switch S1 is connected to one end of the analog-to-digital converter ADC, and the other end of the analog-to-digital converter ADC is connected to the main controller 201; the output of the comparator U2 is connected to one end of the general-purpose input / output module GPIO, and the other end of the general-purpose input / output module GPIO is connected to the main controller 201. The other end of the second switch S2 and one end of the first switch S1 are respectively connected to the output terminal of the operational amplifier U1 and the inverting input terminal of the operational amplifier U1; the non-inverting input terminal of the operational amplifier U1 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is connected to one end of the third switch S3, and the other end of the third switch S3 is connected to the voltage output terminal VOUT and the chip under test 102.

[0030] When testing the first of the multiple test boards, the main controller controls the third and fourth switches to open the first channel, while simultaneously controlling the first switch to close and the second switch to open. The main controller outputs voltage point by point through the first digital-to-analog converter according to the preset voltage adjustment step size from small to large. The main controller collects the voltage at the output terminal of the operational amplifier point by point through the analog-to-digital converter, records and saves the voltage one by one, and generates a mapping relationship between the output value of the first digital-to-analog converter and the output voltage of the switching power supply.

[0031] When testing the second of the multiple test boards, the main controller controls the third and fourth switches to open the second channel, while simultaneously controlling the first switch to open and the second switch to close. The main controller uses the second digital-to-analog converter as the reference voltage for the inverting input of the comparator, and outputs the first digital-to-analog converter value corresponding to the test voltage value according to the mapping relationship between the output value of the first digital-to-analog converter of the first test board and the output voltage of the switching power supply.

[0032] The main controller detects the output voltage value of the comparator in real time through the general-purpose input / output module; When the output voltage is low, the output voltage of the first digital-to-analog converter is gradually reduced according to the mapping relationship between the output value of the first digital-to-analog converter of the first board under test and the output voltage of the switching power supply, until the general-purpose input / output module detects an interrupt signal. The output voltage of the first digital-to-analog converter when the corresponding interrupt signal is generated is retained until the voltage under test is switched.

[0033] When the output voltage is high, the output voltage of the first digital-to-analog converter is gradually increased according to the mapping relationship between the output value of the first digital-to-analog converter of the first board under test and the output voltage of the switching power supply, until the general-purpose input / output module detects an interrupt signal. The output voltage of the first digital-to-analog converter when the corresponding interrupt signal is generated is retained until the voltage under test is switched.

[0034] At this point, the voltage Vref at the non-inverting input and the inverting input of the comparator are equal, thus completing the adjustment of the test voltage value corresponding to the second board under test. There is no need to test the mapping relationship between the output value of the first digital-to-analog converter and the output voltage of the switching power supply of the second board under test separately, which improves the consistency of the output voltage VOUT of the switching power supply of different test boards, greatly reduces the test time cost, and can control the third and fourth switches to open different channels through the main controller, which can quickly and efficiently complete all board voltage regulation scenario tests.

[0035] Figure 2 A schematic flowchart of a voltage regulation method provided in an embodiment of this application is shown, as follows: Figure 2 As shown, the method includes: Step 301: The main controller adjusts the voltage of the multiple test boards by controlling the first voltage regulating unit or the second voltage regulating unit.

[0036] The voltage regulation method provided in this application embodiment allows the main controller to regulate the voltage of multiple test boards by controlling the first voltage regulation unit or the second voltage regulation unit. The mapping relationship between the output value of the first digital-to-analog converter and the output voltage of the switching power supply can be determined for the first test board by the first voltage regulation unit and the second voltage regulation unit. This eliminates the need to regulate the voltage of multiple test boards individually, improves the consistency of the output voltage of the switching power supply of different test boards, and greatly reduces the test time cost.

[0037] Optional, Figure 3 This document shows a schematic flowchart of another voltage regulation method provided in an embodiment of this application. See also... Figure 3 The voltage regulation method includes: Step 401: The main controller loads the output voltage of the first digital-to-analog converter onto the feedback pin of the switching power supply, thereby changing the output voltage of the switching power supply.

[0038] In this application, the main controller loads the output voltage of the first digital-to-analog converter (DAC1) onto the FB feedback pin of the switching power supply. The output voltage VOUT of the switching power supply changes with the output voltage of the first digital-to-analog converter (DAC1), thereby achieving voltage regulation. The calculation formula is as follows: .

[0039] Step 402: When testing the first of the multiple test boards, the main controller controls the third switch and the fourth switch to open the first channel, while simultaneously controlling the first switch to close and the second switch to open. The main controller outputs voltage point by point through the first digital-to-analog converter according to the preset voltage adjustment step size from small to large.

[0040] The preset voltage adjustment step can be from 5 millivolts to 10 millivolts. This application embodiment does not limit the specific step, but can make specific adjustments according to the actual application scenario. Specifically, the adjustment range is 0-VCC.

[0041] Step 403: The main controller collects the voltage at the output terminal of the operational amplifier point by point through the analog-to-digital converter, records and saves the voltage one by one, and generates a mapping relationship between the output value of the first digital-to-analog converter and the output voltage of the switching power supply.

[0042] In this application, the main controller acquires the voltage at the output terminal of the corresponding operational amplifier point by point through the analog-to-digital converter (ADC). Since the operational amplifier is a voltage follower, the voltage at the output terminal of the operational amplifier is equal to the output voltage VOUT of the switching power supply. At the same time, the VOUT values ​​are recorded and saved one by one to form a mapping table between the DAC1 output value and the switching power supply output voltage VOUT. The mapping table is as follows: Table 1 Step 404: When testing the second board under test among multiple boards under test, the main controller controls the third switch and the fourth switch to open the second channel, while simultaneously controlling the first switch to open and the second switch to close. The main controller uses the second digital-to-analog converter as the reference voltage for the inverting input terminal of the comparator, and outputs the first digital-to-analog converter value corresponding to the test voltage value according to the mapping relationship between the output value of the first digital-to-analog converter of the first board under test and the output voltage of the switching power supply.

[0043] Step 405: The main controller detects the output voltage value of the comparator in real time through the general-purpose input / output module.

[0044] Step 406: When the output voltage value is low, the output voltage of the first digital-to-analog converter is gradually reduced according to the mapping relationship between the output value of the first digital-to-analog converter of the first board under test and the output voltage of the switching power supply, until the general-purpose input / output module detects an interrupt signal. The output voltage of the first digital-to-analog converter when the corresponding interrupt signal is generated is retained until the voltage under test is switched.

[0045] Step 407: When the output voltage value is high, gradually increase the output voltage of the first digital-to-analog converter according to the mapping relationship between the output value of the first digital-to-analog converter of the first board under test and the output voltage of the switching power supply, until the general-purpose input / output module detects an interrupt signal, retain the output voltage of the first digital-to-analog converter when the corresponding interrupt signal is generated, until the voltage under test is switched.

[0046] At this point, the voltage Vref at the non-inverting input and the inverting input of the comparator are equal, thus completing the adjustment of the test voltage value corresponding to the second board under test. There is no need to test the mapping relationship between the output value of the first digital-to-analog converter and the output voltage of the switching power supply of the second board under test separately. This improves the consistency of the output voltage Vout of the switching power supply of different test boards, greatly reduces the test time cost, and can control the third and fourth switches to open different channels through the main controller, so as to quickly and efficiently complete all board voltage regulation scenario tests.

[0047] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, the disclosure, and the appended claims in carrying out the claimed invention. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0048] Although the invention has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made therein without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely exemplary descriptions of the invention as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if such modifications and modifications of the invention fall within the scope of the claims and their equivalents, the invention is also intended to include such modifications and modifications.

Claims

1. A voltage regulating circuit, characterized in that, The circuit includes: Multiple circuit boards under test, and a voltage regulating sub-circuit electrically connected to the circuit boards under test; The voltage regulation sub-circuit includes a main controller, and a first voltage regulation unit and a second voltage regulation unit respectively connected to the main controller; each of the boards under test includes a switching power supply; the first voltage regulation unit includes a first digital-to-analog converter; The main controller adjusts the voltage of multiple circuit boards under test by controlling the first voltage regulating unit or the second voltage regulating unit; each circuit board under test includes a corresponding chip under test; the main controller loads the output voltage of the first digital-to-analog converter onto the feedback pin of the switching power supply to change the output voltage of the switching power supply. The second voltage regulation unit is connected between the voltage output terminal and the chip under test; The second voltage regulation unit includes an operational amplifier, a comparator, a second digital-to-analog converter, an analog-to-digital converter, a general-purpose input / output module, a fourth resistor, a first switch, a second switch, and a third switch; In this configuration, one end of the second digital-to-analog converter (DAC) is connected to the main controller, and the other end of the DAC is connected to the inverting input of the comparator; one end of the second switch is connected to the non-inverting input of the comparator, and the other end of the second switch is connected to one end of the first switch; the other end of the first switch is connected to one end of the DAC, and the other end of the DAC is connected to the main controller; the output of the comparator is connected to one end of the general-purpose input / output module, and the other end of the general-purpose input / output module is connected to the main controller. The other end of the second switch and one end of the first switch are respectively connected to the output terminal and the inverting input terminal of the operational amplifier; the non-inverting input terminal of the operational amplifier is connected to one end of the fourth resistor, the other end of the fourth resistor is connected to one end of the third switch, and the other end of the third switch is connected to the voltage output terminal and the chip under test.

2. The voltage regulating circuit according to claim 1, characterized in that, Each of the circuit boards under test also includes an inductor, a first resistor, and a second resistor; The switching pin of the switching power supply is connected to one end of the inductor, and the other end of the inductor is connected to the first resistor and the chip under test, respectively. The feedback pin of the switching power supply is connected to the other end of the first resistor and the second resistor; the first resistor and the second resistor are connected in series, the other end of the second resistor is grounded, and the connection point of the first resistor and the inductor is connected to the voltage output terminal. The first voltage regulating unit is connected to the feedback pin at a position after the first resistor and the second resistor.

3. The voltage regulating circuit according to claim 2, characterized in that, The first voltage regulating unit also includes a third resistor and a fourth switch; Wherein, one end of the first digital-to-analog converter is connected to the main controller, and the other end is connected to one end of the third resistor; the other end of the third resistor is connected to one end of the fourth switch, and the other end of the fourth switch is connected to the node of the first resistor, the second resistor and the feedback pin of the switching power supply.

4. A voltage regulation method, characterized in that, The method for regulating the voltage of the voltage regulating circuit according to any one of claims 1-3 includes: The main controller adjusts the voltage of multiple test boards by controlling the first voltage regulating unit or the second voltage regulating unit.

5. The voltage regulation method according to claim 4, characterized in that, The main controller controls the first voltage regulating unit or the second voltage regulating unit to regulate the voltage of multiple boards under test, including: When testing the first of the multiple test boards, the main controller controls the third and fourth switches to open the first channel, while simultaneously controlling the first switch to close and the second switch to open. The main controller outputs the voltage point by point through the first digital-to-analog converter according to the preset voltage adjustment step size from small to large. The main controller collects the voltage at the output terminal of the operational amplifier point by point through the analog-to-digital converter, records and saves the voltage one by one, and generates a mapping relationship between the output value of the first digital-to-analog converter and the output voltage of the switching power supply.

6. The voltage regulation method according to claim 5, characterized in that, After the controller acquires the voltage at the output terminal of the operational amplifier point by point through the analog-to-digital converter, records and saves the voltage in a one-to-one correspondence, and generates a mapping relationship between the output value of the first digital-to-analog converter and the output voltage of the switching power supply, the method further includes: When testing the second of the multiple test boards, the main controller controls the third and fourth switches to open the second channel, while simultaneously controlling the first switch to open and the second switch to close. The main controller uses the second digital-to-analog converter as the reference voltage for the inverting input of the comparator, and outputs the first digital-to-analog converter value corresponding to the test voltage value according to the mapping relationship between the output value of the first digital-to-analog converter of the first test board and the output voltage of the switching power supply.

7. The voltage regulation method according to claim 6, characterized in that, After the first digital-to-analog conversion value corresponding to the output voltage value to be tested, the following is also included: The main controller detects the output voltage value of the comparator in real time through a general-purpose input / output module; When the output voltage is low, the output voltage of the first digital-to-analog converter is gradually reduced according to the mapping relationship between the output value of the first digital-to-analog converter of the first board under test and the output voltage of the switching power supply, until the general-purpose input / output module detects an interrupt signal. The output voltage of the first digital-to-analog converter when the corresponding interrupt signal is generated is retained until the voltage under test is switched.

8. The voltage regulation method according to claim 7, characterized in that, After the main controller detects the output voltage value of the comparator in real time through the general-purpose input / output module, the method further includes: When the output voltage is high, the output voltage of the first digital-to-analog converter is gradually increased according to the mapping relationship between the output value of the first digital-to-analog converter of the first board under test and the output voltage of the switching power supply, until the general-purpose input / output module detects an interrupt signal. The output voltage of the first digital-to-analog converter when the corresponding interrupt signal is generated is retained until the voltage under test is switched.

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