Thermal resistance testing equipment and power supply self-adaptive adjusting device thereof

Abstract

The utility model relates to a thermal resistance test device and a power supply adaptive adjustment device thereof, and the device comprises a switching power supply module which comprises a switching power supply topology circuit, an output voltage collection circuit and an output voltage control circuit, and the switching power supply topology circuit is used for being connected with an external power supply; the output voltage acquisition circuit is connected with the switching power supply topology circuit and the output voltage control circuit, and the output voltage control circuit is connected with the switching power supply topology circuit; and the thermal resistance heating constant-voltage linear power supply circuit is connected with the first end of the device to be tested and the switching power supply topology circuit, receives the output voltage of the switching power supply topology circuit, and keeps the difference value between the input voltage of the thermal resistance heating constant-voltage linear power supply circuit and the output voltage of the thermal resistance heating constant-voltage linear power supply circuit unchanged. By adopting the switching power supply module to output the voltage to the thermal resistance heating constant-voltage linear power supply circuit, compared with adopting an industrial frequency transformer to adjust the voltage, the size and the weight of an equipment power supply are reduced, and the test convenience is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor testing technology, and in particular to a thermal resistance testing device and a power supply adaptive regulating device thereof. Background Art

[0002] Semiconductor devices are core components in the fields of new energy, smart grid, industrial automation, etc., and their reliability research has become a hot research topic for domestic universities, scientific research institutions and high-tech enterprises. Related studies have shown that most semiconductor device failures are caused by excessive internal junction temperature. During operation, the junction temperature is determined by the thermal resistance of its package in addition to heat dissipation under external conditions. The quality of the package determines the reliability of the device when it is working at high power, so it is necessary to test whether the package has defects.

[0003] In traditional thermal resistance test equipment power supply regulators, the input of linear power supplies generally uses a fixed multi-level bus voltage, such as through multiple output windings of power frequency transformers in series and parallel. Since power frequency transformers have low power density, large size, and are bulky, they are not suitable for miniaturization of instruments. In addition, due to cost and process reasons, the windings of power frequency transformers cannot be made into many levels, that is, the input voltage is composed of several fixed voltage levels, which cannot meet actual test needs. Traditional power supply regulators for thermal resistance test equipment have the disadvantage of low test convenience. Utility Model Content

[0004] Based on this, it is necessary to provide a thermal resistance testing device and a power supply adaptive adjustment device thereof that can improve the testing convenience in order to address the above problems.

[0005] A power adaptive regulating device for thermal resistance testing equipment, comprising:

[0006] A switching power supply module, comprising a switching power supply topology circuit, an output voltage acquisition circuit and an output voltage control circuit, wherein the switching power supply topology circuit is used to connect to an external power supply, the output voltage acquisition circuit is connected to the switching power supply topology circuit and the output voltage control circuit, and the output voltage control circuit is connected to the switching power supply topology circuit;

[0007] The thermistor heating constant voltage linear power supply circuit is connected to the first end of the device under test and the switching power supply topology circuit, and receives the output voltage of the switching power supply topology circuit; wherein the output voltage acquisition circuit samples the output voltage of the switching power supply topology circuit, obtains the sampled voltage and sends it to the output voltage control circuit; the output voltage control circuit receives the sampled voltage, outputs a voltage control signal to the switching power supply topology circuit, and adjusts the output voltage of the switching power supply topology circuit, so that the difference between the input voltage of the thermistor heating constant voltage linear power supply circuit and the output voltage of the thermistor heating constant voltage linear power supply circuit remains unchanged.

[0008] In one embodiment, the switching power supply module further includes a rectifier and filter circuit, and the switching power supply topology circuit is connected to an external power supply via the rectifier and filter circuit.

[0009] In one embodiment, the power adaptive regulation device also includes a series-parallel switching module, the number of the switching power supply modules is more than two, and the series-parallel switching module connects the switching power supply topology circuit in each of the switching power supply modules, and the thermal resistance heating constant voltage linear power supply circuit.

[0010] In one embodiment, the series-parallel switching module is a relay matrix.

[0011] In one embodiment, the power adaptive regulation device further includes a controller, which is connected to the series-parallel switching module and the output voltage control circuit in each of the switching power modules.

[0012] A thermal resistance testing device comprises the above-mentioned power supply adaptive regulating device.

[0013] In one of the embodiments, the thermal resistance testing device further includes a constant current driving circuit, and the constant current driving circuit is connected to the control terminal of the device under test.

[0014] In one of the embodiments, the thermal resistance testing device further includes a thermal resistance difference voltage measuring circuit, wherein the thermal resistance difference voltage measuring circuit is connected to a first terminal and a second terminal of the device under test.

[0015] In one embodiment, the thermal resistance testing equipment also includes a switching module, a thermal resistance heating constant current linear power supply circuit and a thermal resistance measurement constant current linear power supply circuit, the switching module is connected to the second end of the device to be tested, the thermal resistance heating constant current linear power supply circuit and the thermal resistance measurement constant current linear power supply circuit, and the thermal resistance heating constant current linear power supply circuit and the thermal resistance measurement constant current linear power supply circuit are both connected to the thermal resistance heating constant voltage linear power supply circuit.

[0016] In one embodiment, the switch module includes a switch K1 and a switch K2, the first end of the switch K1 is connected to the second end of the device under test, the second end of the switch K1 is connected to the thermistor heating constant current linear power supply circuit, the first end of the switch K2 is connected to the second end of the device under test, and the second end of the switch K2 is connected to the thermistor measurement constant current linear power supply circuit.

[0017] In the above-mentioned thermal resistance test equipment and its power adaptive adjustment device, the output voltage acquisition circuit samples the output voltage of the switching power supply topology circuit, obtains the sampled voltage and sends it to the output voltage control circuit; the output voltage control circuit receives the sampled voltage, outputs the voltage control signal to the switching power supply topology circuit, and adjusts the output voltage of the switching power supply topology circuit so that the difference between the input voltage of the thermal resistance heating constant voltage linear power supply circuit and the output voltage of the thermal resistance heating constant voltage linear power supply circuit remains unchanged. By using the switching power supply module to output the voltage to the thermal resistance heating constant voltage linear power supply circuit, the output voltage can be adjusted according to the actual test needs. Compared with using the power frequency transformer to adjust the voltage, the volume and weight of the equipment power supply are reduced, and the test convenience is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of a power adaptive regulation device in one embodiment;

[0019] Figure 2 Schematic diagram of the structure of a thermal resistance testing device in one embodiment. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0022] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0023] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0024] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, operations, components, parts or combinations thereof.

[0025] Generally speaking, the connection defect between the semiconductor core and the package substrate will manifest as an increase in transient thermal resistance. Therefore, the thermal resistance test equipment can generally set the output voltage and current, and this voltage and current will be added to the sample under test to simulate the heating of the sample under test. Due to the high requirements for the response speed and ripple noise of the output voltage and current, the voltage and current corresponding to the output of the linear power supply are basically added to the sample under test at the end, and the efficiency and heat generation of the linear power supply are directly determined by the difference between the input voltage and the output voltage of the linear power supply, so this voltage difference is very critical. The current power supply adjustment device of the thermal resistance test equipment adopts multiple output windings of the power frequency transformer in series and parallel to realize multi-level bus voltage. Due to the low power density, large volume and bulky size of the power frequency transformer, it is not suitable for the miniaturization of the instrument, and due to cost and process reasons, the windings of the power frequency transformer cannot be made a lot, that is, the input voltage is composed of several fixed voltage levels. Based on this, the present application provides a power supply adaptive adjustment device for thermal resistance test equipment, including a switching power supply module and a thermal resistance heating constant voltage linear power supply circuit, and the switching power supply module includes a switching power supply topology circuit, an output voltage acquisition circuit and an output voltage control circuit. The output voltage acquisition circuit samples the output voltage of the switching power supply topology circuit, obtains the sampled voltage and sends it to the output voltage control circuit; the output voltage control circuit receives the sampled voltage, outputs the voltage control signal to the switching power supply topology circuit, and adjusts the output voltage of the switching power supply topology circuit, so that the difference between the input voltage of the thermal resistance heating constant voltage linear power supply circuit and the output voltage of the thermal resistance heating constant voltage linear power supply circuit remains unchanged. By using the switching power supply module to output the voltage to the thermal resistance heating constant voltage linear power supply circuit, the output voltage can be adjusted according to actual test needs.

[0026] In one embodiment, Figure 1As shown, a power adaptive regulation device for a thermal resistance testing device is provided, including a switching power supply module 110 and a thermal resistance heating constant voltage linear power supply circuit 120, the switching power supply module 110 includes a switching power supply topology circuit 112, an output voltage acquisition circuit 114 and an output voltage control circuit 116, the switching power supply topology circuit 112 is used to connect to an external power supply, the output voltage acquisition circuit 114 is connected to the switching power supply topology circuit 112 and the output voltage control circuit 116, and the output voltage control circuit 116 is connected to the switching power supply topology circuit 112; the thermal resistance heating constant voltage linear power supply circuit 120 is connected to the first end of the device under test DUT and the switching power supply topology circuit 112, and receives the output voltage of the switching power supply topology circuit 112. The output voltage acquisition circuit 114 samples the output voltage of the switching power supply topology circuit 112, and obtains the sampled voltage to the output voltage control circuit 116; the output voltage control circuit 116 receives the sampled voltage, outputs a voltage control signal to the switching power supply topology circuit 112, and adjusts the output voltage of the switching power supply topology circuit 112, so that the difference between the input voltage of the thermal resistance heating constant voltage linear power supply circuit 120 and the output voltage of the thermal resistance heating constant voltage linear power supply circuit 120 remains unchanged. The difference between the input voltage of the thermal resistance heating constant voltage linear power supply circuit 120 and the output voltage of the thermal resistance heating constant voltage linear power supply circuit 120 remains unchanged, and the difference may be fixed or within a set allowable error range.

[0027] Specifically, the device under test DUT includes a control end, a first end, and a second end. The device under test DUT may be a semiconductor power device, wherein the gate serves as the control end of the device under test DUT, the source / drain serves as the first end of the device under test DUT, and the drain / source DUT serves as the second end of the device under test. Further, the switching power supply module 110 also includes a rectifier filter circuit DB, and the switching power supply topology circuit 112 is connected to an external power supply via the rectifier filter circuit DB. The external power supply connected to the switching power supply topology circuit 112 may be a mains power supply or other power supply. The rectifier filter circuit DB may use a full-bridge rectifier filter circuit to rectify and filter the connected external mains power supply, and obtain direct current to be transmitted to the switching power supply topology circuit 112.

[0028] The switching power supply topology circuit 112 adopts a BUCK and forward topology structure, which can achieve a wide range of output voltage regulation. Specifically, Figure 2As shown, the switching power supply topology circuit 112 may include devices such as filter capacitors, switch tubes, transformers, and diodes connected in sequence, and the switch tube may be a MOS tube. The primary winding of the transformer is connected to the switch tube, and is connected to the rectifier filter circuit DB through the filter circuit, and the secondary winding of the transformer is connected to the thermal resistance heating constant voltage linear power supply circuit 120 through the diode. The switch tube is switched on and off according to the voltage control signal output by the output voltage control circuit 116, so that the secondary winding of the transformer generates an induced voltage and is output from the switching power supply topology circuit 112 after passing through the diode, and is transmitted to the thermal resistance heating constant voltage linear power supply circuit 120 as the output voltage of the switching power supply module 110.

[0029] The output voltage acquisition circuit 114 and the output voltage control circuit 116 can both be composed of devices such as operational amplifiers and resistors. The output voltage acquisition circuit 114 samples the output voltage of the switching power supply topology circuit 112, and sends the sampled voltage to the output voltage control circuit 116. The output voltage control circuit 116 compares the sampled voltage with the reference voltage, and adjusts the output voltage control signal according to the comparison result, so that the output voltage of the switching power supply module 110 is stable, and the output voltage regulation of the switching power supply module 110 is achieved. It can be understood that the output voltage adjustment of the switching power supply module 110 can be stepless adjustment or segmented adjustment, which can be set according to actual needs. According to the output voltage required by the thermal resistance device (the output voltage of the thermal resistance heating constant voltage linear power supply circuit 120), the input voltage of the thermal resistance heating constant voltage linear power supply circuit 120 can be adaptively adjusted to reduce the voltage stress and power consumption of the linear power supply.

[0030] The number of the switching power supply modules 110 can be one or more. When the number of the switching power supply modules 110 is more than one, the structures of the switching power supply modules 110 can be completely the same or different, depending on the specific parameters of the actual device power supply, as long as each switching power supply module 110 has an adjustable output voltage function. Each switching power supply module 110 is used as a variable voltage source, and only a single isolated variable voltage source can be used to directly convert the mains power into a controllable output voltage; or the mains power can be converted into a fixed voltage output through an isolated variable voltage source, and then input into another non-isolated variable voltage source to achieve a controllable voltage output.

[0031] In the power adaptive adjustment device of the thermal resistance test equipment, the output voltage acquisition circuit 114 samples the output voltage of the switching power supply topology circuit 112, obtains the sampled voltage and sends it to the output voltage control circuit 116; the output voltage control circuit 116 receives the sampled voltage, outputs a voltage control signal to the switching power supply topology circuit 112, and adjusts the output voltage of the switching power supply topology circuit 112, so that the difference between the input voltage of the thermal resistance heating constant voltage linear power supply circuit 120 and the output voltage of the thermal resistance heating constant voltage linear power supply circuit 120 remains unchanged. By using the switching power supply module 110 to output the voltage to the thermal resistance heating constant voltage linear power supply circuit 120, the output voltage can be adjusted according to the actual test needs. Compared with using the power frequency transformer to adjust the voltage, the volume and weight of the equipment power supply are reduced, and the convenience of testing is improved.

[0032] In one embodiment, Figure 2 As shown, the power adaptive regulation device further includes a series-parallel switching module 130, the number of the switching power modules 110 is more than two, and the series-parallel switching module 130 connects the switching power topology circuit 112 in each switching power module 110, and the thermal resistance heating constant voltage linear power circuit 120. The structure of the series-parallel switching module 130 is not unique, and can be composed of relays or switch tubes. In this embodiment, the series-parallel switching module 130 is a relay matrix.

[0033] Specifically, the series-parallel switching module 130 connects the output positive electrode (Vout1+, Voutn+) and the output negative electrode (Vout1-, Voutn-) of the switching power topology circuit 112 in each switching power module 110, and the series-parallel switching module 130 also connects the input positive electrode Vbus+ and the input negative electrode Vbus- of the thermal resistance heating constant voltage linear power circuit 120, and the output positive electrode Vout+ of the thermal resistance heating constant voltage linear power circuit 120 is connected to the first end of the device under test DUT. When each switching power module 110 needs to be switchable in series or in parallel, each switching power module 110 can be connected to the thermal resistance heating constant voltage linear power circuit 120 in series or in parallel through the series-parallel switching module 130.

[0034] Furthermore, the power adaptive regulation device further includes a controller 140, which is connected to the series-parallel switching module 130 and the output voltage control circuit 116 in each switching power module 110. The controller 140 may be a microcontroller, a central processing unit or a programmable logic device. Figure 2As shown, the controller 140 adjusts the reference voltage of the output voltage control circuit 116 in the corresponding switching power supply module 110 by sending signals Signal_V1 and Signal_Vn, and the controller 140 controls the switching of the series-parallel switching module 130 by sending a signal Signal_K. Vfeedback1 and Vfeedbackn represent the sampled voltage output by the output voltage acquisition circuit 114 in the corresponding switching power supply module 110. The controller 140 has a different way of adjusting the reference voltage, and can adjust the reference voltage of the output voltage control circuit 116 by analog signals, pulse width modulation signals, digital communication signals, etc.

[0035] The thermal resistance heating constant voltage linear power supply circuit 120 can be composed of a power amplifier tube, and the input positive electrode Vbus+ and the input negative electrode Vbus- of the thermal resistance heating constant voltage linear power supply circuit 120 receive the input voltage Vbus, and the output voltage Vout is output through the output positive electrode Vout+ and the output negative electrode Vout-. It should be noted that when there is only one switching power supply module 110 and no series-parallel switching module 130, the input voltage Vbus of the thermal resistance heating constant voltage linear power supply circuit 120 is equal to the output voltage of the switching power supply topology circuit 112; when there are multiple switching power supply modules 110 and series-parallel switching modules 130, the input voltage Vbus of the thermal resistance heating constant voltage linear power supply circuit 120 is equal to the output voltage of each switching power supply topology circuit 112 after being modulated by the series-parallel switching module 130.

[0036] Since the power consumption of the back-end linear power supply is limited by the volume of the entire device, the maximum loss is a fixed value, P = (Vbus-Vout) * Iout. If multiple traditional switching power supplies are connected in series and parallel, although the problem of low power density of the power frequency transformer can be solved, due to the limited number of switching power supplies, the bus voltage is still composed of several fixed voltage levels. For example, if the output is 10V~190V, the input switching power supply is composed of 4 50V, and the bus voltage level is 50V, 100V, 150V, and 200V. Then within an output voltage range, such as 10V~40V, the bus voltage is a fixed 50V, that is, Vbus = 50V. At this time, since the power consumption P of the back-end linear power supply is unchanged, when the output voltage Vout is smaller, the output current Iout is also smaller, and the loss will be very large.

[0037] In order to reduce the loss of the subsequent linear power supply, the output voltage of the switching power supply module 110 in the solution of the present application is adjustable, so that the input voltage Vbus of the thermal resistance heating constant voltage linear power supply circuit 120 is adjustable. The input voltage Vbus is determined according to the voltage Vds required by the test conditions (i.e., the target output voltage of the thermal resistance heating constant voltage linear power supply circuit 120). Vbus-Vds is a fixed value, which only needs to meet the minimum input-output voltage difference of the linear power supply. Generally, the value of Vbus-Vds can be between 10V and 15V. When the device under test DUT is replaced, Vds changes accordingly. Since Vds=Vout, Vbus-Vds does not change, then Vbus-Vout also remains unchanged, so that the output current Iout remains unchanged, solving the problem of excessive circuit loss.

[0038] During the thermal resistance test, the adjustment process of the power adaptive device is as follows: first, determine whether the target output voltage Vds required by the test conditions has changed. If there is no change, the entire adjustment process can be skipped directly. If the target output voltage Vds required by the test conditions has been adjusted, the relay matrix switching judgment is entered; if there is actually only one switching power module 110 and no relay matrix, the relay matrix switching process is skipped. If the relay matrix is ​​to be adjusted, the output of the switching power module 110 is first cleared to avoid damage to the relay due to thermal cutting. After the output of the switching power module 110 is cleared, the controller 140 sends the signal Signal_K according to the demand to realize the series and parallel operation of each switching power module 110. After completion, enter the power supply voltage adjustment link, adjust the signals Signal_V1 and Signal_Vn according to actual needs, at this time, the switching power module 110 compares the actual collected output voltage with the set reference voltage, adjusts the switch tube duty cycle, and when the output voltage of the switching power module 110 is stable within the required set voltage range, the voltage adjustment link is jumped out and the subsequent thermal resistance test link is entered.

[0039] In one embodiment, a thermal resistance testing device is also provided, comprising the above-mentioned power adaptive adjustment device. Figure 2 As shown, the thermal resistance test equipment also includes a constant current drive circuit 210, and the constant current drive circuit 210 is connected to the control end of the device under test DUT. The constant current drive circuit 210 can also be composed of components such as a switch tube, and the constant current drive circuit 210 can be connected to the controller 140 to control the on and off of the device under test DUT according to the received instructions during the thermal resistance test.

[0040] In one embodiment, the thermal resistance test device further includes a thermal resistance difference voltage measurement circuit 220, which is connected to the first terminal and the second terminal of the device under test DUT. The thermal resistance difference voltage measurement circuit 220 can be composed of devices such as an operational amplifier, and detects the voltage difference between the first terminal and the second terminal of the device under test DUT in the thermal resistance test.

[0041] In one embodiment, the thermal resistance testing equipment also includes a switching module 230, a thermal resistance heating constant current linear power supply circuit 240 and a thermal resistance measurement constant current linear power supply circuit 250, the switching module 230 is connected to the second end of the device under test DUT, the thermal resistance heating constant current linear power supply circuit 240 and the thermal resistance measurement constant current linear power supply circuit 250, and the thermal resistance heating constant current linear power supply circuit 240 and the thermal resistance measurement constant current linear power supply circuit 250 are both connected to the thermal resistance heating constant voltage linear power supply circuit 120.

[0042] Specifically, the switch module 230 includes a switch K1 and a switch K2, wherein the first end of the switch K1 is connected to the second end of the device under test DUT, the second end of the switch K1 is connected to the thermal resistance heating constant current linear power supply circuit 240, the first end of the switch K2 is connected to the second end of the device under test DUT, the second end of the switch K2 is connected to the thermal resistance measurement constant current linear power supply circuit 250, and the thermal resistance heating constant current linear power supply circuit 240 and the thermal resistance measurement constant current linear power supply circuit 250 are both connected to the output negative electrode Vout1- of the thermal resistance heating constant voltage linear power supply circuit 120. Among them, the thermal resistance heating constant current linear power supply circuit 240 and the thermal resistance measurement constant current linear power supply circuit 250 can also be composed of devices such as power amplifier tubes, and the switch K1 and the switch K2 can be controllable switches such as switch tubes and relays. The control ends of the switch K1 and the switch K2 can be connected to the controller 140, and are switched on and off according to the received instructions.

[0043] The above-mentioned thermal resistance test equipment and its power adaptive adjustment device can reduce the volume and weight of the power supply of the equipment, significantly improve the power density of the equipment, and reduce the equipment cost. In addition, it also reduces the voltage stress of the power amplifier tube of the thermal resistance linear power supply and the heat dissipation power of the power amplifier, significantly reduces the output burrs of the thermal resistance equipment in various scenarios, and improves the test efficiency and test convenience of the thermal resistance equipment.

[0044] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0045] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A power adaptive regulation device for thermal resistance testing equipment, characterized in that: include: A switching power supply module, comprising a switching power supply topology circuit, an output voltage acquisition circuit and an output voltage control circuit, wherein the switching power supply topology circuit is used to connect to an external power supply, the output voltage acquisition circuit is connected to the switching power supply topology circuit and the output voltage control circuit, and the output voltage control circuit is connected to the switching power supply topology circuit; The thermistor heating constant voltage linear power supply circuit is connected to the first end of the device under test and the switching power supply topology circuit, and receives the output voltage of the switching power supply topology circuit; wherein the output voltage acquisition circuit samples the output voltage of the switching power supply topology circuit, obtains the sampled voltage and sends it to the output voltage control circuit; the output voltage control circuit receives the sampled voltage, outputs a voltage control signal to the switching power supply topology circuit, and adjusts the output voltage of the switching power supply topology circuit, so that the difference between the input voltage of the thermistor heating constant voltage linear power supply circuit and the output voltage of the thermistor heating constant voltage linear power supply circuit remains unchanged.

2. The device according to claim 1, characterized in that The switching power supply module also includes a rectifying and filtering circuit, and the switching power supply topology circuit is connected to an external power supply through the rectifying and filtering circuit.

3. The device according to claim 1, characterized in that It also includes a series-parallel switching module, the number of the switching power supply modules is more than two, and the series-parallel switching module connects the switching power supply topology circuit in each of the switching power supply modules and the thermal resistance heating constant voltage linear power supply circuit.

4. The device according to claim 3, characterized in that The series-parallel switching module is a relay matrix.

5. The device according to claim 3, characterized in that It also includes a controller, which is connected to the series-parallel switching module and the output voltage control circuit in each of the switching power supply modules.

6. A thermal resistance testing device, characterized in that: The invention comprises the power supply adaptive regulation device as described in any one of claims 1 to 5.

7. The thermal resistance testing device according to claim 6, characterized in that: It also includes a constant current driving circuit, which is connected to the control end of the device under test.

8. The thermal resistance testing device according to claim 6, characterized in that: It also includes a thermal resistance difference voltage measurement circuit, and the thermal resistance difference voltage measurement circuit is connected to the first end and the second end of the device under test.

9. The thermal resistance testing device according to any one of claims 6 to 8, characterized in that: It also includes a switch module, a thermistor heating constant current linear power supply circuit and a thermistor measuring constant current linear power supply circuit. The switch module is connected to the second end of the device to be tested, the thermistor heating constant current linear power supply circuit and the thermistor measuring constant current linear power supply circuit. The thermistor heating constant current linear power supply circuit and the thermistor measuring constant current linear power supply circuit are both connected to the thermistor heating constant voltage linear power supply circuit.

10. The thermal resistance testing device according to claim 9, characterized in that: The switch module includes a switch K1 and a switch K2, wherein the first end of the switch K1 is connected to the second end of the device under test, and the second end of the switch K1 is connected to the thermistor heating constant current linear power supply circuit, the first end of the switch K2 is connected to the second end of the device under test, and the second end of the switch K2 is connected to the thermistor measurement constant current linear power supply circuit.

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