Closed loop liquid cooling burn-in apparatus and method of controlling the same

Abstract

To provide a closed-loop liquid-cooled burn-in device and its control method.SOLUTION: A closed-loop liquid-cooled burn-in apparatus includes a water tank and at least one test socket. The water tank is fluidly coupled to the at least one test socket via a loop. The water tank includes a first water storage part and a second water storage part, the first water storage part is used for storing a relatively low-temperature cooling liquid, and the second water storage part is used for storing a relatively high-temperature cooling liquid. The first water storage part is provided with a heating unit for heating the cooling liquid of a relatively low temperature to adjust the temperature of the cooling liquid supplied to the at least one test socket.SELECTED DRAWING: Figure 2B

Description

[Technical Field]

[0001] The present invention relates to a burn-in test apparatus, and more particularly to a burn-in test apparatus that adjusts the test temperature using a liquid cooling mechanism, and a method for controlling this liquid-cooled burn-in apparatus. [Background technology]

[0002] Packaged integrated circuits (ICs) typically undergo a burn-in test for a certain period of time to ensure that the IC product can operate in harsh environments. The packaged chip (device under test, DUT) is placed in a test socket, and its bottom is electrically connected to multiple signal contacts in the test socket. The test socket's lid is part of a liquid-cooling loop and contacts the chip to regulate the chip's test temperature. The lid may include multiple heat-dissipating fins arranged in a specific pattern to dissipate heat through convection. The lid may also have a fan attached to the heat-dissipating fins to enhance convection. The liquid-cooling loop primarily includes a cold water network that delivers low-temperature coolant to the test socket and a hot water network that recovers the coolant from the test socket. The liquid-cooling loop can effectively control the test temperature by stably maintaining a constant temperature for each chip under test. However, if the coolant temperature in the cold water network is too low, the heat dissipation rate becomes too fast, resulting in instability in temperature control.

[0003] Furthermore, the liquid cooling loop was made up of a flexible pipe connected to a rigid pipe, which could leak coolant. If the flexible pipe were to break due to improper operation, the loop could open, causing the coolant to leak. If the coolant leaked, the test socket would lose its temperature control function. Summary of the Invention [Problem to be solved by the invention]

[0004] To improve the temperature control efficiency and avoid excessively large temperature difference between cold and hot water (e.g., reaching 20°C or more) when the system is started, long standby times, and excessive temperature fluctuations, the present invention provides a water tank with a heating function.

[0005] The water level is also used to monitor the water level in the water tank, and when the recovery mechanism is activated or restored, the liquid in the closed loop is pumped or filled to prevent coolant spillage. [Means for solving the problem]

[0006] To solve the above problems, an object of the present invention is to provide a closed-loop liquid-cooled burn-in apparatus including a loop with a cold water network and a hot water network, and a water tank and a test socket fluidly connected to at least one test socket via the loop. The water tank has a first water reservoir and a second water reservoir, the first water reservoir being used to store a relatively low-temperature coolant, and the second water reservoir being used to store a relatively high-temperature coolant. The first water reservoir is provided with a heating unit for heating the relatively low-temperature coolant, thereby adjusting the temperature of the coolant supplied to the at least one test socket.

[0007] In one embodiment, the first water reservoir is fluidly connected to the at least one test socket via the cold water network, and the second water reservoir is fluidly connected to the at least one test socket via the hot water network.

[0008] In one embodiment, the first water reservoir is fluidly connected to a heat exchange unit via the cold water network, and the second water reservoir is fluidly connected to the heat exchange unit via the hot water network.

[0009] In one embodiment, the heating unit is attached to an outer wall of the first water storage section and is electrically connected to a circuit board.

[0010] In one embodiment, the heating unit is a PTC device.

[0011] In one embodiment, a control method for a closed-loop liquid-cooled burn-in apparatus includes the steps of preparing a loop and supplying coolant from a water tank to at least one test socket; maintaining a pressure value of the water tank within a predetermined range less than 1 atmosphere; causing one or more pumps to recover coolant from within the loop to the water tank in response to the loop being opened; and reading the water level of the water tank with a water level detection unit, and determining that there is no substantial outflow of coolant due to the loop being opened based on the water level of the water tank reaching a predetermined position.

[0012] In one embodiment, the method further includes determining, by the water level detection unit, that the burn-in device is operating in a normal state based on at least the water level in the water tank reaching a first preset position, indicating that coolant is circulating in the loop.

[0013] In one embodiment, the method further includes determining, by the water level detection unit, that the burn-in device is operating in a maintenance state based on at least the water level in the water tank reaching a second preset position, indicating that coolant is collected in the water tank and is not present in the loop.

[0014] In one embodiment, the second preset position is higher than the first preset position.

[0015] In one embodiment, the pressure value of the water tank is maintained within a predetermined range lower than atmospheric pressure, and the predetermined range is 80 to 85 kPa, or 0.6 to 0.8 atmospheric pressure.

[0016] The foregoing and other aspects of the present invention will become more apparent based on the following detailed description of specific non-limiting embodiments and with reference to the accompanying drawings.

[0017] For a better understanding of the present invention, reference may be made to the following drawings and description. Non-limiting and non-exhaustive embodiments are described with reference to the following drawings. It should be noted that the components in the drawings are not necessarily drawn to actual size, but are instead drawn with the focus on explaining the structure and principles. [Brief explanation of the drawings]

[0018] [Figure 1] 1 illustrates a closed-loop liquid-cooled burn-in apparatus according to an embodiment of the present invention; [Figure 2A] FIG. 2 is a diagram showing a water tank included in the liquid-cooled burn-in apparatus. [Figure 2B] FIG. 2 is a diagram showing a water tank included in the liquid-cooled burn-in apparatus. [Figure 3A] FIG. 10 is a diagram showing a heat dissipation means of the test socket. [Figure 3B] FIG. 10 is a diagram showing a heat dissipation means of the test socket. [Figure 4] 1 is a diagram showing the configuration of a water tank according to the present invention. [Figure 5A] 1 is a schematic diagram showing the closing and opening of the loop of a liquid-cooled burn-in apparatus. FIG. [Figure 5B] 1 is a schematic diagram showing the closing and opening of the loop of a liquid-cooled burn-in apparatus. FIG. [Figure 6] FIG. 2 is a diagram showing the control flow of the closed-loop liquid-cooled burn-in apparatus of the present invention. [Figure 7] FIG. 2 is a diagram showing the control flow of the closed-loop liquid-cooled burn-in apparatus of the present invention. [Figure 8] FIG. 10 is a diagram showing the relationship between the control state and the water level. DETAILED DESCRIPTION OF THE INVENTION

[0019] The following more fully describes the present invention with reference to the drawings, illustrating specific embodiments. However, the claimed subject matter may be specifically embodied in a variety of different forms, and therefore the construction of the claimed subject matter of the coverage or application is not limited to the specific embodiments disclosed herein. The specific embodiments are merely exemplary. Likewise, the present invention is intended to provide a reasonably broad scope for the subject matter of the application or coverage claims.

[0020] As used herein, the phrase "in one embodiment" does not necessarily refer to the same specific embodiment, and the phrase "in some other / specific embodiments" as used herein does not necessarily refer to different specific embodiments. Claimed subject matter is intended to include all or any combination of the specific embodiments.

[0021] 1 is a diagram showing a closed-loop liquid-cooled burn-in apparatus according to an embodiment of the present invention, which mainly includes a water tank (10), a plurality of test sockets (12), liquid cooling loops (14C, 14H), and a heat exchange unit (16).

[0022] The water tank (10) is primarily used to distribute relatively low-temperature and relatively high-temperature coolants. Figures 2A and 2B are perspective and front views, respectively, of the water tank (10). The water tank (10) comprises a first (bottom) water reservoir (101) connected to the cold water network (14C) and a second (top) water reservoir (102) connected to the hot water network (14H). Referring to Figures 1 and 2A together, the first water reservoir (101) has an inlet connected to the heat exchange unit (16) and two outlets connected to the test socket (12), while the second water reservoir (102) has an outlet connected to the heat exchange unit (16) and two inlets connected to the test socket (12). The first and second water reservoirs (101) and (102) are isolated from each other. Preferably, a suitable distance can be provided between the first water reservoir (101) and the second water reservoir (102), or a thermal insulator can be inserted between them. A heating unit (103), such as a PTC device, is provided at the bottom of the first water reservoir (101), and a control signal is provided via a circuit board (18). The heating unit (103) heats the coolant in the first water reservoir (101) to maintain the temperature of the coolant in the chilled water network (14C) above a specific temperature, thereby preventing overcooling by the heat exchange unit (16). The heating unit (103) is activated when the temperature of the coolant sent from the heat exchange unit (16) to the first water reservoir (101) is lower than a predetermined temperature, or when the temperature of the coolant in the first water reservoir (101) is lower than a predetermined temperature, or when the temperature of the coolant upstream of the test socket (12) is lower than a predetermined temperature. Although the heating unit (103) of this embodiment is attached to the outer wall of the first water storage section (101), the present invention is not limited to this.

[0023] The liquid cooling loops 14C, 14H are networks consisting of manifolds, flow paths, and spaces, and include a cold water network 14C and a hot water network 14H, although the present invention is not limited thereto. The cold water network 14C serves to collect relatively low-temperature cooling liquid from the heat exchange unit 16 to the water tank 10 and to send it from the water tank 10 to the test socket 12. The hot water network 14H serves to collect relatively high-temperature cooling liquid from the test socket 12 to the water tank 10 and to send it from the water tank 10 to the heat exchange unit 16.

[0024] The test socket 12 is fixed to and electrically connected to the circuit board 18, thereby receiving test signals from the circuit board 18 and providing a test environment for a device under test (not shown). The device under test is placed in the test socket 12 for testing. The test socket 12 basically includes a base for accommodating the device under test and a heat dissipation means. Figures 3A and 3B show an example of a heat dissipation means for a test socket, including an inlet port 241 connected to the cold water network 14C and an outlet port 242 connected to the hot water network 14H. The inlet port 241 and the outlet port 242 are both connected to a water-cooled plate 243, and a contact 249 is provided at the bottom of the water-cooled plate 243 for contacting the surface of the device under test. The water-cooled plate 243 and the contact 249 are basically metalwork. 3B is a cross-sectional view taken along the dashed line in FIG. 3A, showing that the water-cooled plate (243) and the contact body (249) jointly define a heat exchange passage (250) when coupled together. Coolant enters the heat exchange passage (250) through the inlet port (241) and exits through the outlet port (242). Fins (252) are disposed within the heat exchange passage (250), allowing the coolant entering the heat exchange passage (250) to come into contact with the fins, resulting in a better heat exchange effect. The test socket (12) can have other modifications, such as providing a pump at the inlet port (241) or outlet port (242) to control the flow rate or speed of the coolant.

[0025] Figure 4 shows the configuration of the water tank of the present invention. This configuration can be applied to the water tank (10) of Figure 1, for example, the first water storage section (101) or the second water storage section (102). The water tank (30) includes a first pump (P1), a second pump (P2), a pressure detection unit (G), and a water level detection unit (L).

[0026] The first pump (P1) is an air pump that removes air from the water tank to create a negative pressure, thereby maintaining the water tank (30) at a predetermined pressure range, for example, 0.6 to 0.8 atmospheres or 80 to 85 kPa, and preventing remaining air from entering the liquid cooling loop.

[0027] The second pump (P2) is a liquid pump that is connected to the chilled water network (14C) shown in Figure 1 to control the direction of circulation of the cooling liquid in the closed loop, for example, sending the cooling liquid from the first water reservoir (101) in Figure 1 to each test socket (12) or recovering the cooling liquid from each test socket (12) to the first water reservoir (101).

[0028] The pressure sensing unit (G) is configured to read pressure changes within the water tank (30), for example, the pressure sensing unit (G) generates an alarm signal to the monitoring terminal in response to a sudden increase in air pressure within the water tank (30) exceeding the predetermined range. In a specific embodiment, the pressure sensing unit (G) uses high frequency monitoring, for example, can generate readings 20 or more times per second.

[0029] The water level detection unit (L) is configured to detect whether the coolant in the water tank 30 is at a predetermined level. For example, the water level detection unit (L) starts to detect the water level in response to the alarm signal generated by the pressure detection unit (G) upon detecting a pressure change, thereby determining whether the total amount of coolant returned to the water tank 30 has decreased and using this as a basis for determining whether or not to replenish the coolant. The water level detection unit (L) may be a mechanical unit, an electronic unit, or a hybrid unit, but the present invention is not limited thereto.

[0030] The water tank (30) is also provided with a valve (V) which can be configured to be connected to a coolant source, allowing coolant to be added to the water tank (30) via the valve (V).

[0031] 5A and 5B are schematic diagrams showing the closing and opening of a loop in a liquid-cooled burn-in apparatus. For ease of explanation and understanding, the heat exchange unit (16) shown in FIG. 1 is omitted from this schematic diagram. FIG. 5A shows the configuration of a closed-loop liquid-cooled burn-in apparatus of the present invention, which includes a water tank (30), a transport line (22), and a plurality of test sockets (23). The water tank (30), the transport line (22), and the test sockets (23) form a closed loop, and a cooling liquid can be circulated within the closed loop.

[0032] The water tank 30 has a storage space for storing a coolant, such as water or other chemical liquids known in the art. The water tank 30 is primarily constructed of a robust housing, particularly a housing that can withstand a significant internal-external pressure difference (40 kPa) without deformation. In one embodiment, the water tank is made of acrylic plate (PMMA) with external dimensions of 150 mm x 200 mm x 150 mm and a wall thickness of 10 mm. The water tank 30 has a first port 21A and a second port 21B. The coolant can enter and exit the water tank 30 via the first port 21A and the second port 21B.

[0033] The transport line 22 has two ends connected to the first port 21A and the second port 21B of the water tank 30, respectively. In reality, the transport line 22 is a circulation path defined by a combination of one or more rigid and flexible pipes, valves, and / or connectors. The transport line 22 may extend appropriately above the circuit board and pass through the target socket, depending on the configuration of the burn-in apparatus. Although not shown, the transport line 22 may also include a valve for controlling the flow rate or distribution of the coolant.

[0034] The test socket 23 is electrically connected to the circuit board 18 shown in FIG. 1 and can be operated to perform various tests on a loaded device under test. The test socket 23 is appropriately configured to be fluidly connected to the transport pipeline 22. Specifically, the test socket 23 is provided with a specific connection interface, which allows the coolant in the transport pipeline 22 to pass through a portion of the test socket 23, absorb heat, and then return to the transport pipeline 22 from the connection interface of the test socket 23, as shown in FIG. 3A. It should be understood that the illustrated configuration is merely exemplary and is not intended to limit the present invention, and other possible configurations are also included.

[0035] 5B shows the direction of coolant flow after the loop is opened. When the transport line (22) is blocked, the pressure detection unit (G) detects a pressure change occurring in the water tank (30) or the entire loop (e.g., the air pressure in the water tank (30) rises sharply and exceeds the predetermined range for maintaining negative pressure).

[0036] At the moment the transport line 22 is shut off, the coolant is under negative pressure due to the water tank 30 or the entire loop, allowing the transport line 22 connected to the second port 21B to retain the coolant within the loop. The second pump P2 immediately stops, reverses the flow direction, and then turns on again, allowing the coolant in the transport line 22A connected to the first port 21A to be collected in the water tank 30. After the transport line 22 is shut off, the pressure in the loop rises sharply, and the water tank 21 may approach atmospheric pressure in the external space. To prevent coolant leakage from the shutoff point due to pressure balance, the first pump P1 can be turned on in response to the pressure change caused by the shutoff. The first pump P1 evacuates air from the water tank 30, forcing the coolant in the transport line 22B to be collected in the water tank 21, while also allowing outside air to enter the transport line 22B through the shutoff point. The control terminal will halt the test procedure until the loop is operating normally.

[0037] After the loop is opened, the water level detection unit (L) is activated to read the coolant level. The first pump (P1) continues to operate to maintain negative pressure in the water tank (30), while the second pump (P2) continues to withdraw coolant from the transport line (22A) to the water tank (30), raising the coolant level. When the water level reaches a preset point, it is ensured that a significant amount of coolant is withdrawn without remaining in the transport line (22A). Then, the attendant can inspect the transport line (22) until the open problem is resolved.

[0038] FIG. 6 shows a control flow of the closed-loop liquid-cooling burn-in apparatus of the present invention, including steps S400 to S404.

[0039] 5A, in step S400, the first pump (P1) and the second pump (P2) are turned on. The first pump (P1) continues to remove air from the water tank (30) to maintain a negative pressure in the water tank (30). The second pump (P2) continues to push the coolant in the water tank (30) into the transport line (22) so that the coolant can circulate in a closed loop.

[0040] In step S401, the pressure sensing unit (G) continuously monitors the pressure in the water tank (30) to obtain real-time pressure values. The pressure sensing unit (G) generates multiple readings per second (real-time pressure values) and transmits them to the control terminal, allowing the control terminal to calculate the pressure change (e.g., rate of change in atm / s) within a certain period of time, the average pressure value, and the pressure difference between the previous and current pressure values.

[0041] In step S402, the control unit compares the real-time pressure value, pressure change, average pressure, and / or pressure difference according to and based on a predetermined range (such as greater than a threshold, less than a threshold, or between two thresholds). In one embodiment, the predetermined range is less than 1 atmosphere. Preferably, the predetermined range is 0.6 to 0.8 atmospheres, although the present invention is not limited thereto.

[0042] If the real-time pressure value or a series of consecutive pressure values ​​exceeds the predetermined range (if condition 1 is met), i.e., if the real-time pressure value or a series of consecutive pressure values ​​is greater than the upper limit of the predetermined range or less than the lower limit of the predetermined range, the process proceeds from step S402 to step S403. If the pressure difference between two measured points in time is greater than the critical pressure difference and greater than the average pressure over a certain period (if condition 2 is met), the process proceeds from step S402 to step S404. If the pressure change exceeds the critical rate of change and / or the real-time pressure value is greater than the upper limit of the predetermined range (if condition 3 is met), the pressure in the water tank 30 is rising rapidly, indicating the possibility of the transport pipeline 22 bursting or being blocked, the process proceeds from step S402 to step S500.

[0043] In step S403, the first pump (P1) switches between on and off according to a predetermined on-off strategy, and then returns to steps S401 and S402.

[0044] In step S404, the second pump (P2) is turned off and then turned on again after a predetermined time has elapsed, and steps S401 and S402 are repeated. In one embodiment, the second pump (P2) is turned off for 2 seconds to stop circulation, and then turned on again to continue circulation in the same direction.

[0045] In the flow circulation of steps S400 to S404, the coolant still circulates in a closed loop, and no leakage occurs, so the burn-in device can continue to perform routine tests.

[0046] FIG. 7 shows the control flow of the closed-loop liquid-cooling burn-in apparatus of the present invention, that is, step S500 includes steps S501 to S506.

[0047] In response to the pressure abnormality determined in step S402 (the pressure change exceeds the critical change rate and / or the real-time pressure value is greater than the upper limit value of the predetermined range), the process proceeds to step S500.

[0048] In step S501, the flow direction of the second pump (P2) is changed to stop the supply of the coolant to the test socket (23), and the coolant is collected in the water tank (30).

[0049] In step S502, the water level detection unit (L) reads the water level in the water tank (30). If the water level reaches a predetermined position, it indicates that the expected amount of coolant has been collected in the water tank (30) and no excess coolant has been spilled due to a loop-open event, and proceeds to step S503; otherwise, continue to execute step S501.

[0050] In step S503, the pressure sensing unit (G) continues to monitor the pressure value in the water tank (30) to calculate the pressure change and average pressure value within a certain period of time, as well as the pressure difference between the previous pressure value and the current pressure value. Similarly, the pressure sensing unit (G) can generate the same number of readings per second or more to increase the monitoring sensitivity.

[0051] In step S504, the control terminal compares the real-time pressure value, pressure change, average pressure, and / or pressure difference before and after the predetermined range with the predetermined range as a reference. In one embodiment, the predetermined range is less than 1 atmosphere. Preferably, the predetermined range is 0.6 to 0.8 atmospheres. Alternatively, the predetermined range based on step S504 may be different from the predetermined range based on step S402.

[0052] If the real-time pressure value or a series of consecutive pressure values ​​exceeds the predetermined range, i.e., if the real-time pressure value or a series of consecutive pressure values ​​is greater than the upper limit value of the predetermined range or less than the lower limit value of the predetermined range, proceed from step S504 to step S505. If the real-time pressure value or a series of consecutive real-time pressure values ​​is within the predetermined range and / or the pressure change is decreasing normally, proceed from step S504 to step S506. The stable decrease means that the monitored pressure change satisfies the change rate.

[0053] In step S505, the first pump (P1) switches between on and off according to a predetermined on / off strategy, and then returns to steps S503 and S504 to determine again. In one embodiment, the first pump (P1) and the second pump (P2) can be turned on simultaneously to simultaneously maintain a negative pressure state in the water tank (30) and return the coolant to the water tank (30). It will be understood that the turning on and off of the first pump (P1) and the second pump (P2) can be performed simultaneously or asynchronously, or can be performed according to a predetermined rule, in order to maintain a target negative pressure state in the loop and force the coolant to return to the water tank (30).

[0054] In step S506, the first pump (P1) switches between on and off according to a predetermined on-off strategy, and then returns to the normal closed-loop circulation of step S400.

[0055] FIG. 8 shows an example of the relationship between the control state and the water level, but the present invention is not limited to this.

[0056] Under normal conditions, the pressure of the water tank read by the pressure detection unit is in the range of 80 kPa to 85 kPa (preset pressure range). Water level 1 represents the first preset position of the water level in the water tank during the circulation of the coolant in the closed loop. Water level 2 represents the second preset position that the coolant should reach when it is completely collected in the water tank without circulating in the loop, so the second preset position is higher than the first preset position. When water level 1 reads "1", it indicates that the water tank has been filled to the first preset position, and when water level 2 reads "0", it indicates that the water tank has not been filled to the second preset position. At this time, the air pump continues to operate and there is no alarm signal.

[0057] In a leak condition, an open circuit anywhere in the loop will cause the pressure in the water tank to rise above 85 kPa. At this time, the control terminal will generate an alarm signal in response to the change in pressure reading. At the same time, one or more liquid pumps (the second pump P2 in Figure 5B) will perform a reverse flow to withdraw the coolant from the loop back into the water tank.

[0058] In the maintenance state, the pressure in the water tank is still higher than 85 kPa, but the coolant in the loop has almost completely returned to the water tank. When the water level 2 reading is "2," it indicates that the water level has reached the second preset position and there is no substantial coolant leakage due to the loop opening event. If the water level 2 reading is not yet "2," you can manually check and add the appropriate amount of coolant.

[0059] In the recovery state, one or more liquid pumps are redirected to re-transport the liquid coolant in the water tank back into the loop. The water level in the water tank drops, causing Water Level 2 to read "0." A return to the normal state can then be achieved.

[0060] However, if there are still other problems with normal operation or if recalibration is required, enter the reset state, reset the pressure reading, water level 1 and water level 2 readings to zero, turn off the air pump, and then restart the liquid-cooled burn-in device.

[0061] In summary, the closed-loop liquid-cooled burn-in apparatus and its control method of the present invention have been described based on the above description and drawings. However, each of the above-described embodiments (or technical contents / technical features) can be used or applied alone. Those skilled in the art can also combine or partially combine any two or more of the above-described embodiments (or technical contents / technical features) in the same embodiment as needed. It should be noted that each specific embodiment of the present invention is merely illustrative, and many modifications may be made without departing from the scope and spirit of the claims of the present invention, and such modifications are within the scope of the patent of the present invention. Therefore, the specific embodiments described herein should not be used to limit the present invention. The true scope and spirit of the present invention are disclosed in the claims below. [Explanation of symbols]

[0062] 10 Water Tank 101 First Water Reservoir 102 Second Water Reservoir 103 Heating Unit 12 test sockets 14C Chilled Water Network 14-hour hot water network 16 Heat Exchange Unit 18 Circuit Board 241 Inlet Port 242 Outlet Port 243 Water-cooled Plate 249 Contact body 250 Heat exchange passageway 252 Finn 30 Water Tank P1 First pump P2 Second pump G Pressure detection unit V-valve L Water level detection unit 21A Port 1 21B Second port 22, 22A, 22B Transport pipeline 23 Test Socket S400~S404 steps S500~S506 Step

Claims

1. a loop comprising a cold water network and a hot water network; a water tank in fluid communication with at least one test socket through the loop; and a test socket, the water tank includes a first water storage section and a second water storage section, the first water storage section being used to store a relatively low-temperature coolant, and the second water storage section being used to store a relatively high-temperature coolant; The first reservoir is provided with a heating unit for heating a relatively low temperature cooling liquid, thereby adjusting the temperature of the cooling liquid supplied to the at least one test socket. Closed-loop liquid-cooled burn-in equipment.

2. 2. The closed-loop liquid-cooled burn-in apparatus of claim 1, wherein the first water reservoir is fluidly connected to the at least one test socket via the cold water network, and the second water reservoir is fluidly connected to the at least one test socket via the hot water network.

3. 2. The closed-loop liquid-cooled burn-in apparatus of claim 1, wherein the first water reservoir is fluidly connected to the heat exchange unit via the cold water network, and the second water reservoir is fluidly connected to the heat exchange unit via the hot water network.

4. 2. The closed-loop liquid-cooling burn-in apparatus according to claim 1, wherein the heating unit is attached to an outer wall of the first water reservoir and electrically connected to a circuit board.

5. 5. The closed-loop liquid-cooled burn-in apparatus of claim 4, wherein the heating unit is a PTC device.

6. providing a loop to supply coolant from a water tank to at least one test socket; maintaining the pressure value of the water tank within a predetermined range less than 1 atmosphere; In response to the loop being opened, causing one or more pumps to withdraw coolant from within the loop to the water tank; a step of reading the water level of the water tank using a water level detection unit, and determining that there is no substantial outflow of coolant due to the opening of the loop based on whether the water level of the water tank has reached a predetermined level; A method for controlling a closed-loop liquid-cooled burn-in apparatus, comprising:

7. 7. The control method of claim 6, further comprising the step of determining, by the water level detection unit, that the burn-in device is operating in a normal state based on at least the water level in the water tank reaching a first preset position, which indicates that coolant is circulating in the loop.

8. 8. The control method of claim 7, further comprising the step of determining, by the water level detection unit, that the burn-in device is operating in a maintenance state based on at least the water level in the water tank reaching a second preset position, indicating that coolant is recovered in the water tank and is not present in the loop.

9. The control method of claim 8 , wherein the second preset position is higher than the first preset position.

10. 7. The control method according to claim 6, wherein the pressure value of the water tank is maintained within a predetermined range lower than atmospheric pressure, the predetermined range being 80 to 85 kPa or 0.6 to 0.8 atmospheric pressure.

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