Control device, pump unit, and refrigerant circulation device

Abstract

To provide a technique for preventing an inrush current in a power supply path when an external device is connected to a load device after the connection between the external device and the load device is detected.SOLUTION: A control device includes a first connector to which an external device can be attached and detached, a power supply path that electrically connects a load device and the first connector, a load switch that switches between connection and disconnection of the power supply path, a protection circuit for an inrush current to the load switch, and a control circuit. The control circuit detects that the first connector is connected to the external device and then outputs a drive signal that switches the load switch from disconnection to connection. The protection circuit has at least a capacitor, and switches the load switch from disconnection to connection over a predetermined first time that is a time for gradually transitioning the load switch from off to on based on the charging time of the capacitor by the drive signal.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a control device, a pump unit, and a refrigerant circulation device. [Background technology]

[0002] The following Patent Document 1 describes a hot-plug function for disk drives in a RAID (Redundant Array of Inexpensive Disks) system. In the RAID system, a power-on delay circuit controls the supply of power to a disk drive when the disk drive is inserted into the array. In particular, the power-on delay circuit detects that a connection is established between a hard drive and a backplane connector of the array. When the connection is first sensed, the power-on delay circuit starts timing a predetermined time (i.e., a timeout). Power to the disk drive is applied via a solid-state switch only when the power-on delay circuit's predetermined time has elapsed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 09-505418 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, power is supplied from an external device (i.e., a RAID system) to a load device (i.e., a disk drive) in response to a predetermined time having elapsed since a connection between the external device and the load device was first detected. The length of the predetermined time is required to be as short as possible. Note that Patent Document 1 does not describe the length of the predetermined time.

[0005] The present disclosure has been made in consideration of the above circumstances, and has a purpose to provide a technique for preventing an inrush current in a power supply path when an external device and a load device are connected. [Means for solving the problem]

[0006] A control device according to an embodiment of the present disclosure includes a first connector, a power supply path, a load switch, a protection circuit for protecting the load switch from an inrush current, and a control circuit. An external device is detachably attached to the first connector. The power supply path electrically connects the load device and the first connector. The load switch switches between connection and disconnection of the power supply path. The protection circuit has at least a capacitor. The control circuit switches the load switch from disconnection to connection after a total time of a preset set time and a first time based on a charging time of the capacitor has elapsed after detecting that the first connector is connected to the external device.

[0007] A pump unit according to another aspect of the present disclosure includes a first connector, a motor, a pump rotor, a power supply path, a load switch, a protection circuit for protecting the load switch from an inrush current, and a control circuit. The first connector is detachable from an external device. The pump rotor rotates by power generated by the motor. The power supply path is electrically connected between the motor and the first connector. The load switch switches between connection and disconnection of the power supply path. The protection circuit has at least a capacitor. The control circuit switches the load switch from disconnection to connection after a total time of a preset set time and a first time based on a charging time of the capacitor has elapsed after detecting that the first connector is connected to the external device. The motor generates power in response to the load switch being switched to connection.

[0008] A coolant circulation device according to a further aspect of the present disclosure includes a pump unit and a flow path, the coolant flowing through the flow path by rotation of a pump rotor. Effect of the Invention

[0009] According to the exemplary embodiment of the present disclosure, it is possible to prevent an inrush current in a power supply path when an external device and a load device are connected. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing a configuration of a cooling system according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic diagram showing in detail how each pump unit is inserted into and removed from the casing. [Diagram 3] FIG. 3 is a block diagram showing a detailed configuration of the pump unit shown in FIGS. [Figure 4] FIG. 4 is a timing chart showing the operation of the refrigerant circulating device shown in FIG. 1 when the pump unit is attached to the casing. [Diagram 5] FIG. 5 is a timing chart showing the operation of the refrigerant circulation device shown in FIG. 1 when the main power switch of the casing is turned off. [Figure 6] FIG. 6 is a timing chart showing the operation of the refrigerant circulating device shown in FIG. 1 when the pump unit is removed from the casing. [Figure 7] FIG. 7 is a timing chart showing the operation of the pump unit when an operator attempts to remove the pump unit from the casing and then reattaches the pump unit to the casing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and description thereof will not be repeated.

[0012] 1 is a block diagram showing a configuration of a cooling system 100 according to an embodiment of the present disclosure. The cooling system 100 includes a cooling device 1 and a refrigerant circulation device 2.

[0013] The cooling device 1 includes a distribution manifold 11, a plurality of cold plates 12, a plurality of heat sources 13, and a collection manifold 14. Note that the number of each of the cold plates 12 and heat sources 13 needs to be at least one.

[0014] In the cooling system 100, the refrigerant circulates among the refrigerant circulation device 2, the distribution manifold 11, the cold plates 12, and the collection manifold 14 as shown by the arrows A01 to A05. The refrigerant is, for example, a cooling liquid. Examples of the cooling liquid include antifreeze liquid and pure water. Typical examples of antifreeze liquid are an ethylene glycol aqueous solution and a propylene glycol aqueous solution. A high-temperature refrigerant flows into the refrigerant circulation device 2 from the collection manifold 14 (see arrow A01). The refrigerant circulation device 2 pressurizes and cools the refrigerant. The refrigerant is pressurized, thereby circulating in the cooling system 100 (see arrows A01 to A05). In detail, the low-temperature refrigerant flows into the cold plates 12 through the distribution manifold 11 (see arrow A04), and flows through the cold plates 12. The cold plates 12 are in thermal contact with the heat sources 13. Each heat source 13 is a heat-generating device. In an embodiment, each heat source 13 is a component of a computer device. Examples of heat sources 13 include electrolytic capacitors, power semiconductor modules, or printed circuit boards.

[0015] Each cold plate 12 has an inlet 121 and an outlet 122. For convenience, in FIG. 1, the reference symbols "121" and "122" are representatively attached to only one cold plate 12. A refrigerant flows into each inlet 121 from the downstream end 111 of the distribution manifold 11 (see arrow A04). The refrigerant flows from the inlet 121 to the outlet 122 in each cold plate 12. Therefore, heat generated in the heat source 13 is transferred to the refrigerant flowing in each cold plate 12. That is, the refrigerant becomes hot. The hot refrigerant flows out from each outlet 122 to each upstream end 141 of the collection manifold 14 and flows in the collection manifold 14 (see arrow A05).

[0016] The refrigerant circulation device 2 includes a casing 21, two pump units 22, a cooling section 23, a flow path 24 including pipes 241-243, a power supply section 25, and a control circuit 26. The portion of the refrigerant circulation device 2 excluding the pump unit 22 is an example of the "external device" of the present disclosure.

[0017] The casing 21 has a refrigerant inlet 211 and a refrigerant outlet 212. The inlet 211 is connected to the downstream end 142 of the collection manifold 14. The refrigerant flows into the inlet 211 from the downstream end 142. The outlet 212 is connected to the upstream end 112 of the distribution manifold 11. The refrigerant flows out from the outlet 212 to the upstream end 112.

[0018] The casing 21 houses two pump units 22 and a cooling section 23. The cooling section 23 and each pump unit 22 are connected by pipes 241-243 between an inlet 211 and an outlet 212. As a result, in the casing 21 (i.e., the cooling device 1), the refrigerant can flow from the inlet 211 to the outlet 212 via the cooling section 23 and each pump unit 22 in that order (see arrows A01-A03).

[0019] Each pump unit 22 has a suction port 221, a discharge port 222, and a pump rotor 223 to pressurize the refrigerant in the pipes 241 to 243. The suction port 221 is connected to the downstream end of the pipe 242. The discharge port 222 is connected to the upstream end of the pipe 243. In the pump unit 22, the pump rotor 223 rotates to apply pressure to the refrigerant in the pump unit 22. As a result, the refrigerant in the pipe 242 is sucked from the suction port 221. The sucked refrigerant is discharged from the discharge port 222 to the pipe 243.

[0020] The type of the pump unit 22 is not particularly limited. That is, for example, a centrifugal pump, a propeller pump, a viscous pump, or a rotary pump can be adopted as the pump unit 22. When the pump unit 22 is a centrifugal pump, a propeller pump, a viscous pump, or a gear pump, the pump rotor 223 is an impeller. When the pump unit 22 is a screw pump, the pump rotor 223 is a screw. The number of pump units 22 may be at least one.

[0021] The cooling unit 23 cools the refrigerant flowing in the refrigerant circulation device 2. The type of the cooling unit 23 is not particularly limited. That is, the cooling unit 23 may be an air-cooling type or a water-cooling type. In the case of an air-cooling type, the cooling unit 23 has a radiator and a fan. The radiator is connected to the downstream end of the pipe 241. A high-temperature refrigerant flows into the radiator from the downstream end of the pipe 241. The radiator is connected to the upstream end of the pipe 242. The radiator guides the refrigerant that flows in from its inlet to its outlet. In the process, the refrigerant flowing in the radiator is cooled by the airflow generated by the fan. As a result, a low-temperature refrigerant flows out from the outlet of the radiator.

[0022] The power supply unit 25 is a power supply circuit or the like, and generates, for example, a DC voltage Vcc from an AC voltage supplied from, for example, a commercial power supply. The value of the DC voltage Vcc is not particularly limited, but is, for example, 54 V. The power supply unit 25 supplies the generated DC voltage Vcc to each pump unit 22 and the cooling unit 23.

[0023] The control circuit 26 includes a microcomputer, a memory, etc. (not shown). The microcomputer operates according to a program stored in the memory to control the operation of each pump unit 22 and the cooling section 23.

[0024] FIG. 2 is a schematic diagram showing in detail the insertion and removal of the casing 21 and each pump unit 22. As shown in FIG. 1 and FIG. 2, the casing 21 has a predetermined shape. The predetermined shape is, for example, a substantially rectangular parallelepiped shape. A first surface 213 of the casing 21 has openings 214 in a number corresponding to the pump units 22. A storage space 215 is formed from each opening 214 toward the inside of the casing 21. Each pump unit 22 can be moved manually in the approach direction D01 and the separation direction D02 in the storage space 215 through the opening 214. The approach direction D01 is a direction from the opening 214 toward the mounting position P01 that is predefined in the storage space 215. The separation direction D02 is the opposite direction to the approach direction D01 and is a direction from the mounting position P01 toward the opening 214. At the back of the storage space 215, the downstream end of the pipe 242, the upstream end of the pipe 243, and the connector 216 are arranged. The connector 216 is an example of a "second connector" in the present disclosure. The connector 216 will be described in detail later.

[0025] The pump unit 22 has a shape corresponding to the opening 214 and the accommodation space 215, that is, a substantially rectangular parallelepiped shape. When each pump unit 22 is located at the mounting position P01, the suction port 221 of the pump unit 22 is connected to the downstream end of the pipe 242, and the discharge port 222 of the pump unit 22 is connected to the upstream end of the pipe 243. Each pump unit 22 is further fixed to the first surface 213 with a fastener such as a screw (not shown) while located at the mounting position P01. As a result, the refrigerant can flow from the pipe 242 to the suction port 221, and the refrigerant can flow from the discharge port 222 to the pipe 243. In addition, since each pump unit 22 is fixed to the first surface 213, the pipe 242 is prevented from coming off the suction port 221, and the pipe 243 is prevented from coming off the discharge port 222.

[0026] Each pump unit 22 further has a connector 224 that is detachable from the connector 216 (i.e., an external device). The connector 224 is an example of a "first connector" in the present disclosure. When the pump unit 22 moves in the approaching direction D11 and is located at the mounting position P01, the connector 224 is electrically connected to the connector 216. In the process of the pump unit 22 moving from the mounting position P01 in the separating direction D02, the connector 224 is removed from the connector 216. Further details of the connector 224 will be described later.

[0027] FIG. 3 is a block diagram showing a detailed configuration of the pump unit 22 shown in FIGS.

[0028] 3 also shows a connector 216 and a power supply unit 25 in addition to the detailed configuration of the pump unit 22. The connector 216 has at least terminals 216A to 216C. A DC voltage Vcc generated by the power supply unit 25 is applied between the terminals 216A and 216B. Of the terminals 216A to 216C, the terminals 216B and 216C are grounded. In particular, the terminals 216B and 216C are electrically connected to the ground of the power supply unit 25. The terminal 216C is an example of a "second detection terminal" in the present disclosure.

[0029] 3, the pump unit 22 has, in addition to the above-mentioned pump rotor 223 and connector 224, a power supply unit 2213, a drive unit 225, a motor 226, a control circuit 227, a power supply path 228, a load switch 229, a protection circuit 2210, a drive unit 2211, and a control circuit 2212. Note that at least the connector 224, the power supply path 228, the load switch 229, the protection circuit 2210, and the control circuit 2212 configure a control device 27.

[0030] The connector 224 has at least terminals 224A to 224C. When the connectors 216 and 224 are electrically connected, the terminals 224A, 224B, and 224C are electrically connected to the terminals 216A, 216B, and 216C. Here, in the process of connecting the connectors 216 and 224 to each other, the timing at which the terminals 216B and 224B become conductive substantially coincides with the timing at which the terminals 216A and 224A become conductive. On the other hand, for example, by making the terminal 216C have a different shape from the terminal 216A, the timing at which the terminals 216C and 224C become conductive is delayed by a predetermined time from the timing at which the terminals 216A and 224A become conductive. The terminal 224C is an example of a "first detection terminal" in the present disclosure.

[0031] The power supply unit 2213 is a power supply circuit or the like, and generates a DC voltage Vdd from a DC voltage Vcc supplied from the terminal 224A. The value of the DC voltage Vdd is not particularly limited, but is a voltage lower than the withstand voltage of each microcomputer of the control circuits 227 and 2212. The DC voltage Vdd is lower than the DC voltage Vcc, for example, 3.3 V. The DC voltage Vdd is supplied to the control circuit 2212. The control circuit 2212 operates by the DC voltage Vdd. The power supply unit 2213 may be a battery that outputs the DC voltage Vdd, instead of a power supply circuit.

[0032] The driving unit 225 is, for example, an H-bridge circuit. The driving unit 225 has terminals 225A and 225B. In the driving unit 225, a driving voltage based on a DC voltage Vcc is applied between the terminals 225A and 225B through the connector 224 or the like in response to a predetermined time having elapsed since the connectors 216 and 224 were electrically connected. In the H-bridge circuit, the four switching elements are turned on and off under the control of the control circuit 227. As a result, the driving unit 225 controls the direction of the current flowing through the motor 226 and the rotation speed of the motor 226.

[0033] The motor 226 has a rotatable output shaft. The pump rotor 223 is mechanically connected to the output shaft. The motor 226 rotates under the control of the drive unit 225 to generate power. The motor 226 is an example of a "load device" of the present disclosure. As is well known, the motor 226 detects the rotation speed of the output shaft and outputs a signal indicating the detected rotation speed (hereinafter simply referred to as "rotation speed") to the control circuit 227.

[0034] The pump rotor 223 rotates due to the power generated by the motor 226 .

[0035] The control circuit 227 includes a microcomputer and a memory (not shown). The microcomputer operates according to a program stored in the memory. In detail, the control circuit 227 outputs the rotation speed input from the motor 226 to the control circuit 2212. The control circuit 227 also turns on and off each switching element of the H-bridge circuit based on a PWM (Pulse Width Modulation) signal output from the control circuit 2212. The PWM signal is an example of a "pulse signal" in the present disclosure. The control circuit 227 may be integrated with the control circuit 2212.

[0036] The power supply path 228 electrically connects the motor 226 (i.e., the load device) and the connector 224. In particular, the power supply path 228 has two power lines 228A and 228B. The power line 228A electrically connects the terminals 224A and 225A. The power line 228B electrically connects the terminals 224B and 225B.

[0037] The load switch 229 switches between connection and disconnection of the power supply path 228. In detail, the load switch 229 is provided on the power line 228A. The load switch 229 typically has a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). In the MOSFET, the source is disposed on the input side of the DC voltage Vcc. That is, the source is electrically connected to the terminal 224A. The drain is disposed on the output side of the DC voltage Vcc. That is, the drain is connected to the Vcc terminal of the drive unit 225. The gate is electrically connected to the drive unit 2211 described later. In response to a high-level switch signal being output from the control circuit 2212 to the drive unit 2211, a current flows between the collector and emitter of the NPN transistor in the drive unit 2211, and as a result, a current flows between the source and drain of the load switch 229.

[0038] The protection circuit 2210 protects the load switch 229 from an inrush current that may flow through the load switch 229 when the connectors 224 and 216 are connected to each other. The protection circuit 2210 may include at least a capacitor. In the embodiment, the protection circuit 2210 includes a diode, a capacitor, and a resistor. The diode, the capacitor, and the resistor are all connected between the connector 224 and the load switch 229 and between the load switch 229 and the driver 2211 on the power line 228A.

[0039] The driving unit 2211 controls the on / off of the load switch 229 (i.e., a MOSFET). In detail, the driving unit 2211 has an NPN transistor. In the NPN transistor, the collector is electrically connected to the gate of the MOSFET via a resistor. The emitter is electrically connected to the power line 228B. The base is electrically connected to the terminal 2212B in the control circuit 2212.

[0040] As is well known, the driving unit 2211 can be realized using a PNP transistor and a photocoupler other than an NPN transistor.

[0041] The control circuit 2212 includes a microcomputer and a memory (not shown). The microcomputer includes at least terminals 2212A to 2212E. The microcomputer operates on a DC voltage Vdd supplied to the terminal 2212E. The operation of the microcomputer is defined by a program stored in the memory.

[0042] The terminal 2212A is an input terminal for a hot plug signal (hereinafter, referred to as "HP signal"). The terminal 2212A is electrically connected to the terminal 224C. The terminal 2212A is also supplied with a DC voltage Vdd generated by the power supply unit 2213 via a pull-up resistor 2212F. Therefore, when the terminals 216C and 224C are not electrically connected to each other (i.e., when the pump unit 22 is not attached to the casing 21), the DC voltage Vdd is input to the terminal 2212A. That is, the HP signal is at a high level (DC voltage Vdd). On the other hand, when the terminals 216C and 224C are electrically connected to each other, the terminal 2212A is connected to the ground of the power supply unit 25. That is, the HP signal is at a low level (0V).

[0043] Terminal 2212B is an output terminal for a switch signal (hereinafter, referred to as "SW signal"). In control circuit 2212, the microcomputer has a built-in timer. The timer may be an external integrated circuit to the microcomputer. The timer starts timing when triggered by the transition of the HP signal from high level to low level. When the timer value reaches a preset time set for the microcomputer, the microcomputer outputs a high-level SW signal from terminal 2212B.

[0044] The terminal 2212C is an input terminal for the rotation speed. The terminal 2212D is an output terminal for the PWM signal. The microcomputer outputs a PWM (Pulse Width Modulation) signal, the pulse width of which is adjusted so that the actual rotation speed of the motor 226 approaches the target rotation speed of the motor 226, to the control circuit 227.

[0045] FIG. 4 is a timing chart showing the operation of the refrigerant circulating device 2 shown in FIG. 1 when the pump unit 22 is attached to the casing 21. In FIG.

[0046] As shown in FIG. 4, it is assumed that the pump unit 22 is not attached to the casing 21 before time t01. That is, the connector 216 is not connected to the connector 224 (see FIG. 2). Therefore, the DC voltage Vcc is not applied between the terminals 224A and 224B (see FIG. 3). In addition, the DC voltage Vdd is 0V. In addition, a drive signal is not input to the motor 226 (i.e., the load device). Both the SW signal and the HP signal are at a low level. Therefore, the load switch 229 does not connect the power line 228A. In addition, at the point of time t01, the control circuit 2212 has not started timing by the timer, and has not output a PWM signal.

[0047] Also, assume that before time t01, a main power switch (not shown) provided in casing 21 is operated by an operator. Therefore, in connector 216, DC voltage Vcc generated by power supply unit 25 appears between terminals 216A and 216B.

[0048] At time t01, the operator inserts the pump unit 22 into the accommodation space 215 of the casing 21 and moves it to the mounting position P01 (see FIG. 2). Therefore, among the terminals 224A, 224B, and 224C (see FIG. 3), the terminals 224A and 224B are electrically connected to the terminals 216A and 216B, respectively. As a result, the DC voltage Vcc is applied between the terminals 224A and 224B. In addition, the power supply unit 2213 generates a DC voltage Vdd from the DC voltage Vcc and supplies it to the control circuits 227 and 2212. The control circuits 227 and 2212 start operating by the DC voltage Vdd generated by the power supply unit 2213. Thereafter, the control circuit 227 waits for the PWM signal from the control circuit 2212 and the number of revolutions from the motor 226 to be input. The control circuit 2212 starts monitoring the HP signal. The HP signal remains at high level until the terminals 216C and 224C are brought into electrical continuity with each other after the DC voltage Vdd is input.

[0049] After time t01, at time t02, the terminals 216C and 224C are rendered conductive. The control circuit 2212 detects the continuity of the terminals 216C and 224C (i.e., the connector 224 is connected to the connector 216) based on the voltage value of the terminal 2212A. In detail, when the terminals 216C and 224C are rendered conductive, the HP signal transitions from high level to low level. The control circuit 2212 recognizes that the HP signal has transitioned from high level to low level based on the voltage of the terminal 2212A. When this is recognized, the control circuit 2212 detects that the connector 224 is connected to the connector 216. In this way, the control circuit 2212 can easily detect the attachment / detachment of the connector 224 to / from the connector 216. Furthermore, the control circuit 2212 starts counting time using a timer, triggered by the detection of the connection. The control circuit 2212 periodically monitors the elapsed time measured by the timer.

[0050] After time t02, at time t03, when the control circuit 2212 recognizes that the timer has reached the set time ("20" in the figure), it outputs a high-level SW signal from the terminal 2212B. In response to the input of the high-level SW signal, the drive unit 2211 provides a drive signal to the gate of the load switch 229. However, the protection circuit 2210 is provided in front of the load switch 229. Therefore, immediately after the drive signal is provided to the load switch 229, a current flows through the capacitor of the protection circuit 2210, and the capacitor is charged. That is, the load switch 229 is slowly switched from disconnected to connected. As a result, an inrush current is prevented from flowing through the load switch 229 and the drive unit 225. This prevents the power supply unit 25 from stopping or the drive unit 225 from being damaged due to a spark.

[0051] The time when the first time has elapsed from time t03 is set as t04. The first time is a predetermined time based on the charging time of the capacitor of the protection circuit 2210. In detail, the first time is the charging time of the capacitor itself, a time slightly shorter than the charging time of the capacitor, or a time slightly longer than the charging time of the capacitor. When the capacitor is fully charged or close to being fully charged at time t04, the load switch 229 is switched to the connection. As a result, a DC voltage Vcc is applied between the gate and source of the MOSFET of the load switch 229 and between the terminals 225A and 225B of the drive unit 225. That is, the load switch 229 is slowly switched from disconnection to connection at the first time after the set time has elapsed since the control circuit 2212 detected that the connector 224 is connected to the connector 216 (i.e., an external device). The first time is also based on the charging time of the capacitor. This allows power supply from the external device to the component (i.e., the motor 226) to start in a shorter time after the connection with the external device is detected. In particular, the time during which the load switch 229 is disconnected can be made relatively short while preventing the flow of inrush current. As a result, power supply to the motor 226 starts relatively quickly.

[0052] In addition, the load switch 229 is in a disconnected state for a set time, which allows power to be supplied to the motor 226 after the connection state of the connectors 216 and 224 has stabilized.

[0053] Also, the time when the second time has elapsed from time t03 is set as t05. The second time is a preset time. More specifically, the second time is shorter than the preset time and slightly longer than the first time. When the control circuit 2212 recognizes that the second time has elapsed, it starts outputting a PWM signal to the control circuit 227. Since the start of outputting the PWM signal is delayed from the connection of the load switch 229, the operation of the motor 226 is stabilized. As a result, the motor 226 is driven by the drive unit 225 and starts rotating the pump rotor 223. Thereafter, the control circuit 2212 outputs to the control circuit 227 a PWM signal whose pulse width has been adjusted based on the number of rotations from the control circuit 227.

[0054] Furthermore, since the second time period is shorter than the set time period, the supply of power to the motor 226 begins relatively quickly.

[0055] FIG. 5 is a timing chart showing the operation of the refrigerant circulation device 2 shown in FIG. 1 when the main power switch of the casing 21 is turned off.

[0056] As shown in FIG. 5, it is assumed that the pump unit 22 is attached to the casing 21 before time t11. That is, the connector 216 is in a state of being connected to the connector 224 (see FIG. 2). Therefore, the DC voltage Vcc is applied between the terminals 224A and 224B (see FIG. 3). Also, the DC voltage Vdd is 3.3 V. Also, it is assumed that a drive signal is input to the motor 226 (i.e., the load device). That is, the load switch 229 connects the power line 228A. Also, the SW signal is at a high level, but the HP signal is at a low level. Also, at the point of time t11, the timer in the control circuit 2212 is still counting the set time.

[0057] At time t11, the operator turns off the main power switch of the casing 21. The DC voltage Vcc and the power supplied to the motor 226 start to decrease. Also, the DC voltage Vdd starts to decrease from 3.3 V toward 0 V. Since the connectors 216 and 224 are connected to each other, the HP signal remains at a low level. When the DC voltage Vdd starts to decrease, the control circuit 2212 detects that the main power switch has been turned off or that the connector 224 has been removed from the connector 216. In response to the detection, the control circuit 2212 starts outputting a low-level SW signal, stops outputting a PWM signal, and further initializes the timer (shown as "0").

[0058] FIG. 6 is a timing chart showing the operation of the refrigerant circulation device 2 shown in FIG. 1 when the pump unit 22 is removed from the casing 21. In FIG.

[0059] As shown in FIG. 6, before time t21, the refrigerant circulation device 2 is in the same state as before time t11 (see FIG. 5). At time t21, the worker starts to remove the pump unit 22 from the accommodation space 215 (see FIG. 2). As a result, the pump unit 22 moves from the mounting position P01 in the separation direction D02 (see FIG. 2). In the process of moving in the separation direction D02, among the terminals 216A to 216C, the terminal 224C first separates from the terminal 216C, and then, with a time lag, the terminals 224A and 224B separate from the terminals 216A and 216B, respectively. Therefore, the HP signal input to the terminal 2212A transitions from a low level to a high level (i.e., a DC voltage Vdd) in response to the terminal 224C being separated from the terminal 216C, and thereafter, maintains the high level until the terminal 224A is separated from the terminal 216A.

[0060] After time t21, at time t22, when the terminals 224A and 224B start to move away from the terminals 216A and 216B, respectively, the DC voltage Vcc and the power supplied to the motor 226 start to decrease. The DC voltage Vdd also starts to decrease from 3.3V toward 0V. Similarly, the HP signal also starts to decrease. When the DC voltage Vdd starts to decrease, the control circuit 2212 detects that the main power switch has been turned off or that the connector 224 has been removed from the connector 216. In response to this detection, the control circuit 2212 starts outputting a low-level SW signal, stops outputting the PWM signal, and further initializes the timer (shown as "0"). The control circuit 2212 may start outputting a low-level SW signal in response to the HP signal transitioning from a low level to a high level.

[0061] In response to the SW signal transitioning from high level to low level, the load switch 229 disconnects the power line 228A. That is, in response to detection of removal of the connector 224 from the connector 216, the control circuit 2212 switches the load switch 229 from connected to disconnected. Therefore, the motor 226 can be stopped stably.

[0062] FIG. 7 is a timing chart showing the operation of pump unit 22 when an operator attempts to remove pump unit 22 from casing 21 and then reinstalls pump unit 22 in casing 21. In FIG.

[0063] 7, at time t31, the control circuit 2212 detects that the connector 224 is removed from the connector 216, similarly to the case of time t22 (see FIG. 6). In response to this detection, the control circuit 2212 starts outputting a low-level SW signal, stops outputting a PWM signal, and further initializes the timer. Furthermore, the terminals 224A and 224B start to move away from the terminals 216A and 216B, respectively, so that the DC voltage Vcc and the power supplied to the motor 226 start to decrease. Furthermore, the DC voltage Vdd starts to decrease from 3.3V toward 0V. Similarly, the HP signal also starts to decrease.

[0064] After time t31, at time t32, the operator moves the pump unit 22 to the mounting position P01 in the accommodation space 215 (see FIG. 2). As a result, of the terminals 224A, 224B, and 224C (see FIG. 3), the terminals 224A and 224B become conductive with the terminals 216A and 216B, respectively. As a result, the control circuits 227 and 2212 start operating with the DC voltage Vdd generated by the power supply unit 2213. In particular, the control circuit 2212 starts monitoring the level of the HP signal. The input of the DC voltage Vdd causes the HP signal to go high.

[0065] After time t32, at time t33, the control circuit 2212 detects that the terminals 216C and 224C are brought into conduction, which is a trigger to start time measurement by the timer. The control circuit 2212 periodically monitors the time measured by the timer.

[0066] After time t33, at time t34, when the control circuit 2212 recognizes that the timer has reached the set time ("20" in the figure), it outputs a high-level SW signal from the terminal 2212B. In response to the input of the high-level SW signal, the drive unit 2211 provides a drive signal to the gate of the load switch 229. Therefore, immediately after the drive signal is provided to the load switch 229, as described with reference to FIG. 4, a current flows through the capacitor of the protection circuit 2210, and the capacitor is charged.

[0067] The time when the first hour has elapsed from time t33 is set to t35. When the capacitor is fully charged or close to being fully charged at time t35, as described with reference to FIG. 4, the load switch 229 is switched to the connected state, and the DC voltage Vcc is applied between the gate and source of the MOSFET of the load switch 229 and further to the terminals 225A and 225B of the drive unit 225.

[0068] The time when the second time has elapsed from time t33 is defined as t36. At time t36, the control circuit 2212 starts to provide the PWM signal to the control circuit 227, as described with reference to FIG.

[0069] The embodiments of the present disclosure have been described above with reference to the drawings. However, the present disclosure is not limited to the above embodiments, and can be implemented in various aspects without departing from the gist of the present disclosure. In addition, the components disclosed in the above embodiments can be modified as appropriate. For example, a certain component among all the components shown in one embodiment may be added to a component of another embodiment, or some components among all the components shown in one embodiment may be deleted from the embodiment.

[0070] In addition, the drawings are mainly schematic illustrations of each component to facilitate understanding of the present disclosure, and the thickness, length, number, spacing, etc. of each illustrated component may differ from the actual ones due to the convenience of creating the drawings. In addition, the configurations of each component shown in the above embodiment are merely examples and are not particularly limited, and it goes without saying that various modifications are possible within a range that does not substantially deviate from the effects of the present disclosure.

[0071] The present technology can also adopt the following configuration.

[0072] (1) a first connector to which an external device can be attached and detached; a power supply path that electrically connects a load device and the first connector; A load switch for switching between connection and disconnection of the power supply path; A protection circuit for protecting the load switch from an inrush current; Control circuit Equipped with the control circuit outputs a drive signal for switching the load switch from disconnection to connection after a preset time has elapsed since the control circuit detected that the first connector is connected to an external device; The protection circuit switches the load switch from disconnected to connected for a first predetermined time period.

[0073] (2) The control device according to (1), wherein the protection circuit has at least a capacitor, and switches the load switch from disconnected to connected by inputting a charging voltage of the capacitor to the load switch at the first time based on a charging time of the capacitor by the drive signal.

[0074] (3) The control device according to (1) or (2), wherein the control circuit starts outputting a pulse signal to the load device when a second time has elapsed after the set time has elapsed.

[0075] (4) The control device described in (3), wherein the second time is shorter than the set time.

[0076] (5) the external device includes a second connector to which the first connector is detachable, the second connector has a second detection terminal that is grounded; the first connector has a first detection terminal that is connected to the second detection terminal when the first connector is connected to the second connector; The control device according to any one of (1) to (3), wherein the control circuit detects that the first connector is connected to the second connector based on a voltage of the first detection terminal.

[0077] (6) The control device according to (5), wherein the control circuit switches the load switch from connected to disconnected in response to detecting removal of the first connector from the second connector.

[0078] (7) a first connector that is detachable from an external device; A motor; a pump rotor that rotates by the power generated by the motor; a power supply path electrically connected between the motor and the first connector; A load switch for switching between connection and disconnection of the power supply path; A protection circuit for protecting the load switch from an inrush current; a control circuit that outputs a drive signal for switching the load switch from disconnection to connection after a preset time has elapsed since the first connector is detected to be connected to the external device; Equipped with The protection circuit switches the load switch from disconnected to connected for a first predetermined time period; The motor generates power in response to the load switch being switched to a connected state.

[0079] (8) The pump unit according to (7), a flow path through which a coolant circulates as the pump rotor rotates; A refrigerant circulation device comprising: [Industrial Applicability]

[0080] The technology according to the present disclosure is suitable for cooling electronic devices, for example. [Explanation of symbols]

[0081] 100 Cooling System 1 Cooling device 2 Refrigerant circulation device 22 Pump unit 25 Power supply section 27 Control Device 224 Connector (1st Connector) 224C terminal (first detection terminal) 226 Motor 228 Power supply path 229 Load Switch 2210 protection circuit 2212 Control circuit 216 Connector 216C terminal (second detection terminal) 223 Pump rotor 24 Flow Path

Claims

1. a first connector to which an external device can be detachably attached; a power supply path electrically connecting a load device and the first connector; A load switch for switching between connection and disconnection of the power supply path; A protection circuit for protecting the load switch from an inrush current; Control circuit Equipped with the control circuit detects that the first connector is connected to an external device, and then outputs a drive signal for switching the load switch from disconnection to connection; The protection circuit has at least a capacitor, and switches the load switch from disconnected to connected for a predetermined first time period that is a time period for gradually transitioning the load switch from off to on based on a charging time of the capacitor by the drive signal.

2. The control device according to claim 1 , wherein the protection circuit switches the load switch from disconnection to connection by inputting a charging voltage of the capacitor to the load switch during the first time period.

3. 3. The control device according to claim 1, wherein the control circuit starts outputting a drive signal to the load device when a second time period longer than the first time period has elapsed.

4. the external device includes a second connector to which the first connector is detachable, the second connector has a second detection terminal that is grounded; the first connector has a first detection terminal that is connected to the second detection terminal when the first connector is connected to the second connector; 3 . The control device according to claim 1 , wherein the control circuit detects that the first connector is connected to the second connector based on a voltage of the first detection terminal. 4 .

5. The control device according to claim 4 , wherein the control circuit switches the load switch from connection to disconnection in response to detection of removal of the first connector from the second connector.

6. a first connector that is detachable from an external device; A motor; a pump rotor that rotates by the power generated by the motor; a power supply path electrically connected between the motor and the first connector; A load switch for switching between connection and disconnection of the power supply path; A protection circuit for protecting the load switch from an inrush current; a control circuit that detects that the first connector is connected to the external device and then outputs a drive signal for switching the load switch from disconnection to connection; Equipped with the protection circuit has at least a capacitor, and switches the load switch from disconnection to connection for a predetermined first time period that is a time period for gradually transitioning the load switch from OFF to ON based on a charging time of the capacitor by the drive signal; The motor generates power in response to the load switch being switched to a connected state.

7. A pump unit according to claim 6; a flow path through which a coolant circulates as the pump rotor rotates; A refrigerant circulation device comprising:

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