Power supply automatic switching device

Abstract

The utility model discloses a power supply automatic switching device which comprises a commercial power detection module, a voltage comparison module, a battery switching module, a power supply module, a first commercial power port and a battery power supply port, the battery switching module comprises a first field effect transistor assembly, and the commercial power detection module is connected with external commercial power through the first commercial power port. The first field effect transistor assembly is connected with an external battery through the battery power supply port. The mains supply detection module is used for outputting a first detection level when detecting that no external mains supply is connected; the voltage comparison module is used for receiving the first detection level and outputting a first driving signal; the battery switching module is used for receiving the first driving signal and conducting the first field effect transistor assembly to output a first power supply voltage provided by an external battery; and the power supply module is used for receiving the first power supply voltage and supplying power to the cryoprecipitate preparation instrument and related monitoring equipment. According to the utility model, uninterrupted stable switching between the commercial power and the battery can be realized, so that the problem of data loss of monitoring equipment is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply application, in particular to an automatic power supply switching device. Background Art

[0002] The cryoprecipitate preparation instrument is an important equipment in the blood collection and supply industry. When the cryoprecipitate preparation instrument loses power unexpectedly during the blood preparation process, the monitoring equipment associated with the cryoprecipitate preparation instrument will lose data, and the blood product currently being prepared may face scrapping. At present, some technicians have proposed to install a high-power UPS power supply at the main power supply of the cryoprecipitate preparation instrument as a backup power supply to enable it in the event of an unexpected power outage. However, the high-power UPS power supply needs to switch the power supply through a high-power relay. The contacts of the high-power relay have mechanical action time during the switching process, which can easily cause the monitoring equipment to lose data due to unstable power supply, and the high-power UPS power supply also has certain safety hazards. Utility Model Content

[0003] The utility model provides an automatic power switching device to solve one or more technical problems existing in the prior art and at least provide a beneficial choice or create conditions.

[0004] The utility model provides an automatic power switching device, the device comprising a mains detection module, a voltage comparison module, a battery switching module, a power supply module, a first mains port and a battery power supply port, the battery switching module comprising a first field effect tube assembly;

[0005] The input end of the mains detection module is connected to the external mains through the first mains port, the output end of the mains detection module is connected to the input end of the voltage comparison module, the first output end of the voltage comparison module is connected to the driving end of the battery switching module, the input end of the first field effect tube assembly is connected to the external battery through the battery power supply port, and the output end of the first field effect tube assembly is connected to the input end of the power supply module;

[0006] The AC power detection module is used to output a first detection level when it is detected that there is no external AC power access; the voltage comparison module is used to receive the first detection level and output a first drive signal; the battery switching module is used to receive the first drive signal, turn on the first field effect transistor component to output a first power supply voltage provided by an external battery; the power supply module is used to receive the first power supply voltage to power the cold precipitation preparation instrument and its associated monitoring equipment.

[0007] Furthermore, the device further comprises a mains switching module and a second mains port, wherein the mains switching module comprises a second field effect transistor assembly;

[0008] The second output end of the voltage comparison module is connected to the driving end of the mains switching module, the input end of the second field effect tube assembly is connected to the external DC power supply through the second mains port, the external DC power supply is obtained by converting the external mains power through the external switching power supply, and the output end of the second field effect tube assembly is connected to the input end of the power supply module;

[0009] The AC power detection module is used to output a second detection level when detecting that an external AC power supply is connected; the voltage comparison module is used to receive the second detection level and output a second drive signal; the AC power switching module is used to receive the second drive signal, turn on the second field effect transistor component to output a second supply voltage provided by an external DC power supply; the power supply module is used to receive the second supply voltage and power the cold precipitation preparation instrument and the monitoring equipment.

[0010] Furthermore, the device also includes a voltage stabilizing module;

[0011] The input end of the voltage stabilizing module is respectively connected to the battery power supply port and the second AC power port, and the output end of the voltage stabilizing module is respectively connected to the power supply end of the AC power detection module, the power supply end of the voltage comparison module, the power supply end of the battery switching module and the power supply end of the AC power switching module; the voltage stabilizing module is used to convert the first power supply voltage or the second power supply voltage into a low-voltage power supply.

[0012] Further, the mains power detection module includes a rectifier, an RC filter and a first photoelectric coupler;

[0013] The rectifier is connected to the first mains power port, the rectifier is connected to the RC filter, the RC filter is connected to the light emitter in the first photoelectric coupler, and the light receiver in the first photoelectric coupler is connected to the low-voltage power supply.

[0014] Further, the voltage comparison module includes a first comparator, a second comparator, a first voltage divider circuit, a second voltage divider circuit, an adjustable resistor, a first resistor, a first capacitor and a first field effect transistor;

[0015] The low-voltage power supply is connected to the inverting input terminal of the first comparator through the first voltage-dividing circuit, the light receiver in the first photocoupler is connected to the non-inverting input terminal of the first comparator, the output terminal of the first comparator is respectively connected to the inverting input terminal of the second comparator, the positive electrode of the first capacitor, the first end and the adjustable end of the adjustable resistor, the low-voltage power supply is connected to the non-inverting input terminal of the second comparator through the second voltage-dividing circuit, the output terminal of the second comparator is respectively connected to the first end of the first resistor and the gate of the first field effect transistor, the second end of the adjustable resistor and the second end of the first resistor are connected to the low-voltage power supply, and the negative electrode of the first capacitor and the source of the first field effect transistor are grounded.

[0016] Further, the battery switching module further includes a second photocoupler and a third voltage divider circuit, and the first field effect tube assembly includes a second field effect tube and a third field effect tube;

[0017] The light emitter of the second photocoupler is respectively connected to the low-voltage power supply and the drain of the first field effect tube, the light receiver of the second photocoupler, the third voltage divider circuit and the battery power supply port form a loop, the battery power supply port is respectively connected to the gate of the second field effect tube and the gate of the third field effect tube through the third voltage divider circuit, the battery power supply port is respectively connected to the source of the second field effect tube and the source of the third field effect tube, and the input end of the power supply module is respectively connected to the drain of the second field effect tube and the drain of the third field effect tube.

[0018] Further, the mains switching module further comprises a third photoelectric coupler and a fourth voltage divider circuit, and the second field effect transistor assembly comprises a fourth field effect transistor and a fifth field effect transistor;

[0019] The light emitter of the third photoelectric coupler is respectively connected to the low-voltage power supply and the first end of the first resistor, the light receiver of the third photoelectric coupler, the fourth voltage divider circuit and the second mains power port form a loop, the second mains power port is respectively connected to the gate of the fourth field effect tube and the gate of the fifth field effect tube through the fourth voltage divider circuit, the second mains power port is respectively connected to the source of the fourth field effect tube and the source of the fifth field effect tube, and the input end of the power supply module is respectively connected to the drain of the fourth field effect tube and the drain of the fifth field effect tube.

[0020] Furthermore, the voltage stabilization module includes a step-down voltage stabilization chip and its peripheral circuits.

[0021] Furthermore, the device also includes an anti-backflow module, the input end of the anti-backflow module is connected to the output end of the external switching power supply, and the output end of the anti-backflow module is connected to the second AC power port.

[0022] Furthermore, the backflow prevention module includes a plurality of diodes arranged in parallel.

[0023] The utility model has at least the following beneficial effects: through the coordinated operation of the mains detection module, the voltage comparison module, the mains switching module and the battery switching module, uninterrupted and stable switching between the mains and the battery can be achieved; the field effect transistor is used as a key component required for power switching, so that the battery can be quickly and stably connected to power the cold precipitation preparation instrument and related monitoring equipment in the event of an unexpected power outage, thereby solving the problem of data loss of the monitoring equipment that may be caused by the activation of a high-power UPS power supply as a backup battery in the event of an unexpected power outage; there is no need to use an expensive high-power UPS power supply, which can reduce the safety of the cold precipitation preparation instrument in the event of an unexpected power outage. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the technical solution of the utility model and constitute a part of the specification. Together with the embodiments of the utility model, they are used to explain the technical solution of the utility model and do not constitute a limitation on the technical solution of the utility model.

[0025] Figure 1 It is a schematic diagram of the composition of an automatic power switching device in an embodiment of the utility model;

[0026] Figure 2 It is a schematic diagram of the circuit structure of the voltage stabilizing module in the embodiment of the utility model;

[0027] Figure 3 It is a schematic diagram of the circuit structure of the mains power detection module in the embodiment of the utility model;

[0028] Figure 4 It is a schematic diagram of the circuit structure of a voltage comparison module, a battery switching module, a mains switching module and a power supply module in an embodiment of the utility model;

[0029] Figure 5 It is a schematic diagram of the circuit structure of the anti-backflow module in the embodiment of the utility model. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0031] It should be noted that, although the functional modules are divided in the system schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the system or the order in the flowchart. The terms "first", "second", etc. in the specification, claims and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0032] Please refer to Figure 1 , Figure 1 It is a schematic diagram of the composition of an automatic power switching device provided by an embodiment of the utility model, wherein the device mainly includes a voltage stabilizing module, a mains detection module, a voltage comparison module, a mains switching module, a battery switching module, a power supply module, a battery power supply port, a first mains port and a second mains port, and the battery switching module includes a first field effect transistor assembly, and the mains switching module includes a second field effect transistor assembly.

[0033] Basically, the external mains power (i.e., 220V AC mains power) is connected to the input end of the mains power detection module via the first mains power port, the output end of the mains power detection module is connected to the input end of the voltage comparison module, the first output end of the voltage comparison module is connected to the driving end of the battery switching module, the second output end of the voltage comparison module is connected to the driving end of the mains power switching module, the external battery is connected to the input end of the first field effect tube assembly via the battery power supply port, the external DC power supply is connected to the input end of the second field effect tube assembly via the second mains power port, and the output end of the first field effect tube assembly and the output end of the second field effect tube assembly are both connected to the input end of the power supply module;

[0034] The input end of the voltage stabilizing module is respectively connected to the second AC power port and the battery power supply port, and the output end of the voltage stabilizing module is respectively connected to the power supply end of the voltage comparison module, the power supply end of the AC power detection module, the power supply end of the AC power switching module and the power supply end of the battery switching module.

[0035] In an embodiment of the utility model, when the mains detection module detects that there is no external mains access, the first detection level is output to the voltage comparison module; after obtaining the first detection level, the voltage comparison module outputs a first drive signal to the battery switching module; after obtaining the first drive signal, the battery switching module drives the first field effect tube component to be in a conducting state, and then outputs the first power supply voltage provided by the external battery to the power supply module; after obtaining the first power supply voltage, the power supply module supplies power to the cold precipitation preparation instrument and related monitoring equipment;

[0036] And in this process, the first supply voltage needs to be converted into a low-voltage power supply through the voltage stabilizing module, so that the voltage comparison module, the AC power detection module, the battery switching module and the AC power switching module can rely on the low-voltage power supply to start and operate normally.

[0037] In an embodiment of the utility model, when the mains detection module detects that the external mains is connected, the second detection level is output to the voltage comparison module; after obtaining the second detection level, the voltage comparison module outputs a second drive signal to the mains switching module; after obtaining the second drive signal, the mains switching module drives the second field effect tube component to be in a conducting state, and then outputs the second power supply voltage provided by the external DC power supply to the power supply module; after obtaining the second power supply voltage, the power supply module supplies power to the cold precipitation preparation instrument and related monitoring equipment;

[0038] And in this process, the second supply voltage needs to be converted into a low-voltage power supply through the voltage stabilizing module, so that the voltage comparison module, the AC power detection module, the battery switching module and the AC power switching module can rely on the low-voltage power supply to start and operate normally.

[0039] In some embodiments of the utility model, the external battery adopts a battery assembly formed by five strings of lithium phosphate batteries connected in series, wherein each string of lithium phosphate batteries can provide a voltage of 3.2V, and the voltage that the battery assembly can provide during actual use varies between 14V and 18.25V. The battery assembly can be understood as a 16V low-voltage battery with over- and under-voltage protection functions; the external DC power supply is obtained by converting the external AC power supply via an external switching power supply, and the external switching power supply adopts a 12V switching power supply, which is used to convert 220V AC AC power into 12V DC output.

[0040] In some embodiments of the present invention, see Figure 2 As shown, the voltage stabilizing module specifically includes a step-down voltage stabilizing chip U1 and its peripheral circuit; wherein, the peripheral circuit includes a first diode D1, a second diode D2, a third diode D3, a first light-emitting diode LED1, a second resistor R1, a third resistor R2, a second capacitor C1, a third capacitor C2 and a first inductor L1; the step-down voltage stabilizing chip U1 adopts a DC-DC step-down chip model LM2596R-5.0, and its maximum allowable input voltage is 45V DC voltage, and the corresponding output voltage is 5V DC voltage.

[0041] Among them, the input end of the first diode D1 is connected to the battery power supply port J1, the input end of the second diode D2 is connected to the second AC power port J2, the output end of the first diode D1, the output end of the second diode D2 and the first end of the second capacitor C1 are all connected to the first pin of the buck voltage regulator chip U1, the first end of the second resistor R1 is connected to the fifth pin of the buck voltage regulator chip U1, the cathode of the third diode D3 and the first end of the first inductor L1 are all connected to the second pin of the buck voltage regulator chip U1, the second end of the first inductor L1 and the The first end and the positive electrode of the third capacitor C2 are connected to the fourth pin of the buck regulator chip U1, the second end of the third resistor R2 is connected to the positive electrode of the first light-emitting diode LED1, the second end of the second capacitor C1, the second end of the second resistor R1, the positive electrode of the third diode D3, the negative electrode of the third capacitor C2, the negative electrode of the first light-emitting diode LED1 and the third pin of the buck regulator chip U1 are grounded V-, and the second pin of the buck regulator chip U1 is used as the output end of the voltage regulator module to provide a low-voltage power supply VCC, and the low-voltage power supply VCC is a 5V power supply.

[0042] In some embodiments of the present invention, see Figure 3 As shown, the AC power detection module specifically includes a rectifier D1, an RC filter, a fourth resistor R3 and a first photocoupler T1. The RC filter includes a fourth capacitor C3 and a fifth resistor R4. The first photocoupler T1 can be a photocoupler of model TLP521.

[0043] Among them, the input end of the rectifier D1 is connected to the first AC power port J3, the output end of the rectifier D1 is connected to the RC filter, the RC filter is connected to the light emitter in the first photoelectric coupler T1, the fourth resistor R3 is arranged on the connecting line between the positive electrode of the light emitter in the first photoelectric coupler T1 and the RC filter, the collector of the light receiver in the first photoelectric coupler T1 is connected to the low-voltage power supply VCC, and the emitter of the light receiver in the first photoelectric coupler T1 is used as the output end DET_IN of the AC power detection module.

[0044] In actual application, when the first mains power port J3 has no external mains power access, the first photocoupler T1 is in an off state, and the output end DET_IN of the mains power detection module provides the first detection level, which is a 0V low-level signal; when the first mains power port J3 has external mains power access, the first photocoupler T1 is in an on state, and the output end DET_IN of the mains power detection module provides the second detection level, which is a 5V high-level signal.

[0045] It should be noted that the fifth resistor R4 can be used to consume the excess electric energy of the fourth capacitor C3 outside the low-peak period of the external AC power pulse to compensate for the excess electric energy generated by the charging of the fourth capacitor C3 after the external AC power outage, thereby avoiding power switching delay caused by the excess electric energy generated by the charging of the fourth capacitor C3; the fourth resistor R3 is a current limiting resistor that isolates the input side of the first photocoupler T1.

[0046] In some embodiments of the present invention, see Figure 4 As shown, the voltage comparison module specifically includes a first comparator U1B, a second comparator U1A, a first voltage divider circuit, a second voltage divider circuit, a first field effect transistor Q1, a first resistor R5, a sixth resistor R6, a seventh resistor R7, an adjustable resistor W1 and a first capacitor C4; wherein, the first comparator U1B and the second comparator U1A can be uniformly replaced by a universal comparator of model LM393DR2G, and the first field effect transistor Q1 can be an N-channel field effect transistor of model AO3400A.

[0047] Among them, the inverting input terminal of the first comparator U1B is connected to the low-voltage power supply VCC via the first voltage divider circuit, the non-inverting input terminal of the first comparator U1B is connected to the first end of the sixth resistor R6, the second end of the sixth resistor R6 is respectively connected to the emitter of the light receiver in the first photocoupler T1 and the first end of the seventh resistor R7, the non-inverting input terminal of the second comparator U1A is connected to the low-voltage power supply VCC via the second voltage divider circuit, the inverting input terminal of the second comparator U1A is respectively connected to the adjustable end and the first end of the adjustable resistor W1, the positive terminal of the first capacitor C4 The output end of the second comparator U1A is connected to the first end of the first resistor R5 and the gate of the first field effect tube Q1 respectively, the second end of the first resistor R5 and the second end of the adjustable resistor W1 are both connected to the low voltage power supply VCC, the source of the first field effect tube Q1, the negative electrode of the first capacitor C4 and the second end of the seventh resistor R7 are all grounded V-; the drain of the first field effect tube Q1 is used as the first output end of the voltage comparison module, and the first end of the first resistor R5 is used as the second output end of the voltage comparison module.

[0048] More specifically, the first voltage-dividing circuit includes an eighth resistor R8 and a ninth resistor R9, the first end of the eighth resistor R8 is connected to the low-voltage power supply VCC, the second end of the eighth resistor R8 and the first end of the ninth resistor R9 are both connected to the inverting input terminal of the first comparator U1B, and the second end of the ninth resistor R9 is connected to the ground V-; the second voltage-dividing circuit includes a tenth resistor R10 and an eleventh resistor R11, the first end of the tenth resistor R10 is connected to the low-voltage power supply VCC, the second end of the tenth resistor R10 and the first end of the eleventh resistor R11 are both connected to the non-inverting input terminal of the second comparator U1A, and the second end of the eleventh resistor R11 is connected to the ground V-.

[0049] In practical applications, the first voltage-dividing circuit is used to divide the low-voltage power supply VCC, so that the reverse input terminal of the first comparator U1B is connected to a 2.5V DC voltage; the second voltage-dividing circuit is used to divide the low-voltage power supply VCC, so that the non-inverting input terminal of the second comparator U1A is connected to a 3.4V DC voltage;

[0050] When the output terminal DET_IN of the mains detection module provides the first detection level, the voltage of the non-inverting input terminal of the first comparator U1B is less than the voltage of its reverse input terminal, so that the output terminal of the first comparator U1B is grounded V-. At this time, the voltage of the reverse input terminal of the second comparator U1A is lower than the voltage of its non-inverting input terminal, so that the output terminal of the second comparator U1A is open, and the low-voltage power supply VCC pulls up the level of the first end of the first resistor R5, and the first field effect transistor Q1 is in a conducting state, thereby generating the first drive signal;

[0051] When the output terminal DET_IN of the AC power detection module provides the second detection level, the voltage at the non-inverting input terminal of the first comparator U1B is greater than the voltage at its reverse input terminal, so that the output terminal of the first comparator U1B is open. At this time, the low-voltage power supply VCC charges the first capacitor C4 through the adjustable resistor W1 until the voltage at the reverse input terminal of the second comparator U1A is higher than the voltage at its non-inverting input terminal, so that the output terminal of the second comparator U1A is grounded V-, thereby generating the second drive signal.

[0052] It should be noted that by using the adjustable resistor W1 to adjust the charging speed of the first capacitor C4, the time for switching to external AC power can be changed, thereby avoiding the delay in the initial power-on of the external switching power supply affecting the continuity of the power supply required for the monitoring equipment and the cold precipitation preparation instrument.

[0053] In some embodiments of the present invention, see Figure 4As shown, the battery switching module specifically also includes a third voltage divider circuit, a second photocoupler T2, a twelfth resistor R12 and a second light-emitting diode LED2, and the first field effect tube assembly is composed of a third field effect tube Q3 and a second field effect tube Q2; the second photocoupler T2 can adopt a photocoupler with a model number of EL357N(B)(TA)-G, and the third field effect tube Q3 and the second field effect tube Q2 can adopt an N-channel field effect tube with a model number of IRF4905.

[0054] Among them, the positive electrode of the light emitter of the second photocoupler T2 is connected to the low-voltage power supply VCC, the negative electrode of the light emitter of the second photocoupler T2 is connected to the drain of the first field effect tube Q1 via the twelfth resistor R12, the battery power supply port J1 is respectively connected to the source of the third field effect tube Q3 and the source of the second field effect tube Q2, the battery power supply port J1, the third voltage divider circuit and the light receiver of the second photocoupler T2 form a loop, the battery power supply port J1 is respectively connected to the gate of the third field effect tube Q3 and the gate of the second field effect tube Q2 via the third voltage divider circuit, and the input end of the power supply module is respectively connected to the drain of the third field effect tube Q3 and the drain of the second field effect tube Q2.

[0055] More specifically, the third voltage-dividing circuit includes a thirteenth resistor R13, a fourteenth resistor R14 and a fifteenth resistor R15, the battery power supply port J1 is connected to the first end of the thirteenth resistor R13 through the second light-emitting diode LED2, the second end of the thirteenth resistor R13, the first end of the fourteenth resistor R14 and the first end of the fifteenth resistor R15 are all connected to the gate of the third field effect transistor Q3 and the gate of the second field effect transistor Q2, the second end of the fourteenth resistor R14 is connected to the battery power supply port J1, the second end of the fifteenth resistor R15 is connected to the collector of the light receiver of the second photocoupler T2, and the emitter of the light receiver of the second photocoupler T2 is grounded V-.

[0056] In actual applications, when the first output end of the voltage comparison module provides the first drive signal, the second photocoupler T2 is in an on state, thereby making the third field effect transistor Q3 and the second field effect transistor Q2 in an on state, and the first power supply voltage provided by the external battery is output to the input end of the power supply module via the battery power supply port J1.

[0057] In some embodiments of the present invention, see Figure 4As shown, the AC power switching module specifically also includes a fourth voltage divider circuit, a third photocoupler T3, a sixteenth resistor R16 and a third light-emitting diode LED3, and the second field effect tube assembly is composed of a fifth field effect tube Q5 and a fourth field effect tube Q4; the third photocoupler T3 can adopt a photocoupler with model EL357N(B)(TA)-G, and the fifth field effect tube Q5 and the fourth field effect tube Q4 can adopt an N-channel field effect tube with model IRF4905.

[0058] Among them, the positive electrode of the light emitter of the third photocoupler T3 is connected to the low-voltage power supply VCC, the negative electrode of the light emitter of the third photocoupler T3 is connected to the first end of the first resistor R5 via the sixteenth resistor R16, the second mains port J2 is respectively connected to the source of the fifth field effect transistor Q5 and the source of the fourth field effect transistor Q4, a loop is formed between the second mains port J2, the fourth voltage divider circuit and the light receiver of the third photocoupler T3, the second mains port J2 is respectively connected to the gate of the fifth field effect transistor Q5 and the gate of the fourth field effect transistor Q4 via the fourth voltage divider circuit, and the input end of the power supply module is respectively connected to the drain of the fifth field effect transistor Q5 and the drain of the fourth field effect transistor Q4.

[0059] More specifically, the fourth voltage-dividing circuit includes a seventeenth resistor R17, an eighteenth resistor R18 and a nineteenth resistor R19, the second AC power port J2 is connected to the first end of the seventeenth resistor R17 through the third light-emitting diode LED3, the second end of the seventeenth resistor R17, the first end of the eighteenth resistor R18 and the first end of the nineteenth resistor R19 are all connected to the gate of the fifth field effect transistor Q5 and the gate of the fourth field effect transistor Q4, the second end of the eighteenth resistor R18 is connected to the second AC power port J2, the second end of the nineteenth resistor R19 is connected to the collector of the light receiver of the third photocoupler T3, and the emitter of the light receiver of the third photocoupler T3 is grounded V-.

[0060] In actual applications, when the second output terminal of the voltage comparison module provides the second drive signal, the third photocoupler T3 is in an on state, thereby making the fourth field effect transistor Q4 and the fifth field effect transistor Q5 in an on state, and the second supply voltage provided by the external DC power supply is output to the input end of the power supply module through the second AC power port J2.

[0061] It should be noted that when the output end of the second comparator U1A is open, the second photocoupler T2 is in the on state and the third photocoupler T3 is in the off state; when the output end of the second comparator U1A is grounded V-, the second photocoupler T2 is in the off state and the third photocoupler T3 is in the on state.

[0062] In some embodiments of the present invention, the monitoring device includes an industrial computer host, an industrial computer display and a solid-state relay, see Figure 4 As shown, the device also includes a first port J4, a second port J5, a third port J6, a fourth port J7, a fifth port J8, a sixth port J9, a seventh port J10 and an eighth port J11; the first port J4 is connected to the power switch of the cold precipitate preparation instrument, the first port J4 is respectively connected to the second port J5 and the third port J6, the second port J5 is connected to an external 12V voltage regulator module, the second port J5 is connected to the fourth port J7, the third port J6 is connected to an external 5V voltage regulator module, the fourth port J7 is connected to the industrial control computer host, the fifth port J8 is connected to the industrial control computer display, the sixth port J9 is connected to an external solid-state relay, the seventh port J10 is connected to the circuit board inside the cold precipitate preparation instrument, and the eighth port J11 is connected to the USB interface of the industrial control computer host.

[0063] Among them, the external 12V voltage stabilizing module is used to stabilize the voltage of the switching stage at 12V, and output the 12V voltage to the industrial computer host and the industrial computer display for power supply; the external 5V voltage stabilizing module is used to step down and stabilize the voltage of the switching stage at 5V, and output the 5V voltage to the circuit board inside the cold precipitation preparation instrument and the external solid-state relay for power supply; the external solid-state relay is used to realize the synchronization of the strong and weak current opening and closing of the cold precipitation preparation instrument and the opening and closing of the industrial computer host.

[0064] In some embodiments of the present invention, see Figure 4As shown, the power supply module includes a fourth photocoupler T4, a fifth photocoupler T5, a sixth field effect transistor Q6, a seventh field effect transistor Q7, an eighth field effect transistor Q8, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9 and a fourth light-emitting diode LED4; the sixth field effect transistor Q6, the seventh field effect transistor Q7 and the eighth field effect transistor Q8 can all adopt N-channel field effect transistors with model number IRF4905, and the fourth photocoupler T4 and the fifth photocoupler T5 can both adopt photocouplers with model number EL357N(B)(TA)-G.

[0065] The drain of the second field effect transistor Q2, the drain of the third field effect transistor Q3, the drain of the fourth field effect transistor Q4, and the drain of the fifth field effect transistor Q5 are all connected to the first port J4, the second port J5 is respectively connected to the source of the sixth field effect transistor Q6 and the first end of the twentieth resistor R20, the drain of the sixth field effect transistor Q6 is connected to the fifth port J8, the gate of the sixth field effect transistor Q6 is respectively connected to the second end of the twentieth resistor R20 and the first end of the twenty-second resistor R22, the second end of the twenty-second resistor R22 is connected to the collector of the light receiver of the fourth photoelectric coupler T4, and the emitter of the light receiver of the fourth photoelectric coupler T4 is grounded V-;

[0066] The third port J6 is respectively connected to the first end of the twenty-first resistor R21, the source of the seventh field effect transistor Q7 and the source of the eighth field effect transistor Q8, the drain of the seventh field effect transistor Q7 is respectively connected to the drain of the eighth field effect transistor Q8, the sixth port J9 and the seventh port J10, the gate of the seventh field effect transistor Q7 is respectively connected to the gate of the eighth field effect transistor Q8, the second end of the twenty-first resistor R21 and the first end of the twenty-third resistor R23, the second end of the twenty-third resistor R23 is connected to the collector of the light receiver of the fifth photoelectric coupler T5, and the emitter of the light receiver of the fifth photoelectric coupler T5 is grounded V-;

[0067] The eighth port J11 is provided with a first pin USB+ and a second pin USB-, the first pin USB+ is respectively connected to the positive electrode of the light emitter of the fourth photocoupler T4 and the positive electrode of the light emitter of the fifth photocoupler T5 through the fourth light emitting diode LED4, and the second pin USB- is respectively connected to the negative electrode of the light emitter of the fourth photocoupler T4 and the negative electrode of the light emitter of the fifth photocoupler T5 through the twenty-fourth resistor R24;

[0068] The fifth capacitor C5 and the sixth capacitor C6 are arranged in parallel at the first port J4, the seventh capacitor C7 is arranged at the fourth port J7, the eighth capacitor C8 is arranged at the fifth port J8, and the ninth capacitor C9 is arranged at the sixth port J9 and the seventh port J10. Each of the above capacitors plays a role in filtering the port input voltage.

[0069] It should be noted that the purpose of setting the eighth port J11 is to obtain a 5V voltage through the USB interface of the industrial computer host after it is turned on, so that the fourth photocoupler T4 and the fifth photocoupler T5 are both in the on state, and then the sixth field effect transistor Q6, the seventh field effect transistor Q7 and the eighth field effect transistor Q8 are in the on state, thereby managing the industrial computer display, the circuit board inside the cold precipitation preparation instrument and the external solid-state relay.

[0070] In some embodiments of the present invention, see Figure 5 As shown, the device further includes a backflow prevention module, and the output end of the external switching power supply (at Figure 5 The ninth port J12 is connected to the input end of the anti-backflow module, and the output end of the anti-backflow module is connected to the second AC power port J2.

[0071] More specifically, the backflow prevention module includes a plurality of diodes and is used in parallel. In the embodiment of the utility model, six diodes are preferably provided, the positive electrode of each diode is connected to the ninth port J12, and the negative electrode of each diode is connected to the second AC power port J2.

[0072] It should be noted that see Figure 4 As shown, due to the actual connection relationship between the battery switching module and the AC power switching module, the second supply voltage provided by the external DC power supply is stable, but the first supply voltage provided by the external battery is variable. When the first supply voltage flows back to the second AC power port J2 via the diode in the fourth field effect transistor Q4 and the diode in the fifth field effect transistor Q5, if the anti-backflow module is not set for isolation protection, the external switching power supply will be damaged.

[0073] In some embodiments of the present invention, see Figure 2As shown, the device also includes a tenth port J13, which is connected to an external battery charger with an overcharge protection function. The external battery charger is used to charge the external battery. A resettable fuse F1 is arranged between the tenth port J13 and the battery power supply port J1 to provide overload protection for both the external battery and the external battery charger.

[0074] In the embodiment of the utility model, through the coordinated operation of the AC power detection module, the voltage comparison module, the AC power switching module and the battery switching module, uninterrupted and stable switching between the AC power and the battery can be achieved; the field effect transistor is used as a key component required for power switching, so that the battery can be quickly and stably connected to power the cold precipitation preparation instrument and related monitoring equipment in the event of an unexpected power outage, thereby solving the problem of data loss of the monitoring equipment that may be caused by the activation of a high-power UPS power supply as a backup battery in the event of an unexpected power outage; there is no need to use an expensive high-power UPS power supply, which can reduce the safety of the cold precipitation preparation instrument in the event of an unexpected power outage.

[0075] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the above implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present invention. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A power automatic switching device, characterized in that: The device comprises a mains detection module, a voltage comparison module, a battery switching module, a power supply module, a first mains port and a battery power supply port, wherein the battery switching module comprises a first field effect tube assembly; The input end of the mains detection module is connected to the external mains through the first mains port, the output end of the mains detection module is connected to the input end of the voltage comparison module, the first output end of the voltage comparison module is connected to the driving end of the battery switching module, the input end of the first field effect tube assembly is connected to the external battery through the battery power supply port, and the output end of the first field effect tube assembly is connected to the input end of the power supply module; The AC power detection module is used to output a first detection level when it is detected that there is no external AC power access; the voltage comparison module is used to receive the first detection level and output a first drive signal; the battery switching module is used to receive the first drive signal, turn on the first field effect transistor component to output a first power supply voltage provided by an external battery; the power supply module is used to receive the first power supply voltage to power the cold precipitation preparation instrument and its associated monitoring equipment.

2. The automatic power switching device according to claim 1, characterized in that: The device further comprises a mains switching module and a second mains port, wherein the mains switching module comprises a second field effect transistor assembly; The second output end of the voltage comparison module is connected to the driving end of the mains switching module, the input end of the second field effect tube assembly is connected to the external DC power supply through the second mains port, the external DC power supply is obtained by converting the external mains power through the external switching power supply, and the output end of the second field effect tube assembly is connected to the input end of the power supply module; The mains detection module is used to output a second detection level when detecting that an external mains connection is detected; the voltage comparison module is used to receive the second detection level and output a second drive signal; the mains switching module is used to receive the second drive signal and turn on the second field effect transistor component to output a second supply voltage provided by an external DC power supply; The power supply module is used to receive the second power supply voltage to power the cold precipitation preparation instrument and the monitoring device.

3. The automatic power switching device according to claim 2, characterized in that: The device also includes a voltage stabilizing module; The input end of the voltage stabilizing module is respectively connected to the battery power supply port and the second AC power port, and the output end of the voltage stabilizing module is respectively connected to the power supply end of the AC power detection module, the power supply end of the voltage comparison module, the power supply end of the battery switching module and the power supply end of the AC power switching module; the voltage stabilizing module is used to convert the first power supply voltage or the second power supply voltage into a low-voltage power supply.

4. The automatic power switching device according to claim 3, characterized in that: The mains power detection module includes a rectifier, an RC filter and a first photoelectric coupler; The rectifier is connected to the first mains power port, the rectifier is connected to the RC filter, the RC filter is connected to the light emitter in the first photoelectric coupler, and the light receiver in the first photoelectric coupler is connected to the low-voltage power supply.

5. The automatic power switching device according to claim 4, characterized in that: The voltage comparison module includes a first comparator, a second comparator, a first voltage divider circuit, a second voltage divider circuit, an adjustable resistor, a first resistor, a first capacitor and a first field effect transistor; The low-voltage power supply is connected to the inverting input terminal of the first comparator through the first voltage-dividing circuit, the light receiver in the first photocoupler is connected to the non-inverting input terminal of the first comparator, the output terminal of the first comparator is respectively connected to the inverting input terminal of the second comparator, the positive electrode of the first capacitor, the first end and the adjustable end of the adjustable resistor, the low-voltage power supply is connected to the non-inverting input terminal of the second comparator through the second voltage-dividing circuit, the output terminal of the second comparator is respectively connected to the first end of the first resistor and the gate of the first field effect transistor, the second end of the adjustable resistor and the second end of the first resistor are connected to the low-voltage power supply, and the negative electrode of the first capacitor and the source of the first field effect transistor are grounded.

6. The automatic power switching device according to claim 5, characterized in that: The battery switching module further includes a second photocoupler and a third voltage divider circuit, and the first field effect transistor assembly includes a second field effect transistor and a third field effect transistor; The light emitter of the second photocoupler is respectively connected to the low-voltage power supply and the drain of the first field effect tube, the light receiver of the second photocoupler, the third voltage divider circuit and the battery power supply port form a loop, the battery power supply port is respectively connected to the gate of the second field effect tube and the gate of the third field effect tube through the third voltage divider circuit, the battery power supply port is respectively connected to the source of the second field effect tube and the source of the third field effect tube, and the input end of the power supply module is respectively connected to the drain of the second field effect tube and the drain of the third field effect tube.

7. The automatic power switching device according to claim 5, characterized in that: The mains switching module further includes a third photoelectric coupler and a fourth voltage divider circuit, and the second field effect transistor assembly includes a fourth field effect transistor and a fifth field effect transistor; The light emitter of the third photoelectric coupler is respectively connected to the low-voltage power supply and the first end of the first resistor, the light receiver of the third photoelectric coupler, the fourth voltage divider circuit and the second mains power port form a loop, the second mains power port is respectively connected to the gate of the fourth field effect tube and the gate of the fifth field effect tube through the fourth voltage divider circuit, the second mains power port is respectively connected to the source of the fourth field effect tube and the source of the fifth field effect tube, and the input end of the power supply module is respectively connected to the drain of the fourth field effect tube and the drain of the fifth field effect tube.

8. The automatic power switching device according to claim 3, characterized in that: The voltage stabilization module includes a step-down voltage stabilization chip and its peripheral circuits.

9. The automatic power switching device according to claim 2, characterized in that: The device further comprises an anti-backflow module, an input end of the anti-backflow module is connected to an output end of an external switching power supply, and an output end of the anti-backflow module is connected to the second mains power port.

10. The automatic power switching device according to claim 9, characterized in that: The backflow prevention module includes a plurality of diodes arranged in parallel.

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