A front-end detection circuit for a box-type transformer

Abstract

The present invention discloses a front-end detection circuit of a box-type transformer, including a chip U3, a cable temperature detection circuit, a transformer oil temperature detection circuit and a communication circuit; the chip U3 is respectively connected to the cable temperature detection circuit, the transformer oil temperature detection circuit and the communication circuit; wherein the cable temperature detection circuit is used to detect the temperature of the cable; the transformer oil temperature detection circuit is used to detect the oil temperature inside the transformer, and the communication circuit is used for communication. In the present invention, the temperature of the cable can be monitored in real time by the cable temperature detection circuit, which helps to timely discover abnormal cable temperature conditions and improve the safety and reliability of the cable. The transformer oil temperature detection circuit can monitor the real-time oil temperature of the transformer, timely grasp the working status of the transformer, and help protect the transformer equipment. Through the communication circuit, data communication with other devices or systems can be realized, which facilitates data transmission and monitoring.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power maintenance equipment, and in particular relates to a front-end detection circuit of a box-type transformer. Background Art

[0002] Box-type transformer is an electrical device used in power distribution system, usually installed in a metal box outdoors or indoors. Box-type transformer usually includes components such as transformer, switchgear, protection equipment and control equipment, which are used to convert the voltage of high-voltage power system into the voltage required by low-voltage power system for user use. Box-type transformer is mainly used to convert the voltage of high-voltage power grid into low-voltage voltage suitable for user needs to meet the working requirements of different electrical equipment, and distribute the electric energy output by transformer to different users or electrical equipment through switchgear to realize power distribution and control.

[0003] In the prior art, for example, the technical solution described in the utility model patent with publication number CN215221508U is: a transformer room temperature alarm automatic cooling device, which measures the transformer room temperature through a temperature sensor, transmits the temperature signal to the temperature controller through a cable, and the temperature controller detects and judges the temperature. When it is judged that the detected temperature exceeds the preset high temperature value, the temperature controller starts the exhaust fan for ventilation and cooling, and starts the alarm for alarm prompts. When it is judged that the detected temperature is lower than the preset value, the temperature controller delays 1 minute to stop the alarm and exhaust fan.

[0004] In the prior art, the transformer room temperature alarm automatic cooling device has the problem that the delayed stop function may cause excessive temperature and the temperature control method is simple. Summary of the invention

[0005] The purpose of the present invention is to provide a front-end detection circuit for a box-type transformer to solve the problem in the prior art proposed in the background technology that the transformer room temperature alarm automatic cooling device has a delayed stop function that may cause excessive temperature and a simple temperature control method.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A front-end detection circuit of a box-type transformer, comprising a chip U3, a cable temperature detection circuit, a transformer oil temperature detection circuit and a communication circuit;

[0008] Chip U3 is connected to the cable temperature detection circuit, the transformer oil temperature detection circuit and the communication circuit respectively; wherein the cable temperature detection circuit is used to detect the temperature of the cable; the transformer oil temperature detection circuit is used to detect the oil temperature of the transformer; and the communication circuit is used for communication.

[0009] According to the above technical solution, including chip U1, chip U9, sensor U2, resistor R41, resistor R42, resistor R47, resistor R48, resistor R50, resistor R51, resistor R52, capacitor C52, capacitor C54 and capacitor C55;

[0010] Pin 7 of chip U1 is connected to sensor U2; pin 1 of sensor U2 is connected to one end of resistor R41 and one end of resistor R42 respectively; the other end of resistor R41 is connected to the power supply, and the other end of resistor R42 is connected to pin 1 of chip U9;

[0011] Pin 2 of sensor U2 is connected to one end of resistor R48 and capacitor C55 respectively; the other end of resistor R48 is connected to one end of resistor R47 and resistor R51 respectively; the other end of resistor R47 is connected to pin 3 of chip U9 and one end of resistor R52 respectively; the other end of resistor R51 is connected to the other end of capacitor C55;

[0012] The other end of the resistor R52 is respectively connected to the resistor R50, one end of the capacitor C54 and the pin 4 of the chip U9, and the other end of the resistor R50 is respectively connected to the other end of the capacitor C54 and one end of the capacitor C52;

[0013] The other end of capacitor C52 is connected to pin 5 of chip U9.

[0014] According to the above technical solution, pin 2 of the sensor U2, the resistor R48 and the capacitor C55 are all grounded.

[0015] According to the above technical solution, the other ends of the capacitor C55 and the resistor R51 are also connected to the power supply.

[0016] According to the above technical solution, the cable detection circuit includes a sensor J1, an operational amplifier U2, a capacitor C60, a capacitor C61, a resistor R54 and a resistor R64;

[0017] Pin 1 of sensor J1 is respectively connected to one end of resistor R64 and pin 1 of operational amplifier U2; the other end of resistor R64 is connected to the power supply; pin 3 of operational amplifier U2 is respectively connected to pin 4 of operational amplifier U2, resistor R54 and one end of capacitor C60;

[0018] The other end of the resistor R54 is connected to the signal input terminal and one end of the capacitor C61 respectively, and the other end of the capacitor C61 is connected to the other end of the capacitor C60 and the pin 2 of the operational amplifier U2 respectively;

[0019] The other end of the capacitor C61, the other end of the capacitor C60, and pin 2 of the operational amplifier U2 are all grounded.

[0020] According to the above technical solution, the detection circuit also includes a voltage stabilizing circuit, which is used to stabilize the voltage of the detection circuit. The voltage stabilizing circuit includes a first voltage stabilizing circuit and a second voltage stabilizing circuit.

[0021] According to the above technical solution, the first voltage stabilizing circuit includes a voltage stabilizer U5, a capacitor C82, a capacitor C44 and a capacitor C46;

[0022] Pin 1 of the voltage regulator U5 is grounded; Pin 2 of the voltage regulator U5 is respectively connected to the power supply, capacitor C44 and one end of capacitor C46; the other end of capacitor C44 is respectively connected to the other end of capacitor C46 and one end of capacitor C82;

[0023] The other end of the capacitor C82 is connected to pin 3 of the voltage regulator U5, and pin 3 of the voltage regulator U5 is also connected to the power supply.

[0024] According to the above technical solution, the second voltage stabilizing circuit includes a voltage stabilizer U11, a capacitor C83, a capacitor C84 and a capacitor C85;

[0025] Pin 1 of the voltage regulator U11 is grounded; Pin 2 of the voltage regulator U11 is respectively connected to the power supply, capacitor C84 and one end of capacitor C85; the other end of capacitor C84 is respectively connected to the other end of capacitor C85 and one end of capacitor C83;

[0026] The other end of the capacitor C83 is connected to pin 3 of the voltage regulator U11, and pin 3 of the voltage regulator U11 is also connected to a power supply.

[0027] According to the above technical solution, the communication circuit includes a chip U18, a resistor R80, a resistor R82, a transistor Q6 and an interface J4; one end of the resistor R80 is connected to the pin 34 of the chip U3, and the other end of the resistor R80 is connected to the base of the transistor Q6; the emitter of the transistor Q6 is connected to the power supply, and the collector of the transistor Q6 is respectively connected to one end of the resistor R82 and the pins 2 and 3 of the chip U18;

[0028] The other end of the resistor R82 is connected to pin 4 of the chip U18;

[0029] Pin 1 of chip U18 is connected to pin 35 of chip U3; pin 8 of chip U18 is connected to the power supply; pin 7 of chip U18 is connected to pin 2 of interface J4, and pin 6 of chip U18 is connected to pin 1 of interface J4; pin 5 of chip U18 is grounded.

[0030] According to the above technical solution, a relay circuit is also included, and the relay circuit includes a switch K1, a resistor R35, a transistor Q2 and an interface J5;

[0031] One end of the resistor R35 is connected to the pin 23 of the chip U3, and the other end of the resistor R35 is connected to the base of the transistor Q2, and the collector of the transistor Q2 is grounded; the emitter of the transistor Q2 is connected to the pin 2 of the switch K1; and the pin 1 of the switch K1 is connected to the power supply;

[0032] Pin 3 of the switch K1 is also connected to pin 2 of the interface J5; pin 4 of the switch K1 is also connected to pin 1 of the interface J5.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] In the present invention, the cable temperature detection circuit can monitor the temperature of the cable in real time, which helps to find abnormal cable temperature in time and improve the safety and reliability of the cable. The transformer oil temperature detection circuit measures the oil temperature inside the transformer through a sensor placed in the oil tank inside the transformer, so as to grasp the working status of the transformer in time, help protect the transformer equipment and extend the service life of the equipment. Through the communication circuit, data communication with other equipment or systems can be realized, which is convenient for data transmission and monitoring, and improves the intelligence level and remote control capability of the equipment.

[0035] In summary, the solution of the present invention can improve the monitoring and communication functions of the box-type transformer, help improve the safety, reliability and intelligence level of the equipment, and ensure the normal operation and maintenance of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a circuit diagram of the chip U3 of the present invention;

[0037] Figure 2 is a schematic diagram of a data processing circuit of the present invention;

[0038] Figure 3 This is a schematic diagram of a data acquisition circuit of the present invention;

[0039] Figure 4 This is the oil temperature detection circuit diagram of the present invention;

[0040] Figure 5 This is the first voltage stabilizing circuit diagram of the present invention;

[0041] Figure 6 This is a second voltage stabilizing circuit diagram of the present invention;

[0042] Figure 7 This is a power supply circuit diagram of the present invention;

[0043] Figure 8 This is a temperature and humidity detection circuit diagram of the present invention;

[0044] Fig. 9 The communication circuit diagram of the present invention;

[0045] Fig.10 It is the relay circuit diagram of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] Embodiment 1

[0048] like Figure 1 As shown, a front-end detection circuit of a box-type transformer includes a chip U3, a cable detection circuit, an oil temperature detection circuit and a communication circuit;

[0049] The chip U3 is connected to the cable detection circuit, the oil temperature detection circuit and the communication circuit respectively; wherein the cable detection circuit is used to detect the temperature of the cable; the oil temperature detection circuit is used to detect the oil temperature of the transformer; and the communication circuit is used for communication.

[0050] In the present invention, the cable temperature can be monitored in real time through the cable detection circuit, which helps to timely discover abnormal cable temperature and improve the safety and reliability of the cable. The oil temperature detection circuit can monitor the oil temperature of the transformer and timely grasp the working status of the transformer, which helps to protect the transformer equipment and extend the service life of the equipment. Through the communication circuit, data communication with other equipment or systems can be achieved, which facilitates data transmission and monitoring and improves the intelligence level and remote control capability of the equipment.

[0051] In summary, the solution of the present invention can improve the monitoring and communication functions of the box-type transformer, help improve the safety, reliability and intelligence level of the equipment, and ensure the normal operation and maintenance of the equipment.

[0052] Embodiment 2

[0053] This embodiment is a further refinement of the first embodiment.

[0054] like Figure 2 and Figure 3 As shown, the oil temperature detection circuit includes a chip U1, a chip U9, a sensor U2, a resistor R41, a resistor R42, a resistor R47, a resistor R48, a resistor R50, a resistor R51, a resistor R52, a capacitor C52, a capacitor C54 and a capacitor C55;

[0055] like Figure 2As shown, pin 7 of chip U1 is connected to sensor U2; pin 1 of sensor U2 is connected to one end of resistor R41 and one end of resistor R42 respectively; the other end of resistor R41 is connected to the power supply, and the other end of resistor R42 is connected to pin 1 of chip U9;

[0056] like Figure 3 As shown, the No. 2 pin of the sensor U2 is connected to one end of the resistor R48 and the capacitor C55 respectively; the other end of the resistor R48 is connected to one end of the resistor R47 and the resistor R51 respectively; the other end of the resistor R47 is connected to the No. 3 pin of the chip U9 and one end of the resistor R52 respectively; the other end of the resistor R51 is connected to the other end of the capacitor C55;

[0057] The other end of the resistor R52 is respectively connected to the resistor R50, one end of the capacitor C54 and the pin 4 of the chip U9, and the other end of the resistor R50 is respectively connected to the other end of the capacitor C54 and one end of the capacitor C52;

[0058] The other end of capacitor C52 is connected to pin 5 of chip U9.

[0059] Pin 2 of sensor U2, resistor R48 and capacitor C55 are all grounded.

[0060] The other ends of the capacitor C55 and the resistor R51 are also connected to the power supply.

[0061] Pin 2 of chip U9 is grounded.

[0062] The capacitor C52, the capacitor C54 and the resistor R50 are all grounded.

[0063] The chip U1 is also connected to an external circuit; the external circuit includes capacitor C1, capacitor C2, capacitor C9, capacitor C8, resistor R5 and resistor R17;

[0064] One end of the capacitor C1 is connected to the No. 2 pin of the chip U1 and one end of the capacitor C2 respectively; the other end of the capacitor C1 is connected to the other end of the capacitor C2; the other ends of the capacitor C1 and the capacitor C2 are both grounded;

[0065] One end of the resistor R5 is connected to the power supply, and the other end of the resistor R5 is respectively connected to one end of the capacitor C6, and the No. 3 pin and the No. 4 pin of the chip U1; the other end of the capacitor C6 is grounded;

[0066] One end of the capacitor C8 is connected to one end of the resistor R17 and pin 6 of the chip U1 respectively; the other end of the capacitor C8 is connected to the other end of the resistor R17; the other end of the capacitor C8 and the other end of the resistor R17 are both grounded.

[0067] The external circuit also includes a sensor U3, a resistor R1, a resistor R2, a resistor R3, a capacitor C4, a capacitor C5, a capacitor C15 and a capacitor C16;

[0068] Pin 1 of the sensor U3 is connected to one end of the resistor R2 and one end of the resistor R1 respectively, the other end of the resistor R2 is grounded, the other end of the resistor R1 is connected to one end of the capacitor C4 and pin 8 of the chip U1 respectively; the other end of the capacitor C4 is grounded;

[0069] Pin 2 of sensor U3 is grounded;

[0070] One end of the capacitor C5 is connected to one end of the resistor R3 and the No. 9 pin of the chip U1 respectively; the other end of the capacitor C5 is connected to the other end of the resistor R3, and the other end of the capacitor C5 and the other end of the resistor R3 are both grounded;

[0071] One end of capacitor C15 is connected to one end of capacitor C16 and pin 10 of chip U1; the other end of capacitor C15 is connected to the other end of capacitor C16; the other end of capacitor C15 and the other end of capacitor C16 are both grounded.

[0072] The external circuit also includes capacitor C3, capacitor C7 and crystal oscillator B1;

[0073] One end of capacitor C3 is connected to one end of crystal oscillator B1 and pin 23 of chip U1; the other end of capacitor C23 is connected to one end of capacitor C7, and the other end of capacitor C7 is respectively connected to crystal oscillator B1 and pin 22 of chip U1; capacitor C7 and capacitor C3 are both grounded.

[0074] Embodiment 3

[0075] This embodiment is a further refinement of the second embodiment.

[0076] like Figure 4 As shown, the cable detection circuit includes a sensor J1, an operational amplifier U2, a capacitor C60, a capacitor C61, a resistor R54 and a resistor R64;

[0077] Pin 1 of sensor J1 is respectively connected to one end of resistor R64 and pin 1 of operational amplifier U2; the other end of resistor R64 is connected to the power supply; pin 3 of operational amplifier U2 is respectively connected to pin 4 of operational amplifier U2, resistor R54 and one end of capacitor C60;

[0078] The other end of the resistor R54 is connected to the signal input terminal and one end of the capacitor C61 respectively, and the other end of the capacitor C61 is connected to the other end of the capacitor C60 and the pin 2 of the operational amplifier U2 respectively;

[0079] The other end of the capacitor C61, the other end of the capacitor C60, and pin 2 of the operational amplifier U2 are all grounded.

[0080] The control chip uses ATT7053CU chip.

[0081] The detection circuit also includes a voltage stabilizing circuit, which is used for stabilizing the voltage of the detection circuit. The voltage stabilizing circuit includes a first voltage stabilizing circuit and a second voltage stabilizing circuit.

[0082] like Figure 5 As shown, the first voltage stabilizing circuit includes a voltage stabilizer U5, a capacitor C82, a capacitor C44 and a capacitor C46;

[0083] Pin 1 of the voltage regulator U5 is grounded; Pin 2 of the voltage regulator U5 is respectively connected to the power supply, capacitor C44 and one end of capacitor C46; the other end of capacitor C44 is respectively connected to the other end of capacitor C46 and one end of capacitor C82;

[0084] The other end of the capacitor C82 is connected to pin 3 of the voltage regulator U5, and pin 3 of the voltage regulator U5 is also connected to the power supply.

[0085] Capacitor 46, capacitor C44 and capacitor C82 are all grounded.

[0086] like Figure 6 As shown, the second voltage stabilizing circuit includes a voltage stabilizer U11, a capacitor C83, a capacitor C84 and a capacitor C85;

[0087] Pin 1 of the voltage regulator U11 is grounded; Pin 2 of the voltage regulator U11 is respectively connected to the power supply, capacitor C84 and one end of capacitor C85; the other end of capacitor C84 is respectively connected to the other end of capacitor C85 and one end of capacitor C83;

[0088] The other end of the capacitor C83 is connected to pin 3 of the voltage regulator U11, and pin 3 of the voltage regulator U11 is also connected to a power supply.

[0089] Capacitor 84 , capacitor C85 , and capacitor C83 are all grounded.

[0090] Also includes power supply circuits, such as Figure 7 As shown, the power supply circuit includes an interface J3, a resistor RV1, a power supply module, a capacitor C73 and a capacitor C74;

[0091] Pin 2 of the interface J3 is connected to one end of the resistor RV1 and pin 4 of the power module respectively; pin 1 of the interface J3 is connected to the other end of the resistor RV1 and pin 3 of the power module respectively;

[0092] Pin No. 1 of the power module is connected to the power supply, capacitor C73 and one end of capacitor C74 respectively; Pin No. 2 of the power module is connected to the other end of capacitor C73 and capacitor C74 respectively.

[0093] It also includes a temperature and humidity detection circuit, which detects the interior of the box-type transformer through temperature and humidity to ensure the stable operation of the box-type transformer.

[0094] like Figure 8 As shown, the temperature and humidity detection circuit includes: pin J2, resistor RT1, resistor R44, resistor R53, resistor R49, diode D24, transistor Q5 and transistor Q6;

[0095] Pin 1 of the pin J2 is connected to the power supply, pin 2 of the pin J2 is connected to one end of the resistor RT1, and pin 3 of the pin J2 is grounded.

[0096] The other end of the resistor RT1 is respectively connected to the diode D24, one end of the resistor R49 and the emitter of the transistor Q6; the other end of the diode D24 is grounded; the other end of the resistor R49 is connected to the base of the transistor Q5; the collector of the transistor Q5 is grounded; the emitter of the transistor Q5 is respectively connected to one end of the resistor R44 and the control chip; the other end of the resistor R44 is connected to the power supply; the other end of the transistor Q6 is grounded to the collector, the base of the transistor Q6 is connected to one end of the resistor R53, and the other end of the resistor R53 is connected to the control chip.

[0097] Embodiment 4

[0098] like Fig. 9 As shown, the communication circuit includes a chip U18, a resistor R80, a resistor R82, a transistor Q6 and an interface J4; one end of the resistor R80 is connected to the pin 34 of the chip U3, and the other end of the resistor R80 is connected to the base of the transistor Q6; the emitter of the transistor Q6 is connected to the power supply, and the collector of the transistor Q6 is respectively connected to one end of the resistor R82 and the pins 2 and 3 of the chip U18;

[0099] The other end of the resistor R82 is connected to pin 4 of the chip U18;

[0100] Pin 1 of chip U18 is connected to pin 35 of chip U3; pin 8 of chip U18 is connected to the power supply; pin 7 of chip U18 is connected to pin 2 of interface J4, and pin 6 of chip U18 is connected to pin 1 of interface J4; pin 5 of chip U18 is grounded.

[0101] Pin 4 of the chip U18 and the other end of the resistor R82 are both grounded.

[0102] Also includes relay circuits, such as Fig.10As shown, the relay circuit includes a switch K1, a resistor R35, a transistor Q2 and an interface J5;

[0103] One end of the resistor R35 is connected to the pin 23 of the chip U3, and the other end of the resistor R35 is connected to the base of the transistor Q2, and the collector of the transistor Q2 is grounded; the emitter of the transistor Q2 is connected to the pin 2 of the switch K1; and the pin 1 of the switch K1 is connected to the power supply;

[0104] Pin 3 of the switch K1 is also connected to pin 2 of the interface J5; pin 4 of the switch K1 is also connected to pin 1 of the interface J5.

[0105] Chip U3 is also connected to the crystal oscillator circuit; the peripheral circuit includes crystal oscillator Y1, and pins 3 and 4 of crystal oscillator Y1 are both grounded; pin 2 of crystal oscillator Y1 is connected to pin 1 of chip U3, and pin 1 of crystal oscillator Y1 is connected to pin 48 of chip U3.

[0106] The chip U3 is also connected to a peripheral circuit; the peripheral circuit includes a resistor R25, a capacitor C36 and a capacitor C33;

[0107] One end of the resistor R25 is connected to the power supply, and the other end of the resistor R25 is respectively connected to the No. 5 pin of the chip U3 and one end of the capacitor C36; the other end of the capacitor C36 is grounded;

[0108] One end of the capacitor C33 is grounded, and the other end of the capacitor C33 is connected to pin 4 of the chip U3.

[0109] The peripheral circuit also includes a capacitor C39, one end of the capacitor C39 is connected to pin 31 of the chip U3, and the other end of the capacitor C39 and pin 32 of the chip U3 are both grounded.

[0110] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0111] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A front-end detection circuit for a box-type transformer, characterized in that: It includes chip U3, cable temperature detection circuit, transformer oil temperature detection circuit and communication circuit; The chip U3 is connected to the cable temperature detection circuit, the transformer oil temperature detection circuit and the communication circuit respectively; wherein the cable temperature detection circuit is used to detect the temperature of the cable; the transformer oil temperature detection circuit is used to detect the oil temperature of the transformer; and the communication circuit is used for communication; The transformer oil temperature detection circuit includes a chip U1, a chip U9, a sensor U2, a resistor R41, a resistor R42, a resistor R47, a resistor R48, a resistor R50, a resistor R51, a resistor R52, a capacitor C52, a capacitor C54 and a capacitor C55; Pin 7 of chip U1 is connected to sensor U2; pin 1 of sensor U2 is connected to one end of resistor R41 and one end of resistor R42 respectively; the other end of resistor R41 is connected to a 2.8V power supply, and the other end of resistor R42 is connected to pin 1 of chip U9; Pin 2 of sensor U2 is connected to one end of resistor R48 and capacitor C55 respectively; the other end of resistor R48 is connected to one end of resistor R47 and resistor R51 respectively; the other end of resistor R47 is connected to pin 3 of chip U9 and one end of resistor R52 respectively; the other end of resistor R51 is connected to the other end of capacitor C55; The other end of the resistor R52 is respectively connected to the resistor R50, one end of the capacitor C54 and the pin 4 of the chip U9, and the other end of the resistor R50 is respectively connected to the other end of the capacitor C54 and one end of the capacitor C52; The other end of capacitor C52 is connected to pin 5 of chip U9 and a 2.8V power supply respectively; Pin 2 of sensor U2, resistor R48, and capacitor C55 are all grounded; The other ends of the capacitor C55 and the resistor R51 are also connected to a 2.8V power supply.

2. The front-end detection circuit of a box-type transformer according to claim 1 is characterized in that: The cable detection circuit includes a sensor J1, an operational amplifier U2, a capacitor C60, a capacitor C61, a resistor R54, and a resistor R64; Pin 1 of sensor J1 is connected to one end of resistor R64 and pin 1 of operational amplifier U2 respectively; the other end of resistor R64 is connected to a 1.2V power supply; pin 3 of operational amplifier U2 is connected to pin 4 of operational amplifier U2, resistor R54 and one end of capacitor C60 respectively; The other end of the resistor R54 is connected to the 44th pin of the chip U3 and one end of the capacitor C61 respectively. The other end of the capacitor C61 is connected to the other end of the capacitor C60 and the 2nd pin of the operational amplifier U2 respectively. The 5th pin of the operational amplifier U2 is connected to the 2.8V power supply. The other end of the capacitor C61, the other end of the capacitor C60, and pin 2 of the operational amplifier U2 are all grounded.

3. The front-end detection circuit of a box-type transformer according to claim 2 is characterized in that: The detection circuit also includes a voltage stabilizing circuit, which is used for stabilizing the voltage of the detection circuit. The voltage stabilizing circuit includes a first voltage stabilizing circuit and a second voltage stabilizing circuit.

4. The front-end detection circuit of a box-type transformer according to claim 3 is characterized in that: The first voltage stabilizing circuit includes a voltage stabilizer U5, a capacitor C82, a capacitor C44 and a capacitor C46; Pin 1 of the voltage regulator U5 is grounded; Pin 2 of the voltage regulator U5 is respectively connected to Pin 5 of the operational amplifier U2, resistor R41, capacitor C55, resistor R51, capacitor C52, Pin 5 of the chip U9, capacitor C44 and one end of capacitor C46; the other end of capacitor C44 is respectively connected to the other end of capacitor C46 and one end of capacitor C82; The other end of capacitor C82 is connected to pin 3 of voltage regulator U5, and pin 3 of voltage regulator U5 is also connected to a 5V power supply.

5. The front-end detection circuit of a box-type transformer according to claim 3 is characterized in that: The second voltage stabilizing circuit includes a voltage stabilizer U11, a capacitor C83, a capacitor C84 and a capacitor C85; Pin 1 of the voltage regulator U11 is grounded; Pin 2 of the voltage regulator U11 is connected to the resistor R64, the capacitor C84 and one end of the capacitor C85 respectively; the other end of the capacitor C84 is connected to the other end of the capacitor C85 and one end of the capacitor C83 respectively; The other end of the capacitor C83 is connected to pin 3 of the voltage regulator U11, and pin 3 of the voltage regulator U11 is also connected to a 5V power supply.

6. The front-end detection circuit of a box-type transformer according to claim 1, characterized in that: The communication circuit includes a chip U18, a resistor R80, a resistor R82, a transistor Q6 and an interface J4; one end of the resistor R80 is connected to the pin 34 of the chip U3, and the other end of the resistor R80 is connected to the base of the transistor Q6; the emitter of the transistor Q6 is connected to the power supply, and the collector of the transistor Q6 is respectively connected to one end of the resistor R82 and the pins 2 and 3 of the chip U18; The other end of the resistor R82 is connected to pin 4 of the chip U18; Pin 1 of chip U18 is connected to pin 35 of chip U3; pin 8 of chip U18 is connected to the power supply; pin 7 of chip U18 is connected to pin 2 of interface J4, and pin 6 of chip U18 is connected to pin 1 of interface J4; pin 5 of chip U18 is grounded.

7. The front-end detection circuit of a box-type transformer according to claim 6 is characterized in that: It also includes a relay circuit, which includes a switch K1, a resistor R35, a transistor Q2 and an interface J5; One end of the resistor R35 is connected to the pin 23 of the chip U3, and the other end of the resistor R35 is connected to the base of the transistor Q2, and the collector of the transistor Q2 is grounded; the emitter of the transistor Q2 is connected to the pin 2 of the switch K1; and the pin 1 of the switch K1 is connected to the power supply; Pin 3 of the switch K1 is also connected to pin 2 of the interface J5; pin 4 of the switch K1 is also connected to pin 1 of the interface J5.

Images