Automatic lossless discharge circuit and electronic equipment

Abstract

The invention relates to the technical field of power electronic devices, in particular to an automatic lossless discharge circuit and electronic equipment. The circuit comprises a voltage conversion module, a first switching module, at least one second switching module and at least one discharging module, the input end of the voltage conversion module is used for being connected with a power supply; the output end of the voltage conversion module is respectively connected with the first switching module and the second switching module, the first switching module is arranged on a connecting path between the power supply and the circuit board, and the second switching module is connected with the discharging module and is used for being connected with a discharging capacitor. The problems that in the prior art, capacitor discharging efficiency is low, and automatic lossless discharging cannot be achieved are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic devices, and in particular to an automatic lossless discharge circuit and electronic equipment. Background Art

[0002] Existing circuit boards are generally provided with a power supply for power supply, and are usually provided with a capacitor for auxiliary power supply. When designing a circuit, in order to save costs, reduce circuit interference, and reduce the power loss of the entire machine, a discharge circuit or a discharge resistor is often not provided at both ends of the capacitor. In this case, when the bare circuit board is tested and the power is turned off, there is often residual electrical energy inside the capacitor. This residual electrical energy can make some circuits or components work, so when the circuit board is moved or placed, the components between the boards touch, which may cause damage to the components / circuits. In the prior art, the capacitors are discharged one by one, but when the capacity of the capacitor is large, the discharge efficiency of this discharge method is low, and automatic lossless discharge cannot be achieved. Summary of the invention

[0003] The present invention provides an automatic lossless discharge circuit and electronic equipment, which are used to solve the technical problems in the prior art that the capacitor discharge efficiency is low and automatic lossless discharge cannot be achieved.

[0004] In one aspect, the present invention provides an automatic lossless discharge circuit, comprising: a voltage conversion module, a first switching module, at least one second switching module and at least one discharge module;

[0005] The input end of the voltage conversion module is used to connect to a power source;

[0006] The output end of the voltage conversion module is connected to the first switching module and the second switching module respectively, and is used to convert the voltage of the power supply into a target voltage when the power supply is connected;

[0007] The first switching module is arranged in a connection path between the power supply and the circuit board, and is used to connect the circuit between the power supply and the circuit board when the target voltage is received, and is used to disconnect the circuit between the power supply and the circuit board when the target voltage is not received;

[0008] The second switching module is connected to the discharge module, used to connect the discharge capacitor, and is used to disconnect the circuit between the discharge module and the discharge capacitor when the target voltage is received, and is used to connect the circuit between the discharge module and the discharge capacitor when the target voltage is not received.

[0009] Optionally, the second switching module includes: a first relay and a seventh diode;

[0010] The two ends of the coil of the first relay are respectively connected to the output end of the voltage conversion module and the ground; the seventh diode is connected in parallel to the two ends of the coil of the first relay;

[0011] The moving contact of the first relay is used to be connected to one end of the discharge capacitor;

[0012] The first static contact of the first relay is connected to one end of the discharge module; the second static contact of the first relay is left empty;

[0013] The other end of the discharge module is used to connect to the other end of the discharge capacitor.

[0014] Optionally, the number of the discharge capacitor is at least one; the moving contact of the first relay includes a first moving contact and a second moving contact;

[0015] The discharge module includes a first rectifying unit, a first discharge branch, and a second discharge branch;

[0016] The AC connection end of the first rectifier unit is connected to the first static contact through a fourteenth resistor;

[0017] The positive electrode connection end of the first rectifying unit is connected to the input end of the first discharge branch;

[0018] The negative electrode connection end of the first rectifying unit is connected to the output end of the second discharge branch;

[0019] The first moving contact and the output end of the first discharge branch are used to connect two ends of at least one of the discharge capacitors;

[0020] The second moving contact and the input end of the second discharge branch are respectively used to connect two ends of at least one of the discharge capacitors.

[0021] Optionally, the first discharge branch includes: a thirteenth diode, a fourteenth diode, a fifteenth diode, a twelfth resistor, a third triode, a fifth MOS transistor, a fourth voltage regulator, and a thirteenth resistor;

[0022] The positive electrode connection end of the first rectifying unit is respectively connected to the anode of the thirteenth diode and one end of the twelfth resistor;

[0023] The thirteenth diode, the fourteenth diode, and the fifteenth diode are connected in series;

[0024] The cathode of the fifteenth diode is connected to the drain of the fifth MOS tube;

[0025] The other end of the twelfth resistor is connected to the collector of the third triode, the gate of the fifth MOS tube, and the cathode of the fourth voltage regulator tube;

[0026] One end of the thirteenth resistor is respectively connected to the anode of the fourth voltage-stabilizing tube, the base of the third transistor, and the source of the fifth MOS tube;

[0027] The emitter of the third transistor is connected to the other end of the thirteenth resistor and is used to be connected to the discharge capacitor.

[0028] Optionally, the second discharge branch includes: a tenth resistor, a second triode, a third voltage regulator, a fourth MOS transistor, a seventh resistor, a twelfth diode, a tenth diode, and an eleventh diode;

[0029] The negative electrode connection end of the first rectifying unit is respectively connected to one end of the tenth resistor and the emitter of the second transistor;

[0030] The other end of the tenth resistor is connected to the base of the second transistor;

[0031] The base of the second triode is connected to the anode of the third voltage regulator tube and the source of the fourth MOS tube respectively;

[0032] The collector of the second triode is respectively connected to the gate of the fourth MOS tube, the cathode of the third voltage regulator tube, and one end of the seventh resistor;

[0033] The drain of the fourth MOS tube is connected to the cathode of the eleventh diode;

[0034] The eleventh diode, the tenth diode, and the twelfth diode are connected in series;

[0035] An anode of the twelfth diode is connected to the other end of the seventh resistor and is used to be connected to the discharge capacitor.

[0036] Optionally, the voltage conversion module includes: a second rectifier unit, a power chip, a first electrolytic capacitor, a first capacitor, a second capacitor, a first resistor, a second resistor, a second electrolytic capacitor, a third diode, a second diode, a first inductor, a third electrolytic capacitor, a third capacitor, a third resistor, a first voltage regulator tube, an eighth resistor, and a first light-emitting diode;

[0037] The first input end of the second rectifier unit is connected between the neutral line input end and the neutral line output end; the second input end of the second rectifier unit is connected to the live line input end; the neutral line output end is connected to the circuit board; the neutral line input end and the live line input end are respectively used to connect to the power supply;

[0038] The positive connection end of the second rectifier unit is respectively connected to the anode of the first electrolytic capacitor, one end of the first capacitor, and the fifth end of the power chip;

[0039] The seventh end and the eighth end of the power chip are connected, and are connected to the first end of the power chip, one end of the second capacitor, and one end of the first resistor; the second end of the power chip is connected to the first end of the power chip;

[0040] The other end of the second capacitor is connected to the third end of the power chip; the other end of the first resistor is connected to one end of the second resistor and the fourth end of the power chip respectively;

[0041] The other end of the second resistor is connected to the anode of the second electrolytic capacitor and the cathode of the third diode respectively; the anode of the third diode is connected to one end of the third resistor;

[0042] The cathode of the second electrolytic capacitor is respectively connected to the cathode of the second diode, one end of the first inductor, and the first end of the power chip;

[0043] The other end of the first inductor is respectively connected to the anode of the third electrolytic capacitor, one end of the third capacitor, one end of the third resistor, one end of the first voltage regulator tube, and one end of the eighth resistor; the other end of the eighth resistor is connected to the anode of the first light-emitting diode;

[0044] The cathode of the first electrolytic capacitor, the negative connection end of the second rectifier unit, the other end of the first capacitor, the anode of the second diode, the cathode of the third electrolytic capacitor, the other end of the third capacitor, the other end of the third resistor, the other end of the first voltage regulator, and the cathode of the first light-emitting diode are grounded; wherein one end of the third resistor serves as the output end of the voltage conversion module.

[0045] Optionally, the first switching module includes: a second relay, a ninth resistor, a second light emitting diode, a first triode, a second voltage regulator tube, a fourth electrolytic capacitor, a fifth resistor, and a sixth diode;

[0046] The output end of the voltage conversion module is respectively connected to one end of the coil of the second relay, the cathode of the sixth diode, and one end of the fifth resistor;

[0047] The anode of the sixth diode is connected to the other end of the coil of the second relay and the collector of the first transistor respectively;

[0048] The other end of the fifth resistor is connected to the cathode of the second voltage regulator tube and the anode of the fourth electrolytic capacitor respectively;

[0049] The anode of the second voltage regulator tube is connected to the base of the first triode;

[0050] The cathode of the fourth electrolytic capacitor and the emitter of the first transistor are grounded;

[0051] The moving contact of the second relay is connected to the ninth resistor; the ninth resistor is connected in series with the second light emitting diode;

[0052] The static contact of the second relay is connected to the live wire input terminal;

[0053] The cathode of the second light emitting diode is connected to the neutral line input terminal;

[0054] A live wire output terminal is provided at the connection point between the moving contact of the second relay and the ninth resistor, and the live wire output terminal is connected to the circuit board.

[0055] Optionally, the first discharge branch further includes an eleventh resistor and a third light emitting diode;

[0056] One end of the eleventh resistor is connected to one end of the twelfth resistor and the anode of the thirteenth diode respectively;

[0057] The other end of the eleventh resistor is connected to the anode of the third light emitting diode;

[0058] The cathode of the third light emitting diode is connected to the drain of the fifth MOS tube and the cathode of the fifteenth diode respectively.

[0059] Optionally, the second discharge branch further includes a sixth resistor and a fourth light emitting diode;

[0060] One end of the sixth resistor is connected to the anode of the twelfth diode;

[0061] The other end of the sixth resistor is connected to the anode of the fourth light emitting diode;

[0062] The cathode of the fourth light emitting diode is connected to the cathode of the eleventh diode.

[0063] Another aspect of the present invention provides an electronic device, the device comprising the circuit as described above.

[0064] It can be seen from the above technical solutions that the present invention has the following advantages:

[0065] The present invention provides an automatic lossless discharge circuit, comprising: a voltage conversion module, a first switching module, at least one second switching module and at least one discharge module; the input end of the voltage conversion module is used to connect to a power supply; the output end of the voltage conversion module is respectively connected to the first switching module and the second switching module, and is used to convert the voltage of the power supply into a target voltage when the power supply is connected; the first switching module is arranged in a connection path between the power supply and a circuit board, and is used to connect the loop between the power supply and the circuit board when the target voltage is received, and is used to disconnect the loop between the power supply and the circuit board when the target voltage is not received; the second switching module is connected to the discharge module, and is used to connect a discharge capacitor, and is used to disconnect the loop between the discharge module and the discharge capacitor when the target voltage is received, and is used to connect the loop between the discharge module and the discharge capacitor when the target voltage is not received.

[0066] In the present invention, when the power supply is connected, the voltage conversion module converts the voltage of the power supply into the target voltage, so that the first switching module and the second switching module are powered, so that the first switching module conducts the loop between the power supply and the circuit board, the power supply provides electrical energy for the operation of the circuit board, and at the same time, the second switching module disconnects the connection between the discharge capacitor and the discharge module, thereby avoiding the discharge module from being connected to the main circuit of the circuit board, reducing the power consumption of the circuit board; and when the power supply is not connected, the second switching module loses power, so that the discharge module is connected to the discharge capacitor, and the discharge capacitor discharges to the discharge module, achieving lossless discharge. In addition, in the present invention, multiple capacitors can be discharged at the same time through the second switching module and the discharge module, thereby improving the discharge efficiency.

[0067] Therefore, the automatic lossless discharge circuit provided by the present invention solves the technical problems in the prior art that the capacitor discharge efficiency is low and automatic lossless discharge cannot be achieved. After testing, the automatic lossless discharge circuit of the present invention can discharge a 1000μF capacitor to a safe voltage (<4V) within 10 seconds, and the discharge efficiency is improved by 50%. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0069] Figure 1 A schematic structural diagram of an automatic lossless discharge circuit provided in an embodiment of the present invention.

[0070] Figure 2 Another structural schematic diagram of an automatic lossless discharge circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0071] In the prior art, when the capacitor set on the circuit board is a high-voltage capacitor, the residual voltage is also high, which may cause electric shock to the human body and cause safety accidents of varying degrees. For example, in the design of digital power amplifier circuits, in order to ensure the stability of the power supply and the volume of the capacitor can adapt to the volume of the whole machine, the power supply circuit is often separated from the power amplifier circuit, and each has a high-voltage and large-capacity capacitor. In this design, when testing the circuit board online, the capacitors of both circuit boards need to be discharged. If the operator misses one, when testing the next board and connecting the wiring at both ends of the capacitor, it often causes sparks or explosions at the wiring terminals and other safety incidents. For large capacitors, it takes a long time for operators to discharge them using a discharger, and discharging them one by one is more time-consuming and has low discharge efficiency.

[0072] The embodiments of the present invention provide an automatic lossless discharge circuit and an electronic device, which are used to improve the discharge efficiency of a capacitor and achieve automatic lossless discharge.

[0073] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below 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.

[0074] See also Figure 1 The present invention provides an automatic lossless discharge circuit, comprising: a voltage conversion module 1, a first switching module 2, at least one second switching module 3 and at least one discharge module 4; the input end of the voltage conversion module 1 is used to connect to a power supply; the output end of the voltage conversion module 1 is respectively connected to the first switching module 2 and the second switching module 3, and is used to convert the voltage of the power supply into a target voltage when the power supply is connected; the first switching module 2 is arranged in a connection path between the power supply and the circuit board, and is used to connect the circuit between the power supply and the circuit board when the target voltage is received, and is used to disconnect the circuit between the power supply and the circuit board when the target voltage is not received; the second switching module 3 is connected to the discharge module 4, and is used to connect the discharge capacitor 5, and is used to disconnect the circuit between the discharge module 4 and the discharge capacitor 5 when the target voltage is received, and is used to connect the circuit between the discharge module 4 and the discharge capacitor 5 when the target voltage is not received.

[0075] It should be noted that the circuit board is provided with a power port for connecting to a power source. The discharge capacitor 5 is provided on the circuit board and refers to a capacitor with a discharge requirement, such as a high-voltage and large-capacity capacitor provided in the aforementioned digital power amplifier circuit.

[0076] The power supply may be a mains power supply. Taking the mains power supply as an example, the mains power supply has a neutral terminal and a live terminal, and the circuit board is provided with corresponding ports connected to the live terminal and the neutral terminal of the mains power supply. Figure 1 As shown, IN1 and IN2 are the neutral line input terminal and the live line input terminal, respectively, for connecting the 220V neutral line N and the 220V live line L, respectively, and OUT1 and OUT2 are the neutral line output terminal and the live line output terminal, respectively connected to the circuit board. It can be understood that OUT1 and OUT2 are ports in the circuit board for connecting to the power supply. When the power supply is connected, the power is input from IN1 and IN2, and output from OUT1 and OUT2 to the circuit board.

[0077] In this embodiment, the input end of the voltage conversion module 1 is connected to the neutral line input end and the live line input end, respectively, so as to be connected to the power supply through the neutral line input end and the live line input end. The output end of the voltage conversion module 1 is connected to the first switching module 2 and the second switching module 3, respectively, to supply power to the first switching module 2 and the second switching module 3. When the power supply is connected, the voltage conversion module 1 converts the power supply voltage into the target voltage, and transmits the target voltage to the first switching module 2 and the second switching module 3, respectively. When the power supply is not connected, the voltage module loses power, does not output voltage, and the first switching module 2 and the second switching module 3 lose power.

[0078] The two ends of the first switching module 2 are respectively connected to the neutral line input end and the live line input end, and the other two ends are respectively connected to the output end of the power conversion module and the live line output end. Therefore, in this embodiment, the first switching module 2 is arranged on the live line path between the power supply and the circuit board, and is used to control the conduction and disconnection of the live line path. Among them, the first switching module 2 has an on state and an off state. When it is powered on, it is in the on state, and when it is powered off, it is in the off state. When the first switching module 2 is in the on state, the live line path between the power supply and the circuit board is in the on state, and the power supply can normally provide electrical energy to the circuit board. When the first switching module 2 is in the off state, the live line path between the power supply and the circuit board is disconnected, and the circuit board loses power supply.

[0079] The second switching module 3 is connected to the voltage conversion module 1 and the discharge module 4, and is used to connect the discharge capacitor 5. Among them, the second switching module 3 has two states, namely the first state and the second state. When the target voltage output by the voltage conversion module 1 is received, the second switching module 3 is powered on and is in the first state; when the power supply is not connected, the second switching module 3 is powered off and is in the second state. Among them, when the second switching module 3 is in the first state, the loop from the discharge capacitor 5 to the second switching module 3 to the discharge module 4 is in a disconnected state, that is, no conductive path is established between the discharge capacitor 5 and the discharge module 4. When the second switching module 3 is in the second state, the loop from the discharge capacitor 5 to the second switching module 3 to the discharge module 4 is in a conductive state, and a conductive path is established between the discharge capacitor 5 and the discharge module 4, so that the discharge capacitor 5 can discharge to the discharge module 4.

[0080] The working principle of this embodiment is as follows: when the power supply is connected to the neutral input terminal IN1 and the live input terminal IN2, the voltage conversion module 1 converts the AC power supply voltage into the target voltage, and outputs the target voltage to the first switching module 2 and the second switching module 3. Among them, the first switching module 2 is electrically conductive, so that the live path between the power supply and the circuit board is conductive (that is, the loop between IN2 to the first switching module 2 to OUT2 is conductive), and the power supply provides electrical energy to the circuit board through the neutral output terminal OUT1 and the live output terminal OUT2. At this time, the second switching module 3 is in the first state, and the discharge capacitor 5 is disconnected from the discharge module 4, so that the discharge module 4 is not connected to the main circuit, and the power consumption of the circuit board is not increased, thereby reducing the power consumption of the circuit board.

[0081] When the power supply is not connected, the voltage conversion module 1 loses power, thereby causing the first switching module 2 and the second switching module 3 to lose power, disconnecting the power supply from the circuit board, and the discharge capacitor 5 is connected to the discharge module 4, and the discharge capacitor 5 discharges to the discharge module 4 to achieve automatic discharge. Therefore, the circuit provided in this embodiment can achieve automatic lossless discharge according to whether the power supply is connected or not, and the operation is simple.

[0082] Moreover, in the present embodiment, the second switching module 3 and the discharge module 4 are connected in one-to-one correspondence, and the number of the two can be set according to the actual discharge demand. For example: the number of the second switching modules 3 can be more than two, and the number of the discharge modules 4 can be more than two, each second switching module 3 is respectively connected to the output end of the voltage conversion module 1, and is connected to the discharge module 4 in one-to-one correspondence, and each discharge module 4 can be connected to two discharge capacitors 5. When the mains power supply is connected to the voltage conversion module 1, the voltage conversion module 1 converts the mains power supply voltage into a target voltage, and transmits the target voltage to the first switching module 2 and each second switching module 3. Each second switching module 3 is powered and is in the first state, so that each discharge module 4 discharges the discharge capacitor 5 connected thereto. Therefore, according to the actual discharge demand, a corresponding number of second switching modules 3 and discharge modules 4 can be set, and multiple capacitors can be discharged at the same time to improve the discharge efficiency.

[0083] Based on the above, the automatic lossless discharge circuit provided in this embodiment solves the technical problems in the prior art that the capacitor discharge efficiency is low and automatic lossless discharge cannot be achieved.

[0084] In a specific embodiment, Figure 1 As shown, a fuse F1 is provided between IN1 and the voltage conversion module 1 to improve the safety of the circuit.

[0085] In a specific embodiment, the number of the discharge capacitor is at least one.

[0086] It should be noted that each discharge module is provided with two discharge branches, which can discharge two discharge capacitors at the same time or discharge one discharge capacitor. Therefore, the second switching module can be connected to two discharge capacitors respectively. When the second switching module loses power, the two discharge capacitors are connected to the two discharge branches of the discharge module respectively for discharge, thereby further improving the discharge efficiency.

[0087] In a specific embodiment, Figure 2 As shown, the second switching module includes: a first relay JK1 and a seventh diode D7;

[0088] The two ends of the coil of the first relay JK1 are connected to the output end of the voltage conversion module and the ground respectively; the seventh diode D7 is connected in parallel to the two ends of the coil of the first relay JK1;

[0089] The moving contact of the first relay JK1 is used to be connected to one end of the discharge capacitor;

[0090] The first static contact of the first relay JK1 is connected to one end of the discharge module; the second static contact of the first relay JK1 is left empty;

[0091] The other end of the discharge module is used to connect to the other end of the discharge capacitor.

[0092] It should be noted that, when the power is off, one end of the moving contact of the first relay JK1 is connected to the first static contact. When the power is on, one end of the moving contact of the first relay JK1 is connected to the second static contact.

[0093] The working principle of this embodiment is: when the second switching module is connected to two discharge capacitors, if the second switching module loses power, the coil of the first relay JK1 loses power, and the moving contact of the first relay JK1 is connected to the first static contact, so that the discharge module establishes a conductive connection with the two discharge capacitors, and then the two discharge capacitors are correspondingly connected to the two discharge branches in the discharge module, and the discharge operation is performed simultaneously. When the second switching module is powered, the coil of the first relay JK1 is powered, so that the moving contact of the first relay JK1 is connected to the second static contact. Since the second static contact is empty, the two discharge capacitors are disconnected from the discharge module.

[0094] In an example, the first relay JK1 may be a double-pole double-throw relay, which is provided with two moving contacts and can be connected to two discharge capacitors respectively.

[0095] In a specific embodiment, the moving contact of the first relay JK1 includes a first moving contact and a second moving contact;

[0096] The discharge module includes a first rectifier unit D8, a first discharge branch, and a second discharge branch;

[0097] The AC connection end of the first rectifier unit D8 is connected to the first static contact through a fourteenth resistor R14;

[0098] The positive electrode connection end of the first rectifier unit D8 is connected to the input end of the first discharge branch;

[0099] The negative electrode connection end of the first rectifier unit D8 is connected to the output end of the second discharge branch;

[0100] The first moving contact and the output end of the first discharge branch are used to connect two ends of at least one of the discharge capacitors;

[0101] The second moving contact and the input end of the second discharge branch are respectively used to connect two ends of at least one of the discharge capacitors.

[0102] It should be noted that the first rectifier unit D8 is provided with two AC connection terminals, namely the first AC connection terminal and the second AC connection terminal. Both ends of the first static contact are respectively provided with two connection ports, the two connection ports at one end are respectively connected to the two AC connection terminals of the first rectifier unit D8, and the two connection ports at the other end are respectively used to connect to one end of the first moving contact and one end of the second moving contact.

[0103] In this embodiment, there are two discharge capacitors, namely, a first discharge capacitor and a second discharge capacitor. The positive electrode of the first discharge capacitor is connected to the other end F1 of the first movable contact, and the negative electrode is connected to the output end (i.e., the COM end) of the first discharge branch; the positive electrode of the second discharge capacitor is connected to the input end (i.e., the COM end) of the second discharge branch, and the negative electrode is connected to the other end F2 of the second movable contact.

[0104] Therefore, this embodiment can constitute two discharge circuits. Among them, one discharge circuit is: the positive electrode of the first discharge capacitor-the first moving contact-the first static contact-the fourteenth resistor R14-the first AC connection end of the first rectifier unit D8-the positive connection end of the first rectifier unit D8-the first discharge branch-the negative electrode of the first discharge capacitor. The other discharge circuit is: the positive electrode of the second discharge capacitor-the second discharge branch-the negative connection end of the first rectifier unit D8-the second AC connection end of the first rectifier unit D8-the fourteenth resistor R14-the first static contact-the second moving contact-the negative electrode of the second discharge capacitor.

[0105] In another embodiment, the discharge capacitors connected to the first discharge branch and the second discharge branch may also be the same discharge capacitors, and the number of the capacitors may be one or more.

[0106] For example, when the same discharge capacitor is connected, the first discharge branch and the second discharge branch are connected respectively according to the polarity of the discharge capacitor, so that the two discharge branches discharge one discharge capacitor; or any discharge branch is selected to be connected to the discharge capacitor, so that one discharge branch discharges one capacitor.

[0107] For example: when multiple discharge capacitors are connected, the multiple discharge capacitors are connected in parallel or in series to form a capacitor group, and are connected to one of the discharge branches according to the polarity of the capacitor group, so that one discharge branch discharges the capacitor group composed of multiple discharge capacitors, or the capacitor group can be connected to two discharge branches at the same time, and two discharge branches are used to discharge the same capacitor group, or multiple capacitors are divided into two capacitor groups, which are respectively connected to two discharge branches, so that the two discharge branches discharge the two capacitor groups respectively.

[0108] In a specific embodiment, Figure 2As shown, the first discharge branch includes: a thirteenth diode D13, a fourteenth diode D14, a fifteenth diode D15, a twelfth resistor R12, a third triode Q3, a fifth MOS transistor Q5, a fourth voltage regulator DZ4, and a thirteenth resistor R13;

[0109] The positive connection end of the first rectifier unit D8 is respectively connected to the anode of the thirteenth diode D13 and one end of the twelfth resistor R12;

[0110] The thirteenth diode D13, the fourteenth diode D14, and the fifteenth diode D15 are connected in series;

[0111] The cathode of the fifteenth diode D15 is connected to the drain of the fifth MOS transistor Q5;

[0112] The other end of the twelfth resistor R12 is connected to the collector of the third triode Q3, the gate of the fifth MOS tube Q5, and the cathode of the fourth voltage regulator tube DZ4;

[0113] One end of the thirteenth resistor R13 is respectively connected to the anode of the fourth voltage-stabilizing tube DZ4, the base of the third triode Q3, and the source of the fifth MOS tube Q5;

[0114] The emitter of the third transistor Q3 is connected to the other end of the thirteenth resistor R13 and is used to be connected to the discharge capacitor.

[0115] It should be noted that the input end of the first discharge branch is one end of the twelfth resistor R12 and the anode of the thirteenth diode D13. The output end of the first discharge branch is the other end of the thirteenth resistor R13.

[0116] The thirteenth resistor R13 is used as a discharge resistor. In practical applications, the discharge current value can be adjusted by adjusting the resistance of the thirteenth resistor R13. The fourth voltage regulator DZ4 is used to prevent the voltage of the fifth MOS tube Q5 from being too large.

[0117] In this embodiment, when the fifth MOS transistor Q5 is turned on, the first discharge branch discharges the discharge capacitor connected thereto, and when the fifth MOS transistor Q5 is turned off, the first discharge branch stops discharging.

[0118] In a specific embodiment, the second discharge branch includes: a tenth resistor R10, a second triode Q2, a third voltage regulator DZ3, a fourth MOS transistor Q4, a seventh resistor R7, a twelfth diode D12, a tenth diode D10, and an eleventh diode D11;

[0119] The cathode connection end of the first rectifier unit D8 is respectively connected to one end of the tenth resistor R10 and the emitter of the second transistor Q2;

[0120] The other end of the tenth resistor R10 is connected to the base of the second transistor Q2;

[0121] The base of the second transistor Q2 is connected to the anode of the third voltage regulator tube DZ3 and the source of the fourth MOS tube Q4 respectively;

[0122] The collector of the second triode Q2 is respectively connected to the gate of the fourth MOS tube Q4, the cathode of the third voltage regulator tube DZ3, and one end of the seventh resistor R7;

[0123] The drain of the fourth MOS tube Q4 is connected to the cathode of the eleventh diode;

[0124] The eleventh diode D11, the tenth diode D10, and the twelfth diode D12 are connected in series;

[0125] An anode of the twelfth diode D12 is connected to the other end of the seventh resistor R7 and is used to be connected to the discharge capacitor.

[0126] It should be noted that the input end of the second discharge branch is the anode of the twelfth diode D12 and the other end of the seventh resistor R7. The output end of the second discharge branch is one end of the tenth resistor R10 and the emitter of the second triode Q2. The tenth resistor R10 is used as a discharge resistor. In practical applications, the discharge current value can be adjusted by adjusting the resistance value of the tenth resistor R10. The third voltage regulator DZ3 is used to prevent the voltage of the fourth MOS tube Q4 from being too large.

[0127] In this embodiment, when the fourth MOS transistor Q4 is turned on, the second discharge branch discharges the discharge capacitor connected thereto, and when the fourth MOS transistor Q4 is turned off, the second discharge branch stops discharging.

[0128] In a specific embodiment, the first discharge branch further includes an eleventh resistor R11 and a third light emitting diode D17;

[0129] One end of the eleventh resistor R11 is respectively connected to one end of the twelfth resistor R12 and the anode of the thirteenth diode D13;

[0130] The other end of the eleventh resistor R11 is connected to the anode of the third light emitting diode D17;

[0131] The cathode of the third light emitting diode D17 is connected to the drain of the fifth MOS transistor Q5 and the cathode of the fifteenth diode D15 respectively.

[0132] It should be noted that the third light-emitting diode D17 is used to indicate the state of the discharge branch. When the third light-emitting diode D17 is in a light-emitting state, it indicates that the first discharge branch is discharging, and when the third light-emitting diode D17 is in an extinguished state, it indicates that the first discharge branch has been discharged, indicating that the voltage of the discharge capacitor is within a safe voltage range.

[0133] In a specific embodiment, the second discharge branch further includes a sixth resistor R6 and a fourth light emitting diode D16;

[0134] One end of the sixth resistor R6 is connected to the anode of the twelfth diode D12;

[0135] The other end of the sixth resistor R6 is connected to the anode of the fourth light emitting diode D16;

[0136] A cathode of the fourth light emitting diode D16 is connected to a cathode of the eleventh diode D11 .

[0137] It should be noted that the fourth light-emitting diode D16 is used to indicate the state of the discharge branch. When the fourth light-emitting diode D16 is in a light-emitting state, it indicates that the second discharge branch is discharging, and when the fourth light-emitting diode D16 is in an extinguished state, it indicates that the second discharge branch has been discharged, indicating that the voltage of the discharge capacitor is within a safe voltage range.

[0138] In a specific embodiment, the other end of the thirteenth resistor R13 of the first discharge branch (i.e., the output end of the first discharge branch), the anode of the twelfth diode D12 of the second discharge branch, the other end of the seventh resistor R7, and one end of the sixth resistor R6 (i.e., the input end of the second discharge branch) can also be connected to form a common end, thereby saving space resources.

[0139] like Figure 2 As shown, the output end of the first discharge branch is connected to the input end of the second discharge branch to form a common end COM, wherein the COM end can be used to connect two or a group of discharge capacitors with opposite polarities. In the circuit structure of this embodiment, the first discharge branch and the second discharge branch are connected to different discharge capacitors, and the polarities of the connected discharge capacitors are also different.

[0140] Taking the example that the first discharge branch and the second discharge branch are respectively connected to a discharge capacitor, the positive electrode of the first discharge capacitor is connected to the other end F1 of the first moving contact, and the negative electrode of the first discharge capacitor is connected to the output end (i.e. COM) of the first discharge branch. The positive electrode of the second discharge capacitor is connected to the input end (i.e. COM) of the second discharge branch, and the negative electrode of the second discharge capacitor is connected to the other end F2 of the second moving contact. The COM end is respectively connected to multiple branches, and a corresponding diode is set in each branch to prevent voltage backflow. Therefore, the first discharge branch and the second discharge branch can be discharged with the discharge capacitor connected with the correct polarity.

[0141] Understandably, Figure 2 Only the case where the first discharge branch and the second discharge branch share the port COM is shown.

[0142] In a specific embodiment, the voltage conversion module includes: a second rectifier unit D1, a power chip U1, a first electrolytic capacitor E1, a first capacitor C1, a second capacitor C2, a first resistor R1, a second resistor R2, a second electrolytic capacitor E2, a third diode D3, a second diode D2, a first inductor, a third electrolytic capacitor E3, a third capacitor C3, a third resistor R3, a first voltage regulator tube DZ1, an eighth resistor R8, and a first light-emitting diode D18;

[0143] The first input end of the second rectifier unit D1 is connected between the neutral line input end and the neutral line output end; the second input end of the second rectifier unit D1 is connected to the live line input end; the neutral line output end is connected to the circuit board; the neutral line input end and the live line input end are respectively used to connect to the power supply;

[0144] The positive connection end of the second rectifier unit D1 is respectively connected to the anode of the first electrolytic capacitor E1, one end of the first capacitor C1, and the fifth end of the power chip U1;

[0145] The seventh end and the eighth end of the power chip U1 are connected, and are connected to the first end of the power chip U1, one end of the second capacitor C2, and one end of the first resistor R1; the second end of the power chip U1 is connected to the first end of the power chip U1;

[0146] The other end of the second capacitor C2 is connected to the third end of the power chip U1; the other end of the first resistor R1 is connected to one end of the second resistor R2 and the fourth end of the power chip U1 respectively;

[0147] The other end of the second resistor R2 is connected to the anode of the second electrolytic capacitor E2 and the cathode of the third diode D3 respectively; the anode of the third diode D3 is connected to one end of the third resistor R3;

[0148] The cathode of the second electrolytic capacitor E2 is respectively connected to the cathode of the second diode D2, one end of the first inductor, and the first end of the power chip U1;

[0149] The other end of the first inductor is respectively connected to the anode of the third electrolytic capacitor E3, one end of the third capacitor C3, one end of the third resistor R3, one end of the first voltage regulator DZ1, and one end of the eighth resistor R8; the other end of the eighth resistor R8 is connected to the anode of the first light-emitting diode D18;

[0150] The cathode of the first electrolytic capacitor E1, the negative connection end of the second rectifier unit D1, the other end of the first capacitor C1, the anode of the second diode D2, the cathode of the third electrolytic capacitor E3, the other end of the third capacitor C3, the other end of the third resistor R3, the other end of the first voltage regulator DZ1, and the cathode of the first light-emitting diode D18 are grounded; wherein one end of the third resistor R3 serves as the output end of the voltage conversion module.

[0151] It should be noted that the second rectifier unit D1 is provided with two AC input terminals, a positive connection terminal and a negative input output terminal. The two AC input terminals are used as input terminals of the voltage conversion module, and are respectively connected to the neutral line input terminal and the live line input terminal. The other end of the third resistor R3 is the output terminal of the voltage conversion module, which is used to output the target voltage.

[0152] In this embodiment, the second rectifier unit D1 is used to convert the AC power supply from AC to DC and output it to the power chip U1. The power chip U1 and its peripheral components are used to convert the voltage of the received DC power into a target voltage and stably output the target voltage to the first switching module and the second switching module. In addition, the target voltage output by the power chip U1 passes through the eighth resistor R8 and the first light-emitting diode D18, so that the first light-emitting diode D18 is powered and emits light, and when the power supply is not connected or the power supply is turned off, the power chip U1 loses power, causing the first light-emitting diode D18 to lose power and extinguish. Therefore, the first light-emitting diode D18 can be used to indicate the connected state and disconnected state of the power supply.

[0153] In a specific embodiment, the first switching module includes: a second relay JK2, a ninth resistor R9, a second light emitting diode D19, a first transistor Q1, a second voltage regulator DZ2, a fourth electrolytic capacitor E4, a fifth resistor R5, and a sixth diode D6;

[0154] The output end of the voltage conversion module is respectively connected to one end of the coil of the second relay JK2, the cathode of the sixth diode D6, and one end of the fifth resistor R5;

[0155] The anode of the sixth diode D6 is connected to the other end of the coil of the second relay JK2 and the collector of the first transistor Q1 respectively;

[0156] The other end of the fifth resistor R5 is connected to the cathode of the second voltage regulator tube DZ2 and the anode of the fourth electrolytic capacitor E4 respectively;

[0157] The anode of the second voltage regulator tube DZ2 is connected to the base of the first transistor Q1;

[0158] The cathode of the fourth electrolytic capacitor E4 and the emitter of the first transistor Q1 are grounded;

[0159] The moving contact of the second relay JK2 is connected to the ninth resistor R9; the ninth resistor R9 is connected in series with the second light emitting diode D19;

[0160] The static contact of the second relay JK2 is connected to the live wire input terminal;

[0161] The cathode of the second light emitting diode D19 is connected to the neutral line input terminal;

[0162] A live wire output terminal is provided at the connection between the moving contact of the second relay JK2 and the ninth resistor R9, and the live wire output terminal is connected to the circuit board.

[0163] It should be noted that the second light-emitting diode D19 can be used to indicate the on-state or off-state of the live wire input terminal and the live wire output terminal. When the second light-emitting diode D19 is lit, it indicates that the path between the live wire input terminal and the live wire output terminal is on, and when the second light-emitting diode D19 is off, it indicates that the path between the live wire input terminal and the live wire output terminal is off.

[0164] The working principle of this embodiment is as follows: when the power supply is connected, the voltage conversion module is powered, and the power supply voltage is converted into the target voltage, and the target voltage is output. At this time, the coil of the second relay JK2 is powered. When the coil of the second relay JK2 is powered, the movable contact and the static contact of the second relay JK2 are triggered to be attracted, so that the circuit of the power supply-live line input end-static contact of the second relay JK2-moving contact of the second relay JK2-live line output end-circuit board is connected. At the same time, the access of the power supply also makes the circuit of the power supply-neutral line input end-neutral line output end-circuit board in a conducting state, and the second light-emitting diode D19 is powered and emits light. Therefore, when the power supply is connected, the power supply supplies power to the circuit board. When the power supply is not connected or turned off, the coil of the second relay JK2 loses power, and the movable contact of the second relay JK2 is disconnected from the static contact, thereby disconnecting the circuit where the live line output end is located, and the second light-emitting diode D19 loses power and extinguishes.

[0165] Therefore, in the circuit provided in this embodiment, the first light-emitting diode D18 and the second light-emitting diode D19 can indicate the status of the power supply and the status of the path between the live wire input terminal and the live wire output terminal, so that when a fault occurs, the cause of the fault can be quickly found out, and the power supply status can be clearly and intuitively displayed, so that the operating personnel can clearly understand the status of the circuit, which is convenient for the operating personnel to carry out testing work.

[0166] In a specific embodiment, the first rectifying unit D8 and the second rectifying unit D1 may adopt MB10S chips.

[0167] In a specific embodiment, the power chip U1 may be a LNK306P chip.

[0168] In a specific embodiment, the fourth MOS transistor Q4 and the fifth MOS transistor Q5 may be MOS transistors of model IRFP250.

[0169] In a specific embodiment, the first transistor Q1 to the third transistor Q3 may be 5551 transistors.

[0170] In a specific embodiment, the first relay JK1 may be a relay of model HK19F-DC-12V.

[0171] The working principle of the automatic lossless discharge circuit provided by the present invention will be described below with reference to examples.

[0172] Assume that the connected power supply is a 220V mains power supply, the target voltage is +12V, the second switching module and the discharge module are both set to one, and each discharge branch is connected to a discharge capacitor, and the first discharge branch and the second discharge branch share the port COM. The two discharge capacitors are divided into a first discharge capacitor and a second discharge capacitor. The first discharge capacitor is connected to the first discharge branch, and the second discharge capacitor is connected to the second discharge branch.

[0173] Before connecting to the power supply, connect OUT1 and OUT2 to the circuit board, and connect the ports F1 and F2 of the two moving contacts of the second relay, as well as COM, to the two discharge capacitors provided in the circuit board, respectively. The positive electrode of the first discharge capacitor is connected to the other end F1 of the first moving contact, and the negative electrode of the first discharge capacitor is connected to the output end (i.e., COM) of the first discharge branch. The positive electrode of the second discharge capacitor is connected to the input end (i.e., COM) of the second discharge branch, and the negative electrode of the second discharge capacitor is connected to the other end F2 of the second moving contact.

[0174] like Figure 2As shown, when the city power 220V is connected, the 220V power supply is input to the second rectifier unit D1 through IN1 and IN2, and the second rectifier unit D1 outputs a voltage of about 310V. This voltage is input to the power chip U1 through the fifth terminal (i.e., pin 5) of the power chip U1. The power chip U1 and the surrounding components output a stable power supply of +12V. At this time, the first light-emitting diode D18 is powered and emits light, indicating that the 220V power supply is in a normal power supply state and can be output through the OUT1 and OUT2 terminals to power the circuit board. At the same time, the power supply is output from the neutral line input terminal 220V N to the OUT1 terminal.

[0175] When the voltage conversion module outputs a stable power supply of +12V, the contacts of the second relay JK2 are energized, and the live wire input terminal 220V L is connected to OUT2 through the contacts of the second relay JK2. At this time, the 220V power supply is output from the OUT1 and OUT2 terminals to the circuit board to power the circuit board.

[0176] At the same time, when the +12 power supply is normal, the contact of the first relay JK1 is closed, that is, the 6th terminal of the first relay JK1 is disconnected from the 7th terminal, the 3rd terminal is disconnected from the 2nd terminal, and the 6th terminal is connected to the 8th terminal, the 3rd terminal is connected to the 1st terminal, and the discharge module is disconnected from the discharge capacitor, so that the overall state of the discharge circuit changes from discharging the capacitor to a non-discharging state. At this time, the entire circuit board is in a normal working state, which is convenient for operators to test performance, functions, parameters, etc.

[0177] When the operator has finished testing the circuit board and turned off the 220V power supply, there is no voltage output between IN1, IN2 and the second rectifier unit D1 due to the lack of 220V power supply conditions. Therefore, the power chip U1 and surrounding components also have no +12V voltage output. At this time, the first light-emitting diode D18 is off, indicating that the power supply is in the disconnected state.

[0178] When the voltage conversion module has no +12V voltage output, the contacts of the second relay JK2 are not energized and are in the disconnected state, so that the live wire input terminal 220V L is disconnected from the OUT2 terminal. At this time, the OUT1 terminal and the OUT2 terminal stop supplying power to the power board.

[0179] At the same time, when there is no +12 voltage output, the contacts of the first relay JK1 are not energized, the 6th terminal and the 7th terminal of the first relay JK1 are connected, the 3rd terminal and the 2nd terminal are connected, the discharge module is connected to the discharge capacitor, and the overall operating state of the discharge circuit changes from not discharging the capacitor to discharging the capacitor, thereby discharging the discharge capacitor of the circuit board.

[0180] The discharge principle of the first discharge capacitor is as follows: the negative electrode of the first discharge capacitor is connected to the COM terminal, and the positive electrode is connected to the F1 terminal. When the first discharge capacitor is discharged, the electric energy of the positive electrode of the first discharge capacitor is input to the F1 terminal, and is input to the first AC connection terminal of the first rectifier unit D8 through the third terminal and the second terminal of the first relay JK1 and the fourteenth resistor R14, and is output from the positive electrode connection terminal of the first rectifier unit D8 after the rectification operation of the first rectifier unit D8, and reaches the fifth MOS tube Q5 through the twelfth resistor R12. The gate of the fifth MOS tube Q5 and the collector of the third triode Q3; because the source of the fifth MOS tube Q5 is only connected to the thirteenth resistor R13 with a smaller resistance, and is connected to the COM terminal and the negative electrode of the first discharge capacitor through the thirteenth resistor R13, the gate voltage of the fifth MOS tube Q5 is greater than the source, and the fifth MOS tube Q5 starts to work in the amplification state; at the same time, another current is output from the positive electrode connection end of the first rectifier unit D8, and flows to the fifth MO through the thirteenth diode D13, the fourteenth diode D14, and the fifteenth diode D15. The electric current flows to the drain of the S tube Q5, and then flows from the source of the fifth MOS tube Q5 to the thirteenth resistor R13, returns to the COM terminal, and flows to the negative electrode of the first discharge capacitor, that is, the positive electrode of the first discharge capacitor → F1 terminal → the third terminal of the first relay JK1 → the second terminal of the first relay JK1 → the fourteenth resistor R14 → the first AC connection terminal of the first rectifier unit D8 → the positive electrode connection terminal of the first rectifier unit D8 → the drain of the fifth MOS tube Q5 → the source of the fifth MOS tube Q5 → the thirteenth resistor R13 → the COM terminal → the first discharge capacitor. The negative electrode of the discharge capacitor forms a discharge loop; at this time, the voltage of the base and emitter of the third triode Q3 is less than 0.6V, the third triode Q3 is in the cut-off state, the gate voltage of the fifth MOS tube Q5 remains unchanged, and the circuit is still in the discharge state; when discharging, the thirteenth diode D13, the fourteenth diode D14, and the fifteenth diode D15 form a voltage drop of 3×0.7V=2.1V, and the third light-emitting diode D17 is lit through the eleventh resistor R11, indicating that there is still charge remaining in the first discharge capacitor. The fourth voltage regulator DZ4 in the circuit can not only prevent the gate voltage of the fifth MOS tube Q5 from being too high to avoid breakdown damage, but also stabilize the gate working voltage of the fifth MOS tube Q5 when the discharge capacitor voltage becomes smaller. Therefore, the first discharge branch can realize the discharge work of the discharge capacitor; when the voltage of the first discharge capacitor is less than 5V, the discharge current becomes smaller, and the brightness of the third light-emitting diode D17 gradually dims. When it is completely extinguished, it means that the residual voltage of the capacitor is less than 4V, and the capacitor voltage is in a safe voltage. At this time, the discharge circuit stops discharging, and the first discharge capacitor is completely discharged.

[0181] The discharge principle of the second discharge capacitor is as follows: the negative electrode of the second discharge capacitor is connected to the F2 terminal, and the positive electrode is connected to the COM terminal. When the second discharge capacitor is discharged, the electric energy of the positive electrode of the second discharge capacitor is input to the COM terminal, and reaches the collector of the second triode Q2 and the gate of the fourth MOS tube through the seventh resistor R7. Since the source of the fourth MOS tube Q4 is only connected to the tenth resistor R10 with a smaller resistance, and is connected to the first rectifier unit D8 and the negative electrode of the first discharge capacitor through the tenth resistor R10, the gate voltage of the fourth MOS tube Q4 is greater than the source voltage, and the fourth MOS tube Q4 starts to work in the amplification state; at the same time, another current flows from the COM terminal, through the twelfth diode D12, the tenth diode D10, and the eleventh diode D11, to the drain of the fourth MOS tube Q4, and then from the source of the fourth MOS tube Q4 to R10, to the negative electrode connection terminal of the first rectifier unit D8, and then from the second AC connection terminal of the first rectifier unit D8, through the fourteenth resistor R14, the 7th and 6th terminals of the first relay JK1, F2 terminal, flows to the negative electrode of the second discharge capacitor, that is, the positive electrode of the second discharge capacitor → COM terminal → the drain of the fourth MOS tube Q4 → the source of the fourth MOS tube Q4 → the tenth resistor R10 → the negative electrode connection terminal of the first rectifier unit D8 → the second AC connection terminal of the first rectifier unit D8 → the fourteenth resistor R14 → the seventh terminal of the first relay JK1 → the sixth terminal of the first relay JK1 → the F2 terminal → the negative electrode of the second discharge capacitor, forming a discharge loop; at this time, the base and emitter voltages of the second triode Q2 are less than 0.6V, the second triode Q2 is in the cut-off state, the gate voltage of the fourth MOS tube Q4 remains unchanged, and the circuit is still in the discharge state; when discharging, the twelfth diode D12, the tenth diode D10, and the eleventh diode D11, the three diodes form a voltage drop of 3×0.7V=2.1V, and the fourth light-emitting diode D16 is lit through the sixth resistor R6, indicating that there is still residual charge in the second discharge capacitor. The third voltage regulator tube DZ3 in the circuit can not only prevent the gate voltage of the fourth MOS tube Q4 from being too high and avoid breakdown damage, but also stabilize the gate working voltage of the fourth MOS tube Q4 when the discharge capacitor voltage becomes smaller. Therefore, the second discharge branch operates in the discharge state, and the second discharge capacitor is in the process of discharge. At this time, the fourth light-emitting diode D16 is on, indicating that the second discharge capacitor is in the process of discharge. When the voltage value of the second discharge capacitor is less than 5V, the discharge current becomes smaller, and the fourth light-emitting diode D16 gradually becomes darker. When it is completely extinguished, it means that the residual voltage of the second discharge capacitor is less than 4V, and the capacitor voltage is in a safe voltage. At this time, the discharge circuit cuts off the discharge, and the second discharge capacitor is discharged.

[0182] Therefore, when the indicator lights of the third light-emitting diode D17 and the fourth light-emitting diode D16 are both off, it means that the residual energy in the two capacitors has been discharged. After that, the operator can perform the next operation on the circuit board, such as picking up and placing, and transporting. After testing, the automatic lossless discharge circuit of the present invention can discharge a 1000μF capacitor to a safe voltage (<4V) within 10 seconds, and the discharge efficiency is improved by 50%.

[0183] The automatic lossless discharge circuit provided by the present invention can be built into the product circuit, or it can be independently used as a discharge tool for testing; it can also be applied in the automatic discharge scenarios of a single capacitor or multiple capacitors. When the automatic lossless discharge circuit provided by the present invention is built into the product, when the product is powered on, the discharge circuit is automatically disconnected, that is, it is not connected to the main circuit of the product, does not increase the power consumption and temperature of the whole machine, and does not interfere with other circuits.

[0184] It can be understood that the discharge module in the automatic lossless discharge circuit provided by the present invention is completely isolated from the main circuit in a non-working state, and no additional power consumption, noise or signal interference is introduced during the discharge process, thereby having lossless characteristics. Specifically:

[0185] (1) The first relay of the second switching module adopts a magnetic isolation relay, and the insulation withstand voltage between the coil and the contact is >2kV, ensuring that the discharge module is physically isolated from the main circuit. Therefore, when the power is connected, the discharge module can be physically isolated from the main circuit, and the impedance is >1MΩ.

[0186] (2) The power supply of the discharge module is provided by the residual power of the capacitor itself, and there is no direct connection with the power supply and ground wire of the main circuit, thereby avoiding common mode interference. Therefore, in the automatic lossless discharge circuit provided by the embodiment of the present invention, during the discharge process, the discharge module can work through an independent loop, without a common ground or common power supply path with the main circuit, thereby avoiding common mode interference.

[0187] (3) In the first discharge branch and the second discharge branch of the discharge module, the thirteenth diode D13 to the fifteenth diode D15, the eleventh diode D10 to the twelfth diode D12, the twelfth resistor R12 and the tenth resistor R10 are connected in series to form a low-pass filter network, which suppresses high-frequency noise (>100kHz) during the discharge process and achieves noise suppression. Therefore, the discharge action of the automatic lossless discharge circuit provided in the embodiment of the present invention has an impact of less than 1% on the signal integrity (such as ripple, noise) of the main circuit, and has a good noise suppression effect.

[0188] In an application example, the beneficial effects achieved by the automatic lossless discharge circuit provided by the present invention will be specifically described in combination with an experimental example.

[0189] Before testing, configure the test conditions. The test conditions include environmental conditions, test equipment, and test objects. Environmental conditions include temperature (such as 25±2℃) and humidity (such as 50%±5%). Test equipment includes oscilloscope, multimeter, and capacitance tester. The model of the test equipment can be selected according to the actual situation. Test objects include: 1) Discharge capacitor: 1000μF, 470μF, 2200μF (comparison of different capacities); 2) Power supply: 220V AC (simulated AC input); 3) Target voltage: +12V (voltage conversion module output); 4) Safety voltage threshold: safety voltage (such as <4V).

[0190] The test items set in this application example and the test data obtained are shown below.

[0191] 1. Discharge efficiency test

[0192] Test purpose: To verify the discharge speed of the circuit for capacitors of different capacities.

[0193] Test method: Charge the capacitor to the initial voltage (e.g. 100V), disconnect the power supply, and record the time required for the capacitor voltage to drop to a safe voltage (<4V). The discharge efficiency test data is shown in Table 1.

[0194] Table 1 Discharge efficiency test data

[0195]

[0196] According to Table 1, the automatic lossless discharge circuit provided by the present invention has a discharge time of ≤10 seconds for a 1000μF capacitor, and its efficiency is 50% higher than that of a traditional discharge method (such as resistor discharge). Moreover, the discharge time is linearly related to the capacitance, indicating that the automatic lossless discharge circuit provided by the present invention is suitable for capacitors of different capacities.

[0197] 2. Energy loss test

[0198] Test purpose: To verify whether the energy loss during the discharge process meets the "lossless" characteristic.

[0199] Test method: First, measure the energy stored in the capacitor before discharge; then, measure the remaining energy in the capacitor after discharge; finally, calculate the energy loss rate.

[0200] Among them, the energy stored in the capacitor before discharge is:

[0201]

[0202] The remaining energy of the capacitor after discharge is:

[0203]

[0204] The energy loss rate is:

[0205]

[0206] Where C is the capacitance value of the capacitor, is the initial voltage across the capacitor before discharge, is the residual voltage across the capacitor after discharge.

[0207] The energy loss test data is shown in Table 2.

[0208] Table 2 Energy loss test data

[0209]

[0210] According to Table 2, the energy loss rate of the automatic lossless discharge circuit provided by the present invention is <1%, which means that the automatic lossless discharge circuit provided by the present invention does not damage the capacitor during the discharge process and meets the "lossless" requirement.

[0211] 3. Automatic switching function test

[0212] Test purpose: To verify whether the discharge module starts automatically after power is disconnected.

[0213] The test method is as follows:

[0214] (1) When the power is connected, measure the path resistance between the discharge module and the capacitor (should be >1MΩ);

[0215] (2) After disconnecting the power supply, measure the path resistance between the discharge module and the capacitor (should be <1Ω).

[0216] Among them, the test data of the automatic switching function test is shown in Table 3.

[0217] Table 3 Automatic switching function test data

[0218]

[0219] It can be seen from Table 3 that the automatic lossless discharge circuit provided by the present invention can realize automatic conduction of the discharge circuit after the power is disconnected without manual intervention.

[0220] 4. Anti-interference test

[0221] 1. Main circuit noise test

[0222] Test purpose: To verify the effect of discharge process on main circuit noise

[0223] The test method is as follows:

[0224] (1) When the main circuit is operating normally, use an oscilloscope to measure the power supply ripple (peak value).

[0225] (2) Trigger the discharge operation and record the changes in the power supply ripple during the discharge period.

[0226] Among them, the main circuit noise test data is shown in Table 4.

[0227] Table 4 Main circuit noise test data

[0228]

[0229] According to Table 4, the discharge operation of the automatic lossless discharge circuit provided by the present invention has an impact of less than 5% on the main circuit noise, meeting the "lossless" requirement.

[0230] 2. Common mode interference test

[0231] Test purpose: To verify the isolation between the discharge module and the main circuit.

[0232] Test method: Apply 1kV common mode voltage between the discharge module and the main circuit and measure the leakage current.

[0233] Among them, the common mode interference test data is shown in Table 5.

[0234] Table 5 Common mode interference test data

[0235]

[0236] According to Table 5, the discharge module of the automatic lossless discharge circuit provided by the present invention has an isolation impedance of >1 GΩ from the main circuit, and there is no common-mode interference risk.

[0237] V. Comparative Experiment

[0238] Test purpose: To verify the advantages of the automatic lossless discharge circuit provided by the present invention.

[0239] Test method: (1) Compare the discharge time of the same capacitor (capacity of 1000μF, initial voltage of 100V) in the traditional resistor discharge and the circuit of the present invention. (2) Compare the energy loss rate.

[0240] The comparative experimental data obtained are shown in Table 6.

[0241] Table 6 Comparative experimental data

[0242]

[0243] According to Table 6, compared with the traditional resistance discharge circuit, the discharge efficiency of the automatic lossless discharge circuit provided by the present invention is increased by 50%, and the energy loss is reduced by more than 90%.

[0244] 6. Safety Testing

[0245] Test purpose: To verify that there are no safety hazards (such as overheating, sparks) during the discharge process.

[0246] Test method:

[0247] (1) Use an infrared thermal imager to monitor the temperature changes of key components of the discharge module (such as MOS tubes and resistors).

[0248] (2) Record whether there are any abnormal phenomena (such as sparks, noise) during the discharge process.

[0249] Among them, the safety test data is shown in Table 7.

[0250] Table 7 Safety test data

[0251]

[0252] According to Table 7, it can be seen that in the automatic lossless discharge circuit provided by the present invention, the temperature rise of the components during the discharge process is less than 10°C, no sparks or noise occur, and the safety standards are met.

[0253] The present invention also provides an electronic device, which includes the circuit described in the above embodiment.

[0254] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0255] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0256] It should also be noted that in the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present invention.

Claims

1. An automatic lossless discharge circuit, characterized in that: include: A voltage conversion module, a first switching module, at least one second switching module and at least one discharge module; The input end of the voltage conversion module is used to connect to a power source; The output end of the voltage conversion module is connected to the first switching module and the second switching module respectively, and is used to convert the voltage of the power supply into a target voltage when the power supply is connected; The first switching module is arranged in a connection path between the power supply and the circuit board, and is used to connect the circuit between the power supply and the circuit board when the target voltage is received, and is used to disconnect the circuit between the power supply and the circuit board when the target voltage is not received; The second switching module is connected to the discharge module, used to connect the discharge capacitor, and is used to disconnect the circuit between the discharge module and the discharge capacitor when the target voltage is received, and is used to connect the circuit between the discharge module and the discharge capacitor when the target voltage is not received.

2. The circuit according to claim 1, characterized in that The second switching module includes: a first relay and a seventh diode; The two ends of the coil of the first relay are respectively connected to the output end of the voltage conversion module and the ground; the seventh diode is connected in parallel to the two ends of the coil of the first relay; The moving contact of the first relay is used to be connected to one end of the discharge capacitor; The first static contact of the first relay is connected to one end of the discharge module; the second static contact of the first relay is left empty; The other end of the discharge module is used to connect to the other end of the discharge capacitor.

3. The circuit according to claim 2, characterized in that The number of the discharge capacitor is at least one; the moving contact of the first relay includes a first moving contact and a second moving contact; The discharge module includes a first rectifying unit, a first discharge branch, and a second discharge branch; The AC connection end of the first rectifier unit is connected to the first static contact through a fourteenth resistor; The positive electrode connection end of the first rectifying unit is connected to the input end of the first discharge branch; The negative electrode connection end of the first rectifying unit is connected to the output end of the second discharge branch; The first moving contact and the output end of the first discharge branch are used to connect two ends of at least one of the discharge capacitors; The second moving contact and the input end of the second discharge branch are respectively used to connect two ends of at least one of the discharge capacitors.

4. The circuit according to claim 3, characterized in that The first discharge branch includes: a thirteenth diode, a fourteenth diode, a fifteenth diode, a twelfth resistor, a third triode, a fifth MOS transistor, a fourth voltage regulator, and a thirteenth resistor; The positive electrode connection end of the first rectifying unit is respectively connected to the anode of the thirteenth diode and one end of the twelfth resistor; The thirteenth diode, the fourteenth diode, and the fifteenth diode are connected in series; The cathode of the fifteenth diode is connected to the drain of the fifth MOS tube; The other end of the twelfth resistor is connected to the collector of the third triode, the gate of the fifth MOS tube, and the cathode of the fourth voltage regulator tube; One end of the thirteenth resistor is respectively connected to the anode of the fourth voltage-stabilizing tube, the base of the third transistor, and the source of the fifth MOS tube; The emitter of the third transistor is connected to the other end of the thirteenth resistor and is used to be connected to the discharge capacitor.

5. The circuit according to claim 3, characterized in that The second discharge branch includes: a tenth resistor, a second triode, a third voltage regulator, a fourth MOS transistor, a seventh resistor, a twelfth diode, a tenth diode, and an eleventh diode; The negative electrode connection end of the first rectifying unit is respectively connected to one end of the tenth resistor and the emitter of the second transistor; The other end of the tenth resistor is connected to the base of the second transistor; The base of the second triode is connected to the anode of the third voltage regulator tube and the source of the fourth MOS tube respectively; The collector of the second triode is respectively connected to the gate of the fourth MOS tube, the cathode of the third voltage regulator tube, and one end of the seventh resistor; The drain of the fourth MOS tube is connected to the cathode of the eleventh diode; The eleventh diode, the tenth diode, and the twelfth diode are connected in series; An anode of the twelfth diode is connected to the other end of the seventh resistor and is used to be connected to the discharge capacitor.

6. The circuit according to claim 1, characterized in that The voltage conversion module includes: a second rectifier unit, a power chip, a first electrolytic capacitor, a first capacitor, a second capacitor, a first resistor, a second resistor, a second electrolytic capacitor, a third diode, a second diode, a first inductor, a third electrolytic capacitor, a third capacitor, a third resistor, a first voltage regulator tube, an eighth resistor, and a first light-emitting diode; The first input end of the second rectifier unit is connected between the neutral line input end and the neutral line output end; the second input end of the second rectifier unit is connected to the live line input end; the neutral line output end is connected to the circuit board; the neutral line input end and the live line input end are respectively used to connect to the power supply; The positive connection end of the second rectifier unit is respectively connected to the anode of the first electrolytic capacitor, one end of the first capacitor, and the fifth end of the power chip; The seventh end and the eighth end of the power chip are connected, and are connected to the first end of the power chip, one end of the second capacitor, and one end of the first resistor; the second end of the power chip is connected to the first end of the power chip; The other end of the second capacitor is connected to the third end of the power chip; the other end of the first resistor is connected to one end of the second resistor and the fourth end of the power chip respectively; The other end of the second resistor is connected to the anode of the second electrolytic capacitor and the cathode of the third diode respectively; the anode of the third diode is connected to one end of the third resistor; The cathode of the second electrolytic capacitor is respectively connected to the cathode of the second diode, one end of the first inductor, and the first end of the power chip; The other end of the first inductor is respectively connected to the anode of the third electrolytic capacitor, one end of the third capacitor, one end of the third resistor, one end of the first voltage regulator tube, and one end of the eighth resistor; the other end of the eighth resistor is connected to the anode of the first light-emitting diode; The cathode of the first electrolytic capacitor, the negative connection end of the second rectifier unit, the other end of the first capacitor, the anode of the second diode, the cathode of the third electrolytic capacitor, the other end of the third capacitor, the other end of the third resistor, the other end of the first voltage regulator, and the cathode of the first light-emitting diode are grounded; wherein one end of the third resistor serves as the output end of the voltage conversion module.

7. The circuit according to claim 6, characterized in that The first switching module includes: a second relay, a ninth resistor, a second light emitting diode, a first triode, a second voltage regulator, a fourth electrolytic capacitor, a fifth resistor, and a sixth diode; The output end of the voltage conversion module is respectively connected to one end of the coil of the second relay, the cathode of the sixth diode, and one end of the fifth resistor; The anode of the sixth diode is connected to the other end of the coil of the second relay and the collector of the first transistor respectively; The other end of the fifth resistor is connected to the cathode of the second voltage regulator tube and the anode of the fourth electrolytic capacitor respectively; The anode of the second voltage regulator tube is connected to the base of the first triode; The cathode of the fourth electrolytic capacitor and the emitter of the first transistor are grounded; The moving contact of the second relay is connected to the ninth resistor; the ninth resistor is connected in series with the second light emitting diode; The static contact of the second relay is connected to the live wire input terminal; The cathode of the second light emitting diode is connected to the neutral line input terminal; A live wire output terminal is provided at the connection point between the moving contact of the second relay and the ninth resistor, and the live wire output terminal is connected to the circuit board.

8. The circuit according to claim 4, characterized in that The first discharge branch further includes an eleventh resistor and a third light emitting diode; One end of the eleventh resistor is connected to one end of the twelfth resistor and the anode of the thirteenth diode respectively; The other end of the eleventh resistor is connected to the anode of the third light emitting diode; The cathode of the third light emitting diode is connected to the drain of the fifth MOS tube and the cathode of the fifteenth diode respectively.

9. The circuit according to claim 5, characterized in that The second discharge branch further includes a sixth resistor and a fourth light emitting diode; One end of the sixth resistor is connected to the anode of the twelfth diode; The other end of the sixth resistor is connected to the anode of the fourth light emitting diode; The cathode of the fourth light emitting diode is connected to the cathode of the eleventh diode.

10. An electronic device, characterized in that: The device comprises a circuit as claimed in any one of claims 1-9.

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