A constant power load circuit, a welding power supply circuit, and an electronic device

Abstract

The application discloses a constant power load circuit, a welding power supply circuit and an electronic device. The constant power load circuit comprises a first power supply connection end, a second power supply connection end, a current sampling circuit, a control circuit and a switching circuit. The first power supply connection end and the second power supply connection end receive a first power supply and provide the first power supply to a load. The current sampling circuit receives a current signal sent by the first power supply connection end. The control circuit receives the current signal sent by the current sampling circuit, compares the current signal with a preset reference current, generates a control signal based on a current comparison result, and receives the current signal and the control signal. The switching circuit changes its conduction state under the action of the control signal, adjusts the current signal, and sends the adjusted current signal to the first power supply connection end. The constant power load circuit in the application has small invalid power consumption, and can effectively avoid the safety risk of an excessively large no-load voltage to a worker.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power regulation, and in particular to a constant power load circuit, a welding power supply circuit and an electronic device. BACKGROUND

[0002] Nowadays, with the increasing variety of electronic products, the working modes of the power loads in the electronic products during use are also increasingly diverse, and thus the requirements for the corresponding power supplies are also increasing.

[0003] However, with the changes in the use of the power load, some problems will occur in the existing power supply. For example, in the welding power supply at home and abroad at present, a resistance load is usually connected in parallel with the positive and negative terminals of the welding power supply output as a dead load, so that when the welding power supply provides power to the power load, i.e. when the welding power supply provides power to the power load, the actual dynamic output voltage of the welding power supply is at least 5V, and the highest no-load voltage of the national standard cannot exceed 113V, so that when the welding power supply outputs low voltage, the above-mentioned resistance load connected in parallel with the positive and negative terminals of the welding power supply output cannot effectively play a load role due to its large size; and when the welding power supply outputs high voltage, the power consumption of the resistance load will be very large, and when the three-phase input voltage provides power to the welding power supply, the output no-load voltage of the welding power supply may exceed the highest voltage of 113V of the national standard due to the usually high three-phase input voltage, and thus the personal safety risk of the welding workers may be caused. SUMMARY

[0004] The present application provides a constant power load circuit, a welding power supply circuit and an electronic device, which can solve the problem that the power supply product in the prior art cannot effectively drive the load to work when outputting low voltage to the load, and is easy to cause large invalid power consumption when outputting high voltage to the load, and brings risk to the personal safety of the workers.

[0005] To solve the above technical problems, one technical scheme adopted by the present application is to provide a constant power load circuit, wherein the constant power load circuit comprises: a first power supply connection end and a second power supply connection end, which are respectively connected to a first power supply end and a second power supply end of an external first power supply and are used for connecting an external load, the first power supply connection end and the second power supply connection end receive the first power supply and provide the first power supply to the load; a current sampling circuit connected to the first power supply connection end to receive a current signal sent by the first power supply connection end; a control circuit connected to the current sampling circuit to receive the current signal sent by the current sampling circuit and compare the current signal with a preset reference current to generate a control signal based on a current comparison result; and a switching circuit connected to the current sampling circuit, the control circuit, the first power supply connection end and the second power supply connection end to receive the current signal sent by the current sampling circuit and the control signal sent by the control circuit and change its conduction state under the action of the control signal to adjust the current signal and send the adjusted current signal to the first power supply connection end.

[0006] Among them, the control signal is a pulse width modulation signal, and the comparison result includes that the current signal is less than the preset reference current and the current signal is greater than the preset reference current; wherein, when it is determined that the current signal is less than the preset reference current, the control circuit increases the duty cycle of the control signal currently provided to the switching circuit, and when it is determined that the current signal is greater than the preset reference current, the control circuit reduces the duty cycle of the control signal currently provided to the switching circuit, so that the adjusted current signal is equal to the preset reference current.

[0007] Among them, the constant power load circuit further comprises a first diode, and the switching circuit comprises a boost sub-circuit and a second diode, the first end of the first diode is connected to the first power supply connection end, the second end of the first diode is connected to the current sampling circuit, the first end of the boost sub-circuit is connected to the current sampling circuit, the second end of the boost sub-circuit is connected to the first end of the second diode, and the second end of the second diode is connected to the first power supply connection end; wherein, when the first power supply is provided to the load through the first power supply connection end and the second power supply connection end, the first diode and the second diode cooperate with each other to make the input voltage of the load equal to the output voltage.

[0008] Among them, the boost sub-circuit further comprises an inductor and a switch tube, the first end of the inductor is connected to the current sampling circuit, the second end of the inductor is connected to the first end of the switch tube and the first end of the second diode, the second end of the switch tube is connected to the control circuit, and the third end of the switch tube is connected to the second power supply connection end.

[0009] Among them, the constant power load circuit further comprises a filter circuit, the first end of the filter circuit is connected to the current sampling circuit and the first end of the inductor, and the second end of the filter circuit is connected to the third end of the switch tube and the second power supply connection end.

[0010] The control circuit comprises a current regulating circuit and a signal driving circuit, the current regulating circuit is connected with the current sampling circuit and the signal driving circuit, the signal driving circuit is connected with the switch circuit, the current regulating circuit receives the current signal sent by the current sampling circuit, compares and adjusts the current signal by a preset reference current, and sends the compared and adjusted current signal to the signal driving circuit, so that the signal driving circuit generates a control signal correspondingly and sends the control signal to the switch circuit.

[0011] The control circuit further comprises a signal amplifying circuit, the signal amplifying circuit is connected with the signal driving circuit and the switch circuit, receives the control signal sent by the signal driving circuit, amplifies the control signal, and sends the amplified control signal to the switch circuit.

[0012] The constant power load circuit further comprises a voltage sampling circuit, the voltage sampling circuit is connected with the first power supply connection end and the control circuit, receives the voltage signal sent by the first power supply connection end, and sends the voltage signal to the control circuit.

[0013] To solve the above technical problems, the application adopts another technical scheme: providing a welding power supply circuit, wherein the welding power supply circuit comprises a power conversion circuit and a constant power load circuit, the power conversion circuit is connected with an external second power supply and the constant power load circuit, the constant power load circuit is connected with an external load, the power conversion circuit receives the second power supply, converts the second power supply into a first power supply, and provides the first power supply to the constant power load circuit, so that the constant power load circuit provides the first power supply to the load; wherein the constant power load circuit is the constant power load circuit as any one of the above.

[0014] To solve the above technical problems, the application adopts another technical scheme: providing an electronic device, wherein the electronic device comprises a shell and a constant power load circuit connected with each other; wherein the constant power load circuit is the constant power load circuit as any one of the above.

[0015] The beneficial effects of the present application are: different from the prior art, the first power supply connection end and the second power supply connection end in the constant power load circuit provided by the present application are connected with the first power supply end and the second power supply end of the external first power supply respectively, and are used for connecting the external load, so as to be able to receive the first power supply and provide the first power supply to the load, the current sampling circuit can receive the current signal sent by the first power supply connection end and send the current signal to the control circuit, the control circuit compares the current signal with the preset reference current, generates a control signal based on the current comparison result, and sends the control signal to the switch circuit, and when the switch circuit receives the current signal sent by the current sampling circuit and the control signal sent by the control circuit, the switch circuit can change its conduction state under the action of the control signal, so as to adjust the current signal and send the adjusted current signal to the first power supply connection end, so that the self-feedback constant power load is adopted in parallel with the load, the constant power output to the load is effectively maintained, the problem that the parallel resistance type dead load has large power consumption and easily causes the electric load to be unable to work effectively is avoided, and the no-load voltage exceeding the national standard is effectively avoided, so that the risk to the personal safety of the workers is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0017] Figure 1 is a structural schematic diagram of the first embodiment of the constant power load circuit of the present application;

[0018] Figure 2 is a structural schematic diagram of the second embodiment of the constant power load circuit of the present application;

[0019] Figure 3 is a structural schematic diagram of the third embodiment of the constant power load circuit of the present application;

[0020] Figure 4 is Figure 3 is a flowchart of the control circuit in the constant power load circuit adjusting the current signal;

[0021] Figure 5 is a structural schematic diagram of an embodiment of the welding power supply circuit of the present application;

[0022] Figure 6 is Figure 5 is a structural schematic diagram of a specific embodiment of the power conversion circuit in the welding power supply circuit in the present application;

[0023] Figure 7 is a structural schematic diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort fall within the protection scope of the present application.

[0025] The terms "first", "second", "third" in the present application are only for descriptive purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second", "third" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise explicitly and specifically limited. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between the components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product or device.

[0026] In this document, reference to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. As used herein, a plurality includes at least two.

[0027] The present application will be described in detail below with reference to the drawings and embodiments.

[0028] Please refer to Figure 1 , Figure 1 is a structural schematic diagram of a first embodiment of a constant power load circuit according to the present application. In the embodiment, the constant power load circuit 10 includes a first power connection end 11, a second power connection end 12, a current sampling circuit 13, a control circuit 14 and a switching circuit 15.

[0029] The constant power load circuit 10 is particularly used in a power supply product, such as a welding power supply, to maintain the constant power output to the load 102 when the welding power supply is used to perform welding work, so as to ensure the load 102 to work normally under the dynamic voltage variation and avoid the over-high output voltage.

[0030] It should be noted that the welding power supply refers to the CO2 (carbon dioxide) gas shielded welding power supply, which adopts the flat characteristic or the slow descending external characteristic, and the no-load voltage is usually 38-70V.

[0031] Specifically, the first power connection end 11 and the second power connection end 12 of the constant power load circuit 10 are respectively connected to the first power supply end and the second power supply end of the external first power supply 101 to receive the first power supply 101 and connect to the external load 102 to provide the first power supply 101 to the load 102 to drive the load 102 to work.

[0032] Further, the current sampling circuit 13 is connected to the first power connection end 11 to receive the current signal sent by the first power connection end 11, i.e. the current signal corresponding to the input of the first power supply 101 through the first power connection end 11.

[0033] The control circuit 14 is further connected to the current sampling circuit 13 to receive the current signal sent by the current sampling circuit 13, compare the current signal with the preset reference current set in the control circuit 14, and generate a control signal based on the current comparison result, such as the current signal being greater than or less than the preset reference current.

[0034] It can be understood that the different comparison results correspond to different control signals, and the switch circuit 15 is connected to the current sampling circuit 13, the control circuit 14, the first power connection end 11 and the second power connection end 12 to change its conduction state, such as the time length in the conduction and off states, under the action of the control signal when receiving the current signal sent by the current sampling circuit 13 and the control signal sent by the control circuit 14, so as to adjust the current signal and return the adjusted current signal to the first power connection end 11.

[0035] Therefore, the current signal returned to the first power supply connection end 11 by the switch circuit 15 can achieve dynamic balance with the current signal corresponding to the first power supply 101 input through the first power supply connection end 11, and can be repeatedly compared with the preset reference current by the control circuit 14 to dynamically adjust it, and finally make the current signal corresponding to the preset reference current equal, so as to ensure that the current signal corresponding to the load 102 is also constant as the preset reference current, thereby avoiding the situation that the load 102 cannot work normally, or the output voltage of the first power supply 101 provided to the load 102 by the first power supply connection end 11 and the second power supply connection end 12 is too high, so as to exceed the national standard.

[0036] The above scheme can effectively maintain the constant power output to the load 102 by adopting the form of self-feedback constant power load 102 in parallel with the load 102, thereby avoiding the problem that the parallel resistance type dead load 102 has large power consumption and easily causes the electric load 102 to work effectively; and can also effectively avoid the situation that the no-load voltage exceeds the national standard, so as to cause the risk of electric shock to the workers; accordingly, the output voltage of the constant power load circuit 10 corresponding to the output to the load 102 can also follow the output voltage provided by the external first power supply 101 to quickly respond dynamically, so as to ensure that the load 102 can be in normal working state at all times when the actual application voltage dynamically changes, and avoid the situation that the output voltage is too high.

[0037] In another embodiment, the switch circuit 15 in the constant power load circuit 10 can also be directly connected to the first power supply connection end 11 without being connected to the current sampling circuit 13, to directly receive the current signal corresponding to the first power supply connection end 11; and the current sampling circuit 13 specifically samples the current of the first power supply connection end 11, and the specific acquisition is the current value of the current signal, and the current sampling circuit 13 can also specifically include an analog-to-digital conversion circuit, so as to correspondingly convert the current signal into a digital signal form of current value, and send the current value to the control circuit 14, so as to facilitate the control circuit 14 to compare the current value with the preset reference current, and generate a control signal according to the current comparison result.

[0038] In an embodiment, the control signal is specifically a pulse width modulation signal, that is, a PWM (Pulse Width Modulation) signal, and the comparison result of the current signal corresponding to the first power supply connection end 11 with the preset reference current specifically includes that the current signal is less than the preset reference current and the current signal is greater than the preset reference current.

[0039] Wherein, the control circuit 14 determines that the current signal is less than the preset reference current, then the duty cycle of the control signal currently provided to the switching circuit 15 is increased to increase the current signal, and the first power connection end 11 is returned to send; and the control circuit 14 determines that the current signal is greater than the preset reference current, then the duty cycle of the control signal currently provided to the switching circuit 15 is reduced to reduce the current signal, and the first power connection end 11 is returned to send, so that the current signal is adjusted to be equal to the preset reference current through at least one dynamic adjustment of the current signal.

[0040] Optionally, the control circuit 14 can be any reasonable functional circuit with program processing, such as MCU (Microcontroller Unit), single-chip microcomputer or system-on-chip, etc., to facilitate users to set, reset or update the control signal generation program according to the actual application scenario of the constant power load circuit 10, which is not limited in the present application.

[0041] Please refer to Figure 2 , Figure 2 is the structural schematic diagram of the second embodiment of the constant power load circuit provided in the present application. Based on the first embodiment of the constant power load circuit provided in the present application, the constant power load circuit 20 further comprises a first diode 26, and the switching circuit 25 specifically comprises a boost sub-circuit 251 and a second diode 252.

[0042] Specifically, the first end of the first diode 26 is connected to the first power connection end 21 to be able to step-down regulate the first power 101 provided by the first power connection end 21 and the second power connection end 22, and the second end of the first diode 26 is connected to the current sampling circuit 23. The first end of the boost sub-circuit 251 is connected to the current sampling circuit 23, and the second end of the boost sub-circuit 251 is connected to the first end of the second diode 252. The second end of the second diode 252 is connected to the first power connection end 21, so that the corresponding current signal is boosted and regulated by the boost sub-circuit 251, and then returned to the first power connection end 21.

[0043] Wherein, when the first power connection end 21 and the second power connection end 22 provide the first power 101 to the load 102, the first diode 26 can correspond to the second diode 252 to make the input voltage and the output voltage of the load 102 equal, that is, through the mutual clamping effect between the first diode 26 and the second diode 252, the input and output voltages of the first power connection end 21 and the second power connection end 22 of the constant power load circuit 20 corresponding to the load 102 can be equal.

[0044] For the convenience of understanding, in the case of the voltage across the first diode 26 and the second diode 252 being VF and the preset reference current I, it can be known that the constant power load circuit 20 corresponds to the follow-up constant power W output to the load 102, and through theoretical calculation, it can be obtained that W = 2*VF*I + the power consumption of the switching circuit 25.

[0045] Further, in an embodiment, the boost sub-circuit 251 further includes an inductor 2511 and a switching tube 2512, and the first end of the inductor 2511 is specifically connected to the current sampling circuit 23, the second end of the inductor 2511 is connected to the first end of the switching tube 2512 and the first end of the second diode 252, the second end of the switching tube 2512 is connected to the control circuit 24, and the third end of the switching tube 2512 is connected to the second power supply connection end 22.

[0046] It can be understood that the control circuit 24 specifically controls the switching tube 2512 to be turned on or turned off by sending a corresponding pulse width modulation signal to the second end of the switching tube 2512, so as to dynamically adjust the corresponding current signal and finally enable the current signal to correspond to the preset reference current.

[0047] Further, in an embodiment, the constant power load circuit 20 further includes a filter circuit 27, the first end of the filter circuit 27 is connected to the current sampling circuit 23 and the first end of the inductor 2511, and the second end of the filter circuit 27 is connected to the third end of the switching tube 2512 and the second power supply connection end 22, so as to be able to filter and adjust the current signal corresponding to the current sampling circuit 23 sent to the boost sub-circuit 251, so as to ensure the stability of the current signal, and also be able to cooperate with the boost sub-circuit 251 to achieve a better boost effect.

[0048] Optionally, the filter circuit 27 specifically can include a capacitor, or a plurality of mutually connected capacitors and inductors 2511, so as to achieve a better filtering effect, which is not limited in the application.

[0049] In an embodiment, the constant power load circuit 20 can further include a voltage sampling circuit 28, and the voltage sampling circuit 28 is specifically connected to the first power supply connection end 21 and the control circuit 24, so as to be able to receive the voltage signal sent by the first power supply connection end 21 and send the voltage signal to the control circuit 24, so that the control circuit 24 can determine whether the voltage currently output to the load 102 exceeds the national standard or the threshold range determined according to the actual application scene according to the voltage signal sampled by the voltage sampling circuit 28.

[0050] It can be understood that in the embodiment, the first power connection end 21, the second power connection end 22, the current sampling circuit 23 and the control circuit 24 are the same as the first power connection end 11, the second power connection end 12, the current sampling circuit 13 and the control circuit 14 respectively, and details are described with reference to Figure 1 and related text content, which will not be repeated here.

[0051] Please refer to Figure 3 , Figure 3 is a structural schematic diagram of a third embodiment of the constant power load circuit of the application. Based on the first embodiment of the constant power load circuit provided by the application, the control circuit 34 in the constant power load circuit 30 further includes a current adjusting circuit 341 and a signal driving circuit 342.

[0052] Specifically, the current adjusting circuit 341 is connected to the current sampling circuit 33 and the signal driving circuit 342, and the signal driving circuit 342 is connected to the switching circuit 35. When the current adjusting circuit 341 receives the current signal sent by the current sampling circuit 33, it can compare and adjust the current signal by a preset reference current, and send the current signal after comparison and adjustment to the signal driving circuit 342, so that the signal driving circuit 342 generates a control signal corresponding to the current signal, and sends the control signal to the switching circuit 35.

[0053] Alternatively, the adjustment of the current adjusting circuit 341 to the corresponding current signal can be current PI (proportion integral) adjustment or any other reasonable comparison adjustment, which is not limited by the application.

[0054] Further, in an embodiment, the control circuit 34 further includes a signal amplification circuit, which is specifically connected to the signal driving circuit 342 and the switching circuit 35, so that when receiving the control signal sent by the signal driving circuit 342, it can amplify the control signal, and send the control signal after signal amplification to the switching circuit 35, so as to effectively trigger the switching circuit 35 to turn on or turn off.

[0055] Please continue to refer to Figure 4 , Figure 4 is Figure 3 the flowchart of the control circuit in the constant power load circuit adjusting the current signal.

[0056] For the convenience of understanding, taking the control signal as a PWM signal as an example, it can be known that the steps of adjusting the current signal by the control circuit 34 include:

[0057] S41: system initialization.

[0058] Start the adjustment program of the current signal.

[0059] S42: voltage detection.

[0060] The end-point voltage of the first power connection end 31 is acquired to determine whether it is within a set threshold range.

[0061] S43: current reference.

[0062] The current signal corresponding to the first power connection end 31 is acquired, or the current value of the current signal, and the current signal is compared with a preset reference current.

[0063] S44: current PI regulation.

[0064] The current signal is subjected to current PI regulation based on the comparison result.

[0065] S45: PWM driving.

[0066] A corresponding PWM signal is generated.

[0067] S46: signal amplification.

[0068] After the PWM signal is amplified, it is sent to the switching circuit to trigger the switching circuit to turn on or turn off.

[0069] It can be understood that in an embodiment, when the control circuit 34 determines that the end-point voltage of the first power connection end 31 is within a set threshold range, and after the current signal sent by the first power connection end 31 is stepped down by the first diode D1 (not shown in the figure), the current signal is compared with a preset reference current, when the current signal is less than the preset reference current, the duty cycle of the PWM signal is increased, otherwise, the duty cycle of the PWM signal is decreased, to realize the constant current dynamic balance of the current signal by repeatedly executing the above S41-S46, and after the current signal is filtered by the capacitor C (not shown in the figure), the inductor L (not shown in the figure), the power field effect transistor Q (not shown in the figure), and the second diode D2 (not shown in the figure), the corresponding current signal is returned to the first power connection end 31 to make the input and output voltages of the load 102 equal by the mutual clamping effect of the first diode D1 and the second diode D2, and voltage following is realized.

[0070] It can be understood that in the present embodiment, the first power connection end 31, the second power connection end 32, the current sampling circuit 33, and the switching circuit 35 are the same as the first power connection end 11, the second power connection end 12, the current sampling circuit 13, and the switching circuit 15 respectively, and details are described in Figure 1 and related text content, which will not be described here.

[0071] The present application also provides a welding power supply circuit, please see Figure 5 ,Figure 5 is a structural schematic diagram of an embodiment of the welding power supply circuit of the present application. In the embodiment, the welding power supply circuit 50 comprises a power conversion circuit 51 and a constant power load circuit 52.

[0072] Specifically, the power conversion circuit 51 connects the external second power supply 103 and the constant power load circuit 52, and the constant power load circuit 52 connects the external load 102. The power conversion circuit 51 receives the second power supply 103, converts the second power supply 103 into a first power supply, and then provides the first power supply to the constant power load circuit 52, so that the constant power load circuit 52 provides the first power supply to the load 102.

[0073] In the embodiment, the constant power load circuit 52 can be the constant power load circuit 10, the constant power load circuit 20 or the constant power load circuit 30 as described in any one of the above embodiments. For details, please refer to Figures 1-4 and the related text content, which will not be repeated here.

[0074] Please continue to refer to Figure 6 , Figure 6 is Figure 5 a structural schematic diagram of an embodiment of the power conversion circuit in the welding power supply circuit.

[0075] In an embodiment, the power conversion circuit 51 further comprises a first rectifier sub-circuit 511, a filter sub-circuit 512, a high-voltage inverter circuit 513 and a second rectifier sub-circuit 514. The filter sub-circuit 512 further comprises a first capacitor C1, a second capacitor C2, a first resistor R1 and a second resistor R2. The second rectifier sub-circuit 514 further comprises a third diode D3, a fourth diode D4 and a set inductance L1. The corresponding connection relationship is shown in the figure, which will not be repeated here.

[0076] Optionally, the external second power supply provided to the power conversion circuit can be a three-phase mains input, and the first power supply corresponds to a direct current power supply.

[0077] The present application also provides a communication device, please refer to Figure 7 , Figure 7 is a structural schematic diagram of an embodiment of the electronic device of the present application.

[0078] In the embodiment, the electronic device 60 comprises a housing 61 and a constant power load circuit 62 connected thereto.

[0079] In the embodiment, the constant power load circuit 62 can be the constant power load circuit 10, the constant power load circuit 20 or the constant power load circuit 30 as described in any one of the above embodiments. For details, please refer to Figures 1-4 and the related text content, which will not be repeated here.

[0080] In another embodiment, the electronic device 60 can further include a housing 61 and a welding power supply circuit (not shown), and the welding power supply circuit is specifically the welding power supply circuit 50 as described in any of the above embodiments, and please refer to Figure 5 and Figure 6 and the related text content, which will not be repeated here.

[0081] Unlike the prior art, the first power connection end and the second power connection end in the constant power load circuit provided by the present application are respectively connected to the first power supply end and the second power supply end of the external first power supply, and are used to connect the external load, so as to be able to receive the first power supply and provide the first power supply to the load. The current sampling circuit can receive the current signal sent by the first power connection end, and send the current signal to the control circuit. The control circuit compares the current signal with the preset reference current, generates a control signal based on the current comparison result, and sends the control signal to the switch circuit. When the switch circuit receives the current signal sent by the current sampling circuit and the control signal sent by the control circuit, it can change its conduction state under the action of the control signal to adjust the current signal and send the adjusted current signal to the first power connection end. Thus, by adopting the form of self-feedback constant power load in parallel with the load, the constant power output to the load can be effectively maintained, so as to avoid the problem that the parallel resistance type dead load has large power consumption and easily causes the electric load to be unable to work effectively. In addition, the no-load voltage can be effectively avoided to exceed the national standard, so as to avoid the risk of personal safety of the workers.

[0082] The above is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A constant power load circuit, characterized by, The constant power load circuit comprises: a first power connection end and a second power connection end, which are connected to a first power supply end and a second power supply end of an external first power supply respectively, and are used for connecting an external load, the first power connection end and the second power connection end receiving the first power supply and providing the first power supply to the load; a current sampling circuit connected to the first power connection end to receive a current signal sent by the first power connection end; a control circuit connected to the current sampling circuit to receive the current signal sent by the current sampling circuit, and compare the current signal with a preset reference current to generate a control signal based on a current comparison result; a switch circuit connected to the current sampling circuit, the control circuit, the first power connection end and the second power connection end to receive the current signal sent by the current sampling circuit and the control signal sent by the control circuit, and change its conduction state under the action of the control signal to adjust the current signal and send the adjusted current signal to the first power connection end.

2. The constant power load circuit according to claim 1, wherein the control signal is a pulse width modulation signal, and the comparison result includes that the current signal is less than the preset reference current and the current signal is greater than the preset reference current; wherein the control circuit increases a duty cycle of the control signal currently provided to the switch circuit when it is determined that the current signal is less than the preset reference current, and decreases the duty cycle of the control signal currently provided to the switch circuit when it is determined that the current signal is greater than the preset reference current, so that the adjusted current signal is equal to the preset reference current.

3. The constant power load circuit according to claim 1, wherein the constant power load circuit further comprises a first diode, the switch circuit comprises a boost sub-circuit and a second diode, a first end of the first diode is connected to the first power connection end, a second end of the first diode is connected to the current sampling circuit, a first end of the boost sub-circuit is connected to the current sampling circuit, a second end of the boost sub-circuit is connected to a first end of the second diode, and a second end of the second diode is connected to the first power connection end; wherein when the first power supply is provided to the load through the first power connection end and the second power connection end, the first diode and the second diode cooperate with each other to make the input voltage of the load equal to the output voltage.

4. The constant power load circuit according to claim 3, wherein the boost sub-circuit further comprises an inductor and a switch tube, a first end of the inductor is connected to the current sampling circuit, a second end of the inductor is connected to a first end of the switch tube and a first end of the second diode, a second end of the switch tube is connected to the control circuit, and a third end of the switch tube is connected to the second power connection end.

5. The constant power load circuit according to claim 4, wherein The constant power load circuit further comprises a filter circuit, a first end of the filter circuit is connected with the current sampling circuit and the first end of the inductor, and a second end of the filter circuit is connected with the third end of the switch tube and the second power supply connection end.

6. The constant power load circuit according to claim 1, characterized in that, The control circuit comprises a current regulating circuit and a signal driving circuit, the current regulating circuit is connected with the current sampling circuit and the signal driving circuit, the signal driving circuit is connected with the switch circuit, the current regulating circuit receives the current signal sent by the current sampling circuit, compares and adjusts the current signal by the preset reference current, and sends the compared and adjusted current signal to the signal driving circuit, so that the signal driving circuit correspondingly generates the control signal and sends the control signal to the switch circuit.

7. The constant power load circuit according to claim 6, characterized in that, The control circuit further comprises a signal amplification circuit, the signal amplification circuit is connected with the signal driving circuit and the switch circuit, receives the control signal sent by the signal driving circuit, amplifies the control signal, and sends the amplified control signal to the switch circuit.

8. The constant power load circuit according to claim 1, characterized in that, The constant power load circuit further comprises a voltage sampling circuit, the voltage sampling circuit is connected with the first power supply connection end and the control circuit, receives the voltage signal sent by the first power supply connection end, and sends the voltage signal to the control circuit.

9. A welding power supply circuit, comprising: The welding power supply circuit comprises a power conversion circuit and a constant power load circuit, the power conversion circuit is connected with an external second power supply and the constant power load circuit, the constant power load circuit is connected with an external load, the power conversion circuit receives the second power supply, converts the second power supply into a first power supply, and then provides the first power supply to the constant power load circuit, so that the constant power load circuit provides the first power supply to the load. The constant power load circuit is the constant power load circuit according to any one of claims 1-8.

10. An electronic device, comprising: The electronic device comprises a shell and a constant power load circuit connected with each other. The constant power load circuit is the constant power load circuit according to any one of claims 1-8.

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