Backflow protection circuit

Abstract

The invention discloses a backward flowing protection circuit, a power supply device and electronic equipment, which are used for absorbing backward flowing current in a circuit and protecting the safety of the circuit and a load. The backward flowing protection circuit is connected between a power supply circuit and a load, and comprises at least one energy consumption branch, a first current sensor and a control circuit, at least one energy consumption branch is connected in parallel with the power supply circuit, and each energy consumption branch is provided with a second current sensor; the first current sensor is used for detecting current between the load and the power supply circuit; the control circuit is respectively connected with the first current sensor and each energy consumption branch, and is used for starting the energy consumption branch when a backward flowing current occurs in the load, and controlling the resistance value of each energy consumption branch according to the current value detected by the first current sensor and the current value detected by the second current sensor on each energy consumption branch. Therefore, the influence of the operation process of the energy consumption branch on the load is reduced.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular, to an anti-backflow protection circuit, a power supply device, and an electronic device. Background Art

[0002] During the power supply process, in some cases, due to reasons such as the type of load or the devices on the power supply line, a backflow current may occur on the load side. For a power supply that can only output power, the backflow current will be transmitted reversely through the devices on the power supply line, affecting the normal operation of the power supply, and in severe cases, it will also cause device damage. Summary of the Invention

[0003] This application provides an anti-backflow protection circuit, a power supply device, and an electronic device for absorbing the backflow current and protecting the safety of the power supply device and the load.

[0004] In a first aspect, this application provides an anti-backflow protection circuit. The anti-backflow protection circuit is connected between a power supply device and a load, and may include at least one energy consumption branch, a first current sensor, and a control circuit.

[0005] Wherein, the at least one energy consumption branch is connected in parallel with the power supply circuit, and a second current sensor is arranged on each energy consumption branch; the first current sensor is used to detect the current between the load and the power supply circuit; the control circuit is respectively connected to the first current sensor and each energy consumption branch, and is used to control the resistance value of each energy consumption branch according to the current value detected by the first current sensor and the current value detected by the second current sensor on each energy consumption branch when the load has a backflow current, so that the sum of the currents on all energy consumption branches is greater than or equal to the backflow current.

[0006] With the above circuit structure, the first current sensor can detect the current value on the load loop. Under normal circumstances, the power supply circuit supplies power to the load, so the supply current flows from the power supply circuit to the load. When a backflow current appears in the circuit, the direction of the current is opposite to the direction of the supply current. Therefore, it is possible to identify whether there is a backflow current on the main loop through the value detected by the first current sensor. When the control circuit determines that a backflow current appears, it can control the energy consumption branch to start and adjust the resistance of the energy consumption branch so that all backflow currents flow to the energy consumption branch, avoiding the backflow current flowing to the power supply circuit, which is beneficial to protecting the safety of the power supply circuit and the load.

[0007] In a possible design, each energy consumption branch includes: a first switch and the second current sensor. The first switch is a voltage-driven switch, which is used to control the on and off of the corresponding energy consumption branch and adjust the total impedance of the corresponding energy consumption branch. The control terminal of the first switch is connected to the control circuit. With the above design, the energy consumption branch uses a voltage-driven switch. The first switch not only controls the on and off of the energy consumption branch, but also has a linear working area, that is, the impedance state of the energy consumption branch can be presented by controlling the conduction degree of the first switch, so as to adjust the resistance value of the energy consumption branch.

[0008] In a possible design, in order to avoid excessive backflow current, which may cause the first switch on the energy consumption branch to be damaged due to receiving excessive power, each energy consumption branch further includes at least one current-limiting resistor, and each current-limiting resistor is connected in series with the first switch and the first switch.

[0009] In a possible design, when the device specifications on each energy consumption branch are the same, the control circuit includes: a first sampling circuit, a second sampling circuit, a control circuit and a driving circuit.

[0010] Among them, the first sampling circuit is used to receive the current value detected by the first current sensor and output a first signal, and the first signal is in a proportional relationship with the current on the load; the second sampling circuit is used to receive the current value detected by the target second current sensor and output a second signal, and the second signal is in a proportional relationship with the current on the energy consumption branch where the target second current sensor is located. The target second current sensor is any one of the second current sensors in the backflow protection circuit; the control circuit is used to generate a control signal for each first switch according to the first signal and the second signal, and the control signal is used to control the conduction degree of each first switch; the driving circuit is used to perform power amplification processing on the control signal and then output it to the control terminal of each first switch.

[0011] With the above design, when the device specifications in multiple energy consumption branches are the same, the current flowing through each energy consumption branch is the same. Therefore, taking the example that there are N energy consumption branches in the backflow protection circuit, 1 / N of the backflow current can flow through each energy consumption branch. The current detected by the second current sensor on one of the energy consumption branches can be collected, and the current detected by the first current sensor can be proportionally stepped down according to the number of energy consumption branches and output to the control circuit as a given value. The conduction degree of the first switch is adjusted through the given value and the detected second signal value, so that 1 / N of the backflow current flows through all energy consumption branches, realizing the distribution of the backflow current.

[0012] In a possible design, the control circuit includes: a first sampling circuit, a second sampling circuit corresponding to each second current sensor one by one, a control circuit corresponding to each second sampling circuit one by one, and a driving circuit corresponding to each control circuit one by one.

[0013] Among them, the first sampling circuit is used to receive the current value detected by the first current sensor and output a first signal, and the first signal is in a proportional relationship with the current on the load; each second sampling circuit is used to receive the current value detected by the corresponding second current sensor and output a second signal, and the second signal is in a proportional relationship with the current on the energy consumption branch where the corresponding second current sensor is located; each control circuit is used to generate a control signal for the first switch on the energy signal branch where the connected second sensor is located according to the first signal output by the first sampling circuit and the second signal output by the corresponding second sampling circuit; each driving circuit is used to perform power amplification processing on the first control signal output by the corresponding control circuit and then output it to the control end of the corresponding first switch.

[0014] With the above design, when the device specifications in multiple energy consumption branches are the same, but due to reasons such as production and manufacturing or working environment, the current values on each energy consumption branch may be different. In order to prevent excessive power received on a single energy consumption branch from being damaged, a second acquisition circuit, a control circuit, and a control circuit can be configured for each energy consumption branch, and the first signal output by the first acquisition circuit is output to the control circuit as a given value after being proportionally stepped down according to the number of energy consumption branches, and the conduction degree of the first switch is adjusted by the given value and the amplitude of the detected numerical second signal, so that the value of the backflow current flowing through each energy consumption branch is the same, thereby realizing the distribution of the backflow current and protecting the safety of the backflow protection circuit.

[0015] In a possible design, if the specifications of the first switches on each energy consumption branch are different, the control circuit further includes a buck circuit corresponding to each control circuit one by one, and each buck circuit is connected between the first sampling circuit and the corresponding control circuit, and each buck circuit is used to perform a fixed-ratio buck processing on the first signal.

[0016] By adopting the above design and configuring different device specifications on each energy consumption branch, different values ​​of feedback current can be made to flow through each energy consumption branch. For example, with two energy consumption branches, 1 / 3 of the feedback current can flow through one energy consumption branch and 2 / 3 of the feedback current can flow through the other energy consumption branch. The first signal is then stepped down by 1 / 3 and 2 / 3 respectively and then output to the control circuits corresponding to the two energy consumption branches as given values, thereby controlling the two energy consumption branches to flow a set proportion of feedback current and completing the distribution of the feedback current.

[0017] In a possible design, if the first current sensor is a first sampling resistor and the second current sensor is a second sampling resistor, the first end of the first sampling resistor is connected to the second end of each second sampling resistor, and the first end of the first sampling resistor is connected to an end of the power supply circuit that outputs a low level.

[0018] In a second aspect, an embodiment of the present application provides a power supply device, one end of which is connected to an AC power supply, and the other end of which is connected to a load, and is used to supply power to the load. The power supply device includes a power supply circuit and a backfeed protection circuit. The power supply circuit is used to connect to an AC power supply, convert the AC power output by the AC power supply into DC power and supply power to the load; the backfeed protection circuit is connected between the power supply circuit and the load, and is used to control the backfeed current to flow to each energy consumption branch when a backfeed current appears in the power supply device, and absorb the above-mentioned backfeed current through the energy consumption branch.

[0019] In a third aspect, an embodiment of the present application provides an electronic device, which may include the backfeed protection circuit provided in the first aspect of the embodiment of the present application, and may also include a load connected to the backfeed protection circuit, wherein the backfeed protection circuit is connected between the switching power supply and the load, and is used to control the backfeed current to flow to each energy consumption branch when a backfeed current appears in the power supply device, and absorb the above-mentioned backfeed current through the energy consumption branch, thereby ensuring the safe operation of the load.

[0020] In addition, the technical effects brought about by any possible design method in the second aspect to the third aspect can refer to the technical effects brought about by different design methods in the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of a power supply circuit provided in an embodiment of the present application;

[0022] Figure 2 A connection diagram of a backfeed protection circuit provided in an embodiment of the present application;

[0023] Figure 3Structural schematic of an anti-backflow protection circuit provided by an embodiment of the present application Figure 1 ;

[0024] Figure 4 Structural schematic of an anti-backflow protection circuit provided by an embodiment of the present application Figure 2 ;

[0025] Figure 5 Structural schematic of an energy consumption branch provided by an embodiment of the present application Figure 1 ;

[0026] Figure 6 Structural schematic of a control circuit provided by an embodiment of the present application Figure 1 ;

[0027] Figure 7 Structural schematic of an anti-backflow protection circuit provided by an embodiment of the present application Figure 3 ;

[0028] Figure 8 Structural schematic of a control circuit provided by an embodiment of the present application Figure 2 ;

[0029] Figure 9 Structural schematic of a control circuit provided by an embodiment of the present application Figure 3 ;

[0030] Figure 10 Structural schematic of a control circuit provided by an embodiment of the present application Figure 4 ;

[0031] Figure 11 Structural schematic of an energy consumption branch provided by an embodiment of the present application Figure 2 。 Detailed implementation manners

[0032] In order to make the objectives, technical solutions, and advantages of this application clearer, the following will further describe this application in detail with reference to the accompanying drawings. The specific operation methods in the method embodiments can also be applied to the device embodiments or system embodiments. It should be noted that in the description of this application, "at least one" means one or more, where multiple means two or more. In view of this, in the embodiments of the present invention, "multiple" can also be understood as "at least two". "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / ", unless otherwise specified, generally represents an "or" relationship between the associated objects before and after. In addition, it should be understood that in the description of this application, terms such as "first" and "second" are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order.

[0033] In modern society, there are a large number of devices that rely on electricity to operate. From small household appliances to large data centers and factory production lines, power supply has become one of the factors maintaining the normal operation of modern society. Currently, most devices use a DC power supply method, that is, the AC electrical energy output by the AC power grid or other AC power sources needs to be converted into DC electrical energy before it can be supplied to them. Therefore, a power supply circuit that converts the electrical energy output by the AC power source into the electrical energy for device power supply is generally provided between the AC power source and the device.

[0034] Figure 1 Fig. shows a schematic structural diagram of a power supply circuit, as Figure 1 shown, the above power supply circuit is applied to a scenario with AC input and DC output. Among them, the AC power source can be an AC power grid or other AC power sources, and provides AC electrical energy for the power supply circuit. The power supply circuit can convert the received AC electrical energy and provide the converted DC electrical energy to the load.

[0035] In Figure 1 the above, the power supply circuit may include an input filter circuit, an inverter, a compensation network, a transformer, a rectifier, and an output filter. The input filter circuit, input rectifier, inverter, compensation network, transformer, output rectifier, and output filter are sequentially connected between the AC power source and the electrical device. Among them, the input filter circuit can filter the AC electrical energy output by the AC power source. The input rectifier can convert the AC electrical energy output by the AC power source into DC electrical energy. The inverter can convert the DC electrical energy output by the input rectifier into AC electrical energy, and after being compensated by a passive compensation network composed of devices such as inductors or capacitors, output the compensated AC electrical energy to the output rectifier. The output rectifier converts the received AC electrical energy into DC electrical energy, and after filtering through the output filter circuit, provides it to the load.

[0036] It should be noted that the structure of the above power supply circuit is a power supply circuit structure with compensation and isolation functions. The above power supply circuit structure is only an example. In actual applications, the power supply circuit may have more or fewer components than the power supply circuit. For example, the power supply circuit may only have a rectifier and a filter circuit, or in addition to the above components, the power supply circuit may also have a protection circuit.

[0037] In some special cases, as shown in Figure 1 it is possible for the load side to reverse output current Ir to the power supply circuit. For example, when the load is an inductive load and the AC power supply supplies power to the load through the power supply circuit, if the induced voltage generated on the load is greater than the voltage output by the power supply circuit to the load, the load will reverse output current to the power supply circuit, which is hereinafter referred to as backflow current. For scenarios that require unidirectional power transmission, when the load outputs backflow current, it may cause abnormal operation of the power supply circuit, and in severe cases, it may also cause device damage. For example, as shown in Figure 1 if the output rectifier is composed of diodes that can only transmit electrical energy unidirectionally, the backflow current Ir cannot be reversely transmitted to the AC power supply side through the diodes. Therefore, the energy of the backflow current may cause overvoltage at the output, which may further lead to diode failure and damage, or an overvoltage fault may occur.

[0038] In view of this, an embodiment of the present application provides an anti-backflow protection circuit. When a backflow current is generated on the electrical load side in a power supply scenario, the anti-backflow protection circuit can absorb the backflow current on the electrical load side, prevent the backflow current from flowing reversely to other devices in the circuit, and ensure the safe operation of the circuit.

[0039] Exemplarily, the anti-backflow protection circuit provided by the embodiment of the present application can be as shown in Figure 2 One end of the anti-backflow protection circuit 20 is connected to the end i+ of the power supply circuit that outputs a high level, the second end of the anti-backflow protection circuit 20 is connected to the first end i- of the power supply circuit that outputs a low level, the third end of the anti-backflow protection circuit 20 is connected to the end o+ of the load that receives a high level, and the fourth end of the anti-backflow protection circuit 20 is connected to the end o- of the load that receives a low level. That is, the anti-backflow protection circuit 20 is connected between the power supply circuit and the load, and can detect and absorb the backflow current on the load side. Among them, the power supply circuit can be the aforementioned power supply circuit.

[0040] Among them, the backflow protection circuit 20 includes an energy consumption branch 21, a first current sensor 22, and a control circuit 23. The first end of the energy consumption branch 21 is connected to the first end of the backflow protection circuit 20, and the second ends of the energy consumption branch 21 are both connected to the second end of the backflow protection circuit 20, that is, the energy consumption branch 21 is connected in parallel with the power supply circuit. The first current sensor 22 is used to collect the current on the load side and send the detected value to the control circuit. The control circuit 23 is respectively connected to the second current sensor in the energy consumption and the first current sensor 22. The control circuit 23 can receive the values detected by the first current sensor 22 and the second current sensor, and determine whether there is a backflow current by detecting the value detected by the first current sensor 22.

[0041] In another example, if the first current sensor is a signal acquisition device such as a giant magnetoresistive magnetic field sensor or a Hall sensor, see Figure 3 As shown, the first end of the first current sensor 22 is connected to the end o+ where the load receives the high level, and the second end of the first current sensor 22 is connected to the first end of the energy consumption branch 21. It should be noted that Figure 3 The connection position of the first current sensor shown is only an example. In actual applications, the first end of the first current sensor 22 can also be connected to the second end of the energy consumption branch 21, and the second end of the first current sensor 22 can also be connected to the end o- where the load receives the low level.

[0042] In one example, if the first current sensor is a signal acquisition device such as a sampling resistor, see Figure 4 As shown, the first end of the first current sensor 22 is connected to the second end of the energy consumption branch 21, and the second end of the first current sensor 22 is connected to the end o- where the load receives the low level. When the power supply circuit normally supplies power to the load, since the first end of the first current sensor 22 is connected to the end i- where the power supply circuit outputs the low level, that is, the lowest potential point on the entire power supply line, therefore, in the absence of backflow current, the voltage at the second end of the first current sensor 22 is greater than the voltage at the first end of the first current sensor 22. When a backflow current Ir appears on the load side, since the backflow current Ir flows to the end o- where the load receives the low level, the voltage at the first end of the first current sensor 22 is greater than the voltage at the second end of the first current sensor 22. Therefore, it is possible to detect whether there is a backflow current Ir in the circuit through the above method.

[0043] By Figure 3 and Figure 4It can be seen that whether there is a reverse injection current Ir in the circuit can be determined by detecting the voltage across the first current sensor 22. When the reverse injection current Ir in the circuit is detected, in order to prevent the reverse injection current Ir from flowing into the power supply circuit and causing damage to the power supply circuit and the load, it is necessary to turn on the energy consumption branch 21 to make the reverse injection current form a closed loop through the energy consumption branch 21 and the load, and consume the reverse injection current Ir on the energy consumption branch 21.

[0044] In this application, as shown in Figure 5 the energy consumption branch 21 may include a second current sensor 211 and a first switch 212, and the second current sensor 211 and the first switch 212 are connected in series. The second current sensor 211 can detect the current value flowing through the energy consumption branch 21, and the first switch 212 can control the opening and closing of the energy consumption branch 21 and the total impedance on the energy consumption branch 21, so as to adjust the value of the reverse injection current flowing through the energy consumption branch 21. Since there is a reverse injection current Ir in the circuit, in order to prevent the reverse injection current Ir from flowing backward into the power supply circuit, the reverse injection current flowing through the energy consumption branch 21 should be equal to the reverse injection current Ir on the total loop. And in order to avoid detection errors, generally it is required that the reverse injection current flowing through the energy consumption branch 21 is slightly greater than the reverse injection current Ir on the total loop to ensure that all the reverse injection currents Ir pass through the energy consumption branch 21 and are absorbed.

[0045] Next, taking the current sensor in the circuit as a sampling resistor as an example, with the first end of the first current sensor 22 being called s-gnd, the second end of the first current sensor 22 being called Iout, and the first end of the second current sensor 211 being called Ishunt, and the second end of the second current sensor 211 being connected to the first end s-gnd of the first current sensor 22, the working process of the reverse injection protection circuit provided by the embodiment of this application will be described.

[0046] In order to reduce the impact of the reverse injection current Ir elimination process on the load, during the process of the control circuit 23 controlling the energy consumption circuit 21 to turn on and consume the reverse injection current Ir, it can control the conduction degree of the first switch 212 according to the change of the reverse injection current and the value of the reverse injection current currently flowing through the energy consumption branch 21, so as to adjust the impedance value on the energy consumption branch 21, avoid voltage fluctuations on the load side, and ensure the safe operation of the load.

[0047] In a specific implementation manner, the first switch 212 is a voltage-driven switching device. The control circuit 23 can be directly connected to the control terminal of the first switch 212, or connected to the control terminal of the first switch 212 through a current-limiting resistor. By sending a first control signal to the control terminal of the first switch 212, the first switch 212 is controlled to conduct and operate in the linear working region, and the conduction degree of the first switch 212 is controlled by adjusting the amplitude of the first control signal, thereby adjusting the total impedance on the energy consumption branch 21.

[0048] As described above, the opening and closing of the energy consumption branch 21 are realized by the conduction and cut-off of the first switch 212. The control circuit 23 sends a control signal to the control terminal of the first switch 212 to control the conduction and cut-off of the first switch 212. In the anti-backflow protection circuit 20 provided in the embodiments of the present application, the control circuit 23 can output a digital signal, and the digital signal can be a level signal. The level signal output by the control circuit 23 can be transmitted to the control terminal of the first switch 212, and control the conduction and cut-off of the first switch 212, as well as the conduction degree of the first switch 212.

[0049] Among them, the control circuit 23 can be an integrated circuit with specific logical operation capabilities. Exemplarily, the control circuit 23 can be a control component such as a processor, a microprocessor, a controller, etc. For example, it can be a general central processing unit (CPU), a general processor, a digital signal processing (DSP), an application specific integrated circuits (ASIC), a field programmable gate array (FPGA). The control circuit 23 can also be composed of discrete devices. The circuit structure when the control circuit 23 is a discrete device will be described below in conjunction with embodiments.

[0050] The following combines Figure 5 Taking the anti-backflow protection circuit structure shown as an example, the structure of the control circuit will be described. Refer to Figure 6 As shown, it is a schematic diagram of a circuit structure of the control circuit. As Figure 6 shown, the control circuit 23 includes a first acquisition circuit AP1, a second acquisition circuit AP2, a control circuit AP3, and a drive circuit amplifier circuit AP4.

[0051] In the control circuit provided by the embodiment of the present application, the first sampling circuit is configured to receive the current value detected by the first current sensor and output a first signal, and the first signal is in a proportional relationship with the current on the load; the second sampling circuit is configured to receive the current value detected by the second current sensor and output a second signal, and the second signal is in a proportional relationship with the current on the energy consumption branch, and the target second current sensor is any one of the second current sensors in the anti-injection protection circuit; the control circuit is configured to generate a control signal for each first switch according to the first signal and the second signal, and the control signal is used to control the conduction degree of each first switch; the driving circuit is configured to perform power amplification processing on the control signal and then output it to the control end of each first switch.

[0052] Wherein, the above-mentioned first acquisition circuit AP1, second acquisition circuit AP2, control circuit AP3 and driving circuit amplification circuit AP4 can be implemented by discrete devices. For example, the above circuits and functions can be implemented by operational amplifiers and peripheral circuits. The above acquisition circuit can also be implemented by an integrated chip or a processor.

[0053] Next, taking the multiple acquisition circuits in the control circuit as an example of using operational amplifiers and peripheral circuits, the working process of the control circuit will be described.

[0054] In the control circuit 23 provided by the embodiment of the present application, the first acquisition circuit AP1 can be a differential amplifier. The first input terminal of the first acquisition circuit AP1 is connected to the first terminal s-gnd of the first current sensor 22, the second input terminal of the first acquisition circuit AP1 is connected to the second terminal Iout of the first current sensor 22, and the output terminal of the first acquisition circuit AP1 is connected to the first input terminal of the control circuit AP3. The first acquisition circuit AP1 is configured to detect the differential pressure across the first current sensor 22 and output a first signal U1. The first signal U1 is in a proportional relationship with the differential pressure across the first current sensor 22. Among them, the first signal can be a voltage signal, and of course it can also be other electrical signals, which are not limited too much in this application.

[0055] In actual application, the first input end of the first acquisition circuit AP1 is the positive input end, and the second input end of the first acquisition circuit AP1 is the negative input end. Since the voltage of the first end of the first current sensor 22 is greater than the voltage of the second end when the circuit has a reverse current Ir, when the circuit has a reverse current Ir, the potential of the positive input end of the first acquisition circuit AP1 is greater than the voltage of the negative input end, and a first signal U1 greater than zero proportional to the voltage difference across the first current sensor 22 is output. Among them, the conversion ratio of the first current sensor AP1 can be set according to the current amplitude flowing through the circuit and the device specifications in the control circuit 23, and this application will not be described in detail here.

[0056] In the control circuit 23 provided in the embodiment of the present application, the second acquisition circuit AP2 may be a differential amplifier, the first input end of the second acquisition circuit AP2 is connected to the first end Ishunt of the second current sensor 211, the second input end of the second acquisition circuit AP2 is connected to the second end s-gnd of the second current sensor 211, the output end of the second acquisition circuit AP2 is connected to the second input end of the control circuit AP3, and the second acquisition circuit AP2 is used to detect the differential pressure across the second current sensor 211 and output the second signal U2. The second signal U2 is proportional to the differential pressure across the second current sensor 212, that is, it is proportional to the current flowing through the energy consumption branch 21. Since the current of the second current sensor 212 flows from the positive end to the lower end regardless of whether there is a reverse current in the circuit, the second signal U2 is a value greater than or equal to zero. Among them, the second signal may be a voltage signal, or other electrical signals, and the present application does not make too many restrictions here.

[0057] In actual application, the first input end of the second acquisition circuit AP2 is a positive input end, and the second input end of the second acquisition circuit AP2 is an inverting input end. When the energy consumption branch 21 is turned on and current appears, a voltage difference will be generated across the second current sensor 211. Therefore, the second acquisition circuit AP2 will output a second signal U2 greater than zero that is proportional to the voltage difference across the second current sensor 211. Among them, the conversion ratio of the second acquisition circuit AP2 can be set according to the device specifications on the energy consumption branch 21 and the device specifications on the control circuit 23, and this application will not be described in detail here.

[0058] In the control circuit 23 provided by the embodiment of the present application, the control circuit AP3 may be a Type-2 compensator with dual inputs and single output. The output end of the control circuit AP3 is connected to the input end of the drive circuit AP4. The control circuit AP3 is configured to generate a control signal for the first switch 212 according to the difference between the first signal U1 and the second signal U2. The control signal is used to control the conduction and cutoff of the first switch 212, and to control the conduction degree of the first switch 212.

[0059] Specifically, the control circuit AP3 uses the first signal U1 output by the first acquisition circuit AP1, which is proportional to the current on the load, as the given value, and uses the second signal U2, which is proportional to the current on the energy consumption branch 21, as the actual output value. The control signal for the first switch 212 is generated through compensation based on the deviation formed by the given value and the actual output value, so as to control the current value on the energy consumption branch 21 to be the reverse injection current Ir on the main circuit.

[0060] In actual application, when there is a reverse injection current Ir in the circuit, if the energy consumption branch 21 is in the off state, the amplitude of the second signal output by the second acquisition circuit AP2 connected to the second current sensor 211 in the energy consumption branch 21 is zero, while the first signal U1 output by the first acquisition circuit AP1 connected to the first current sensor 21 is a value greater than zero. In order to make the current on the energy consumption branch 21 the same as the reverse injection current Ir, which is a value greater than zero, the first switch 212 will be controlled to conduct to turn on the energy consumption branch 21. As the energy consumption branch 21 is turned on, the reverse injection current Ir gradually decreases, and correspondingly, the first signal U1 output by the first acquisition circuit AP1 also gradually decreases, so the given value of the control circuit AP3 also decreases. In order to make the current value on the energy consumption branch 21 the same as the value of the reverse injection current Ir, the control circuit AP3 will generate a first control signal for reducing the conduction degree of the first switch 212 to increase the total impedance on the energy consumption branch 21, thereby reducing the current on the energy consumption branch 21. When the reverse injection current Ir is zero, the first voltage U1 output by the first acquisition circuit AP1 is zero, and the control circuit AP3 will generate a control signal for controlling the cutoff of the first switch 212 to turn off the energy consumption branch 21, so that the current on the energy consumption branch 21 is the same as the reverse injection current, which is zero. Generally, the amplitude of the first control signal output by the control circuit AP3 is relatively low and it is difficult to directly drive the first switch 212. Therefore, a drive circuit AP4 needs to be provided between the control circuit AP3 and the energy consumption branch 21. The output end of the drive circuit AP4 is used to connect to the control end g-mos of the first switch 212. The drive circuit AP4 can be a power amplifier and is configured to perform power amplification processing on the control signal and then output it to the control end of the first switch 212.

[0061] In one example, multiple devices in the control circuit 23 need to be provided with a ground terminal. If the first current sensor 22 and the second current sensor 211 are sampling resistors, in order to reduce the difficulty of circuit design, the connection point s-gnd of the first sampling resistor 22 and the second sampling resistor 211 can be connected to the end i- of the power supply circuit outputting a low level as the ground terminal of multiple operational amplifiers in the control circuit 23. It should be noted that the connection relationship between the first sampling resistor 22 and the second sampling resistor 211 is only an example. In actual applications, if the current sensor is other signal acquisition devices, the first sampling resistor 22 can also be directly connected to the first switch 212, and connected to the second sampling resistor 211 through the first switch 212.

[0062] The above is the entire control process of the control circuit 23 after the backfeed current Ir appears in the circuit. Whether the backfeed current Ir appears is detected by the voltage difference detection circuit at both ends of the first current sensor 22, and by detecting the voltage difference between the first current sensor 22 and the second current sensor 211, the total impedance on the energy consumption branch 21 is adjusted, thereby eliminating the backfeed current Ir while reducing the impact of the backfeed current Ir on the load, thereby ensuring the safe operation of the load.

[0063] In some scenarios, the value of the reverse current Ir is large. In order to quickly eliminate the reverse current Ir and reduce the impact of the large current on the circuit, in a possible implementation, the reverse protection circuit may also include two or more energy consumption branches. The connection method of the energy consumption branch is the same as that of the single energy consumption branch, and both are connected in parallel with the power supply circuit. Figure 7 As shown, when the circuit has a reverse current Ir, the reverse current Ir is divided among multiple energy consumption branches, and a portion of the reverse current flows through each energy consumption branch and is consumed on the load in the energy consumption branch. The structure of each energy consumption branch 21 and the connection relationship of the first current sensor 22 can be referred to the above introduction, and this application will not repeat the introduction.

[0064] Next, in combination with the embodiment, taking the backfeed protection circuit 20 provided with multiple energy consumption branches 21 as an example, the control process of the control circuit 23 is further exemplarily described.

[0065] Embodiment 1:

[0066] If the device specifications on each energy consumption branch 21 are the same, taking the backfeed protection circuit 20 having N energy consumption branches 21, where N is greater than or equal to 2 as an example, when a backfeed current Ir appears in the backfeed protection circuit 20, 1 / N of the backfeed current Ir can be controlled to flow through each energy consumption branch 21. At this time, the sum of the currents on the N energy consumption branches 21 is the backfeed current Ir. In order to reduce the manufacturing cost of the backfeed protection circuit 20, as Figure 8As shown, the control circuit 23 includes a first acquisition circuit AP1, a second acquisition circuit AP2, a control circuit AP3, and a drive circuit AP4.

[0067] Among them, the structures and working modes of the first acquisition circuit AP1, the second acquisition circuit AP2, the control circuit AP3, and the drive circuit AP4 can be referred to the above relevant introductions, and will not be repeated here in this application.

[0068] When controlling the conduction degree of the first switch 212, since the device specifications on each energy consumption branch 21 are the same, the current amplitudes flowing through each energy consumption branch 21 are the same, that is, each energy consumption branch flows through an inverse irrigation current Ir of 1 / N. Therefore, the second current sensor 211 on one of the energy consumption branches 21 can be selected as the current value on all energy consumption branches 21, and the conduction degree of the first switch 212 on all energy consumption branches 21 can be controlled by using the above current value.

[0069] Specifically, the first input end of the second acquisition circuit AP2 is connected to the first end of the target second current sensor, the second input end of the second acquisition circuit AP2 is connected to the second end of the target second current sensor, the output end of the second acquisition circuit AP2 is connected to the second input end of the control circuit AP3, the second acquisition circuit AP2 is used to detect the differential pressure across the target second current sensor and output a second signal, and the second signal is in a proportional relationship with the differential pressure across the target second current sensor. Among them, the energy consumption branch where the target second current sensor is located is any one of the multiple energy consumption branches.

[0070] It should be noted that since N energy consumption branches 21 are provided and each energy consumption branch 21 flows through an inverse irrigation current Ir of 1 / N, the first acquisition circuit AP1 needs to step down the differential pressure across the detected first current sensor 22 by N times and then transmit it to the control circuit AP3 as the given value for controlling each energy consumption branch 21. Among them, the above step-down function can be achieved by configuring the peripheral resistors of the first acquisition circuit AP1 or selecting a differential amplifier with a suitable specification. Of course, other methods can also be used, and this application does not make too many limitations here.

[0071] In an example, in order to reduce the detection error of the first acquisition circuit AP1 caused by voltage fluctuations, as shown in Figure 8 filter capacitors C1 are generally configured in the feedback path and the power supply path of the first acquisition circuit AP1.

[0072] It should be noted that in the above embodiments, by sampling the voltage across the second current sensor on the Nth energy consumption branch and controlling the conduction degree of all the first switches, in actual application, the voltage across the second current sensor of other energy consumption branches can also be selected, and specific limitations are not made here in this application.

[0073] Embodiment 2:

[0074] The device specifications on each energy consumption branch are the same. However, due to reasons such as device manufacturing or environment, the current values flowing through each energy consumption branch 21 are different. In order to prevent the current value flowing through a single energy consumption branch from being too large and causing damage to the first switch 212, as Figure 9 shown, the control circuit 23 includes a first acquisition circuit AP1 corresponding to one, a second voltage acquisition circuit AP2 corresponding to each second current sensor, a control circuit AP3 corresponding to each second acquisition circuit AP2, and a drive circuit AP4 corresponding to each control circuit.

[0075] Specifically, the first sampling circuit is configured to receive the current value detected by the first current sensor and output a first signal, and the first signal is in a proportional relationship with the current on the load; each second sampling circuit is configured to receive the current value detected by the corresponding second current sensor and output a second signal, and the second signal is in a proportional relationship with the current on the energy consumption branch where the corresponding second current sensor is located; each control circuit is configured to generate a control signal for the first switch on the energy signal branch where the connected second sensor is located according to the first signal output by the first sampling circuit and the second signal output by the corresponding second sampling circuit; each drive circuit is configured to perform power amplification processing on the first control signal output by the corresponding control circuit and then output it to the control end of the corresponding first switch.

[0076] In actual application, if both the first current sensor and the second current sensor are sampling resistors, the first input terminal of the first acquisition circuit AP1 is connected to the first terminal of the first current sensor 22, the second input terminal of the first acquisition circuit AP1 is connected to the second terminal of the first current sensor 22, the output terminal of the first acquisition circuit AP1 is connected to the first input terminal of each control circuit AP3. The first acquisition circuit AP1 is used to detect the differential pressure across the first current sensor 22 and output a first signal U1, and the first signal U1 is in a proportional relationship with the differential pressure across the first current sensor 22. The first input terminal of each second acquisition circuit AP2 is connected to the first terminal of the corresponding second current sensor, the second input terminal of each second acquisition circuit AP2 is connected to the second terminal of the corresponding second current sensor, and the output terminal of each second acquisition circuit AP2 is connected to the second input terminal of the corresponding control circuit AP3. Each second acquisition circuit AP2 is used to detect the differential pressure across the corresponding second current sensor and output a second signal U2, and the second signal U2 is in a proportional relationship with the differential pressure across the connected second current sensor. The output terminal of each control circuit AP3 is connected to the input terminal of the corresponding drive circuit AP4. Each control circuit AP3 is used to generate a control signal for the first switch connected to the corresponding second current sensor resistance according to the difference between the signal output by the first acquisition circuit AP1 and the second signal output by the connected second acquisition circuit AP2. Each drive circuit AP4 is used to perform power amplification processing on the control signal output by the corresponding control circuit AP3 and then output it to the control terminal of the corresponding first switch.

[0077] In actual application, 1 / N of the backflow current is used as the reference value for each energy consumption branch. Therefore, the first acquisition circuit AP1 needs to step down the detected differential pressure across the first current sensor 22 by N times and then transmit it to the control circuit AP3. Each control circuit AP3 uses 1 / N of the backflow current Ir as the given value, and adjusts the conduction degree of the first switch on the corresponding energy consumption branch according to the current value on the energy consumption branch connected to it, so as to achieve current sharing among multiple energy consumption branches and make them flow through 1 / N of the backflow current Ir, avoiding the situation that too much power is distributed on a single energy consumption branch, thereby ensuring the safety of the energy consumption branch.

[0078] Among them, the types and working processes of the first acquisition circuit AP1, each second acquisition circuit AP2, each control circuit AP3 and the drive circuit AP4 can be seen in the relevant introductions above, and will not be repeated here in this application.

[0079] Embodiment 3

[0080] See Figure 10As shown, the device specifications on each energy consumption branch are different, that is, different reverse injection current values are allowed to flow through each energy consumption branch. For example, Figure 10 As shown, the control circuit includes a first acquisition circuit AP1, a second acquisition circuit AP2 corresponding to each second current sensor one by one, a control circuit AP3 corresponding to each second acquisition circuit AP2 one by one, and a drive circuit AP4 corresponding to each control circuit AP3 one by one. Among them, the connection relationship of the first acquisition circuit AP1, each second acquisition circuit AP2, each control circuit AP3, and each drive circuit AP4 can be seen in Figure 9 As shown. In addition to the above-mentioned devices, the control circuit further includes a buck circuit corresponding to each control circuit AP3. Each buck circuit is connected between the output end of the first acquisition circuit AP1 and the corresponding control circuit AP3, and each buck circuit is used to perform buck processing on the amplitude of the first signal output by the first acquisition circuit AP1 at a fixed ratio.

[0081] It should be noted that Figure 10 When using a buck resistor as the buck circuit to perform buck processing on the first signal U1 output by the first acquisition circuit AP1, in practical applications, other devices can also be selected to achieve the buck function. For example, a divider can be selected as the buck circuit. Of course, other devices can also be selected to achieve this, which will not be introduced one by one in this application.

[0082] In practical applications, the reverse injection current value flowing through each energy consumption branch can be configured according to the device specifications in each energy consumption branch. For example, taking the reverse injection protection circuit with two energy consumption branches as an example, if it is necessary to control 1 / 3 of the reverse injection current Ir to flow through one energy consumption branch and 2 / 3 of the reverse injection current Ir to flow through the other energy consumption branch, a buck circuit with a buck ratio of 1 / 3 is set between the control circuit AP3 connected to the 1 / 3 reverse injection current Ir and the first acquisition circuit AP1. At this time, the control circuit AP3 connected to the 1 / 3 reverse injection current Ir controls the conduction degree of the first switch on the connected energy consumption branch with 1 / 3 of the reverse injection current Ir as the given value. Similarly, a buck circuit with a buck ratio of 2 / 3 is set between the control circuit AP3 connected to the 2 / 3 reverse injection current Ir and the first acquisition circuit AP1. At this time, the control circuit AP3 connected to the 2 / 3 reverse injection current Ir controls the conduction degree of the first switch on the connected energy consumption branch with 2 / 3 of the reverse injection current Ir as the given value. By using the above method, 1 / 3 of the reverse injection current Ir can be maintained to flow through one energy consumption branch and 2 / 3 of the reverse injection current Ir to flow through the other energy consumption branch, and the sum of the currents on the two energy consumption branches is exactly the reverse injection current Ir, so that all the reverse injection currents are consumed through the energy consumption branches.

[0083] The above is the process of the control circuit 23 controlling the anti - injection protection circuit to eliminate the anti - injection current when one or more energy - consuming branches are set in the circuit. In actual application, in order to prevent the first switch on the energy - consuming branch from being damaged by overheating, refer to Figure 11 As shown, a current - limiting resistor Rd can also be connected in series on each energy - consuming branch, so as to reduce the power value received by the first switch, thereby achieving the purpose of protecting the safety of the first switch.

[0084] In actual application, the anti - injection protection circuit can be arranged inside the power supply circuit. In another example, the anti - injection protection circuit is provided with four external interfaces. The power supply circuit can be connected to the anti - injection protection circuit through one of the external interfaces and a cable, and the load can be connected to the anti - injection protection circuit through the other two external interfaces and a cable. At this time, the anti - injection protection circuit can be regarded as a device independent of the power supply circuit.

[0085] Based on the same concept, an embodiment of the present application also provides a power supply device, which may include a power supply circuit and the aforementioned anti - injection protection circuit. Among them, the power supply circuit can be directly connected to the AC power supply or connected to the AC power supply through other devices, convert the received AC electrical energy into DC electrical energy and output it to the load connected at the back end. The anti - injection protection circuit is connected between the power supply circuit and the load, and is used to absorb the above - mentioned anti - injection current when an anti - injection current appears on the load side.

[0086] Among them, the power supply circuit can be the aforementioned power supply circuit, and of course, other circuit structures can also be adopted. For example, in order to improve the efficiency and power supply safety of the power supply circuit, the power supply circuit can also include a protection device and an energy - storage device. The protection device includes, but is not limited to: over - current protection device, over - voltage protection device and short - circuit protection device.

[0087] Based on the same concept, an embodiment of the present application also provides an electronic device, which includes the aforementioned anti - injection protection circuit.

[0088] In one example, the electronic device may also include a power supply circuit (for realizing various power conversions) and an electrical device. The electronic device can be connected to an AC power supply, and the AC power supply supplies power to multiple components in the electronic device. Among them, the electrical device includes, but is not limited to: transportation tools, robots, lighting devices, industrial devices, intelligent factory devices, etc.

[0089] In a possible design, the electronic device is connected to a power supply system, and the electronic device is used to provide anti - injection protection for the power supply system when an anti - injection fault occurs in the power supply system.

[0090] In a possible design, the electronic device is connected to a power distribution system, and the electronic device is used to provide anti - injection protection for the power distribution system when an anti - injection fault occurs in the power distribution system.

[0091] The protection process of the anti-backflow protection circuit has been described above from the perspective that the control circuit is a discrete device. Those skilled in the art should understand that the control circuit provided by the embodiments of the present application can also be implemented in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can be in the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0092] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0093] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implements the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0094] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0095] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the protection scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. An anti-backflow protection circuit, characterized in that, The reverse current injection protection circuit is connected between the power supply circuit and the load. The reverse current injection protection circuit includes: at least one energy consumption branch, a first current sensor, and a control circuit; The at least one energy consumption branch is connected in parallel with the power supply circuit, and a second current sensor is arranged on each energy consumption branch; The first current sensor is used to detect the current between the load and the power supply circuit; The control circuit is respectively connected to the first current sensor and each energy consumption branch, and is used to, when reverse current injection occurs in the load, control the resistance value of each energy consumption branch according to the current value detected by the first current sensor and the current value detected by the second current sensor on each energy consumption branch, so that the sum of the currents on all energy consumption branches is greater than or equal to the reverse current injection.

2. The circuit according to claim 1, wherein Each energy consumption branch includes a first switch and the second current sensor. The first switch is a voltage-driven switch. The first switch is used to control the opening and closing of the corresponding energy consumption branch and adjust the total impedance of the corresponding energy consumption branch. The control end of the first switch is connected to the control circuit.

3. The circuit according to claim 2, characterized in that, Each energy consumption branch further includes at least one current-limiting resistor Rd, and each current-limiting resistor is connected in series with the first switch.

4. The circuit according to claim 2 or 3, characterized in that, If the device specifications on each energy consumption branch are the same, the control circuit includes: a first sampling circuit, a second sampling circuit, a control circuit, and a driving circuit; The first sampling circuit is used to receive the current value detected by the first current sensor and output a first signal, and the first signal is in a proportional relationship with the current on the load; The second sampling circuit is used to receive the current value detected by the target second current sensor and output a second signal, and the second signal is in a proportional relationship with the current on the energy consumption branch where the target second current sensor is located. The target second current sensor is any one of the second current sensors in the reverse current injection protection circuit; The control circuit is used to generate a control signal for each first switch according to the first signal and the second signal, and the control signal is used to control the conduction degree of each first switch; The driving circuit is used to perform power amplification processing on the control signal and then output it to the control end of each first switch.

5. The circuit according to claim 2 or 3, characterized in that, The control circuit includes: a first sampling circuit, a second sampling circuit corresponding to each second current sensor, a control circuit corresponding to each second sampling circuit, and a driving circuit corresponding to each control circuit; The first sampling circuit is used to receive the current value detected by the first current sensor and output a first signal, and the first signal is in a proportional relationship with the current on the load; Each second sampling circuit is used to receive the current value detected by the corresponding second current sensor and output a second signal, and the second signal is in a proportional relationship with the current on the energy consumption branch where the corresponding second current sensor is located; Each control circuit is used to generate a control signal for the first switch on the energy signal branch where the connected second sensor is located according to the first signal output by the first sampling circuit and the second signal output by the corresponding second sampling circuit; Each driving circuit is used to perform power amplification on the first control signal output by the corresponding control circuit and then output it to the control terminal of the corresponding first switch.

6. The circuit according to claim 5, wherein The specifications of the first switches on each energy consumption branch are different. The control circuit further includes a buck circuit corresponding to each control circuit. Each buck circuit is connected between the first sampling circuit and the corresponding control circuit, and each buck circuit is used to perform a fixed-ratio buck processing on the first signal.

7. The circuit according to any one of claims 1 to 6, characterized in that, The first current sensor is a first sampling resistor, the second current sensor is a second sampling resistor. The first end of the first sampling resistor is connected to the second end of each second sampling resistor, and the first end of the first sampling resistor is connected to the end of the power supply circuit that outputs a low level.

8. A power supply device, characterized in that, It includes a power supply circuit and the reverse injection protection circuit according to any one of claims 1 to 7; The power supply circuit is used to be connected to an AC power supply, convert the alternating current output by the AC power supply into direct current and supply power to the load; The reverse injection protection circuit is connected between the power supply circuit and the load, and is used to control the reverse injection current to flow to each energy consumption branch when a reverse injection current appears in the power supply device.

9. An electronic device, characterized in that, It includes the reverse injection protection circuit according to any one of claims 1-7.

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