Overcurrent protection circuit and electronic device

Abstract

The embodiment of the present application relates to an overcurrent protection circuit and electronic equipment, the circuit comprises: first amplification module, second amplification module, switch module, controller and drive chip, the input end of the first amplification module is connected to the external current output end, the output end of the first amplification module is connected with the input end of the second amplification module and the first input end of the controller respectively, the output end of the second amplification module is connected to the first node, the input end of the switch module is connected to the first node, and the output end is connected to one end of the drive chip, the second input end of the controller is connected to the first node, and the output end is connected to the other end of the drive chip, so that the technical effect of realizing fast overcurrent protection and reducing the probability of switch device damage can be realized.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of over-current protection circuit, in particular to an over-current protection circuit and electronic equipment. BACKGROUND

[0002] Boost type power factor correction (Boost-PFC) circuit is widely used in the field of electrical appliances. For over-current protection problem, generally, a comparator is built by using an operational amplifier, then a high (low) level over-current signal is sent to a controller, the controller forcibly closes a pulse width modulation (PWM) peripheral according to the over-current signal, and finally the protection purpose is realized.

[0003] However, the over-current signal is sent to the controller for processing, which essentially still belongs to software protection, and the protection time will inevitably be prolonged, and if the control period is too long, the protection may fail. SUMMARY

[0004] In view of this, in order to solve the technical problems of slow over-current protection speed and high probability of switch device damage, the embodiment of the present application provides an over-current protection circuit and electronic equipment.

[0005] In the first aspect, the embodiment of the present application provides an over-current protection circuit, comprising:

[0006] a first amplification module, a second amplification module, a switch module, a controller and a drive chip;

[0007] The input end of the first amplification module is connected to an external current output end, and the output end of the first amplification module is connected with the input end of the second amplification module and the first input end of the controller respectively;

[0008] The output end of the second amplification module is connected to a first node;

[0009] The input end of the switch module is connected to the first node, and the output end is connected to one end of the drive chip;

[0010] The second input end of the controller is connected to the first node, and the output end is connected to the other end of the drive chip.

[0011] In one possible implementation, the first amplification module comprises:

[0012] a first amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor;

[0013] The positive input end of the first amplifier is connected to one end of the first resistor and one end of the second resistor, the negative input end is connected to one end of the third resistor and one end of the fourth resistor, and the output end is connected to a second node;

[0014] The other end of the first resistor is connected to the output end of the external current;

[0015] The other end of the second resistor is connected to the output end of the first power supply;

[0016] The other end of the third resistor is connected to a first ground end;

[0017] The other end of the fourth resistor is connected to the second node and the input end of the second amplification module;

[0018] One end of the fifth resistor is connected to the second node, and the other end is connected to a second ground end;

[0019] One end of the sixth resistor is connected to the second node, and the other end is connected to the first input end of the controller.

[0020] In one possible implementation, the second amplification module comprises:

[0021] A second amplifier, a seventh resistor, an eighth resistor, a ninth resistor, and a tenth resistor;

[0022] The positive input end of the second amplifier is connected to the output end of the first amplification module, the negative input end is connected to one end of the seventh resistor and one end of the eighth resistor, and the output end is connected to one end of the ninth resistor and one end of the tenth resistor;

[0023] The other end of the seventh resistor is connected to a second power supply output end;

[0024] The other end of the eighth resistor is connected to a third ground end;

[0025] The other end of the ninth resistor is connected to the output end of the third power supply;

[0026] The other end of the tenth resistor is connected to the first node.

[0027] In one possible implementation, the switch module comprises:

[0028] A first switch submodule and a second switch submodule;

[0029] The input end of the first switch submodule is connected to the first node, and the output end is connected to the input end of the second switch submodule;

[0030] The output end of the second switch submodule is connected to one end of the drive chip.

[0031] In a possible implementation, the first switch sub-module comprises:

[0032] a first triode and an eleventh resistor;

[0033] a first pole of the first triode is connected to the first node, a second pole is connected to a fourth ground terminal, and a third pole is connected to one end of the eleventh resistor;

[0034] the other end of the eleventh resistor is connected to an input terminal of the second switch sub-module.

[0035] In a possible implementation, the second switch sub-module comprises:

[0036] a second triode and a twelfth resistor;

[0037] a first pole of the second triode is connected to an output terminal of the first switch sub-module and one end of the twelfth resistor, a second pole is connected to a fourth power output terminal and the other end of the twelfth resistor, and a third pole is connected to one end of the driving chip.

[0038] In a possible implementation,

[0039] the first amplification module is configured to amplify an initial voltage input by an external circuit and output an amplified first voltage, and feed back the first voltage to the controller for analog-to-digital conversion.

[0040] In a possible implementation,

[0041] the second amplification module is configured to amplify the first voltage output by the first amplification module again, and output an amplified second voltage to the controller, and use the controller to determine whether the second voltage triggers overcurrent control.

[0042] In a possible implementation,

[0043] the switch module is configured to supply power to the driving chip in a normal working state, and is disconnected to stop supplying power to the driving chip when the second amplification module outputs a low-level signal.

[0044] In a second aspect, an embodiment of the present application provides an electronic device, which comprises the overcurrent protection circuit according to any one of the first aspect.

[0045] The overcurrent protection circuit and the electronic device provided by the embodiment of the present application, through setting a first amplification module, a second amplification module, a switch module, a controller and a driving chip, the input end of the first amplification module is connected to an external current output end, the output end of the first amplification module is connected to the input end of the second amplification module and the first input end of the controller respectively, the output end of the second amplification module is connected to a first node, the input end of the switch module is connected to the first node, and the output end of the switch module is connected to one end of the driving chip, the second input end of the controller is connected to the first node, and the output end of the controller is connected to the other end of the driving chip, in the case that the external current exceeds a set value or the first amplification module fails, an amplification signal is output through the second amplification module, so that the switch module is disconnected, the power supply to the driving chip is stopped, the operation of the driving chip is quickly stopped, the fast overcurrent protection mechanism is triggered, the speed of the power-off processing of the driving chip controlled by the controller software is effectively improved, the damage of the circuit device caused by the failure of the amplification module or the excessive current is avoided, the fast overcurrent protection is realized, and the technical effect of reducing the probability of damage of the switch device is realized. BRIEF DESCRIPTION OF DRAWINGS

[0046] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one embodiment consistent with the present application and, together with the description, serve to explain the principles of the application.

[0047] Figure 1 A structure schematic diagram of an overcurrent protection circuit provided by the embodiment of the present application is shown in the figure.

[0048] Figure 2 A structure schematic diagram of another overcurrent protection circuit provided by the embodiment of the present application is shown in the figure.

[0049] Figure 3 A structure schematic diagram of another overcurrent protection circuit provided by the embodiment of the present application is shown in the figure.

[0050] Figure 4 A structure schematic diagram of a PFC power factor correction circuit provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0051] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some 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 those skilled in the art without creative labor fall within the protection scope of the present application.

[0052] The terms "comprising" and "having" in the embodiments of the present application are used in an inclusive sense, and are intended to mean that additional elements / components / etc. can be present in addition to those listed; the terms "first" and "second" etc. are used only as labels, and do not limit the number of objects. In addition, different elements and regions in the drawings are only schematically shown, and thus the present application is not limited to the sizes or distances shown in the drawings.

[0053] For the purpose of understanding the embodiments of the present application, further explanation and description will be made below in conjunction with the drawings and specific embodiments, which do not constitute a limitation on the embodiments of the present application.

[0054] Over current protection (OCP) is a protection mode that makes the protection device act when the current exceeds the predetermined maximum value. In circuit design, electronic devices have their own rated current, which is not allowed to exceed the rated current, otherwise the device will be burned out. With the over-current protection mechanism, when the current exceeds the set current, the device is automatically powered off to protect the device or give an alarm signal.

[0055] Figure 1 A structural schematic diagram of an over-current protection circuit provided by the embodiments of the present application is shown. The over-current protection circuit can be applied to an over-current protection device. As shown in the structure, the over-current protection circuit specifically comprises: Figure 1

[0056] a first amplification module 11, a second amplification module 12, a switch module 13, a controller 14 and a driving chip 15.

[0057] Further, the over-current protection circuit further comprises a first node (hereinafter collectively referred to as P1). The node can be understood as a connection point formed between two modules or three modules, for example, P1 is an electrical connection point formed by the connection of the second amplification module and the switch module and the controller.

[0058] The internal circuit structure of the over-current protection circuit provided by the embodiments of the present application comprises:

[0059] The input end of the first amplification module 11 is connected to an external current output end, and the output end is connected to the input end of the second amplification module 12 and the first input end of the controller 14, respectively;

[0060] The output end of the second amplification module 12 is connected to the first node P1;

[0061] The input end of the switch module 13 is connected to the first node P1, and the output end is connected to one end of the driving chip 15;

[0062] ​The second input end of the controller 14 is connected to the first node P1, and the output end is connected to the other end of the driving chip 15.

[0063] According to Figure 1 According to the provided diagram, when the circuit is normally working and the external current does not exceed the set protection value, the amplified signal is output through the first amplification module, the received amplified signal is converted between the analog signal and the digital signal through the controller and is sent to the driving chip, normal operation is performed through software, at the same time, the received amplified signal is compared through the second amplification module, the high-level output signal is obtained, and the high-level output signal is fed back to the controller, the overcurrent protection mechanism is not triggered, and the output high-level signal reaches the opening voltage of the switch module, so that the switch module is turned on, and the high-level signal is output to the driving chip to supply power for the driving chip.

[0064] When the external current exceeds the set protection value or the first amplification module is invalid, the first amplification module outputs a low-level signal, the second amplification module flips after receiving the low-level signal, and the output signal flips to a low level, the low-level signal cannot reach the opening voltage of the switch module, the switch module is disconnected, and the driving chip cannot be powered, and the driving chip is directly powered off. At this time, the low-level signal is output to the controller through software control, is received and analyzed through the controller, the overcurrent protection mechanism is triggered, the low-level signal is continuously sent to the driving chip, and the driving chip cannot receive the low-level signal because the driving chip has been powered off, so that the fast overcurrent protection of the PFC circuit is realized, and the technical effect of reducing the probability of damage of the switching device is realized.

[0065] The overcurrent protection circuit provided by the embodiment of the application comprises a first amplification module, a second amplification module, a switch module, a controller and a driving chip, and the second amplification module and the switch module are combined to work, when the external current exceeds the set protection value or the first amplification module is invalid, the low-level signal can be obtained through the second amplification module, the opening voltage of the switch module is not reached, the switch module is disconnected, and the driving chip is directly powered off, the fast overcurrent protection is realized without affecting the software control overcurrent protection mechanism, and the technical effect of reducing the probability of damage of the switching device is realized.

[0066] In an optional scheme of the embodiment of the present application, the first amplification module comprises a first amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor; the positive input end of the first amplifier is connected to one end of the first resistor and one end of the second resistor, the negative input end is connected to one end of the third resistor and one end of the fourth resistor, and the output end is connected to the second node; the other end of the first resistor is connected to the output end of the external current; the other end of the second resistor is connected to the output end of the first power supply; the other end of the third resistor is connected to the first ground end; the other end of the fourth resistor is connected to the second node and the input end of the second amplification module; one end of the fifth resistor is connected to the second node, and the other end is connected to the second ground end; one end of the sixth resistor is connected to the second node, and the other end is connected to the first input end of the controller.

[0067] In an optional scheme of the embodiment of the present application, the second amplification module comprises a second amplifier, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor; the positive input end of the second amplifier is connected to the output end of the first amplification module, the negative input end is connected to one end of the seventh resistor and one end of the eighth resistor, and the output end is connected to one end of the ninth resistor and one end of the tenth resistor; the other end of the seventh resistor is connected to the second power supply output end; the other end of the eighth resistor is connected to the third ground end; the other end of the ninth resistor is connected to the output end of the third power supply; and the other end of the tenth resistor is connected to the first node.

[0068] In an optional scheme of the embodiment of the present application, the switch module comprises a first switch submodule and a second switch submodule; the input end of the first switch submodule is connected to the first node, and the output end is connected to the input end of the second switch submodule; and the output end of the second switch submodule is connected to one end of the driving chip.

[0069] In an optional scheme of the embodiment of the present application, the first switch submodule comprises a first triode and an eleventh resistor; the first pole of the first triode is connected to the first node, the second pole is connected to the fourth ground end, and the third pole is connected to one end of the eleventh resistor; and the other end of the eleventh resistor is connected to the input end of the second switch submodule.

[0070] In an optional scheme of the embodiment of the present application, the second switch submodule comprises a second triode and a twelfth resistor; the first pole of the second triode is connected to the output end of the first switch submodule and one end of the twelfth resistor, the second pole is connected to the fourth power supply output end and the other end of the twelfth resistor, and the third pole is connected to one end of the driving chip.

[0071] In an optional scheme of the embodiment of the present application, the first amplification module is configured to amplify the initial voltage input by the external circuit and output the amplified first voltage, and the first voltage is fed back to the controller for analog-to-digital conversion.

[0072] In an optional solution of the embodiment of the application, the second amplification module is configured to amplify the first voltage output by the first amplification module again and output the amplified second voltage to the controller, and the controller is used to determine whether the second voltage triggers the overcurrent control.

[0073] In an optional solution of the embodiment of the application, the switch module is configured to supply power to the driving chip in a normal working state, and is disconnected to stop supplying power to the driving chip when the second amplification module outputs a low-level signal.

[0074] Hereinafter, the first amplification module includes a first amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor, the second amplification module includes a second amplifier, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor, the switch module includes a first switch submodule and a second switch submodule, and the controller and the driving chip are taken as examples for introduction. The resistor in the embodiment of the application represents a resistor device, and can be represented by a resistor device but is not limited to a resistor device. Figure 2 , a structure schematic diagram of another overcurrent protection circuit provided by the embodiment of the application is shown. The overcurrent protection circuit is described on the basis of the first overcurrent protection circuit. As shown in the diagram provided by the embodiment of the application, the overcurrent protection circuit specifically includes: Figure 2

[0075] The first amplification module 11, the second amplification module 12, the switch module 13, the controller (hereinafter collectively referred to as MCU) 14 and the driving chip 15.

[0076] Further, the overcurrent protection circuit further includes an external power supply VCC, which is used to provide a stable power supply voltage for the overcurrent protection circuit.

[0077] Further, the overcurrent protection circuit further includes a second node (hereinafter collectively referred to as P2), and the above node can be understood as a connection point formed by the connection of two devices or the connection of three devices, for example, P2 is an electrical connection point formed by the connection of the first amplifier and the fourth resistor, the fifth resistor and the sixth resistor.

[0078] The first amplification module 11 specifically includes:

[0079] The first amplifier A1, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5 and the sixth resistor R6.

[0080] ​The positive input end of the first amplifier A1 is connected to one end of the first resistor R1 and one end of the second resistor R2, the negative input end is connected to one end of the third resistor R3 and one end of the fourth resistor R4, and the output end is connected to the second node P2; the other end of the first resistor R1 is connected to the output end of the external current I; the other end of the second resistor R2 is connected to the output end of the first power supply VCC; the other end of the third resistor R3 is connected to the first ground end GND; the other end of the fourth resistor R4 is connected to the second node P2 and the input end of the second amplification module 12; one end of the fifth resistor R5 is connected to the second node P2, and the other end is connected to the second ground end GND; one end of the sixth resistor R6 is connected to the second node P2, and the other end is connected to the first input end of the controller MCU.

[0081] Further, Figure 4 The structure diagram of the PFC power factor correction circuit provided by the embodiment of the application is shown in the figure, Figure 4 As can be seen from the figure, a closed loop is formed by connecting the capacitor C, the sampling resistor R, the rectifier bridge structure, the inductor L and the unidirectional conduction diode D at both ends of the direct current load. The current in the rectifier bridge is detected in real time by current sampling. The overcurrent protection mechanism is triggered by detecting the current size to protect the device Q. The reference point in the PFC circuit is set to the right side of the sampling resistor R, and the voltage Ui collected on the left side of the sampling resistor R decreases with the increase of the bus current.

[0082] According to Figure 2 The relationship between the output signal U0 in the circuit and the sampling voltage Ui is as follows according to the figure provided by the embodiment of the application:

[0083] Formula 1

[0084] Formula 2

[0085] As can be seen from the above expression, with the increase of the bus current I, the sampling voltage Ui will decrease, and the voltage at the positive input end of the first amplifier A1 will decrease through the voltage division of the first resistor R1 and the second resistor R2. At this time, the voltage at the reverse input end of the first amplifier A1 is in a small state through the voltage division of the third resistor R3 and the fourth resistor R4, and the output voltage U0 obtained by the first amplifier A1 comparing the voltages at the positive input end and the reverse input end will also decrease. In the case that the external sampling current I exceeds the defined protection value or the first amplifier A1 fails, the first amplifier A1 outputs a low-level signal U0, and under the pull-up action of the fifth resistor R5 and the protection of the sixth resistor R6, the low-level signal is maintained and sent to the controller MCU for digital-to-analog AD conversion processing. At the same time, the low-level signal U0 is input to the input end of the second amplification module 12, so that the second amplification module 12 is flipped to obtain a flipped low-level, control the switching module 13 to be disconnected, and then disconnect the driving chip 15, stop supplying power to the driving chip 15, and play a role of rapid overcurrent protection, avoiding the damage of the device Q.

[0086] As Figure 2 shown in the structure, the second amplification module 12 in the overcurrent protection circuit specifically comprises:

[0087] The second amplifier A2, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9 and the tenth resistor R10.

[0088] The positive input end of the second amplifier A2 is connected to the output end of the first amplification module 11, the inverting input end is connected to one end of the seventh resistor R7 and one end of the eighth resistor R8, and the output end is connected to one end of the ninth resistor R9 and one end of the tenth resistor R10; the other end of the seventh resistor R7 is connected to the second power supply VCC output end; the other end of the eighth resistor R8 is connected to the third ground end GND; the other end of the ninth resistor R9 is connected to the output end of the third power supply VCC; and the other end of the tenth resistor R10 is connected to the first node P1.

[0089] Further, according to Figure 2The provided diagram, when the circuit is working normally, a high level signal Ui is provided through the PFC circuit, and a high level signal U0 is obtained after amplification through the first amplification module 11. The first amplification module 11 inputs the output high level signal U0 to the positive input end of the second comparator A2, and compares it with the voltage Uref obtained after voltage division through the seventh resistor R7 and the eighth resistor R8, to obtain a high level output signal U1. The high level signal U1 is still at a high level after voltage division through the tenth resistor R10, reaches the opening voltage of the switching module 13, so that the switching module 13 is turned on to supply power to the driving chip 15. When the PFC circuit is abnormal, the external sampling current I exceeds the set protection value or the first amplification module 11 fails to work, the sampling signal Ui is a low level signal, and the output signal U0 of the first amplification module 11 is still a low level signal. At this time, the signal U0 is lower than Uref after voltage division through the seventh resistor R7 and the eighth resistor R8, so that the second amplifier A2 signal flips and outputs a low level signal U1. The low level signal U1 is sent to the controller MCU and the switching module 13. After the switching module 13 inputs the low level signal, the opening voltage is not reached, so that the switching module 13 is disconnected, directly making the driving chip 15 power off, and completing the overcurrent protection control of the circuit. At the same time, the controller MCU needs to trigger the overcurrent protection mechanism after receiving, analyzing and judging the signal under software control, and then sends a low level PWM wave to the driving chip 15 to control the driving chip 15 to stop running. At this time, because the driving chip 15 has been powered off under hardware control, it cannot receive the PWM wave, so as to achieve the technical effects of fast overcurrent protection and reducing the probability of damage to the switching device.

[0090] As Figure 2 shown in the structure, the switching module 13 in the overcurrent protection circuit specifically includes:

[0091] The first switching submodule 21 and the second switching submodule 22.

[0092] The input end of the first switching submodule 21 is connected to the first node P1, and the output end is connected to the input end of the second switching submodule 22. The output end of the second switching submodule 22 is connected to one end of the driving chip 15.

[0093] As Figure 2The provided diagram shows that, in a possible example scenario, when the circuit is in a normal working state, the sampling current output by the external circuit does not exceed the set protection value, and the first amplification module 11 is in a normal working state, a high-level signal U0 is output by the first amplification module 11, a high-level output signal U1 is obtained by comparison through the second amplification module 12, the high-level output signal U1 reaches the opening voltage of the first switch submodule 21, so that the first switch submodule 21 is turned on, and a low-level signal is output through the first switch submodule 21; the second switch submodule 22 reaches the opening point under the low-level signal, so that the second switch submodule 22 is also turned on, and can directly supply power to the driving chip 15. In the case that the sampling current I of the external circuit exceeds the set protection value or the first amplification module 11 fails, the sampling signal Ui received by the first amplification module 11 is a low-level signal, so that a low-level signal U0 is output through the first amplification module 11, and the low-level signal is compared as the input signal of the second amplification module 12, so that the second amplification module 12 inverts the signal and outputs a low-level output signal U1; the low-level signal U1 does not reach the opening voltage of the first switch submodule 21, so that the first switch submodule 21 is turned off; the first switch submodule 21 after being turned off makes the input end of the second switch submodule 22 in a high-level signal state, which does not reach the opening voltage of the second switch submodule 22, so that the second switch submodule 22 is turned off, and the driving chip 15 is directly controlled to be powered off; on the basis of not affecting the software control processing process, the technical effect of realizing fast overcurrent protection and reducing the probability of damage to the switching device is achieved.

[0094] Hereinafter, the first amplification module includes a first amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor, the second amplification module includes a second amplifier, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor, the first switch submodule includes a first triode and an eleventh resistor, the second switch submodule includes a second triode and a twelfth resistor, and the controller and the driving chip are taken as examples for introduction. Referring to Figure 3 , a structure schematic diagram of another overcurrent protection circuit provided by the embodiment of the application is shown. The overcurrent protection circuit is described on the basis of the first overcurrent protection circuit. As Figure 3 is shown, it further specifically includes:

[0095] The first amplification module 11, the second amplification module 12, the first switch submodule 21, the second switch submodule 22, the controller 14 and the driving chip 15.

[0096] Further, the first amplification module is configured to amplify an initial voltage input by an external circuit and output an amplified first voltage, and the first voltage is fed back to the controller for analog-to-digital conversion.

[0097] Furthermore, the second amplification module is configured to amplify the first voltage output by the first amplification module again, and output the amplified second voltage to the controller, using the controller to determine whether the second voltage triggers overcurrent control.

[0098] Furthermore, the switching module is configured to: supply power to the driver chip under normal operating conditions, and disconnect when the second amplification module outputs a low-level signal, thereby stopping the power supply to the driver chip.

[0099] like Figure 3 The structure shown, specifically the first switching submodule 21 in the overcurrent protection circuit, includes:

[0100] The first transistor T1 and the eleventh resistor R11.

[0101] The first terminal of the first transistor T1 is connected to the first node P1, the second terminal is connected to the fourth ground terminal GND, and the third terminal is connected to one end of the eleventh resistor R11.

[0102] The other end of the eleventh resistor R11 is connected to the input terminal of the second switch submodule 22.

[0103] Furthermore, the first electrode of the first transistor is the base of the NPN bipolar transistor, the second electrode of the first transistor is the emitter of the NPN bipolar transistor, and the third electrode of the first transistor is the collector of the NPN bipolar transistor.

[0104] like Figure 3The provided diagram shows that when the circuit is in normal operating condition and the bus current supplied by the external circuit is within the set protection value range, a high-level signal U0 is output through the first amplification module 11, and then amplified by the second amplification module to obtain a high-level output signal U1. The high-level output signal U1 reaches the turn-on voltage of the first transistor T1, causing the first transistor T1 to conduct. After the high-level signal is output through the first transistor T1, it is divided by the eleventh resistor R11, so that the second switching submodule 22 obtains a small voltage, reaching the turn-on voltage of the second switching submodule 22. The second switching submodule 22 conducts and can directly supply power to the driver chip 15. When the current I in the external PFC circuit is too large, causing the bus current I to exceed the set protection value, or when the first amplification module 11 fails, a low-level signal Ui is obtained. After being amplified by the first amplification module 11, a low-level signal U0 is output. U0 is then amplified again as the output of the second amplification module 12, causing a flip and outputting a low-level flip signal U1. Because the low-level signal fails to reach the turn-on voltage of the first transistor T1, the first transistor T1 is turned off. After being turned off, the voltage at the collector of the first transistor T1 is very large, far exceeding the turn-on voltage of the second switch submodule 22, causing the second switch submodule 22 to turn off. This directly controls the power-off of the driver chip 15, achieving a fast current protection mechanism and realizing the technical effect of fast overcurrent protection of the circuit, reducing the probability of damage to the switching devices.

[0105] like Figure 3 The structure shown, specifically the second switch submodule 22 in the overcurrent protection circuit, includes:

[0106] The second transistor T2 and the twelfth resistor R12.

[0107] The first terminal of the second transistor T2 is connected to the output terminal of the first switch submodule 21 and one end of the twelfth resistor R12, the second terminal is connected to the output terminal of the fourth power supply VCC and the other end of the twelfth resistor R12, and the third terminal is connected to one end of the driver chip 15.

[0108] Furthermore, the first electrode of the second transistor is the base of the PNP bipolar transistor, the second electrode of the second transistor is the emitter of the PNP bipolar transistor, and the third electrode of the second transistor is the collector of the PNP bipolar transistor.

[0109] like Figure 3The provided diagram shows that when the circuit is in normal working state and the bus current provided by the external circuit is within the set protection value range, a high-level signal U0 is output through the first amplification module 11, and then amplified by the second amplification module to obtain a high-level output signal U1. The high-level output signal U1 reaches the opening voltage of the first switch submodule 21, so that the first switch submodule 21 is turned on. After the high-level signal is output through the first switch submodule 21, the voltage at the base of the second triode T2 is small due to the voltage division effect of the twelfth resistor R12, and the second triode T2 is turned on, so that the power supply for the driving chip 15 can be directly completed. When the current I of the external PFC circuit is too large, so that the bus current I exceeds the set protection value or in the case of failure of the first amplification module 11, a low-level signal Ui is obtained, which is amplified by the first amplification module 11 to output a low-level signal U0. U0 is amplified again as the output of the second amplification module 12, inverts, and outputs a low-level inverted signal U1. Because the low-level signal fails to reach the opening voltage of the first switch submodule 21, the first switch submodule 21 is turned off. The voltage at the output end of the first switch submodule 21 after being turned off is very large, far exceeding the opening voltage of the second triode T2, so that the second triode T2 is turned off, thereby directly controlling the driving chip 15 to be powered off, achieving a fast current protection processing mechanism, realizing fast overcurrent protection of the circuit, and reducing the probability of damage to the switching device.

[0110] According to Figure 3 The provided diagram can maintain the original overcurrent protection mechanism: after the first amplifier A1 is input with the external signal Ui, the output signal U0 is obtained after amplification processing, and the output voltage U0 is input as the in-phase input end of the second amplifier A2 and compared with the voltage Uref at the reverse input end of the second amplifier A2. When the output signal U0 is less than the voltage Uref at the reverse input end of the second amplifier A2, the following situations may occur: one, the bus current exceeds the set protection value; two, the first amplifier A1 fails, and U0 remains low level under the action of the fifth resistor R5 (pull-down resistor). At this time, the output signal of the second amplifier A2 is inverted, the controller 14 receives the output signal from the second amplifier A2, and the controller 14 processes the high and low levels of the signal through software. If the controller 14 determines that the overcurrent condition occurs, the software overcurrent protection mechanism will be triggered to further close the PWM peripheral, so that the PWM output is low to the driving chip 15 to control the turn-on and turn-off of the switching device Q (the device shown in Figure 4 ).

[0111] The hardware fast over-current protection processing can also be realized by the application. In a possible example scenario, when the current in the PFC circuit does not exceed the set protection value, the sampling signal Ui is amplified by the first amplifier A1 to obtain an output signal U0, the output signal U0 is greater than the reverse input end voltage Uref of the second amplifier A2, at this time, the output signal U1 of the second amplifier A2 is high, the output signal U1 reaches the turn-on voltage of the first transistor T1, the first transistor T1 is turned on, and after the first transistor T1 is turned on, the base of the second transistor T2 receives a low voltage through the small eleventh resistor R11 (voltage dividing resistor) and the large twelfth resistor R12 (voltage dividing resistor), and thus the second transistor T2 is turned on, and thus the driving chip 15 is directly powered.

[0112] When the current in the PFC circuit exceeds the set protection value or the output signal U0 is low due to the failure of the first amplifier A1. Since the output signal U0 is less than the voltage Uref of the reverse input end of the second amplifier A2, the output signal U1 of the second amplifier A2 is flipped to low, and the low signal U1 cannot drive the first transistor T1 to turn on. The turn-off of the first transistor T1 causes the circuit to be cut off, and the base of the second transistor T2 can only receive a high voltage, so that the transistor T2 is turned off, the power supply to the driving chip 15 is cut off, and the power device in the PFC circuit is forced to be closed. In this way, the purpose of protecting the power device is achieved, the fast over-current protection of the circuit is realized, and the probability of damage to the switching device is reduced.

[0113] The over-current protection circuit provided by the embodiment of the application comprises a first amplification module, a second amplification module, a first transistor, an eleventh resistor, a second transistor, a twelfth resistor, a controller and a driving chip. In a normal operation state of the circuit, the signal is amplified by the first amplification module and the second amplification module to output a high voltage signal, the high voltage signal reaches the turn-on voltage of the first transistor, the first transistor is turned on, the voltage is divided by the eleventh resistor and the twelfth resistor, the turn-on voltage of the second transistor is reached, and the second transistor is turned on after the voltage is divided by the eleventh resistor and the twelfth resistor. The second transistor can directly supply power to the driving chip. In the case that the external current is too large and the first amplification module fails, the first amplification module outputs a low voltage signal, the signal is flipped by the second amplification module to output a low voltage signal, the first transistor is turned off, the turn-on voltage of the second transistor is not reached, the second transistor is also turned off, and thus the driving chip is directly powered off, the power device in the PFC circuit is forced to be closed. In this way, the purpose of protecting the power device is achieved, the fast over-current protection of the circuit is realized, and the probability of damage to the switching device is reduced.

[0114] Based on the over-current protection circuit provided in the above embodiment, the application further provides an electronic device, which comprises the over-current protection circuit provided in the above embodiment.

[0115] In a possible design, the electronic device can be, but is not limited to, an air conditioning device, a television device, or a refrigerator device, or any electronic device that needs to use the overcurrent protection circuit structure in the application.

[0116] The above description is merely a specific implementation of the present application. It should be understood that the above description is only a specific implementation of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An overcurrent protection circuit, characterized by comprising: The circuit comprises a first amplification module, a second amplification module, a switch module, a controller and a driving chip. An input end of the first amplification module is connected to an external current output end, and output ends of the first amplification module are respectively connected to an input end of the second amplification module and a first input end of the controller. An output end of the second amplification module is connected to a first node. An input end of the switch module is connected to the first node, and an output end of the switch module is connected to one end of the driving chip. A second input end of the controller is connected to the first node, and an output end of the controller is connected to the other end of the driving chip. The first amplification module comprises a first amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor.

2. The circuit of claim 1, wherein, A positive input end of the first amplifier is connected to one end of the first resistor and one end of the second resistor, a negative input end of the first amplifier is connected to one end of the third resistor and one end of the fourth resistor, and an output end of the first amplifier is connected to a second node. The other end of the first resistor is connected to the external current output end. The other end of the second resistor is connected to an output end of a first power supply. The other end of the third resistor is connected to a first ground end. The other end of the fourth resistor is connected to the second node and an input end of the second amplification module. One end of the fifth resistor is connected to the second node, and the other end of the fifth resistor is connected to a second ground end. One end of the sixth resistor is connected to the second node, and the other end of the sixth resistor is connected to the first input end of the controller. The second amplification module comprises a second amplifier, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor. A positive input end of the second amplifier is connected to an output end of the first amplification module, a negative input end of the second amplifier is connected to one end of the seventh resistor and one end of the eighth resistor, and an output end of the second amplifier is connected to one end of the ninth resistor and one end of the tenth resistor.

3. The circuit of claim 1, wherein, The other end of the seventh resistor is connected to a second power supply output end. The other end of the eighth resistor is connected to a third ground end. The other end of the ninth resistor is connected to an output end of a third power supply. The other end of the tenth resistor is connected to the first node. The switch module comprises a first switch submodule and a second switch submodule. An input end of the first switch submodule is connected to the first node, and an output end of the first switch submodule is connected to an input end of the second switch submodule. An output end of the second switch submodule is connected to one end of the driving chip.

4. The circuit of claim 1, wherein, The first switch submodule comprises a first triode and an eleventh resistor. A first pole of the first triode is connected to the first node, a second pole of the first triode is connected to a fourth ground end, and a third pole of the first triode is connected to one end of the eleventh resistor. The other end of the eleventh resistor is connected to an input end of the second switch submodule. The second switch submodule comprises a second triode and a twelfth resistor.

5. The circuit of claim 4, wherein, A first pole of the second triode is connected to an output end of the first switch submodule and one end of the twelfth resistor, a second pole of the second triode is connected to a fourth power supply output end and the other end of the twelfth resistor, and a third pole of the second triode is connected to one end of the driving chip.

7. The circuit according to claim 1, wherein ​ ​ 6. The circuit of claim 4, wherein, ​ ​ ​ ​ The first amplification module is configured to amplify an initial voltage input by an external circuit and output an amplified first voltage, and use the first voltage to feed back to the controller for analog-to-digital conversion.

8. The circuit of claim 1, wherein, The second amplification module is configured to re-amplify the first voltage output by the first amplification module and output an amplified second voltage to the controller, and use the controller to determine whether the second voltage triggers overcurrent control.

9. The circuit of claim 1, wherein, The switch module is configured to supply power to the drive chip in a normal working state, and is disconnected to stop supplying power to the drive chip when the second amplification module outputs a low-level signal.

10. An electronic device, comprising: The electronic device comprises the overcurrent protection circuit according to any one of claims 1-9.

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