Overcurrent protection circuit, overcurrent protection system and terminal equipment

Abstract

The present invention discloses an overcurrent protection circuit, an overcurrent protection system and a terminal device. The overcurrent protection circuit includes: a main control chip, a first port of the main control chip is used to connect to an external power supply, and a second port of the main control chip is used to electrically connect to the subsequent circuit; a feedback unit is used to electrically connect to the main control chip; an anti-locking unit is used to electrically connect to the main control chip and the external power supply respectively; wherein the anti-locking unit is used to control the input voltage of the external power supply to the main control chip, the main control chip is used to control the working state of the feedback unit according to the overcurrent state of the external power supply and the input voltage, and the feedback unit is used to control the input power of the external power supply according to the working state. The overcurrent protection circuit of the embodiment of the present invention avoids the phenomenon of circuit locking, so that the overcurrent protection circuit can work stably and improve the reliability of overcurrent protection.

Description

Technical Field

[0001] The present invention relates to the field of switching power supplies, and in particular to an overcurrent protection circuit, an overcurrent protection system and a terminal device. Background Art

[0002] In the field of switching power supplies, overcurrent protection has become a hot research topic for technical researchers because the efficiency of the power supply will be seriously affected when the power supply is operating in an overcurrent state, which in turn affects the normal operation of the entire electrical equipment.

[0003] In the related art, power supply overcurrent protection implemented by half-bridge series resonance scheme is widely used due to its advantages of high efficiency, high reliability, easy implementation, etc. However, the current half-bridge series resonance scheme is prone to circuit lock-up. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an overcurrent protection circuit that can avoid the phenomenon of circuit locking, so that the overcurrent protection circuit can work stably and improve the reliability of overcurrent protection.

[0005] The present invention also provides an overcurrent protection system having the above-mentioned overcurrent protection circuit, and a terminal device having the above-mentioned backup power control system.

[0006] The overcurrent protection circuit according to the first aspect of the present invention is used to be electrically connected to an external power supply and a subsequent circuit respectively, and the overcurrent protection circuit includes:

[0007] A main control chip, wherein a first port of the main control chip is used to be electrically connected to an external power supply, and a second port of the main control chip is used to be electrically connected to the subsequent circuit;

[0008] A feedback unit, the feedback unit is used to be electrically connected to the main control chip;

[0009] an anti-lock unit, the anti-lock unit being used to be electrically connected to the main control chip and an external power supply respectively;

[0010] Among them, the anti-lock unit is used to control the input voltage of the external power supply to the main control chip, the main control chip is used to control the working state of the feedback unit according to the overcurrent state of the external power supply and the input voltage, and the feedback unit is used to control the input power of the external power supply according to the working state.

[0011] The overcurrent protection circuit according to the embodiment of the present invention has at least the following beneficial effects: after the main control chip detects that the external power supply is in an overcurrent state, the control feedback unit starts working, so that the output power of the main control chip is reduced, thereby limiting the input power of the external power supply to the subsequent circuit, and achieving the effect of overcurrent protection; the anti-lock unit controls the input voltage of the external power supply to the first port of the main control chip to prevent the main control chip from stopping working, thereby avoiding the phenomenon of circuit locking, so that the overcurrent protection circuit can work stably, and the reliability of overcurrent protection is improved.

[0012] According to some embodiments of the present invention, the anti-lock unit comprises:

[0013] A reference regulator, wherein the first port of the reference regulator is used to be electrically connected to an external power supply and the first port of the main control chip respectively, the second port of the reference regulator is used to be electrically connected to an external power supply and the first port of the main control chip respectively, and the third port of the reference regulator is grounded.

[0014] According to some embodiments of the present invention, the feedback unit includes:

[0015] A first capacitor, one end of the first capacitor is used to be electrically connected to the third port of the main control chip, and the other end of the first capacitor is grounded;

[0016] a second capacitor, one end of the second capacitor being electrically connected to the fourth port of the main control chip, and the other end of the second capacitor being grounded;

[0017] A first resistor, one end of the first resistor is used to be electrically connected to the fourth port of the main control chip, and the other end of the first resistor is grounded.

[0018] According to some embodiments of the present invention, the overcurrent protection circuit further includes:

[0019] A half-bridge unit, the half-bridge unit being used to be electrically connected to an external power source, the second port of the main control chip, the fifth port of the main control chip, the sixth port of the main control chip and the subsequent circuit respectively;

[0020] A voltage-dividing flow unit is used to be electrically connected to the first port of the main control chip and the subsequent circuit respectively.

[0021] According to some embodiments of the present invention, the half-bridge unit comprises:

[0022] a first voltage-controlled flow element, wherein the drain of the first voltage-controlled flow element is electrically connected to an external power supply, the source of the first voltage-controlled flow element is electrically connected to the second port of the main control chip and the subsequent circuit respectively, and the gate of the first voltage-controlled flow element is electrically connected to the fifth port of the main control chip;

[0023] A second voltage-controlled flow element, wherein the drain of the second voltage-controlled flow element is electrically connected to the source of the first voltage-controlled flow element, the source of the second voltage-controlled flow element is grounded, and the gate of the second voltage-controlled flow element is electrically connected to the sixth port of the main control chip.

[0024] According to some embodiments of the present invention, the pressure-dividing flow unit comprises:

[0025] a second resistor, one end of the second resistor being electrically connected to the first port of the main control chip, and the other end of the second resistor being grounded;

[0026] A third capacitor, one end of the third capacitor is used to be electrically connected to the first port of the main control chip, and the other end of the third capacitor is grounded;

[0027] A diode group, wherein a first port of the diode group is used to be electrically connected to a first port of the main control chip, and a second port of the diode group is grounded;

[0028] a third resistor, one end of which is electrically connected to the third port of the diode group;

[0029] a fourth capacitor, one end of the fourth capacitor being electrically connected to the other end of the third resistor;

[0030] a fifth capacitor, one end of the fifth capacitor being electrically connected to the other end of the fourth capacitor, and the other end of the fifth capacitor being electrically connected to the subsequent circuit;

[0031] A sixth capacitor, one end of the sixth capacitor is used to be electrically connected to the subsequent circuit, and the other end of the sixth capacitor is grounded.

[0032] An overcurrent protection system according to a second aspect of the present invention includes:

[0033] An overcurrent protection circuit according to the first aspect of the present invention;

[0034] an external power supply, the external power supply being electrically connected to the overcurrent protection circuit;

[0035] A subsequent stage circuit is electrically connected to the overcurrent protection circuit.

[0036] The overcurrent protection system according to the embodiment of the present invention has at least the following beneficial effects: the overcurrent protection system avoids the circuit locking phenomenon by adopting the above-mentioned overcurrent protection circuit, so that the overcurrent protection circuit can work stably, improves the reliability of overcurrent protection, and protects the power supply from damage.

[0037] The terminal device according to the third aspect of the embodiment of the present invention includes the overcurrent protection system according to the above-mentioned second aspect of the embodiment of the present invention.

[0038] The terminal device according to the embodiment of the present invention has at least the following beneficial effects: the terminal device can stably implement the overcurrent protection function and protect the power supply from damage by adopting the above-mentioned overcurrent protection system.

[0039] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0041] Figure 1 A block diagram of a specific embodiment of the overcurrent protection circuit of the present invention;

[0042] Figure 2 The figure is a circuit diagram of a specific embodiment of the overcurrent protection circuit of the present invention.

[0043] Reference numerals:

[0044] External power supply 100 , anti-lock unit 200 , main control chip 300 , feedback unit 400 , post-stage circuit 500 , half-bridge unit 600 , voltage divider unit 700 . DETAILED DESCRIPTION

[0045] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0046] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0047] In the description of the present invention, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0048] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, and electrically connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0049] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0050] like Figure 1 As shown, the overcurrent protection circuit according to the embodiment of the present invention includes a main control chip 300, a feedback unit 400 and an anti-lock unit 200. The first port of the main control chip 300 is used to be electrically connected to the external power supply 100, the second port of the main control chip 300 is used to be electrically connected to the post-stage circuit 500, the feedback unit 400 is used to be electrically connected to the main control chip 300, and the anti-lock unit 200 is used to be electrically connected to the main control chip 300 and the external power supply 100 respectively. The anti-lock unit 200 is used to control the input voltage of the external power supply 100 to the main control chip 300, the main control chip 300 is used to control the working state of the feedback unit 400 according to the overcurrent state and input voltage of the external power supply 100, and the feedback unit 400 is used to control the input power of the external power supply 100 according to the working state.

[0051] Specifically, the external power supply 100 and the anti-lock unit 200 are electrically connected to the first port of the main control chip 300, respectively, the feedback unit 400 is electrically connected to the third port and the fourth port of the main control chip 300, respectively, and the second port of the main control chip 300 is electrically connected to the post-stage circuit 500. Among them, the main control chip 300 can be selected as L6599ADTR. It can be understood that the model of the main control chip 300 can also be adaptively selected according to actual needs. When the first port of the main control chip 300 detects that the external power supply 100 is in an overcurrent state, the voltage of the external power supply 100 received by the first port of the main control chip 300 will gradually increase. When the voltage received by the first port of the main control chip 300 reaches the first voltage threshold, the feedback unit 400 will be controlled to start working. When the voltage received by the first port of the main control chip 300 reaches the second voltage threshold, the main control chip 300 stops working. When the voltage received by the first port of the main control chip 300 reaches the third voltage threshold (the third voltage threshold is less than the second voltage threshold), the anti-lock unit 200 starts to work and controls the input voltage of the external power supply 100 to the first port of the main control chip 300 to maintain at the third voltage threshold to prevent the main control chip 300 from stopping working. After starting to work, the feedback unit 400 will control the output power of the main control chip 300 to decrease, thereby limiting the input power of the external power supply 100 to the subsequent circuit 500, thereby protecting the external power supply 100 from damage.

[0052] According to the overcurrent protection circuit of the embodiment of the present invention, after the main control chip 300 detects that the external power supply 100 is in an overcurrent state, the control feedback unit 400 starts to work, so that the output power of the main control chip 300 is reduced, thereby limiting the input power of the external power supply 100 to the subsequent circuit 500, and achieving the effect of overcurrent protection; the anti-lock unit 200 controls the input voltage of the external power supply 100 to the first port of the main control chip 300 to prevent the main control chip 300 from stopping working, thereby avoiding the phenomenon of circuit locking, so that the overcurrent protection circuit can work stably, and the reliability of overcurrent protection is improved.

[0053] like Figure 2 As shown, in some specific embodiments of the present invention, the anti-lock unit 200 includes a reference regulator U2. The reference regulator U2 has a first port for electrically connecting to the external power supply 100 and the first port ISEN of the main control chip 300, a second port for electrically connecting to the external power supply 100 and the first port ISEN of the main control chip 300, and a third port for grounding.

[0054] Specifically, when the voltage received by the first port of the main control chip 300 reaches the first voltage threshold, the feedback unit 400 will be controlled to start working, and when the voltage received by the first port of the main control chip 300 reaches the second voltage threshold, the main control chip 300 stops working. At this time, when the voltage of the external power supply 100 received by the first port ISEN of the main control chip 300 reaches the third voltage threshold, the reference voltage regulator U2 will start the internal circuit to control the voltage received by the first port ISEN of the main control chip 300 to maintain at the third voltage threshold, so as to prevent the main control chip 300 from stopping working due to excessive input voltage from the external power supply 100. Among them, the model of the reference voltage regulator U2 can be selected as AZ432, and it can be understood that the model of the reference voltage regulator U2 can also be adaptively selected according to actual needs.

[0055] like Figure 2 As shown, in some specific embodiments of the present invention, the feedback unit 400 includes a first capacitor C1, a second capacitor C2 and a first resistor R1. One end of the first capacitor C1 is used to be electrically connected to the third port CSS of the main control chip 300, and the other end of the first capacitor C1 is grounded; one end of the second capacitor C2 is used to be electrically connected to the fourth port DELAY of the main control chip 300, and the other end of the second capacitor C2 is grounded; one end of the first resistor R1 is used to be electrically connected to the fourth port DELAY of the main control chip 300, and the other end of the first resistor R1 is grounded.

[0056] Specifically, the second capacitor C2 and the first resistor R1 are connected in parallel with each other, one end shared by the second capacitor C2 and the first resistor R1 is electrically connected to the fourth port DELAY of the main control chip 300, and the other end shared by the second capacitor C2 and the first resistor R1 is grounded. When the external power supply 100 is in an overcurrent state, the voltage of the first port ISEN of the main control chip 300 will increase. When the voltage of the first port ISEN of the main control chip 300 reaches the first voltage threshold, the switch inside the main control chip 300 will be started, so that the first capacitor C1 starts to discharge, thereby rapidly increasing the oscillation frequency of the main control chip 300, and reducing the output power of the second port OUT of the main control chip 300 to the subsequent circuit 500, thereby limiting the input power of the external power supply 100 to the subsequent circuit 500.

[0057] At the same time, when the external power supply 100 is in an overcurrent state, the constant current source inside the main control chip 300 is turned on to charge the second capacitor C2. When the voltage of the second capacitor C2 reaches the fourth voltage threshold, the main control chip 300 stops working; after the main control chip 300 stops working, the second capacitor C2 starts to discharge the first resistor R1. When the voltage of the second capacitor C2 drops to the fifth voltage threshold, the main control chip 300 restarts working and recharges the second capacitor C2, and this cycle is repeated until the external power supply 100 is no longer in an overcurrent state. Through the charge and discharge cycle of the second capacitor C2, the output power of the second port OUT of the main control chip 300 to the subsequent circuit 500 is limited, protecting the external power supply 100 from damage.

[0058] like Figure 2 As shown, in some specific embodiments of the present invention, the overcurrent protection circuit further includes a half-bridge unit 600 and a voltage divider flow unit 700. The half-bridge unit 600 is used to be electrically connected to the external power supply 100, the second port OUT of the main control chip 300, the fifth port HVG of the main control chip 300, the sixth port LVG of the main control chip 300, and the subsequent circuit 500, respectively, and the voltage divider flow unit 700 is used to be electrically connected to the first port ISEN of the main control chip 300 and the subsequent circuit 500, respectively.

[0059] Specifically, when the external power supply 100 is in an overcurrent state, the current flowing through the half-bridge unit 600 increases, and at the same time, the voltage divider unit 700 divides the power supply of the external power supply 100, and the voltage of the first port ISEN of the main control chip 300 increases. When the voltage of the first port ISEN of the main control chip 300 reaches the voltage threshold, the main control chip 300 controls the feedback unit 400 to start working. At this time, the feedback unit 400 controls the output power of the second port OUT of the main control chip 300, the fifth port HVG of the main control chip 300, and the sixth port LVG of the main control chip 300 to decrease, and then the half-bridge unit 600 limits the input power of the external power supply 100.

[0060] like Figure 2 As shown, in some specific embodiments of the present invention, the half-bridge unit 600 includes a first voltage-controlled flow element Q1 and a second voltage-controlled flow element Q2. The drain of the first voltage-controlled flow element Q1 is electrically connected to the external power supply 100, the source of the first voltage-controlled flow element Q1 is electrically connected to the subsequent circuit 500, the gate of the first voltage-controlled flow element Q1 is electrically connected to the fourth port DELAY of the main control chip 300, the drain of the second voltage-controlled flow element Q2 is electrically connected to the source of the first voltage-controlled flow element Q1, the source of the second voltage-controlled flow element Q2 is grounded, and the gate of the second voltage-controlled flow element Q2 is electrically connected to the fifth port HVG of the main control chip 300.

[0061] Specifically, the connection node between the source of the first voltage-controlled current element Q1 and the drain of the second voltage-controlled current element Q2 is electrically connected to the second port OUT of the main control chip 300 and the subsequent circuit 500 , respectively.

[0062] like Figure 2 As shown, in some specific embodiments of the present invention, the voltage divider unit 700 includes a second resistor R2, a third capacitor C3, a diode group D1, a third resistor R3, a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6. One end of the second resistor R2 is used to be electrically connected to the first port ISEN of the main control chip 300, and the other end of the second resistor R2 is grounded, one end of the third capacitor C3 is used to be electrically connected to the first port ISEN of the main control chip 300, and the other end of the third capacitor C3 is grounded, the first port of the diode group D1 is used to be electrically connected to the first port ISEN of the main control chip 300, the second port of the diode group D1 is grounded, one end of the third resistor R3 is used to be electrically connected to the third port of the diode group D1, one end of the fourth capacitor C4 is used to be electrically connected to the other end of the third resistor R3, one end of the fifth capacitor C5 is used to be electrically connected to the other end of the fourth capacitor C4, and the other end of the fifth capacitor C5 is used to be electrically connected to the subsequent circuit 500, one end of the sixth capacitor C6 is used to be electrically connected to the subsequent circuit 500, and the other end of the sixth capacitor C6 is grounded.

[0063] Specifically, the second resistor R2 and the third capacitor C3 are connected in parallel with each other, one end shared by the second resistor R2 and the third capacitor C3 is electrically connected to the first port ISEN of the main control chip 300, and the other end shared by the second resistor R2 and the third capacitor C3 is grounded; the third resistor R3, the fourth capacitor C4, the fifth resistor and the sixth capacitor C6 are connected in series with each other, and the connection node of the fifth capacitor C5 and the sixth capacitor C6 is electrically connected to the subsequent circuit 500.

[0064] like Figure 2As shown, in a specific embodiment, HV+ is the input terminal of the external power supply 100, and T1-A is the primary coil of the transformer in the subsequent circuit 500. When the external power supply 100 is in an overcurrent state, the current flowing through the half-bridge unit 600 increases, and at the same time, the voltage divider unit 700 divides the power supply of the external power supply 100, and at this time, the voltage received by the first port ISEN of the main control chip 300 gradually increases. When the voltage received by the first port ISEN of the main control chip 300 reaches the first voltage threshold 0.8V, the switch inside the main control chip 300 is started, thereby controlling the feedback unit 400 to start working. When the feedback unit 400 starts working, the first capacitor C1 is discharged, so that the oscillation frequency of the main control chip 300 increases rapidly, and the output power of the second port OUT of the main control chip 300 to the subsequent circuit 500 is reduced; at the same time, the constant current source inside the main control chip 300 is turned on to charge the second capacitor C2. When the voltage of the second capacitor C2 reaches the fourth voltage threshold of 3.5V, the main control chip 300 stops working; after the main control chip 300 stops working, the second capacitor C2 starts to discharge the first resistor R1. When the voltage of the second capacitor C2 drops to the fifth voltage threshold of 0.3V, the main control chip 300 starts working again and recharges the second capacitor C2, and this cycle is repeated until the external power supply 100 is no longer in an overcurrent state. The oscillation frequency of the main control chip 300 is rapidly increased by discharging the first capacitor C1 and the charge and discharge cycle of the second capacitor C2, so that the output power of the second port OUT of the main control chip 300, the fifth port HVG of the main control chip 300 and the sixth port LVG of the main control chip 300 are reduced, thereby limiting the input power of the external power supply 100 to the subsequent circuit 500.

[0065] Among them, the charge and discharge cycle of the second capacitor C2 requires the main control chip 300 to charge the second capacitor C2 to the fourth voltage threshold of 3.5V. However, before the main control chip 300 charges the second capacitor C2 to the fourth voltage threshold of 3.5V, the voltage of the first port ISEN of the main control chip 300 may reach the second voltage threshold of 1.5V first, causing the main control chip 300 to stop working. Even if the external power supply 100 is no longer in an overcurrent state, the main control chip 300 will not restart, resulting in a deadlock phenomenon. In order to prevent the deadlock phenomenon, the reference regulator U2 will start working when the voltage of the first port ISEN of the main control chip 300 reaches the third voltage threshold of 1.25V, so that the voltage of the first port ISEN of the main control chip 300 is maintained at the third voltage threshold of 1.25V, and the voltage of the first port ISEN of the main control chip 300 cannot reach the second voltage threshold of 1.5V, thereby avoiding the problem of circuit deadlock.

[0066] The embodiment of the present invention further provides an overcurrent protection system, comprising an overcurrent protection circuit as described in any of the above embodiments, an external power supply and a subsequent circuit. The external power supply is electrically connected to the overcurrent protection circuit, and the subsequent circuit is electrically connected to the overcurrent protection circuit.

[0067] The overcurrent protection system according to the embodiment of the present invention avoids the circuit locking phenomenon by adopting the above-mentioned overcurrent protection circuit, so that the overcurrent protection circuit can work stably, and the reliability of overcurrent protection is improved.

[0068] An embodiment of the present invention further provides a terminal device, comprising the overcurrent protection system described in the above embodiment.

[0069] According to the terminal device of the embodiment of the present invention, by adopting the above-mentioned overcurrent protection system, it is possible to stably implement the overcurrent protection function and protect the power supply from being damaged.

[0070] The terminal device may be a mobile terminal device or a non-mobile terminal device. The mobile terminal device may be a mobile phone, a tablet computer, a laptop computer, a PDA, a wearable device, a CPE, a UFI (wireless hotspot device), etc. The non-mobile terminal device may be a personal computer, a television, a teller machine or a self-service machine, etc. The embodiment of the present invention is not specifically limited.

[0071] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. An overcurrent protection circuit, used to be electrically connected to an external power supply and a subsequent circuit, and characterized in that: The overcurrent protection circuit comprises: A main control chip, wherein a first port ISEN of the main control chip is used to be electrically connected to an external power supply, and a second port OUT of the main control chip is used to be electrically connected to the subsequent circuit; A feedback unit, the feedback unit is used to be electrically connected to the third port CSS and the fourth port DELAY of the main control chip respectively; an anti-lock unit, the anti-lock unit being used to be electrically connected to the first port ISEN of the main control chip and an external power supply respectively; Among them, the anti-lock unit is used to control the input voltage of the external power supply to the main control chip, the main control chip is used to control the working state of the feedback unit according to the overcurrent state of the external power supply and the input voltage, and the feedback unit is used to control the input power of the external power supply according to the working state.

2. The overcurrent protection circuit according to claim 1, characterized in that: The anti-lock unit comprises: A reference regulator, wherein the first port of the reference regulator is used to be electrically connected to an external power supply and the first port ISEN of the main control chip respectively, the second port of the reference regulator is used to be electrically connected to an external power supply and the first port ISEN of the main control chip respectively, and the third port of the reference regulator is grounded.

3. The overcurrent protection circuit according to claim 1, characterized in that: The feedback unit comprises: A first capacitor, one end of the first capacitor is used to be electrically connected to the third port CSS of the main control chip, and the other end of the first capacitor is grounded; A second capacitor, one end of the second capacitor is used to be electrically connected to the fourth port DELAY of the main control chip, and the other end of the second capacitor is grounded; A first resistor, one end of the first resistor is used to be electrically connected to the fourth port DELAY of the main control chip, and the other end of the first resistor is grounded.

4. The overcurrent protection circuit according to claim 1, characterized in that: Also includes: A half-bridge unit, the half-bridge unit is used to be electrically connected to an external power supply, the second port OUT of the main control chip, the fifth port HVG of the main control chip, the sixth port LVG of the main control chip and the subsequent circuit respectively; A voltage-dividing flow unit is used to be electrically connected to the first port ISEN of the main control chip and the subsequent circuit respectively.

5. The overcurrent protection circuit according to claim 4, characterized in that: The half-bridge unit comprises: a first voltage-controlled flow element, wherein the drain of the first voltage-controlled flow element is electrically connected to an external power supply, the source of the first voltage-controlled flow element is electrically connected to the second port OUT of the main control chip and the subsequent circuit respectively, and the gate of the first voltage-controlled flow element is electrically connected to the fifth port HVG of the main control chip; A second voltage-controlled flow element, wherein the drain of the second voltage-controlled flow element is electrically connected to the source of the first voltage-controlled flow element, the source of the second voltage-controlled flow element is grounded, and the gate of the second voltage-controlled flow element is electrically connected to the sixth port LVG of the main control chip.

6. The overcurrent protection circuit according to claim 4, characterized in that: The pressure-dividing flow unit comprises: a second resistor, one end of the second resistor being electrically connected to the first port ISEN of the main control chip, and the other end of the second resistor being grounded; A third capacitor, one end of the third capacitor is used to be electrically connected to the first port ISEN of the main control chip, and the other end of the third capacitor is grounded; A diode group, wherein a first port of the diode group is used to be electrically connected to a first port ISEN of the main control chip, and a second port of the diode group is grounded; a third resistor, one end of which is electrically connected to the third port of the diode group; a fourth capacitor, one end of the fourth capacitor being electrically connected to the other end of the third resistor; a fifth capacitor, one end of the fifth capacitor being electrically connected to the other end of the fourth capacitor, and the other end of the fifth capacitor being electrically connected to the subsequent circuit; A sixth capacitor, one end of the sixth capacitor is used to be electrically connected to the subsequent circuit, and the other end of the sixth capacitor is grounded.

7. Overcurrent protection system, characterized in that, include: The overcurrent protection circuit according to any one of claims 1 to 6; an external power supply, the external power supply being electrically connected to the overcurrent protection circuit; A subsequent stage circuit is electrically connected to the overcurrent protection circuit.

8. A terminal device, characterized in that: Comprising the overcurrent protection system as claimed in claim 7.

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