An overcurrent detection circuit and charging system

Abstract

Embodiments of the present application provide an overcurrent detection circuit and a charging system. The overcurrent detection circuit comprises a sampling sub-circuit, a first current source, a first sub-circuit, a second sub-circuit and a comparator; a first end of the sampling sub-circuit is electrically connected to a power output end, a second end of the sampling sub-circuit is electrically connected to a load input end, a third end of the sampling sub-circuit is electrically connected to a control end of the first sub-circuit, a fourth end of the sampling sub-circuit is electrically connected to a control end of the second sub-circuit, a first end of the first sub-circuit and a first end of the second sub-circuit are both electrically connected to a negative end of the first current source, a positive end of the first current source is electrically connected to a control signal, a second end of the first sub-circuit is electrically connected to a first input end of the comparator, and a second end of the second sub-circuit is electrically connected to a second input end of the comparator; the comparator is configured to generate an overcurrent detection signal based on a first voltage and a second voltage. The overcurrent detection circuit can reduce the complexity of the circuit and improve the response speed of the circuit.

Description

Technical Field

[0001] This application relates to the field of integrated circuit technology, and in particular to an overcurrent detection circuit and a charging system. Background Technology

[0002] In integrated circuit charging systems, it is usually necessary to detect overcurrent during startup to determine if there is a load short circuit or overload, in order to protect the power supply from being overloaded. Under normal load connection conditions, the input voltage range of the load terminal during startup is from 0V to the power supply output voltage.

[0003] In existing technologies, current can be detected at the load input terminal to determine whether overcurrent exists. However, existing current detection circuits require rail-to-rail input, resulting in complex circuit structure and slow circuit response time. Summary of the Invention

[0004] In view of the above problems, embodiments of this application provide an overcurrent detection circuit and a charging system, which can reduce circuit complexity and improve circuit response speed.

[0005] In a first aspect, embodiments of this application provide an overcurrent detection circuit, including: a sampling sub-circuit, a first current source, a first sub-circuit, a second sub-circuit, and a comparator;

[0006] The first terminal of the sampling sub-circuit is electrically connected to the power supply output terminal, the second terminal of the sampling sub-circuit is electrically connected to the load input terminal, the third terminal of the sampling sub-circuit is electrically connected to the control terminal of the first sub-circuit, the fourth terminal of the sampling sub-circuit is electrically connected to the control terminal of the second sub-circuit, the first terminal of the first sub-circuit and the first terminal of the second sub-circuit are both electrically connected to the negative terminal of the first current source, the positive terminal of the first current source is electrically connected to the control signal, the second terminal of the first sub-circuit is electrically connected to the first input terminal of the comparator, and the second terminal of the second sub-circuit is electrically connected to the second input terminal of the comparator.

[0007] The first sub-circuit is used to convert the output current of the first current source into a first voltage under the action of the first voltage sampling signal output by the sampling sub-circuit;

[0008] The second sub-circuit is used to convert the output current of the first current source into a second voltage under the action of the second voltage sampling signal output by the sampling sub-circuit;

[0009] The comparator is used to generate an overcurrent detection signal based on the first voltage and the second voltage.

[0010] In some embodiments, the comparator is further configured to generate a first detection signal if the difference between the first voltage and the second voltage is greater than a preset voltage value; and to generate a second detection signal if the difference between the first voltage and the second voltage is less than the preset voltage value.

[0011] In some embodiments, the first sub-circuit includes: a first control switch and a first resistor;

[0012] The control terminal of the first control switch is electrically connected to the third terminal of the sampling sub-circuit, the first terminal of the first control switch is electrically connected to the negative terminal of the first current source, the second terminal of the first control switch is electrically connected to the first terminal of the first resistor and the first input terminal of the comparator, and the second terminal of the first resistor is grounded.

[0013] In some embodiments, the second sub-circuit includes: a second control switch and a second resistor;

[0014] The control terminal of the second control switch is electrically connected to the fourth terminal of the sampling sub-circuit, the first terminal of the second control switch is electrically connected to the negative terminal of the first current source, the second terminal of the second control switch is electrically connected to the first terminal of the second resistor and the second input terminal of the comparator, and the second terminal of the second resistor is grounded.

[0015] The resistance value of the second resistor is the same as that of the first resistor.

[0016] In some embodiments, the first sub-circuit further includes a third control switch, and the second sub-circuit further includes a fourth control switch;

[0017] The control terminals of the third control switch and the fourth control switch are both electrically connected to the load input terminal. The first terminal of the third control switch is electrically connected to the second terminal of the first control switch, the first terminal of the fourth control switch is electrically connected to the second terminal of the second control switch, the second terminal of the third control switch is electrically connected to the first terminal of the first resistor, and the second terminal of the fourth control switch is electrically connected to the first terminal of the second resistor.

[0018] In some embodiments, the sampling sub-circuit includes a first sampling resistor, a second sampling resistor, and a third sampling resistor;

[0019] The first end of the first sampling resistor is electrically connected to the power output terminal and the first end of the second sampling resistor. The second end of the first sampling resistor is electrically connected to the load input terminal and the first end of the third sampling resistor. The second end of the second sampling resistor is electrically connected to the control terminal of the first sub-circuit. The second end of the third sampling resistor is electrically connected to the control terminal of the second sub-circuit. The resistance value of the third sampling resistor is the same as that of the second sampling resistor.

[0020] In some embodiments, the overcurrent detection circuit further includes a control sub-circuit;

[0021] The first terminal of the control sub-circuit is electrically connected to a positive voltage signal, the second terminal of the control sub-circuit is electrically connected to the load input terminal, the third terminal of the control sub-circuit is grounded, and the output terminal of the control sub-circuit is electrically connected to the positive terminal of the first current source.

[0022] The control sub-circuit is used to generate the control signal based on the positive voltage signal and the load input signal.

[0023] In some embodiments, the control sub-circuit includes: a first switch, a second switch, a third switch, a fourth switch, and a capacitor;

[0024] The positive voltage signal is electrically connected to the first terminal of the first switch, the second terminal of the first switch is electrically connected to the first terminal of the second switch and the first plate of the capacitor, the second terminal of the second switch is electrically connected to the positive terminal of the first current source, the first terminal of the third switch is grounded, the second terminal of the third switch is electrically connected to the first terminal of the fourth switch and the second plate of the capacitor, and the second terminal of the fourth switch is electrically connected to the load input terminal.

[0025] In some embodiments, the overcurrent detection circuit also includes a protection sub-circuit;

[0026] The first terminal of the protection sub-circuit is electrically connected to the power output terminal, the second terminal of the protection sub-circuit is electrically connected to the first terminal of the sampling sub-circuit, and the control terminal of the protection sub-circuit is electrically connected to the output terminal of the control sub-circuit.

[0027] The protection sub-circuit is used to disconnect the connection between the power output terminal and the load input terminal when the control signal is a disconnect control signal.

[0028] In some embodiments, the control terminal of the control sub-circuit is electrically connected to the output terminal of the comparator;

[0029] The control sub-circuit is configured to generate the disconnect control signal when the overcurrent detection signal is the first detection signal, and to generate the turn-on control signal based on the positive voltage signal and the load input signal when the overcurrent detection signal is the second detection signal.

[0030] In some embodiments, the protection sub-circuit includes: an isolation switch and a second current source;

[0031] The first terminal of the isolating switch is electrically connected to the power output terminal, the second terminal of the isolating switch is electrically connected to the first terminal of the sampling sub-circuit, the control terminal of the isolating switch is electrically connected to the negative terminal of the second current source, and the positive terminal of the second current source is electrically connected to the output terminal of the control sub-circuit.

[0032] In some embodiments, the overcurrent detection circuit further includes a pull-down sub-circuit;

[0033] The first terminal of the pull-down sub-circuit is electrically connected to the control terminal of the isolating switch transistor, the second terminal of the pull-down sub-circuit is grounded, and the control terminal of the pull-down sub-circuit is electrically connected to the output terminal of the control sub-circuit.

[0034] The pull-down sub-circuit is used to connect the control terminal of the isolating switch to ground when the control signal is the disconnect control signal.

[0035] Secondly, embodiments of this application provide a charging system including any of the overcurrent detection circuits provided in the first aspect.

[0036] In the technical solution of this application embodiment, the overcurrent detection circuit includes a sampling sub-circuit, a first current source, a first sub-circuit, a second sub-circuit, and a comparator. The first terminal of the sampling sub-circuit is electrically connected to the power supply output terminal, the second terminal of the sampling sub-circuit is electrically connected to the load input terminal, the third terminal of the sampling sub-circuit is electrically connected to the control terminal of the first sub-circuit, and the fourth terminal of the sampling sub-circuit is electrically connected to the control terminal of the second sub-circuit. The first terminals of both the first and second sub-circuits are electrically connected to the negative terminal of the first current source. The positive terminal of the first current source is electrically connected to a control signal. The second terminal of the first sub-circuit is electrically connected to the first input terminal of the comparator, and the second terminal of the second sub-circuit is electrically connected to the third input terminal of the comparator. The circuit has two input terminals. The first sub-circuit converts the output current of the first current source into a first voltage under the influence of the first voltage sampling signal output from the sampling sub-circuit. The second sub-circuit converts the output current of the first current source into a second voltage under the influence of the second voltage sampling signal output from the sampling sub-circuit. The comparator generates an overcurrent detection signal based on the first and second voltages. This allows the voltage sampling signal to be converted into a voltage and input to the comparator's input, eliminating the need for rail-to-rail input, thus reducing the complexity of the overcurrent detection circuit and improving its response speed. Furthermore, since the voltage sampling signal serves as the control signal for the sub-circuit, it is not scaled during the transfer to the comparator's input, which helps improve the accuracy of the comparator's output and consequently, the accuracy of the overcurrent detection result.

[0037] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more obvious and understandable, specific implementation methods of this application are described below. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of an overcurrent detection circuit provided in an embodiment of this application;

[0040] Figure 2 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application;

[0041] Figure 3 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application;

[0042] Figure 4 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application;

[0043] Figure 5 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application;

[0044] Figure 6 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application;

[0045] Figure 7 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application;

[0046] Figure 8 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application;

[0047] Figure 9 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and drawings of this application are intended to cover non-exclusive inclusion.

[0050] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0051] Furthermore, the terms "first," "second," etc., in the specification and claims of this application or in the aforementioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0052] In the description of this application, unless otherwise expressly specified and limited, the terms "connected" and "connected" shall be interpreted broadly. For example, "connected" or "connected" in circuit structure can refer not only to physical connection, but also to electrical connection or signal connection. For example, it can be a direct connection, i.e., a physical connection, or an indirect connection through at least one intermediate element, as long as the circuit is connected. It can also refer to the internal connection of two elements. Signal connection can refer not only to signal connection through circuit, but also to signal connection through a medium, such as radio waves.

[0053] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists, A and B exist simultaneously, or B exists. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0054] In the description of this application, unless otherwise stated, "multiple" and "at least two" mean two or more (including two), and similarly, "multiple groups" and "at least two groups" mean two or more (including two groups).

[0055] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0056] Figure 1 This is a schematic diagram of an overcurrent detection circuit provided in an embodiment of this application, as shown below. Figure 1 As shown, the overcurrent detection circuit 100 includes: a sampling sub-circuit 110, a first current source Is1, a first sub-circuit 120, a second sub-circuit 130, and a comparator CMP.

[0057] Specifically, the first terminal of the sampling sub-circuit 110 is electrically connected to the power supply output terminal, the second terminal of the sampling sub-circuit 110 is electrically connected to the load input terminal, the third terminal of the sampling sub-circuit 110 is electrically connected to the control terminal of the first sub-circuit 120, the fourth terminal of the sampling sub-circuit 110 is electrically connected to the control terminal of the second sub-circuit 130, the first terminal of the first sub-circuit 120 and the first terminal of the second sub-circuit 130 are both electrically connected to the negative terminal of the first current source Is1, the positive terminal of the first current source Is1 is electrically connected to the control signal VCP, the second terminal of the first sub-circuit 120 is electrically connected to the first input terminal of the comparator CMP, and the second terminal of the second sub-circuit 130 is electrically connected to the second input terminal of the comparator CMP.

[0058] The first sub-circuit 120 is used to convert the output current of the first current source Is1 into a first voltage CSP_LV under the action of the first voltage sampling signal CSP output from the sampling sub-circuit 110. The second sub-circuit 130 is used to convert the output current of the first current source Is1 into a second voltage CSN_LV under the action of the second voltage sampling signal CSN output from the sampling sub-circuit 110. The comparator CMP is used to generate an overcurrent detection signal OCP_Flag based on the first voltage CSP_LV and the second voltage CSN_LV.

[0059] For example, Figure 2 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application. Figure 2 for Figure 1Based on the illustrated embodiment, the sampling sub-circuit 110 includes: a first sampling resistor Rs1, a second sampling resistor Rs2, and a third sampling resistor Rs3. The first terminal of the first sampling resistor Rs1 is electrically connected to the power output terminal and the first terminal of the second sampling resistor Rs2. The second terminal of the first sampling resistor Rs1 is electrically connected to the load input terminal and the first terminal of the third sampling resistor Rs3. The second terminal of the second sampling resistor Rs2 is electrically connected to the control terminal of the first sub-circuit 120, and the second terminal of the third sampling resistor Rs3 is electrically connected to the control terminal of the second sub-circuit 130. The resistance value of the third sampling resistor Rs3 is the same as the resistance value of the second sampling resistor Rs2.

[0060] like Figure 2 As shown, the power output terminal is used to transmit the power output signal BVBSP, and the load input terminal is used to transmit the load input signal BVBSM. The first terminal of the first sampling resistor Rs1 is electrically connected to the power output signal BVBSP, and the second terminal of the first sampling resistor Rs1 is electrically connected to the load input signal BVBSM. The charging current IBUS provided by the power output signal BVBSP can flow into the load input terminal through the first sampling resistor Rs1. At this time, the voltage difference across the first sampling resistor Rs1 is IBUS * Rs1', where Rs1' is the resistance value of the first sampling resistor Rs1.

[0061] The first terminal of the second sampling resistor Rs2 is electrically connected to the first terminal of the first sampling resistor Rs1. The second sampling resistor Rs2 can acquire the first voltage sampling signal CSP and output the first voltage sampling signal CSP based on the second terminal of the second sampling resistor Rs2. The first terminal of the third sampling resistor Rs3 is electrically connected to the second terminal of the first sampling resistor Rs1. The third sampling resistor Rs3 can acquire the second voltage sampling signal CSN and output the second voltage sampling signal CSN based on the second terminal of the third sampling resistor Rs3. In this way, the sampling sub-circuit 110 can acquire and output the first voltage sampling signal CSP and the second voltage sampling signal CSN. In addition, since the resistance value Rs3' of the third sampling resistor Rs3 is the same as the resistance value Rs2' of the second sampling resistor Rs2, IBUS*Rs1' = CSP - CSN.

[0062] The second terminal of the second sampling resistor Rs2 is electrically connected to the control terminal of the first sub-circuit 120, and the second terminal of the third sampling resistor Rs3 is electrically connected to the control terminal of the second sub-circuit 130. Therefore, the first sub-circuit 120 is controlled by the first voltage sampling signal CSP, and the control terminal of the second sub-circuit 130 is controlled by the second voltage sampling signal CSN.

[0063] For example, Figure 3 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application. Figure 3 for Figure 1Based on the embodiment shown, the first sub-circuit 120 includes: a first control switch K1 and a first resistor R1, wherein the control terminal of the first control switch K1 is electrically connected to the third terminal of the sampling sub-circuit 110, the first terminal of the first control switch K1 is electrically connected to the negative terminal of the first current source Is1, the second terminal of the first control switch K1 is electrically connected to the first terminal of the first resistor R1 and the first input terminal of the comparator CMP, and the second terminal of the first resistor R1 is grounded.

[0064] like Figure 3 As shown, the positive terminal of the first current source Is1 is electrically connected to the control signal VCP. Under the action of the control signal VCP, the first current source Is1 generates an output current, which is output based on the negative terminal of the first current source Is1. The first terminal of the first control switch K1 is electrically connected to the negative terminal of the first current source Is1, so the first terminal of the first control switch K1 can receive the output current of the first current source Is1. The control terminal of the first control switch K1 is electrically connected to the third terminal of the sampling sub-circuit 110, that is, the control terminal of the first control switch K1 is electrically connected to the first voltage sampling signal CSP. The first voltage sampling signal CSP can control the magnitude of the first current Im1 output from the second terminal of the first control switch K1. The larger the first voltage sampling signal CSP, the larger the first current Im1.

[0065] The second terminal of the first control switch K1 is grounded through the first resistor R1. The first resistor R1 converts the first current Im1 into a first voltage CSP_LV, where CSP_LV = Im1 * R1', and R1' is the resistance value of the first resistor R1. The first voltage CSP_LV is output based on the second terminal of the first control switch K1. Since the second terminal of the first control switch K1 is electrically connected to the positive input terminal of the comparator CMP, the comparator CMP can receive the first voltage CSP_LV.

[0066] Thus, under the action of the first voltage sampling signal CSP, the first sub-circuit 120 can convert the output current provided by the first current source Is1 into a first voltage CSP_LV. In other words, the first sub-circuit 120 can convert the first voltage sampling signal CSP into a first voltage CSP_LV and input it to the input terminal of the comparator CMP, thereby eliminating the need for rail-to-rail input. Furthermore, since the first voltage sampling signal CSP serves as the control signal for the first sub-circuit 120, it is not scaled during the transfer of the first voltage sampling signal CSP to the input terminal of the comparator CMP, which helps improve the accuracy of the comparator CMP's output result.

[0067] See also Figure 3The second sub-circuit 130 includes: a second control switch K2 and a second resistor R2. The control terminal of the second control switch K2 is electrically connected to the fourth terminal of the sampling sub-circuit 110. The first terminal of the second control switch K2 is electrically connected to the negative terminal of the first current source Is1. The second terminal of the second control switch K2 is electrically connected to the first terminal of the second resistor R2 and the second input terminal of the comparator CMP. The second terminal of the second resistor R2 is grounded. The resistance value of the second resistor R2 is the same as the resistance value of the first resistor R1.

[0068] The first terminal of the second control switch K2 is electrically connected to the negative terminal of the first current source Is1, so the first terminal of the second control switch K2 can receive the output current of the first current source Is1. The control terminal of the second control switch K2 is electrically connected to the fourth terminal of the sampling sub-circuit 110, that is, the control terminal of the second control switch K2 is electrically connected to the second voltage sampling signal CSN, so the second voltage sampling signal CSN can control the magnitude of the second current Im2 output from the second terminal of the second control switch K2, wherein the larger the second voltage sampling signal CSN is, the larger the second current Im2 is.

[0069] The second terminal of the second control switch K2 is grounded through the second resistor R2. The second resistor R2 converts the second current Im2 into a second voltage CSN_LV, where CSN_LV = Im2 * R2', and R2' is the resistance value of the second resistor R2. The second voltage CSN_LV is output based on the second terminal of the second control switch K2. Since the second terminal of the second control switch K2 is electrically connected to the negative input terminal of the comparator CMP, the comparator CMP can receive the second voltage CSN_LV. The resistance value R2' of the second resistor R2 is the same as the resistance value R1' of the first resistor R1, i.e., R1' = R2'. Therefore, based on the same conversion factor, the first current Im1 is converted into the first voltage CSP_LV, and the second current Im2 is converted into the second voltage CSN_LV, which reduces the error introduced by different conversion processes.

[0070] Thus, under the action of the second voltage sampling signal CSN, the second sub-circuit 130 can convert the output current provided by the first current source Is1 into the second voltage CSN_LV. In other words, the second sub-circuit 130 can convert the second voltage sampling signal CSN into the second voltage CSN_LV and input it to the input of the comparator CMP, thereby eliminating the need for rail-to-rail input. Furthermore, since the second voltage sampling signal CSN serves as the control signal for the second sub-circuit 130, it is not scaled during the transfer of the second voltage sampling signal CSN to the input of the comparator CMP, which helps improve the accuracy of the comparator CMP's output.

[0071] After the comparator CMP receives the first voltage CSP_LV and the second voltage CSN_LV, it can first calculate the difference CSP_LV - CSN_LV between the first voltage CSP_LV and the second voltage CSN_LV, and then compare the difference CSP_LV - CSN_LV with the preset voltage value Vth, and generate a corresponding overcurrent detection signal OCP_Flag based on the comparison result. Exemplarily, if CSP_LV - CSN_LV > Vth, the generated overcurrent detection signal OCP_Flag is the first detection signal. For example, the first detection signal is a high-level signal. At this time, it is determined that IBUS > Vth / Rs1’, that is, the charging current IBUS is overcurrent. If CSP_LV - CSN_LV < Vth, the generated overcurrent detection signal OCP_Flag is the second detection signal. For example, the second detection signal is a low-level signal. At this time, it is determined that IBUS < Vth / Rs1’, that is, the charging current IBUS is not overcurrent.

[0072] In the embodiments of the present application, the overcurrent detection circuit includes: a sampling sub-circuit, a first current source, a first sub-circuit, a second sub-circuit, and a comparator. The first end of the sampling sub-circuit is electrically connected to the power output terminal, the second end of the sampling sub-circuit is electrically connected to the load input terminal, the third end of the sampling sub-circuit is electrically connected to the control terminal of the first sub-circuit, the fourth end of the sampling sub-circuit is electrically connected to the control terminal of the second sub-circuit. The first ends of the first sub-circuit and the second sub-circuit are both electrically connected to the negative terminal of the first current source, the positive terminal of the first current source is electrically connected to the control signal, the second end of the first sub-circuit is electrically connected to the first input terminal of the comparator, and the second end of the second sub-circuit is electrically connected to the second input terminal of the comparator; through the first sub-circuit, under the action of the first voltage sampling signal output by the sampling sub-circuit, the output current of the first current source can be converted into a first voltage; the second sub-circuit can convert the output current of the first current source into a second voltage under the action of the second voltage sampling signal output by the sampling sub-circuit; the comparator can generate an overcurrent detection signal based on the first voltage and the second voltage. In this way, the voltage sampling signal can be converted into a voltage and input to the input terminal of the comparator, and the voltage sampling signal can be transferred to the input terminal of the comparator without rail-to-rail input, thereby reducing the complexity of the overcurrent detection circuit and improving the response speed of the overcurrent detection circuit. In addition, the voltage sampling signal is used as the control signal of the sub-circuit, and during the process of transferring the voltage sampling signal to the input terminal of the comparator, the voltage sampling signal will not be scaled, which is beneficial to improving the accuracy of the output result of the comparator and can improve the accuracy of the overcurrent detection result.

[0073] In some embodiments, Figure 4 is a schematic structural diagram of another overcurrent detection circuit provided by the embodiments of the present application, Figure 4 is Figure 3Based on the embodiment shown, the first sub-circuit 120 further includes a third control switch K3, and the second sub-circuit 130 further includes a fourth control switch K4.

[0074] Among them, the control terminals of the third control switch K3 and the fourth control switch K4 are both electrically connected to the load input terminal. The first terminal of the third control switch K3 is electrically connected to the second terminal of the first control switch K1. The first terminal of the fourth control switch K4 is electrically connected to the second terminal of the second control switch K2. The second terminal of the third control switch K3 is electrically connected to the first terminal of the first resistor R1. The second terminal of the fourth control switch K4 is electrically connected to the first terminal of the second resistor R2.

[0075] For example, during the startup process of the charging system, that is, during the process of the power output terminal and the load input terminal being connected, the load input signal BVBUSM gradually increases from 0V to the power output signal BVBUSP, which is typically 3V-21V. Figure 4 As shown, the control terminals of the third control switch K3 and the fourth control switch K4 are both electrically connected to the load input signal VBUSM. Under the action of the load input signal VBUSM, the first terminal and the second terminal of the third control switch K3 are connected, and the first terminal and the second terminal of the fourth control switch K4 are connected.

[0076] The first terminal of the third control switch K3 is electrically connected to the second terminal of the first control switch K1, and the second terminal of the third control switch K3 is electrically connected to the first terminal of the first resistor R1. Therefore, under the action of the load input signal BVBUSM, the second terminal of the first control switch K1 can be connected to ground through the third control switch K3 and the first resistor R1. Based on the third control switch K3, the relative voltages between the first terminal voltage, the second terminal voltage, and the control terminal voltage of the first control switch K1 can be kept within the range of VCP to BVBUSM.

[0077] The first terminal of the fourth control switch K4 is electrically connected to the second terminal of the second control switch K2, and the second terminal of the fourth control switch K4 is electrically connected to the first terminal of the second resistor R2. Therefore, under the influence of the load input signal BVBUSM, the second terminal of the second control switch K2 can be connected to ground through the fourth control switch K4 and the second resistor R2. Based on the fourth control switch K4, the relative voltages between the first terminal voltage of the second control switch K2, the second terminal voltage of the second control switch K2, and the control terminal voltage of the second control switch K2 can be kept within the range of VCP to BVBUSM.

[0078] Thus, the first sub-circuit 120, based on the third control switch K3, can output a lower voltage, and the second sub-circuit 130, based on the fourth control switch K4, can also output a lower voltage. In other words, the first sub-circuit 120 can convert the first voltage sampling signal CSP into a lower first voltage CSP_LV, and the second sub-circuit 130 can convert the second voltage sampling signal CSN into a lower first voltage CSN_LV. Based on the lower first voltages CSP_LV and CSN_LV, the overcurrent detection result can be obtained quickly, improving the response speed of overcurrent detection.

[0079] In this embodiment, the first sub-circuit further includes a third control switch, and the second sub-circuit further includes a fourth control switch. The control terminals of the third and fourth control switches are both electrically connected to the load input terminal. The first terminal of the third control switch is electrically connected to the second terminal of the first control switch, and the first terminal of the fourth control switch is electrically connected to the second terminal of the second control switch. The second terminal of the third control switch is electrically connected to the first terminal of the first resistor, and the second terminal of the fourth control switch is electrically connected to the first terminal of the second resistor. In this way, the voltage sampling signal can be converted into a voltage signal with a lower voltage value, which can improve the response speed of overcurrent detection.

[0080] In some embodiments, Figure 5 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application. Figure 5 for Figure 1 Based on the embodiment shown, the overcurrent detection circuit 100 further includes a control sub-circuit 140.

[0081] The first terminal of the control sub-circuit 140 is electrically connected to the positive voltage signal VDD, the second terminal of the control sub-circuit 140 is electrically connected to the load input terminal, the third terminal of the control sub-circuit 140 is grounded, and the output terminal of the control sub-circuit 140 is electrically connected to the positive terminal of the first current source Is.

[0082] The control sub-circuit 140 is used to generate a control signal VCP based on the positive voltage signal VDD and the load input signal VBUSM.

[0083] For example, Figure 6 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application. Figure 6 for Figure 5 Based on the embodiment shown, the control sub-circuit 140 includes: a first switch S1, a second switch S2, a third switch S3, a fourth switch S4, and a capacitor C.

[0084] The positive voltage signal VDD is electrically connected to the first terminal of the first switch S1. The second terminal of the first switch S1 is electrically connected to the first terminal of the second switch S2 and the first plate of the capacitor C. The second terminal of the second switch S2 is electrically connected to the positive terminal of the first current source Is. The first terminal of the third switch S3 is grounded. The second terminal of the third switch S3 is electrically connected to the first terminal of the fourth switch S4 and the second plate of the capacitor C. The second terminal of the fourth switch S4 is electrically connected to the load input terminal.

[0085] When the control subcircuit 140 is in the first state, both the first switch S1 and the third switch S3 are on, and both the second switch S2 and the fourth switch S4 are off. The first plate of capacitor C is connected to the positive voltage signal VDD, and the second plate of capacitor C is connected to ground. The energy provided by the positive voltage signal VDD is stored in the first plate of capacitor C until the voltage of the first plate of capacitor C reaches VDD. When the control subcircuit 140 is in the second state, both the second switch S2 and the fourth switch S4 are on, and both the first switch S1 and the third switch S3 are off. The first plate of capacitor C is electrically connected to the output terminal of the control subcircuit 140, and the second plate of capacitor C is connected to the load input signal VBUSM. At this time, the voltage of the first plate of capacitor C is the control signal VCP, and VCP = VDD + VBUSM. For example, the control signal VCP can be 5V.

[0086] In some embodiments, Figure 7 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application. Figure 7 for Figure 5 Based on the embodiment shown, the overcurrent detection circuit 100 further includes a protection sub-circuit 150.

[0087] The first terminal of the protection sub-circuit 150 is electrically connected to the power supply output terminal, the second terminal of the protection sub-circuit 150 is electrically connected to the first terminal of the sampling sub-circuit 110, and the control terminal of the protection sub-circuit 150 is electrically connected to the output terminal of the control sub-circuit 140.

[0088] The protection sub-circuit 150 is used to disconnect the connection between the power supply output terminal and the load input terminal when the control signal VCP is the disconnect control signal.

[0089] For example, Figure 8 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application. Figure 8 for Figure 7 Based on the illustrated embodiment, the protection sub-circuit 150 includes: an isolating switch Qs and a second current source Is2. The first terminal of the isolating switch Qs is electrically connected to the power output terminal, the second terminal of the isolating switch Qs is electrically connected to the first terminal of the sampling sub-circuit 110, the control terminal of the isolating switch Qs is electrically connected to the negative terminal of the second current source Is2, and the positive terminal of the second current source Is2 is electrically connected to the output terminal of the control sub-circuit 140.

[0090] The control signal VCP generated by the control sub-circuit 140 may be an off control signal or an on control signal. For example, the off control signal is a low-level signal, and the on control signal is a high-level signal. If the control signal VCP is an on control signal, the second current source Is2 generates an output current under the action of the control signal VCP, and outputs based on the negative terminal of the second current source Is2. The voltage at the control terminal of the isolating switch Qs gradually increases with the accumulation of the output current. The first terminal and the second terminal of the isolating switch Qs gradually conduct. Since the first terminal of the isolating switch Qs is electrically connected to the power supply output terminal, and the second terminal of the isolating switch Qs is electrically connected to the first terminal of the sampling sub-circuit 110, the power supply output terminal and the first terminal of the sampling sub-circuit 110 conduct, that is, the power supply output terminal and the load input terminal gradually conduct.

[0091] If the control signal VCP is a disconnect control signal, the second current source Is2 will stop working under the action of the control signal VCP, that is, no output current will be generated. The voltage at the control terminal of the isolating switch Qs will gradually decrease, and the first terminal and the second terminal of the isolating switch Qs will gradually disconnect, that is, the power supply output terminal and the load input terminal will gradually disconnect.

[0092] Thus, the control signal VCP output by the control sub-circuit 140 can control the on / off state between the power supply output terminal and the load input terminal.

[0093] In some embodiments, see continue to see Figure 5 The control terminal of the control sub-circuit 140 is electrically connected to the output terminal of the comparator CMP. The control sub-circuit 140 is used to generate a disconnect control signal when the overcurrent detection signal OCP_Flag is the first detection signal; and to generate a turn-on control signal based on the positive voltage signal VDD and the load input signal BVBUSM when the overcurrent detection signal OCP_Flag is the second detection signal.

[0094] For example, such as Figure 5 As shown, the control sub-circuit 140 is controlled by the overcurrent detection signal OCP_Flag. If the overcurrent detection signal OCP_Flag is the first detection signal, i.e., when the charging current IBU is overcurrent, the control signal VCP generated by the control sub-circuit 140 is a disconnect control signal under the action of the first detection signal. If the overcurrent detection signal OCP_Flag is the second detection signal, i.e., when the charging current IBU is not overcurrent, the control signal VCP generated by the control sub-circuit 140 is a conduction control signal under the action of the second detection signal.

[0095] In summary, if the charging current IBUs is excessive, the control sub-circuit 140 outputs a disconnect control signal, disconnecting the connection between the power output terminal and the load input terminal; if the charging current IBUs is not excessive, the control sub-circuit 140 outputs a conduction control signal, connecting the power output terminal and the load input terminal. Thus, when the charging current IBUs is excessive, the connection between the power output terminal and the load input terminal can be disconnected, protecting the power supply.

[0096] In this embodiment, the control terminal of the control sub-circuit is electrically connected to the output terminal of the comparator. The control sub-circuit can generate a disconnection control signal when the overcurrent detection signal is the first detection signal; and generate a conduction control signal based on the positive voltage signal and the load input signal when the overcurrent detection signal is the second detection signal. In this way, when the charging current is overcurrent, the connection between the power supply output terminal and the load input terminal can be disconnected, thereby protecting the power supply.

[0097] In some embodiments, Figure 9 This is a schematic diagram of another overcurrent detection circuit provided in an embodiment of this application. Figure 9 for Figure 8 Based on the embodiment shown, the overcurrent detection circuit 100 further includes a pull-down sub-circuit 160. The first terminal of the pull-down sub-circuit 160 is electrically connected to the control terminal of the isolating switch Qs, the second terminal of the pull-down sub-circuit 160 is grounded, and the control terminal of the pull-down sub-circuit 160 is electrically connected to the output terminal of the control sub-circuit 140.

[0098] The pull-down circuit 160 is used to connect the control terminal of the isolating switch Qs to ground when the control signal VCP is the disconnect control signal.

[0099] For example, such as Figure 9 As shown, the control terminal of the pull-down circuit 160 is electrically connected to the control signal VCP. If the control signal VCP is a disconnect control signal, the first and second terminals of the pull-down circuit 160 are connected. Since the first terminal of the pull-down circuit 160 is electrically connected to the control terminal of the isolating switch Qs, and the second terminal of the pull-down circuit 160 is grounded, the control terminal of the isolating switch Qs is connected to ground. This allows the voltage at the control terminal of the isolating switch Qs to be released to ground, causing the voltage at the control terminal of the isolating switch Qs to drop rapidly, quickly disconnecting the connection between the power supply output terminal and the load input terminal, thereby improving the power supply's protection effect.

[0100] In this embodiment, the overcurrent detection circuit further includes a pull-down sub-circuit. The first terminal of the pull-down sub-circuit is electrically connected to the control terminal of the isolating switch, and the second terminal of the pull-down sub-circuit is grounded. The control terminal of the pull-down sub-circuit is electrically connected to the output terminal of the control sub-circuit. The pull-down sub-circuit can conduct the control terminal of the isolating switch to ground when the control signal is the disconnect control signal, so that the voltage at the control terminal of the isolating switch drops rapidly, quickly disconnecting the connection between the power supply output terminal and the load input terminal, thereby improving the protection effect of the power supply.

[0101] This application also provides a charging system, including the overcurrent detection circuit provided in any of the above embodiments. The input terminal of the charging system is electrically connected to an external power source, and the output terminal of the charging system is electrically connected to a load.

[0102] The charging system provided in this application includes the overcurrent detection circuit provided in any embodiment, and has the same functional modules and beneficial effects as the overcurrent detection circuit, which will not be described in detail here.

[0103] The above-disclosed embodiments are merely specific examples of this application. However, the embodiments of this application are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of this application.

[0104] The term "comprising" as used in this application does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims listing several means, several units of these means may be embodied by the same item of hardware. The use of "first," "second," and "third," etc., does not indicate any order and should be interpreted as names. Unless otherwise specified, the steps in the above embodiments should not be construed as limiting the order of execution.

[0105] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An overcurrent detection circuit, characterized by comprising: include: The circuit consists of a sampling sub-circuit, a first current source, a first sub-circuit, a second sub-circuit, and a comparator. The first terminal of the sampling sub-circuit is electrically connected to the power supply output terminal, the second terminal of the sampling sub-circuit is electrically connected to the load input terminal, the third terminal of the sampling sub-circuit is electrically connected to the control terminal of the first sub-circuit, the fourth terminal of the sampling sub-circuit is electrically connected to the control terminal of the second sub-circuit, the first terminal of the first sub-circuit and the first terminal of the second sub-circuit are both electrically connected to the negative terminal of the first current source, the positive terminal of the first current source is electrically connected to the control signal, the second terminal of the first sub-circuit is electrically connected to the first input terminal of the comparator, and the second terminal of the second sub-circuit is electrically connected to the second input terminal of the comparator. The first sub-circuit is used to convert the output current of the first current source into a first voltage under the action of the first voltage sampling signal output by the sampling sub-circuit; The second sub-circuit is used to convert the output current of the first current source into a second voltage under the action of the second voltage sampling signal output by the sampling sub-circuit; The comparator is used to generate an overcurrent detection signal based on the first voltage and the second voltage; The first sub-circuit includes: a first control switch and a first resistor; The control terminal of the first control switch is electrically connected to the third terminal of the sampling sub-circuit, the first terminal of the first control switch is electrically connected to the negative terminal of the first current source, the second terminal of the first control switch is electrically connected to the first terminal of the first resistor and the first input terminal of the comparator, and the second terminal of the first resistor is grounded. The second sub-circuit includes: a second control switch and a second resistor; The control terminal of the second control switch is electrically connected to the fourth terminal of the sampling sub-circuit, the first terminal of the second control switch is electrically connected to the negative terminal of the first current source, the second terminal of the second control switch is electrically connected to the first terminal of the second resistor and the second input terminal of the comparator, and the second terminal of the second resistor is grounded. The resistance value of the second resistor is the same as that of the first resistor.

2. The overcurrent detection circuit of claim 1, wherein The comparator is further configured to generate a first detection signal if the difference between the first voltage and the second voltage is greater than a preset voltage value, and to generate a second detection signal if the difference between the first voltage and the second voltage is less than the preset voltage value.

3. The overcurrent detection circuit of claim 1, wherein The first sub-circuit further includes a third control switch, and the second sub-circuit further includes a fourth control switch; The control terminals of the third control switch and the fourth control switch are both electrically connected to the load input terminal. The first terminal of the third control switch is electrically connected to the second terminal of the first control switch, the first terminal of the fourth control switch is electrically connected to the second terminal of the second control switch, the second terminal of the third control switch is electrically connected to the first terminal of the first resistor, and the second terminal of the fourth control switch is electrically connected to the first terminal of the second resistor.

4. The overcurrent detection circuit according to any one of claims 1 to 3, characterized by The sampling sub-circuit includes a first sampling resistor, a second sampling resistor, and a third sampling resistor; The first end of the first sampling resistor is electrically connected to the power output terminal and the first end of the second sampling resistor. The second end of the first sampling resistor is electrically connected to the load input terminal and the first end of the third sampling resistor. The second end of the second sampling resistor is electrically connected to the control terminal of the first sub-circuit. The second end of the third sampling resistor is electrically connected to the control terminal of the second sub-circuit. The resistance value of the third sampling resistor is the same as that of the second sampling resistor.

5. The overcurrent detection circuit according to any one of claims 1 to 3, characterized by Also includes: Control sub-circuit; The first terminal of the control sub-circuit is electrically connected to a positive voltage signal, the second terminal of the control sub-circuit is electrically connected to the load input terminal, the third terminal of the control sub-circuit is grounded, and the output terminal of the control sub-circuit is electrically connected to the positive terminal of the first current source. The control sub-circuit is used to generate the control signal based on the positive voltage signal and the load input signal.

6. The overcurrent detection circuit of claim 5, wherein, The control sub-circuit includes: a first switch, a second switch, a third switch, a fourth switch, and a capacitor; The positive voltage signal is electrically connected to the first terminal of the first switch, the second terminal of the first switch is electrically connected to the first terminal of the second switch and the first plate of the capacitor, the second terminal of the second switch is electrically connected to the positive terminal of the first current source, the first terminal of the third switch is grounded, the second terminal of the third switch is electrically connected to the first terminal of the fourth switch and the second plate of the capacitor, and the second terminal of the fourth switch is electrically connected to the load input terminal.

7. The overcurrent detection circuit of claim 5, wherein It also includes protection sub-circuits; The first terminal of the protection sub-circuit is electrically connected to the power output terminal, the second terminal of the protection sub-circuit is electrically connected to the first terminal of the sampling sub-circuit, and the control terminal of the protection sub-circuit is electrically connected to the output terminal of the control sub-circuit. The protection sub-circuit is used to disconnect the connection between the power output terminal and the load input terminal when the control signal is a disconnect control signal.

8. The overcurrent detection circuit of claim 7, wherein, The control terminal of the control sub-circuit is electrically connected to the output terminal of the comparator; The control sub-circuit is configured to generate the disconnect control signal when the overcurrent detection signal is the first detection signal, and to generate the turn-on control signal based on the positive voltage signal and the load input signal when the overcurrent detection signal is the second detection signal.

9. The overcurrent detection circuit of claim 7, wherein, The protection sub-circuit includes: an isolation switch and a second current source; The first terminal of the isolating switch is electrically connected to the power output terminal, the second terminal of the isolating switch is electrically connected to the first terminal of the sampling sub-circuit, the control terminal of the isolating switch is electrically connected to the negative terminal of the second current source, and the positive terminal of the second current source is electrically connected to the output terminal of the control sub-circuit.

10. The overcurrent detection circuit of claim 9, wherein, It also includes pull-down sub-circuits; The first terminal of the pull-down sub-circuit is electrically connected to the control terminal of the isolating switch transistor, the second terminal of the pull-down sub-circuit is grounded, and the control terminal of the pull-down sub-circuit is electrically connected to the output terminal of the control sub-circuit. The pull-down sub-circuit is used to connect the control terminal of the isolating switch to ground when the control signal is the disconnect control signal.

11. A charging system, characterized by Includes the overcurrent detection circuit as described in any one of claims 1-10.

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