Electronic fuse circuit, power supply system and vehicle

Abstract

The embodiment of the utility model provides an electronic fuse circuit, a power supply system and a vehicle. The electronic fuse circuit comprises a control circuit, a driving circuit and a sampling circuit, the input end of the sampling circuit is connected with an external switching power supply, the output end of the sampling circuit is connected with the power input end of the driving circuit, and the output end of the driving circuit is connected with an external load; the first input end of the control circuit is connected with the output end of the sampling circuit; the output end of the control circuit is connected with the control input end of the driving circuit; the sampling circuit is used for sampling the output current of the external switching power supply and then outputting a current feedback signal; the control circuit is used for receiving the current feedback signal and controlling the on-off state of the drive circuit according to the current feedback signal. The current in the power supply circuit of the external switching power supply is collected through the sampling circuit, the large current of the external switching power supply can be detected, the small current can also be detected, and monitoring of small current power supply is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of protection circuit, in particular to an electronic fuse circuit, a power supply system and a vehicle. BACKGROUND

[0002] As a substitute for traditional fuses, electronic fuses play an important role in the working condition monitoring of vehicle electrical equipment in the process of vehicle intelligentization. Currently, the mainstream electronic fuse chips on the market are mainly provided by suppliers in the form of integrated chips. The advantages are that the functions are complete, and the overall chip solution can reduce the failure rate of the overall solution. However, the disadvantages are also obvious, such as high price and lack of small current power supply solution. CONTENT OF THE INVENTION

[0003] The electronic fuse circuit, the power supply system and the vehicle provided by the embodiments of the present application are used for monitoring the working condition of a small current circuit.

[0004] In a first aspect, the embodiments of the present application provide an electronic fuse circuit, which comprises a control circuit, a driving circuit and a sampling circuit.

[0005] The input end of the sampling circuit is connected to an external switching power supply, the output end of the sampling circuit is connected to the power input end of the driving circuit, and the output end of the driving circuit is connected to an external load.

[0006] The first input end of the control circuit is connected to the output end of the sampling circuit, and the output end of the control circuit is connected to the control input end of the driving circuit.

[0007] The sampling circuit is used for sampling the output current of the external switching power supply and outputting a current feedback signal; the control circuit is used for receiving the current feedback signal and controlling the on-off state of the driving circuit according to the current feedback signal.

[0008] In a possible implementation, the control circuit comprises a controller and a control sub-circuit.

[0009] The first input end of the controller is connected to the output end of the sampling circuit, the output end of the controller is connected to the first input end of the control sub-circuit, and the output end of the control sub-circuit is connected to the control input end of the driving circuit.

[0010] The first input end of the controller is used for obtaining the current feedback signal and sending a control signal to the control sub-circuit based on the current feedback signal, and the control sub-circuit is used for driving the driving circuit according to the control signal.

[0011] In a possible implementation, the control sub-circuit comprises a first resistor, a second resistor and a first diode.

[0012] The first output end of the controller is connected with the first end of the first resistor, the first end of the first resistor is connected with the active enable signal, and the second end of the first resistor is connected with the first end of the second resistor; the second end of the second resistor is connected with the negative electrode of the first diode and the control input end of the driving circuit, and the positive electrode of the first diode is grounded; and the first resistor is used for connecting the active enable signal sent by the controller.

[0013] In a possible implementation, the control signal comprises an active shutdown signal; and the control sub-circuit further comprises a third resistor, a fourth resistor and a first triode.

[0014] The second output end of the controller is connected with the first end of the third resistor, the first end of the third resistor is connected with the active shutdown signal; the second end of the third resistor is connected with the first end of the fourth resistor and the base of the first triode, the collector of the first triode is connected with the second end of the first resistor, and the emitter of the first triode and the second end of the fourth resistor are grounded; and the third resistor is used for connecting the active shutdown signal sent by the controller.

[0015] In a possible implementation, the driving circuit further comprises a feedback output port, and the feedback output port outputs a feedback control signal.

[0016] The control sub-circuit further comprises a fifth resistor, the first end of the fifth resistor is connected with the feedback output port, and the second end of the fifth resistor is connected with the second end of the first resistor.

[0017] In a possible implementation, the driving circuit comprises a switching sub-circuit and a driving sub-circuit.

[0018] The input end of the driving sub-circuit is connected with the output end of the sampling circuit, and the output end of the driving sub-circuit is connected with the input end of the external load.

[0019] The control input end of the switching sub-circuit is connected with the output end of the control circuit, and the output end of the switching sub-circuit is connected with the control input end of the driving sub-circuit.

[0020] In a possible implementation, the switching sub-circuit comprises a first transistor and a sixth resistor, and the driving sub-circuit comprises a second transistor and a seventh resistor.

[0021] The gate of the first transistor is connected with the output end of the control circuit, the source of the first transistor is grounded, the drain of the first transistor is connected with the first end of the sixth resistor and the gate of the second transistor, and the second end of the sixth resistor is connected with the external switching power supply;

[0022] The source of the second transistor is connected with the first end of the seventh resistor, the drain of the second transistor is connected with the external load, and the second end of the seventh resistor is connected with the external switching power supply.

[0023] In a possible implementation, the driving circuit further comprises an overcurrent protection sub-circuit, the overcurrent protection sub-circuit comprising a second diode and a second triode;

[0024] The negative electrode of the second diode and the emitter of the second triode are connected to the second end of the seventh resistor, the positive electrode of the second diode and the collector of the second triode are connected to the gate of the second transistor, and the base of the second triode is connected to the source of the second transistor.

[0025] In a possible implementation, the sampling circuit comprises an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a third triode and a fourth triode;

[0026] The first end of the eighth resistor and the first end of the ninth resistor are connected to the external switching power supply, and the second end of the eighth resistor and the emitter of the third triode are connected to the power input end of the driving circuit;

[0027] The second end of the ninth resistor is connected to the emitter of the fourth triode, the first end of the tenth resistor is connected to the base of the third triode, the second end of the tenth resistor is connected to the base of the fourth triode and the collector of the fourth triode;

[0028] The collector of the third triode is connected to the first end of the eleventh resistor and the first end of the twelfth resistor, the second end of the eleventh resistor is connected to the first input end of the control circuit, and the second end of the twelfth resistor is grounded;

[0029] The collector of the fourth triode is connected to the first end of the thirteenth resistor, and the second end of the thirteenth resistor is grounded.

[0030] In a possible implementation, the electronic fuse circuit further comprises a voltage feedback circuit;

[0031] The input end of the voltage feedback circuit is connected to the output end of the driving circuit, the input end of the voltage feedback circuit receives the output voltage of the driving circuit, the output end of the voltage feedback circuit is connected to the second input end of the control circuit, and the control circuit is configured to receive the output voltage of the voltage feedback circuit and control the on-off state of the driving circuit according to the current feedback signal and the output voltage.

[0032] In a possible implementation, the voltage feedback circuit comprises a fourteenth resistor, a fifteenth resistor and a capacitor;

[0033] The first end of the fourteenth resistor is connected to the output end of the driving circuit, the second end of the fourteenth resistor is connected to the first end of the fifteenth resistor and the first end of the capacitor, and the first end of the capacitor is connected to the second input end of the control circuit;

[0034] The second end of the fifteenth resistor and the second end of the capacitor are grounded.

[0035] In a second aspect, the embodiments of the present application provide a power supply system, the power supply system comprising an external switching power supply and the electronic fuse circuit according to any one of the above embodiments.

[0036] In a third aspect, the embodiments of the present application provide a vehicle, the vehicle comprising the power supply system according to the above embodiments.

[0037] The electronic fuse circuit, the power supply system and the vehicle provided by the embodiments of the present application comprise a control circuit, a driving circuit and a sampling circuit; an input end of the sampling circuit is connected to an external switching power supply, an output end of the sampling circuit is connected to a power input end of the driving circuit, and an output end of the driving circuit is connected to an external load; a first input end of the control circuit is connected to an output end of the sampling circuit, and an output end of the control circuit is connected to a control input end of the driving circuit; the sampling circuit is configured to sample an output current of the external switching power supply and output a current feedback signal; and the control circuit is configured to receive the current feedback signal and control a turn-on / off state of the driving circuit according to the current feedback signal. The current in the external switching power supply supply circuit is collected by the sampling circuit, which can not only detect large current of the external switching power supply, but also detect small current, thereby realizing monitoring of small current supply. BRIEF DESCRIPTION OF DRAWINGS

[0038] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments consistent with the present application and, together with the description, further serve to explain the principles of the application.

[0039] Figure 1 Structure of the electronic fuse circuit provided for one of the embodiments of the present application Figure 1 ;

[0040] Figure 2 Structure of the electronic fuse circuit provided for one of the embodiments of the present application Figure 2 ;

[0041] Figure 3 Structure of the electronic fuse circuit provided for one of the embodiments of the present application Figure 3 ;

[0042] Figure 4 Structure of the electronic fuse circuit provided for one of the embodiments of the present application Figure 4 ;

[0043] Figure 5 Structure of the electronic fuse circuit provided for one of the embodiments of the present application Figure 5 ;

[0044] Figure 6 Structure of the electronic fuse circuit provided for one of the embodiments of the present application Figure 6 ;

[0045] Figure 7 Structure of electronic fuse circuit provided for one of the embodiments of the present application Figure 7 ;

[0046] Figure 8 Structure of electronic fuse circuit provided for one of the embodiments of the present application Figure 8 ;

[0047] Figure 9 Structure of electronic fuse circuit provided for one of the embodiments of the present application Figure 9 ;

[0048] Figure 10 Structure of electronic fuse circuit provided for one of the embodiments of the present application Figure 10 ;

[0049] Figure 11 Structure of electronic fuse circuit provided for one of the embodiments of the present application Figure 11 ;

[0050] Figure 12 Structure diagram of small current electronic fuse circuit provided for one of the embodiments of the present application.

[0051] Reference signs:

[0052] 100: electronic fuse circuit; 101: control circuit; 1011: controller; 1012: control sub-circuit; 102: sampling circuit; 103: driving circuit; 1031: switch sub-circuit; 1032: driving sub-circuit; 1033: overcurrent protection sub-circuit; 104: voltage feedback circuit; 200: external switching power supply; 300: external load; R1: first resistor; R2: second resistor; R3: third resistor; R4: fourth resistor; R5: fifth resistor; R6: sixth resistor; R7: seventh resistor; R8: eighth resistor; R9: ninth resistor; R10: tenth resistor; R11: eleventh resistor; R12: twelfth resistor; R13: thirteenth resistor; R14: fourteenth resistor; R15: fifteenth resistor; C: capacitor; D1: first diode; D2: second diode; T1: first triode; T2: second triode; T3: third triode; T4: fourth triode; Q1: first transistor; Q2: second transistor.

[0053] The specific embodiments of the present application have been shown and described by the above drawings, and will be described in more detail hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application by any means, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0054] The exemplary embodiments will be described in detail herein with reference to the attached drawings. In the following description, like reference numerals refer to like elements, unless the context clearly dictates otherwise. The following description of exemplary embodiments is not representative of all possible embodiments consistent with the present application. Instead, it is merely an example of apparatus and methods consistent with some aspects of the present application as detailed in the appended claims.

[0055] In the description of the present application, the terms "first", "second", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an indicated number of technical features. Thus, features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0056] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0057] When the circuit fails or is abnormal, the current rises continuously, and the rising current may damage some important devices in the circuit, and may even burn the circuit and cause a fire. If a fuse is properly installed in the circuit, the fuse can cut off the current to ensure the safety of the circuit. The traditional fuse includes a section of wire that melts and cuts off the current when the current abnormally rises to a certain height and heat, thereby protecting the safe operation of the circuit. Although the electronic fuse is called a fuse, it is actually a semiconductor overcurrent protection chip that uses a combination of solid-state elements and sensing circuits to prevent overcurrent conditions in the circuit. The sensing circuit continuously monitors the current flowing through the circuit and compares it with a predetermined threshold. If the current exceeds this threshold, the electronic fuse will trip and disconnect the circuit, cutting off the current to prevent damage to circuit components or equipment.

[0058] The electronic fuse circuit provided in the embodiments of the present application is as shown in Figure 1 The electronic fuse circuit 100 includes a control circuit 101, a sampling circuit 102, and a driving circuit 103;

[0059] The input end of the sampling circuit 102 is connected to the external switching power supply 200, the output end of the sampling circuit 102 is connected to the power input end of the driving circuit 103, and the output end of the driving circuit 103 is connected to the external load 300;

[0060] The first input end of the control circuit 101 is connected with the output end of the sampling circuit 102, and the output end of the control circuit 101 is connected with the control input end of the driving circuit 103;

[0061] The sampling circuit 102 is used for sampling the output current of the external switching power supply 200 and outputting a current feedback signal; the control circuit 101 is used for receiving the current feedback signal and controlling the on-off state of the driving circuit 103 according to the current feedback signal.

[0062] In the embodiment of the present application, the electronic fuse circuit 100 is used in a circuit system with the external switching power supply 200, and the external switching power supply 200 is used for supplying power to the external load 300. The voltage provided by the external switching power supply 200 is sequentially supplied to the external load 300 through the sampling circuit 102 and the driving circuit 103. The sampling circuit 102 is used for collecting the output current on the output circuit of the external switching power supply; the driving circuit 103 is controlled by the control circuit 101 to be in the on-off state, and in the case that the driving circuit 103 is turned on, the external switching power supply 200 provides voltage for the external load, and in the case that the driving circuit 103 is turned off, the external switching power supply 200 cannot provide power supply for the external load.

[0063] The driving circuit 103 includes at least one transistor, which can be a MOSFET (metal oxide semiconductor field effect transistor), an IGBT (insulated gate bipolar transistor), a JFET (junction field effect transistor), a BJT (bipolar junction transistor) or other switch tubes with equivalent functions.

[0064] In the embodiment of the present application, the sampling circuit 102 generates a current feedback signal after collecting the current in the circuit and the current exceeds the set current threshold, and the control circuit 101 is woken up by the current feedback signal, so as to realize the management and control of the driving circuit 103 by the control circuit 101, thereby realizing the function of the fuse.

[0065] In the electronic fuse circuit provided in the above embodiment, the electronic fuse circuit includes a control circuit, a driving circuit and a sampling circuit; the input end of the sampling circuit is connected with the external switching power supply, the output end of the sampling circuit is connected with the power input end of the driving circuit, and the output end of the driving circuit is connected with the external load; the first input end of the control circuit is connected with the output end of the sampling circuit, and the output end of the control circuit is connected with the control input end of the driving circuit; the sampling circuit is used for sampling the output current of the external switching power supply and outputting a current feedback signal; and the control circuit is used for receiving the current feedback signal and controlling the on-off state of the driving circuit according to the current feedback signal. By collecting the current in the external switching power supply circuit through the sampling circuit, not only the large current of the external switching power supply can be detected, but also the small current can be detected, so as to realize the monitoring of the small current power supply.

[0066] In one of the embodiments, as shown in Figure 2 The control circuit includes a controller 1011 and a control sub-circuit 1012.

[0067] The first input terminal of the controller 1011 is connected to the output terminal of the sampling circuit 102, the output terminal of the controller 1011 is connected to the first input terminal of the control sub-circuit 1012, and the output terminal of the control sub-circuit 1012 is connected to the control input terminal of the driving circuit 103.

[0068] The first input terminal of the controller 1011 is used to obtain the current feedback signal, and based on the current feedback signal, the controller 1011 sends a control signal to the control sub-circuit 1012, and the control sub-circuit 1012 drives the driving circuit 103 according to the control signal.

[0069] The controller 1011 is used to analyze and process the received signal or voltage, and send a control signal to the control sub-circuit 1012. After receiving the control signal, the control sub-circuit 1012 drives the driving circuit 103 according to the control signal. Specifically, the controller 1011 can be a micro control unit (MCU) which has the ability of signal processing and analysis, and can receive analog signals and digital signals. After receiving the current feedback signal sent by the sampling circuit 102, the MCU wakes up and starts working based on the current feedback signal. The control sub-circuit 1012 is a circuit composed of electronic components, which does not have control function and can only receive analog signals, such as receiving the control signal sent by the MCU, to drive the driving circuit 103.

[0070] In the electronic fuse circuit provided in the above embodiments, the control circuit is divided according to the function, into a controller with control function and a control sub-circuit for executing the control signal. When the function of the circuit is increased, the local circuit can be adjusted based on the type of the increased function, so that the electronic fuse circuit can be applied to multiple scenarios.

[0071] In one of the embodiments, as shown in Figure 3 The control sub-circuit 1012 includes a first resistor R1, a second resistor R2, and a first diode D1.

[0072] The first output terminal of the controller 1011 is connected to the first terminal of the first resistor R1, the first terminal of the first resistor R1 is connected to the active enable signal, and the second terminal of the first resistor R1 is connected to the first terminal of the second resistor R2. The second terminal of the second resistor R2 is connected to the negative electrode of the first diode D1 and the control input terminal of the driving circuit 103, and the positive electrode of the first diode D1 is grounded. The first resistor R1 is used to connect the active enable signal sent by the controller 1011.

[0073] In Figure 3In the circuit shown, the driving condition of the driving circuit 103 is determined by the voltage at the second end of the second resistor R2, which is determined by the active enable signal and the first diode D1. For example, when the driving circuit 103 is turned on at a high level, the voltage provided by the active enable signal is at a high level, and the voltage at the second end of the second resistor R2 is at a high level through the voltage division of the first resistor R1 and the second resistor R2. In the case where the controller 1011 does not provide the active enable signal, the voltage at the second end of the second resistor R2 is determined by the first diode D1, and the first diode D1 can be a voltage stabilizing diode, so that the second end of the second resistor R2 is stabilized at a low level. In this embodiment, the first resistor R1 and the second resistor R2 realize voltage division, and the resistance values are selected according to the actual application, so that the voltage provided by the active enable signal can actively drive the driving circuit 103. In some embodiments, if only the active enable signal is present, the first resistor R1 and the second resistor R2 can be combined into one resistor.

[0074] In the electronic fuse circuit provided by the above embodiment, through resistance voltage division and the voltage stabilizing effect of the diode, in combination with the active enable signal provided by the controller, active driving of the driving circuit is realized.

[0075] In one of the embodiments, as shown in Figure 4 The control sub-circuit further includes a third resistor R3, a fourth resistor R4, and a first triode T1.

[0076] The second output end of the controller 1011 is connected to the first end of the third resistor R3, the first end of the third resistor R3 is connected to the active shutdown signal, the second end of the third resistor R3 is connected to the first end of the fourth resistor R4 and the base of the first triode T1, the collector of the first triode T1 is connected to the second end of the first resistor R1, and the emitter of the first triode T1 and the second end of the fourth resistor R4 are grounded. The third resistor R3 is used to connect the active shutdown signal sent by the controller 1011.

[0077] The active shutdown signal is used to provide a shutdown level for the driving circuit. As shown in Figure 4 In the circuit shown, the driving circuit 103 is turned on at a high level and is turned off at a low level, a high level is provided by the active enable signal, and if there is no active shutdown signal at this time, the voltage value at the second end of the first resistor R1 is obtained through voltage division, and accordingly, the second end of the second resistor R2, i.e., the input end of the driving circuit 103, is at a high level; if the controller 1011 provides the active shutdown signal, the first triode T1 is turned on, the second end of the first resistor R1 is equivalent to being grounded, and is at a low level, so that the input end of the driving circuit 103 is at a low level, and the active shutdown function is realized.

[0078] It should be noted that the active shutdown signal and the active enable signal sent by the controller 1011 are triggered based on the voltage and current output monitoring of the drive circuit 103 by the controller 1011.

[0079] The active shutdown signal provided by the controller and the transistor in the control sub-circuit realize the active shutdown of the drive circuit in the electronic fuse circuit provided by the above embodiment. In the above circuit, each signal is isolated by a resistor and a diode or a transistor to avoid mutual influence between signals and improve the normal operation of the electronic fuse circuit.

[0080] In one embodiment, as shown in Figure 5 The drive circuit 103 further includes a feedback output port, and the feedback output port outputs a feedback control signal.

[0081] The control sub-circuit 1012 further includes a fifth resistor R5, a first end of the fifth resistor R5 is connected to the feedback output port, and a second end of the fifth resistor R5 is connected to a second end of the first resistor R1.

[0082] The voltage of the drive circuit 103 is output through the feedback output port, and the feedback control signal and the active enable signal at the second end of the first resistor R1 perform an OR logic operation, thereby completing the output latching function of the electronic fuse circuit. The self-locking scheme provided in this embodiment ensures that the power supply of the electronic fuse circuit is maintained in an abnormal scenario, such as a whole-board reset or a low-power sleep, without the need for an external circuit latching signal structure, thereby reducing the design cost.

[0083] In one embodiment, as shown in Figure 6 The drive circuit 103 includes a switch sub-circuit 1031 and a drive sub-circuit 1032.

[0084] The input end of the drive sub-circuit 1032 is connected to the output end of the sampling circuit 102, and the output end of the drive sub-circuit 1032 is connected to the input end of the external load 300.

[0085] The control input end of the switch sub-circuit 1031 is connected to the output end of the control circuit 101, and the output end of the switch sub-circuit is connected to the control input end of the drive sub-circuit.

[0086] The drive state of the drive sub-circuit 1032 directly affects the conduction of the power supply loop on which the external switch power supply 200 supplies power to the external load 300; the switch sub-circuit 1031 is on the control loop of the drive sub-circuit 1032 controlled by the control circuit 101, and the drive signal output by the control circuit 101 controls the drive state of the drive sub-circuit 1032 through the switch sub-circuit 1031.

[0087] Specifically, as shown in Figure 7As shown, the switch sub-circuit 1031 includes a first transistor Q1 and a sixth resistor R6, and the drive sub-circuit 1032 includes a second transistor Q2 and a seventh resistor R7.

[0088] The gate of the first transistor Q1 is connected to the output terminal of the control circuit, the source of the first transistor Q1 is grounded, the drain of the first transistor Q1 is connected to the first terminal of the sixth resistor R6 and the gate of the second transistor Q2, and the second terminal of the sixth resistor R6 is connected to the external switching power supply 200.

[0089] The source of the second transistor Q2 is connected to the first terminal of the seventh resistor R7, the drain of the second transistor Q2 is connected to the external load 300, and the second terminal of the seventh resistor R7 is connected to the external switching power supply 200.

[0090] In the circuit shown in Figure 7 , the first transistor Q1 is an N-type transistor, the second transistor Q2 is a P-type transistor, the gate of the first transistor Q1 is connected to the drive signal, the first transistor Q1 is turned on when the drive signal provides a high level, at this time the gate of the second transistor Q2 is grounded to a low level, and the second transistor Q2 is turned on, after the second transistor Q2 is turned on, the external switching power supply 200 supplies power to the external load 300. When the drive signal provides a low level, the gate of the first transistor Q1 is at a low level, the first transistor Q1 is turned off, at this time, the external switching power supply 200 provides a high level to the gate of the second transistor Q2 through the sixth resistor R6, the second transistor Q2 is turned off, and the external switching power supply 200 cannot supply power to the external load 300.

[0091] The electronic fuse circuit provided in the above embodiment has the advantages that the drive sub-circuit only provides a switching function, the switching of the drive state is controlled by the switch sub-circuit, and compared with a circuit using only one switching device, the electronic fuse circuit has higher stability.

[0092] In one of the embodiments, as shown in Figure 8 , the drive circuit 103 further includes an overcurrent protection sub-circuit 1033, and the overcurrent protection sub-circuit 1033 includes a second diode D2 and a second transistor T2.

[0093] The negative electrode of the second diode D2 and the emitter of the second transistor T2 are connected to the second terminal of the seventh resistor R7, the positive electrode of the second diode D2 and the collector of the second transistor T2 are connected to the gate of the second transistor Q2, and the base of the second transistor T2 is connected to the source of the second transistor Q2.

[0094] The switch of the second triode T2 is controlled by the voltage drop across the seventh resistor R7, so that when the driving current is too large, the seventh resistor R7 reaches the opening threshold to open the second triode T2, so that the gate and the source of the second transistor Q2 are short-circuited, and the turn-off process of the second transistor Q2 is realized; the second diode D2 is a voltage stabilizing tube, which is used to protect the gate and the source of the second transistor Q2 from being damaged due to too high voltage.

[0095] The electronic fuse circuit provided by the above embodiment realizes overcurrent protection of the second transistor Q2 through the overcurrent protection subcircuit, thereby improving the safety of the electronic fuse circuit.

[0096] In one of the embodiments, as shown in FIG. 1, the sampling circuit 102 includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a third triode T3, and a fourth triode T4. Figure 9

[0097] The first end of the eighth resistor R8 and the first end of the ninth resistor R9 are connected to the external switching power supply 200, and the second end of the eighth resistor R8 and the emitter of the third triode T3 are connected to the power input end of the driving circuit 103.

[0098] The second end of the ninth resistor R9 is connected to the emitter of the fourth triode T4, the first end of the tenth resistor R10 is connected to the base of the third triode T3, and the second end of the tenth resistor R10 is connected to the base and the collector of the fourth triode T4.

[0099] The collector of the third triode T3 is connected to the first end of the eleventh resistor R11 and the first end of the twelfth resistor R12, the second end of the eleventh resistor R11 is connected to the first input end of the control circuit 101, and the second end of the twelfth resistor R12 is grounded.

[0100] The collector of the fourth triode T4 is connected to the first end of the thirteenth resistor R13, and the second end of the thirteenth resistor R13 is grounded.

[0101] Figure 9 In the circuit shown in FIG. 1, the sampling circuit 102 completes the sampling of the output current of the power supply circuit through the current mirror structure, and sends a current feedback signal to the control circuit 101 when the current exceeds the set current threshold, thereby realizing the wake-up of the control circuit 101.

[0102] ​The specific calculation process assumes that the currents flowing through R8 and R9 are i1 and i2 respectively, and the magnitude of i2 can be obtained by using KVL (Kirchhoff's voltage loop law) for the loop of R9, Q6 and R13. Here, T4 is a diode-connected transistor, so the voltage drop of T4 is a certain 0.65V (PN junction voltage drop). In the current mirror structure, as the output load current increases to a certain set value to reach a critical state, the corresponding critical state is the base potentials of T3 and T4. In the design, T3 and T4 are generally two channels of a dual-channel PNP, so it is considered that the voltage drop from the emitter to the base of T3 and T4 is also close to equal. Therefore, the voltage drops on R8 and R9 are consistent, and i1 / i2=R9 / R8 is obtained. According to the above content, i2 can be calculated, so i1 can be calculated. i1 corresponds to the output load current at this time (i.e. the set current threshold). The digital signal switches the current feedback signal to the control circuit, completing the control circuit, i.e. the awakening of the electronic fuse circuit.

[0103] The electronic fuse circuit provided by the above embodiment uses a current mirror current detection scheme to realize the switching of the digital signal at a specific threshold value, which can avoid the error problem of the base-emitter opening level in the conventional triode opening scheme, and has a simpler circuit structure and better cost advantage than the traditional operational amplifier current detection scheme.

[0104] In one of the embodiments, as shown in Figure 10 the electronic fuse circuit further includes a voltage feedback circuit 104;

[0105] The input end of the voltage feedback circuit 104 is connected to the output end of the driving circuit 103, and the input end of the voltage feedback circuit 104 receives the output voltage of the driving circuit. The output end of the voltage feedback circuit 104 is connected to the second input end of the control circuit 101, and the second input end of the control circuit 101 receives the output voltage of the voltage feedback circuit 104. The driving signal is related to the output voltage of the voltage feedback circuit 104.

[0106] The function realized by the voltage feedback circuit 104 is the conventional voltage feedback function. The voltage feedback circuit 104 feeds back the size of the output voltage to the control circuit 101, so as to monitor the power supply circuit by the control circuit 101.

[0107] Specifically, as shown in Figure 11 the voltage feedback circuit 104 includes a fourteenth resistor R14, a fifteenth resistor R15 and a capacitor C;

[0108] The first end of the fourteenth resistor R14 is connected to the output end of the driving circuit, and the second end of the fourteenth resistor R14 is connected to the first end of the fifteenth resistor R15 and the first end of the capacitor C. The first end of the capacitor C is connected to the second input end of the control circuit 101.

[0109] The second end of the fifteenth resistor R15 and the second end of the capacitor C are grounded.

[0110] The electronic fuse circuit provided by the above embodiment can judge whether the output voltage is normal at any time by adopting the output voltage through the voltage feedback circuit, can monitor the state of the power supply circuit of the external switching power supply in real time, and can improve the reliability and safety of the power supply system.

[0111] In combination with the above embodiment, the application provides a small-current electronic fuse circuit in an actual application scenario, which is applied to a power supply system of a vehicle, such as Figure 12 As shown in the figure, the external switching power supply 200 is taken as an example of KL30 anti-reverse power supply, and a diode is added to the small-current electronic fuse circuit to realize voltage stabilization and anti-supply. In Figure 12 In the small-current electronic fuse circuit shown in the figure, current sampling is realized through a current mirror structure, and a current feedback signal is sent to wake up the MCU when the current exceeds the set threshold, so as to enrich the small-current electronic fuse scheme; the current mirror current detection scheme is used to realize the specific threshold switching digital signal state, which can not only avoid the error problem of the base-emitter opening level in the conventional triode opening scheme (mainly the temperature influence), but also has a simpler circuit structure and better cost advantage than the traditional operational amplifier detection current scheme. In the circuit, the self-locking scheme is realized through the feedback control signal, so as to ensure that the power supply of the electronic fuse circuit is maintained in an abnormal scene (the whole board is reset / low-power sleep), without the latch signal structure of the external circuit, thereby reducing the design cost.

[0112] The application also provides a power supply system, which comprises an external switching power supply and an electronic fuse circuit according to any one of the above embodiments.

[0113] The application also provides a vehicle, which comprises a power supply system according to the above embodiments.

Claims

1. An electronic fuse circuit, characterized by The electronic fuse circuit (100) comprises a control circuit (101), a sampling circuit (102) and a driving circuit (103); An input end of the sampling circuit (102) is connected with an external switching power supply (200), an output end of the sampling circuit (102) is connected with a power input end of the driving circuit (103), and an output end of the driving circuit (103) is connected with an external load (300); A first input end of the control circuit (101) is connected with an output end of the sampling circuit (102), and an output end of the control circuit (101) is connected with a control input end of the driving circuit (103); The sampling circuit (102) is used for sampling an output current of the external switching power supply (200) and outputting a current feedback signal, and the control circuit (101) is used for receiving the current feedback signal and controlling a turn-on / off state of the driving circuit (103) according to the current feedback signal.

2. The electronic fuse circuit of claim 1, wherein, The control circuit (101) comprises a controller (1011) and a control sub-circuit (1012); A first input end of the controller (1011) is connected with an output end of the sampling circuit (102), an output end of the controller (1011) is connected with a first input end of the control sub-circuit (1012), and an output end of the control sub-circuit (1012) is connected with a control input end of the driving circuit (103); The first input end of the controller (1011) is used for acquiring the current feedback signal and sending a control signal to the control sub-circuit (1012) based on the current feedback signal, and the control sub-circuit (1012) is used for driving the driving circuit (103) according to the control signal.

3. The electronic fuse circuit of claim 2, wherein, The control sub-circuit (1012) comprises a first resistor (R1), a second resistor (R2) and a first diode (D1); A first output end of the controller (1011) is connected with a first end of the first resistor (R1), a second end of the first resistor (R1) is connected with a first end of the second resistor (R2), a second end of the second resistor (R2) is connected with a negative electrode of the first diode (D1) and a control input end of the driving circuit (103), a positive electrode of the first diode (D1) is grounded, and the first resistor (R1) is used for inputting an active enable signal sent by the controller (1011); and / or, The control sub-circuit (1012) further comprises a third resistor (R3), a fourth resistor (R4) and a first triode (T1); A second output end of the controller (1011) is connected with a first end of the third resistor (R3), a second end of the third resistor (R3) is connected with a first end of the fourth resistor (R4) and a base of the first triode (T1), a collector of the first triode (T1) is connected with a second end of the first resistor (R1), an emitter of the first triode (T1) and a second end of the fourth resistor (R4) are grounded, and the third resistor (R3) is used for inputting an active shutdown signal sent by the controller (1011).

4. The electronic fuse circuit of claim 3, wherein, The driving circuit (103) further comprises a feedback output port, which outputs a feedback control signal; The control sub-circuit (1012) further comprises a fifth resistor (R5), a first end of the fifth resistor (R5) is connected to the feedback output port, and a second end of the fifth resistor (R5) is connected to a second end of the first resistor (R1).

5. The electronic fuse circuit of claim 1, wherein, The driving circuit (103) comprises a switch sub-circuit (1031) and a driving sub-circuit (1032); An input end of the driving sub-circuit (1032) is connected to an output end of the sampling circuit (102), an output end of the driving sub-circuit (1032) is connected to an input end of the external load (300), a control input end of the switch sub-circuit (1031) is connected to an output end of the control circuit (101), and an output end of the switch sub-circuit (1031) is connected to a control input end of the driving sub-circuit (1032); The switch sub-circuit (1031) comprises a first transistor (Q1) and a sixth resistor (R6), and the driving sub-circuit (1032) comprises a second transistor (Q2) and a seventh resistor (R7); A gate of the first transistor (Q1) is connected to the output end of the control circuit (101), a source of the first transistor (Q1) is grounded, a drain of the first transistor (Q1) is connected to a first end of the sixth resistor (R6) and a gate of the second transistor (Q2), and a second end of the sixth resistor (R6) is connected to the external switching power supply (200); A source of the second transistor (Q2) is connected to a first end of the seventh resistor (R7), a drain of the second transistor (Q2) is connected to the external load (300), and a second end of the seventh resistor (R7) is connected to the external switching power supply (200).

6. The electronic fuse circuit of claim 5, wherein, The driving circuit (103) further comprises an overcurrent protection sub-circuit (1033), the overcurrent protection sub-circuit (1033) comprises a second diode (D2) and a second transistor (T2); A negative electrode of the second diode (D2) and an emitter of the second transistor (T2) are connected to the second end of the seventh resistor (R7), a positive electrode of the second diode (D2) and a collector of the second transistor (T2) are connected to the gate of the second transistor (Q2), and a base of the second transistor (T2) is connected to the source of the second transistor (Q2).

7. The electronic fuse circuit of claim 1, wherein, The sampling circuit (102) comprises an eighth resistor (R8), a ninth resistor (R9), a tenth resistor (R10), an eleventh resistor (R11), a twelfth resistor (R12), a thirteenth resistor (R13), a third transistor (T3), and a fourth transistor (T4); A first end of the eighth resistor (R8) and a first end of the ninth resistor (R9) are connected to the external switching power supply (200), a second end of the eighth resistor (R8) and an emitter of the third transistor (T3) are connected to a power input end of the driving circuit (103); A second end of the ninth resistor (R9) is connected to an emitter of the fourth transistor (T4), a first end of the tenth resistor (R10) is connected to a base of the third transistor (T3), a second end of the tenth resistor (R10) is connected to a base of the fourth transistor (T4) and a collector of the fourth transistor (T4); A collector of the third transistor (T3) is connected to a first end of the eleventh resistor (R11) and a first end of the twelfth resistor (R12), a second end of the eleventh resistor (R11) is connected to a first input of the control circuit (101), a second end of the twelfth resistor (R12) is grounded; A collector of the fourth transistor (T4) is connected to a first end of the thirteenth resistor (R13), a second end of the thirteenth resistor (R13) is grounded.

8. The electronic fuse circuit according to any one of claims 1 to 7, characterized in that The electronic fuse circuit (100) further comprises a voltage feedback circuit (104); An input of the voltage feedback circuit (104) is connected to an output of the driving circuit (103), the input of the voltage feedback circuit (104) receives an output voltage of the driving circuit (103), an output of the voltage feedback circuit (104) is connected to a second input of the control circuit (101), the control circuit (101) is configured to receive the output voltage sent by the voltage feedback circuit (104) and control a turn-on / off state of the driving circuit (103) according to the current feedback signal and the output voltage; The voltage feedback circuit (104) comprises a fourteenth resistor (R14), a fifteenth resistor (R15) and a capacitor C; A first end of the fourteenth resistor (R14) is connected to the output of the driving circuit (103), a second end of the fourteenth resistor (R14) is connected to a first end of the fifteenth resistor (R15) and a first end of the capacitor C, the first end of the capacitor C is connected to the second input of the control circuit (101); A second end of the fifteenth resistor (R15) and a second end of the capacitor C are grounded.

9. A power supply system characterized by comprising: The power supply system comprises an external switching power supply (200) and the electronic fuse circuit according to any one of claims 1-8.

10. A vehicle characterized by comprising: The vehicle comprises the power supply system according to claim 9. The vehicle comprises the power supply system according to claim 9.

Images