An input protection circuit, a circuit board and an input protection method

Abstract

The present application discloses an input protection circuit, a circuit board and an input protection method, relating to the technical field of electronic circuits. The input protection circuit has a voltage input end and a voltage output end. The input protection circuit includes: a monitoring module and a protection module; a power supply branch is formed from the voltage input end, through the monitoring module and the protection module connected to the monitoring module to the voltage output end; a first control port of the monitoring module is connected to a first receiving port of the protection module to form a first protection branch, the first protection branch; a second control port of the monitoring module is connected to a second receiving port of the protection module to form a second protection branch, the second protection branch; a third control port of the monitoring module is connected to a third receiving port of the protection module to form a third protection branch, the third protection branch. Effective protection is implemented on the input end to avoid voltage overshoot from damaging the transient voltage suppression diode; and avoid large current caused by capacitor short circuit from burning the board.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and particularly relates to an input protection circuit, a circuit board, and an input protection method. Background Art

[0002] For a circuit board that needs to be powered by an external DC power supply, a Transient Voltage Suppressor (TVS) is usually used at the power input terminal to protect and suppress overshoot at the voltage input terminal, and an electronic fuse (EFUSE) is used to protect the backend circuit. However, this method has certain limitations. Once the overshoot exceeds the maximum clamping voltage of the transient voltage suppressor diode, it will be irrecoverable, and the transient voltage suppressor diode will exhibit a low-resistance state, resulting in a short circuit between the EFUSE input terminal and the ground. In severe cases, the circuit board may be burned. In addition, a Schottky diode is designed at the output terminal to protect the electronic fuse.

[0003] Generally, the transient voltage suppressor diode and the Schottky diode are relatively large in size, and the commonly used package is 7.11×6.22, which occupies a large amount of space in the circuit board layout. In the case of a tight circuit board space, it is difficult to set both diodes at the same time, weakening the circuit protection effect. In addition, the capacitor between the external power supply output terminal and the electronic fuse is not protected. If the capacitor is damaged or short-circuited due to collision, there is a risk of burning the board. Summary of the Invention

[0004] In order to provide a relatively high-reliability protection for the external power supply input terminal, the present application provides the following technical solutions:

[0005] In a first aspect, an input protection circuit is provided. The input protection circuit has a voltage input terminal and a voltage output terminal, and the input protection circuit includes: a monitoring module and a protection module;

[0006] A power supply branch is formed from the voltage input terminal, through the monitoring module and the protection module connected to the monitoring module, to the voltage output terminal;

[0007] There is also between the monitoring module and the protection module:

[0008] A first protection branch for protecting the voltage output terminal;

[0009] A second protection branch for enabling or disconnecting an external power supply module;

[0010] A third protection branch for protecting the voltage input terminal against surges.

[0011] Further, the monitoring module has: a first monitoring port, a second monitoring port, a first control port, a second control port, and a third control port;

[0012] The protection module has: a first receiving port, a second receiving port, a third receiving port, a first output port, a second output port, a third output port, and a fourth output port;

[0013] The first monitoring port is connected to the fourth output port as the voltage input terminal, the second monitoring port is connected to the first output port, the second output port is used as the voltage output terminal, the first control port is connected to the first receiving port to form a first protection branch, the second control port is connected to the second receiving port to form a second protection branch, and the third control port is connected to the third receiving port to form a third protection branch;

[0014] The third output port is used to provide an enabling signal for the external power supply module to enable or disconnect the external power supply module.

[0015] Furthermore, the monitoring module includes: a detection unit, a trigger unit, and a first resistor;

[0016] The detection unit has: a first detection port, a second detection port, a third detection port, and a status signal sending port;

[0017] The trigger unit has: a first signal port, a second signal port, a third signal port, and a status signal receiving port;

[0018] The first detection port is connected to the second detection port and one end of the first resistor and then serves as the first monitoring port, the third detection port is connected to the other end of the first resistor and then serves as the second monitoring port, the status signal sending port is connected to the status signal receiving port, the first signal port serves as the first control port, the second signal port serves as the second control port, and the third signal port serves as the third control port.

[0019] Furthermore, the detection unit includes:

[0020] an analog-to-digital converter, a first voltage register, a first current register, a first selection switch, and a first signal interface;

[0021] The analog-to-digital converter has: a first voltage acquisition port, a first current acquisition port, and a second current acquisition port;

[0022] The first voltage acquisition port serves as the first detection port, the first current acquisition port serves as the second detection port, and the second current acquisition port serves as the third detection port;

[0023] The first signal transmission port in the first signal interface serves as the status signal sending port;

[0024] The analog-to-digital converter is respectively connected to the first voltage register and the first current register through the first gating switch, and is used to send the acquired voltage signal to the first voltage register and the acquired current signal to the first current register.

[0025] Further, the triggering unit includes:

[0026] a digital-to-analog converter, a second voltage register, a second current register, a second gating switch, a second signal interface, a first comparator, a second comparator, and a NOR gate;

[0027] The digital-to-analog converter has: a first voltage output port and a second voltage output port;

[0028] The NOR gate has: a first logic input port, a second logic input port, and a logic output port;

[0029] The second signal transmission port in the second signal interface serves as a status signal receiving port;

[0030] The first voltage output port is connected to the non-inverting input port of the first comparator, the inverting input port of the first comparator is connected to the first reference voltage, and the output port of the first comparator serves as the third signal port.

[0031] The second voltage output port is connected to the non-inverting input port of the second comparator, the inverting input port of the second comparator is connected to the second reference voltage, and the output port of the second comparator serves as the second signal port.

[0032] The output port of the first comparator is further connected to the first logic input port, the output port of the second comparator is further connected to the second logic input port, and the logic output port serves as the first signal port.

[0033] Further, the first resistor is a precision resistor.

[0034] Further, the protection module includes: an output protection unit, a power supply protection unit, and a surge protection unit;

[0035] The output protection unit has: a first output protection port, a second output protection port, and a third output protection port;

[0036] The power supply protection unit has: a first power supply protection port and a second power supply protection port;

[0037] The surge protection unit has: a first surge protection port and a second surge protection port;

[0038] The first output protection port serves as the first receiving port, the second output protection port serves as the first output port, the third output protection port serves as the second output port, the first power protection port serves as the second receiving port, the second power protection port serves as the third output port, the first surge protection port serves as the third receiving port, and the second power protection port serves as the fourth output port.

[0039] Furthermore, the output protection unit includes a first switching device;

[0040] The first switching device has: a first pole of the first switching device, a second pole of the first switching device, and a third pole of the first switching device;

[0041] The first pole of the first switching device serves as the first output protection port, the second pole of the first switching device serves as the second output protection port, and the third pole of the first switching device serves as the third output protection port.

[0042] Furthermore, the power protection unit includes a second switching device;

[0043] The second switching device has: a first pole of the second switching device, a second pole of the second switching device;

[0044] The first pole of the second switching device serves as the first power protection port, and the second pole of the second switching device serves as the second power protection port.

[0045] Furthermore, the surge protection unit includes a third switching device and a first diode;

[0046] The third switching device has: a first pole of the third switching device, a second pole of the third switching device;

[0047] The first pole of the third switching device serves as the first surge protection port, the second pole of the third switching device is connected to the anode of the first diode, and the cathode of the first diode serves as the second power protection port.

[0048] Furthermore, the circuit further includes a second diode;

[0049] The cathode of the second diode is connected to the voltage output terminal, and the anode of the second diode is grounded.

[0050] Furthermore, the circuit further includes at least one capacitor;

[0051] One end of any one of the at least one capacitor is connected to the second monitoring port, and the other end of any one of the at least one capacitor is grounded.

[0052] The input protection circuit further includes: an external power supply module;

[0053] The external power supply module has: a power supply output port and a power supply enable port;

[0054] The power supply output port is connected to the voltage input end, and the power supply enable port is connected to the third output port.

[0055] Furthermore, the external power supply module includes: a second resistor;

[0056] One end of the second resistor serves as the power supply enable port, and the other end of the second resistor is connected to the operating voltage, so that when the external power supply module operates normally, the power supply enable port is at a low level.

[0057] In a second aspect, a circuit board is provided, and the circuit board includes the input protection circuit described in the first aspect;

[0058] The circuit board has a first surface and a second surface arranged oppositely;

[0059] A first switching device is arranged on the first surface of the circuit board, and a second diode is arranged on the second surface of the circuit board;

[0060] The pin of the cathode of the second diode and the pin of the third pole of the first switching device are electrically connected through the same through hole.

[0061] In a third aspect, an input protection method is provided, which is applied to the input protection circuit described in the first aspect, and includes:

[0062] Connect the power supply output port of the external power supply module to the voltage input end;

[0063] Obtain the current flowing through the power supply branch and the voltage of the voltage input end through the monitoring module;

[0064] Judge whether the current flowing through the power supply branch exceeds the current threshold, and judge whether the voltage of the voltage input end exceeds the voltage threshold;

[0065] In response to the current flowing through the power supply branch not exceeding the current threshold and the voltage of the voltage input end not exceeding the voltage threshold, the monitoring module transmits a first control signal to the first receiving port to control the first switching device to conduct, transmits a second control signal to the second receiving port to control the second switching device to conduct, and transmits a third control signal to the third receiving port to control the third switching device to conduct.

[0066] Furthermore, the circuit input protection method further includes:

[0067] In response to the current flowing through the power supply branch exceeding the current threshold, the monitoring module transmits a second control signal to the second receiving port, and turns off the second switching device to disconnect the power supply from the external power supply module to the voltage input end.

[0068] Furthermore, the circuit input protection method further includes:

[0069] In response to the voltage at the voltage input terminal exceeding the voltage threshold, the monitoring module transmits a third control signal to the third receiving port, protects the first diode by turning off the third switching device; and transmits a first control signal to the first receiving port to disconnect the power supply branch by turning off the first switching device.

[0070] The beneficial effects brought by the technical solutions provided in the embodiments of the present application are as follows: By implementing an input protection circuit, a circuit board, and an input protection method disclosed in the embodiments of the present application, through the coordinated use of the monitoring module and the protection module, when the current in the power supply branch exceeds the current threshold, the power supply from the external power supply module to the voltage input terminal is disconnected; when the voltage at the voltage input terminal exceeds the voltage threshold, the external power supply module is turned off, and the power supply branch is turned off to effectively protect the input terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0072] Figure 1 is a schematic diagram of an input protection circuit module provided by an embodiment of the present application;

[0073] Figure 2 is a schematic diagram of the monitoring module provided by an embodiment of the present application;

[0074] Figure 3 is a schematic diagram of the detection unit provided by an embodiment of the present application;

[0075] Figure 4 is a schematic diagram of the trigger unit provided by an embodiment of the present application;

[0076] Figure 5 is a schematic diagram of the protection module provided by an embodiment of the present application;

[0077] Figure 6 is a schematic diagram of another input protection circuit provided by an embodiment of the present application;

[0078] Figure 7 is a schematic diagram of an input protection circuit including an external power supply module provided by an embodiment of the present application;

[0079] Figure 8 is a partial schematic diagram of the circuit board connection provided by an embodiment of the present application;

[0080] Figure 9 is a schematic diagram of the circuit input protection method provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0081] To make the objectives, technical solutions, and advantages of this application clearer, the following will, in conjunction with the accompanying drawings in the embodiments of this application, clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are only a part rather than all of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without any creative efforts shall fall within the scope of protection of this application.

[0082] Unless otherwise defined, the technical terms or scientific terms used in this disclosure shall have the ordinary meanings understood by those of ordinary skill in the art to which this disclosure pertains. The terms "first", "second", and similar words used in this disclosure do not denote any order, quantity, or importance, but are only used to distinguish different components. Similarly, words such as "a", "an", or "the" do not denote a quantity limitation, but mean that there is at least one. The numbers in the accompanying drawings of the specification only represent the distinction of each functional component or module, and do not represent the logical relationship between the components or modules. The words such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0083] Next, various embodiments according to this disclosure will be described in detail with reference to the accompanying drawings. It should be noted that in the drawings, the same reference numerals are given to components that basically have the same or similar structures and functions, and repeated descriptions thereof will be omitted.

[0084] Unless otherwise specified, the "connection" described in this application refers to an electrical connection.

[0085] To implement a relatively high-reliability protection for the external power input terminal, the following embodiments are provided in this application:

[0086] In some embodiments, as Figure 1 shown, an input protection circuit has a voltage input terminal A and a voltage output terminal B.

[0087] The input protection circuit includes: a monitoring module 100 and a protection module 200.

[0088] From the voltage input terminal A, through the monitoring module 100 and the protection module 200 connected to the monitoring module to the voltage output terminal B, a power supply branch is formed;

[0089] There is also between the monitoring module 100 and the protection module 200: a first protection branch for protecting the voltage output terminal.

[0090] A second protection branch for enabling or disconnecting the external power supply module; a third protection branch for implementing surge protection on the voltage input terminal.

[0091] Specifically, as Figure 2 shown, the monitoring module 100 has: a first monitoring port 100a, a second monitoring port 100b, a first control port 100c, a second control port 100d, and a third control port 100e;

[0092] The protection module 200 has: a first receiving port 200a, a second receiving port 200b, a third receiving port 200c, a first output port 200d, a second output port 200e, a third output port 200f, and a fourth output port 200g;

[0093] The first monitoring port 100a is connected to the fourth output port 200g as the voltage input terminal A, the second monitoring port 100b is connected to the first output port 200d, the second output port 200e is used as the voltage output terminal B, the first control port 100c is connected to the first receiving port 200a to form a first protection branch, the second control port 100d is connected to the second receiving port 200b to form a second protection branch, and the third control port 100e is connected to the third receiving port 200c to form a third protection branch;

[0094] The third output port 200f is used to provide an enabling signal for the external power supply module to enable or disconnect the external power supply module.

[0095] Specifically, the monitoring module 100 includes: a detection unit 110, a trigger unit 120, and a first resistor R1.

[0096] Since the first resistor R1 is used to collect the current flowing through the power supply branch, preferably, a precision resistor is selected as the first resistor R1. A precision resistor is a resistor component with high precision, low temperature drift, and high reliability. The precision can reach 0.01%, and the temperature drift can reach 1 PPM. By applying the precision resistor, the sampling accuracy of the detection unit 110 for the current of the power supply branch can be improved.

[0097] The detection unit 110 has: a first detection port 110a, a second detection port 110b, a third detection port 110c, and a status signal sending port 110d;

[0098] The trigger unit 120 has: a first signal port 120a, a second signal port 120b, a third signal port 120c, and a status signal receiving port 120d;

[0099] One end of the first detection port 110a, the second detection port 110b, and the first resistor R1 are connected to form a first monitoring port 100a. One end of the third detection port 110c and the other end of the first resistor R1 are connected to form a second monitoring port 100b. The status signal sending port 110d is connected to the status signal receiving port 120d. The first signal port 120a serves as the first control port 100c, the second signal port 120b serves as the second control port 100d, and the third signal port 120c serves as the third control port 100e.

[0100] As Figure 3 shown, the detection unit 110 includes:

[0101] An analog-to-digital converter 111, a first voltage register 112, a first current register 113, a first selection switch K1, and a first signal interface 114; The analog-to-digital converter 111 has: a first voltage acquisition port 111a, a first current acquisition port 111b, and a second current acquisition port 111c; The first voltage acquisition port 111a serves as the first detection port 110a, the first current acquisition port 111b serves as the second detection port 110b, and the second current acquisition port 111c serves as the third detection port 110c; The first signal transmission port in the first signal interface 114 serves as the status signal sending port 110d.

[0102] The analog-to-digital converter 111 is respectively connected to the first voltage register 112 and the first current register 113 through the first selection switch K1, and is used to send the acquired voltage signal to the first voltage register 112 and send the acquired current signal to the first current register 113.

[0103] The first current acquisition port 111b and the second current acquisition port 111c are respectively connected to both ends of the first resistor R1. Through the voltage difference across both ends of the first resistor R1 and the resistance value of the first resistor R1, the current flowing through the first resistor R1, that is, the current of the power supply branch, can be calculated:

[0104]

[0105] Wherein, I D1 represents the current value flowing through the first resistor R1, V 1 represents the voltage value of the first current acquisition port 111b, V 2 represents the voltage value of the second current acquisition port 111c, R 1 represents the resistance value of the first resistor R1.

[0106] The first voltage acquisition port 111a is used to obtain the cathode voltage of the first diode D1.

[0107] The analog-to-digital converter 111 is used to convert the acquired analog quantity into a digital quantity. Through the first strobe switch K1, the converted voltage value is stored in the first voltage register 112, and the converted current value is stored in the first current register 113. The voltage value stored in the first voltage register 112 and the current value stored in the first current register 113 are transmitted to the trigger unit 120 through the I 2 C bus.

[0108] As Figure 4 shown, the trigger unit 120 includes:

[0109] A digital-to-analog converter 121, a second voltage register 122, a second current register 123, a second strobe switch K2, a second signal interface 124, a first comparator 125, a second comparator 126, and a NOR gate 127;

[0110] The digital-to-analog converter 121 has: a first voltage output port 121a and a second voltage output port 121b;

[0111] The NOR gate 127 has: a first logic input port 127a, a second logic input port 127b, and a logic output port 127c;

[0112] The second signal transmission port in the second signal interface 124 serves as the status signal receiving port 120d;

[0113] The first voltage output port 121a is connected to the non-inverting input port of the first comparator 125. The inverting input port of the first comparator 125 is connected to the first reference voltage V ref1 , and the output port of the first comparator 125 serves as the third signal port 120c.

[0114] The second voltage output port 121b is connected to the non-inverting input port of the second comparator 126. The inverting input port of the second comparator is connected to the second reference voltage V ref2 , and the output port of the second comparator 126 serves as the second signal port 120b.

[0115] The output port of the first comparator 125 is also connected to the first logic input port 127a, and the output port of the second comparator is also connected to the second logic input port 127b. The logic output port 127c serves as the first signal port 120a.

[0116] The trigger unit 120 receives the digitized voltage and current quantities from the detection unit through the I 2 C bus.

[0117] Through a digital-to-analog converter, the digitized voltage and current are respectively converted into analog quantities, and a first comparator 125 and a second comparator 126 are respectively used to process the analog voltage and analog current. The first reference voltage V ref1 and the second reference voltage V ref2 The specific values of can be set according to the actual situation. The set first reference voltage V ref1 and the second reference voltage V ref2 can respond to voltage overshoot and current overcurrent in a timely manner. Usually, the maximum overshoot voltage is set to the maximum clamping voltage of the transient voltage suppression diode, and this maximum clamping voltage should be 1.1 to 1.2 times the cathode voltage of the first diode when the circuit is working normally. Usually, the maximum current is set to the maximum current when the circuit is working normally.

[0118] As Figure 5 shown, the protection module 200 includes: an output protection unit 210, a power supply protection unit 220, and a surge protection unit 230;

[0119] The output protection unit 210 has: a first output protection port 210a, a second output protection port 210b, and a third output protection port 210c;

[0120] The power supply protection unit 220 has: a first power supply protection port 220a and a second power supply protection port 220b;

[0121] The surge protection unit 230 has: a first surge protection port 230a and a second surge protection port 230b;

[0122] The first output protection port 210a serves as the first receiving port 200a, the second output protection port 210b serves as the first output port 200d, the third output protection port 210c serves as the second output port 200e, the first power supply protection port 220a serves as the second receiving port 200b, the second power supply protection port 220b serves as the third output port 200f, the first surge protection port 230a serves as the third receiving port 200c, and the second surge protection port 230b serves as the fourth output port 200g.

[0123] Specifically, the output protection unit 210 includes a first switching device T1;

[0124] The first switching device T1 has: a first pole T of the first switching device 11 , a second pole T of the first switching device 12 and a third pole T of the first switching device 13 ;

[0125] The first pole T of the first switching device11 As the first output protection port 210a, the second pole T of the first switching device 12 As the second output protection port 210b, the third pole T of the first switching device 13 As the third output protection port 210c.

[0126] Preferably, the first switching device is an N-channel metal-oxide-semiconductor transistor. When an N-channel metal-oxide-semiconductor transistor is used as the first switching device, the first pole T of the first switching device 11 is the gate, the second pole T of the first switching device 12 is the drain, and the third pole T of the first switching device 13 is the source. When the gate-source voltage of the first switching device is greater than the threshold voltage, the first switching device conducts; when the gate-source voltage of the first switching device is less than the threshold voltage, the first switching device turns off.

[0127] Specifically, the power supply protection unit 220 includes a second switching device T2;

[0128] The second switching device T2 has: the first pole T of the second switching device 21 and the second pole T of the second switching device 22 ;

[0129] The first pole T of the second switching device 21 serves as the first power supply protection port 220a, and the second pole T of the second switching device 22 serves as the second power supply protection port 220b. The third pole T of the second switching device 23 is grounded.

[0130] Preferably, the second switching device is an N-channel metal-oxide-semiconductor transistor. When an N-channel metal-oxide-semiconductor transistor is used as the second switching device, the first pole T of the second switching device 21 is the gate, the second pole T of the second switching device 22 is the drain, and the third pole T of the second switching device 23 is the source. When the gate-source voltage of the second switching device is greater than the threshold voltage, the second switching device conducts; when the gate-source voltage of the second switching device is less than the threshold voltage, the second switching device turns off.

[0131] Specifically, the surge protection unit 230 includes a third switching device T3 and a first diode D1;

[0132] The third switching device T3 has: the first pole T of the third switching device 31 and the second pole T of the third switching device 32 ;

[0133] The first pole T of the third switching device 31As the first surge protection port 230a, the second pole T of the third switching device 32 is connected to the anode of the first diode D1, and the cathode of the first diode D1 serves as the second surge protection port 230b.

[0134] Preferably, the third switching device is an N-channel metal-oxide-semiconductor transistor. When an N-channel metal-oxide-semiconductor transistor is used as the third switching device, the first pole T of the third switching device 31 is the gate, the second pole T of the third switching device 32 is the drain, and the third pole T of the third switching device 33 is the source. When the gate-source voltage of the third switching device is greater than the threshold voltage, the third switching device conducts; when the gate-source voltage of the third switching device is less than the threshold voltage, the third switching device turns off.

[0135] The first diode D1 is a transient voltage suppression diode, which is used to protect the subsequent electronic components from being damaged by voltage spikes.

[0136] Preferably, as Figure 6 shown, the circuit further includes a second diode D2;

[0137] The cathode of the second diode D2 is connected to the voltage output terminal B, and the anode of the second diode D2 is grounded.

[0138] The second diode D2 is a Schottky diode, which is usually used for freewheeling in the output terminal circuit.

[0139] Preferably, the circuit further includes at least one capacitor C;

[0140] One end of any capacitor C in the at least one capacitor C is connected to the second monitoring port 100b, and the other end of any capacitor C in the at least one capacitor C is grounded.

[0141] The capacitor assembled on the circuit board is a fragile electronic component. In the case of physical impact or bump, it is easy to cause a short circuit in the internal structure of the capacitor. When the external power supply module is connected to the input protection circuit, if not specially protected, the short circuit of the capacitor will cause a short circuit from the voltage output terminal of the external power supply module to the ground, and the large current generated will burn the circuit board.

[0142] Optionally, as Figure 7 shown, the input protection circuit further includes: an external power supply module 300;

[0143] The external power supply module 300 has: a power supply output port 300a and a power supply enable port 300b;

[0144] The power supply output port 300a is connected to the voltage input terminal A, and the power supply enable port 300b is connected to the third output port 200f.

[0145] Preferably, the external power supply module 300 includes: a second resistor R2;

[0146] One end of the second resistor R2 serves as the power supply enable port 300b, and the other end of the second resistor R2 is connected to the operating voltage V CC , so that when the external power supply module 300 operates normally, the power supply enable port 300b is at a low level.

[0147] In the case of normal circuit operation, the power supply enable port 300b is at a low level, and the low level enables the external power supply module 300 to supply power to the voltage input terminal A when it is in place.

[0148] When either the first switching device T1 or the third switching device T3 is turned off, the power supply enable port 300b is at a high level, disconnecting the power supply from the external power supply module 300 to the voltage input terminal A.

[0149] Through the coordinated use of the monitoring module and the protection module, when the current in the power supply branch exceeds the current threshold, the power supply from the external power supply module to the voltage input terminal is disconnected; when the voltage at the voltage input terminal exceeds the voltage threshold, the external power supply module is turned off and the power supply branch is turned off, effectively protecting the input terminal: avoiding overvoltage damage to the transient voltage suppression diode; avoiding large current caused by capacitor short - circuit and burning the board.

[0150] In some other embodiments, as Figure 8 shown, a circuit board includes the input protection circuit described in the first aspect.

[0151] Preferably, the circuit board is a printed circuit board.

[0152] The circuit board has a first surface and a second surface arranged oppositely;

[0153] The first surface of the circuit board is provided with the first switching device T1, and the second surface of the circuit board is provided with the second diode D2;

[0154] The pin of the cathode of the second diode D2 and the third pole T of the first switching device 13 are electrically connected through the same through - hole.

[0155] By arranging the transient voltage suppression diode and the Schottky diode on the surface opposite to the surface where the first switching device is located, the transient voltage suppression diode and the Schottky diode can be accommodated simultaneously, saving the circuit board area.

[0156] In some other embodiments, as Figure 9As shown, a circuit input protection method is applied to the input protection circuit described above, including:

[0157] S100: Connect the power supply output port of the external power supply module to the voltage input terminal;

[0158] S200: Obtain the current flowing through the power supply branch and the voltage of the voltage input terminal through the monitoring module;

[0159] S300: Determine whether the current flowing through the power supply branch exceeds the current threshold, and determine whether the voltage of the voltage input terminal exceeds the voltage threshold;

[0160] S400: In response to the current flowing through the power supply branch not exceeding the current threshold and the voltage of the voltage input terminal not exceeding the voltage threshold, the monitoring module transmits a first control signal to the first receiving port to control the first switching device to conduct, transmits a second control signal to the second receiving port to control the second switching device to conduct, and transmits a third control signal to the third receiving port to control the third switching device to conduct.

[0161] Optionally, the circuit input protection method further includes:

[0162] S400': In response to the current flowing through the power supply branch exceeding the current threshold, the monitoring module transmits a second control signal to the second receiving port to turn off the second switching device and disconnect the power supply from the external power supply module to the voltage input terminal.

[0163] Optionally, the circuit input protection method further includes:

[0164] S400'': In response to the voltage of the voltage input terminal exceeding the voltage threshold, the monitoring module transmits a third control signal to the third receiving port to turn off the third switching device to protect the first diode; and transmits a first control signal to the first receiving port to turn off the first switching device and disconnect the power supply branch.

[0165] By implementing an input protection circuit, a circuit board, and an input protection method disclosed in the embodiments of the present application, through the coordinated use of the monitoring module and the protection module, when the current in the power supply branch exceeds the current threshold, the power supply from the external power supply module to the voltage input terminal is disconnected; when the voltage of the voltage input terminal exceeds the voltage threshold, the external power supply module is turned off and the power supply branch is turned off, effectively protecting the input end: avoiding damage to the transient voltage suppression diode caused by voltage overshoot, surge phenomenon, etc.; avoiding large current caused by capacitor short circuit and burning the board. By arranging the transient voltage suppression diode and the Schottky diode on the surface opposite to the surface of the first switching device, the transient voltage suppression diode and the Schottky diode can be accommodated simultaneously, saving the circuit board area.

[0166] Any combination of the above optional technical solutions can be adopted to form optional embodiments of the present application, which will not be elaborated one by one here.

[0167] Note that the above are only the preferred embodiments of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments only. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An input protection circuit, characterized in that: The input protection circuit has a voltage input terminal and a voltage output terminal, and the input protection circuit includes: a monitoring module and a protection module; From the voltage input end, through the monitoring module and the protection module connected to the monitoring module to the voltage output end, a power supply branch is formed; The first control port of the monitoring module is connected to the first receiving port of the protection module to form a first protection branch, and the first protection branch is used to protect the voltage output terminal; The second control port of the monitoring module is connected to the second receiving port of the protection module to form a second protection branch, and the second protection branch is used to enable or disconnect the external power supply module; The third control port of the monitoring module is connected to the third receiving port of the protection module to form a third protection branch, and the third protection branch is used to implement surge protection for the voltage input terminal; Wherein, the monitoring module includes a trigger unit, and the trigger unit has: a first signal port, a second signal port, a third signal port and a status signal receiving port; The trigger unit includes: a digital-to-analog converter, a second voltage register, a second current register, a second selection switch, a second signal interface, a first comparator, a second comparator and an NOR gate; the digital-to-analog converter has: a first voltage output port and a second voltage output port; the NOR gate has: a first logic input port, a second logic input port and a logic output port; the second signal transmission port in the second signal interface serves as a state signal receiving port; the first voltage output port is connected to the same-phase input port of the first comparator, the inverting input port of the first comparator is connected to the first reference voltage, the output port of the first comparator serves as a third signal port, the second voltage output port is connected to the same-phase input port of the second comparator, the inverting input port of the second comparator is connected to the second reference voltage, the output port of the second comparator serves as a second signal port, the output port of the first comparator is also connected to the first logic input port, the output port of the second comparator is also connected to the second logic input port, and the logic output port serves as the first signal port.

2. The input protection circuit according to claim 1, characterized in that: The monitoring module also has: a first monitoring port and a second monitoring port; The protection module further has: a first output port, a second output port, a third output port and a fourth output port; The first monitoring port is connected to the fourth output port as the voltage input port, the second monitoring port is connected to the first output port, and the second output port is used as the voltage output port; The third output port is used to provide an enable signal to the external power supply module to enable or disconnect the external power supply module.

3. The input protection circuit according to claim 2, characterized in that: The monitoring module further includes: a detection unit and a first resistor; The detection unit has: a first detection port, a second detection port, a third detection port and a status signal sending port; The first detection port is connected to the second detection port and one end of the first resistor as the first monitoring port, the third detection port is connected to the other end of the first resistor as the second monitoring port, the status signal sending port is connected to the status signal receiving port, the first signal port is used as the first control port, the second signal port is used as the second control port, and the third signal port is used as the third control port.

4. The input protection circuit according to claim 3, characterized in that: The detection unit comprises: An analog-to-digital converter, a first voltage register, a first current register, a first selection switch and a first signal interface; The analog-to-digital converter has: a first voltage acquisition port, a first current acquisition port and a second current acquisition port; The first voltage acquisition port serves as the first detection port, the first current acquisition port serves as the second detection port, and the second current acquisition port serves as the third detection port; The first signal transmission port in the first signal interface serves as a status signal sending port; The analog-to-digital converter is connected to the first voltage register and the first current register respectively through the first selection switch, and is used to send the acquired voltage signal to the first voltage register and send the acquired current signal to the first current register.

5. The input protection circuit according to claim 3, characterized in that: The first resistor is a precision resistor.

6. The input protection circuit according to claim 2, characterized in that: The protection module includes: an output protection unit, a power protection unit and a surge protection unit; The output protection unit has: a first output protection port, a second output protection port and a third output protection port; The power protection unit has: a first power protection port and a second power protection port; The surge protection unit has: a first surge protection port and a second surge protection port; The first output protection port serves as the first receiving port, the second output protection port serves as the first output port, the third output protection port serves as the second output port, the first power supply protection port serves as the second receiving port, the second power supply protection port serves as the third output port, the first surge protection port serves as the third receiving port, and the second power supply protection port serves as the fourth output port.

7. The input protection circuit according to claim 6, characterized in that: The output protection unit includes a first switching device; The first switch device comprises: a first switch device first pole, a first switch device second pole and a first switch device third pole; The first pole of the first switch device serves as the first output protection port, the second pole of the first switch device serves as the second output protection port, and the third pole of the first switch device serves as the third output protection port.

8. The input protection circuit according to claim 6, characterized in that: The power protection unit includes a second switch device; The second switch device comprises: a second switch device first electrode and a second switch device second electrode; The first pole of the second switch device serves as the first power protection port, and the second pole of the second switch device serves as the second power protection port.

9. The input protection circuit according to claim 6, characterized in that: The surge protection unit includes a third switch device and a first diode; The third switch device comprises: a third switch device first electrode and a third switch device second electrode; The first electrode of the third switch device serves as the first surge protection port, the second electrode of the third switch device is connected to the anode of the first diode, and the cathode of the first diode serves as the second power protection port.

10. The input protection circuit according to claim 1, characterized in that: The circuit also includes a second diode; A cathode of the second diode is connected to the voltage output terminal, and an anode of the second diode is grounded.

11. The input protection circuit according to claim 1, characterized in that: The circuit further comprises at least one capacitor; One end of any one of the at least one capacitor is connected to the second monitoring port, and the other end of any one of the at least one capacitor is grounded.

12. The input protection circuit according to any one of claims 1 to 11, characterized in that: The circuit further comprises: an external power supply module; The external power supply module has: a power supply output port and a power supply enable port; The power supply output port is connected to the voltage input terminal, and the power supply enable port is connected to the third output port.

13. The input protection circuit according to claim 12, characterized in that: The external power supply module includes: a second resistor; One end of the second resistor serves as the power supply enable port, and the other end of the second resistor is connected to a working voltage, so that when the external power supply module works normally, the power supply enable port is at a low level.

14. A circuit board, characterized in that: The circuit board comprises the input protection circuit according to any one of claims 1 to 13; The circuit board has a first surface and a second surface arranged opposite to each other; A first switching device is disposed on the first surface of the circuit board, and a second diode is disposed on the second surface of the circuit board; The pin of the cathode of the second diode is electrically connected to the pin of the third electrode of the first switch device through the same through hole.

15. An input protection method, characterized in that: The method is applied to the input protection circuit according to any one of claims 1 to 13, comprising: Connect the power supply output port of the external power supply module to the voltage input terminal; The current flowing through the power supply branch and the voltage at the voltage input terminal are obtained through the monitoring module; Determine whether the current flowing through the power supply branch exceeds the current threshold, and determine whether the voltage at the voltage input terminal exceeds the voltage threshold; In response to the current flowing through the power supply branch not exceeding the current threshold and the voltage at the voltage input terminal not exceeding the voltage threshold, the monitoring module transmits a first control signal to the first receiving port to control the first switching device to turn on, transmits a second control signal to the second receiving port to control the second switching device to turn on, and transmits a third control signal to the third receiving port to control the third switching device to turn on.

16. The input protection method according to claim 15, characterized in that: The method further comprises: In response to the current flowing through the power supply branch exceeding the current threshold, the monitoring module transmits a second control signal to the second receiving port, and disconnects the power supply from the external power supply module to the voltage input terminal by turning off the second switch device.

17. The input protection method according to claim 15, characterized in that: The method further comprises: In response to the voltage at the voltage input terminal exceeding the voltage threshold, the monitoring module transmits a third control signal to the third receiving port to protect the first diode by turning off the third switching device; and transmits a first control signal to the first receiving port to disconnect the power supply branch by turning off the first switching device.

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