Over-temperature protection circuit, electronic fuse and over-temperature protection method

Abstract

The invention discloses an over-temperature protection circuit, an electronic fuse and an over-temperature protection method, and relates to the technical field of electronic circuits. The circuit comprises an operational amplification module, a current source module, a thermal judgment module and a starting module, the voltage output port is electrically connected with the proportional voltage input port and the current detection port, the current output port is electrically connected with the current input port, the first driving signal input port is electrically connected with the first driving signal output port, and the second driving signal input port is electrically connected with the second driving signal output port. According to the over-temperature protection circuit, the electronic fuse and the over-temperature protection method disclosed by the embodiment of the invention, the heating value of the power tube can be estimated in advance in cooperation with the temperature sensor under the working condition that the current change rate is relatively high, and the power tube is prevented from being burnt due to signal response delay of the temperature sensor.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to an over-temperature protection circuit, an electronic fuse and an over-temperature protection method. Background Art

[0002] An electronic fuse is a circuit protection device. In order to ensure the reliability of the power system, an electronic fuse can be set at the rear end of the input power supply, that is, at the front end of the power equipment, to prevent excessive current from damaging the power system. In order to implement over-temperature protection for the electronic fuse, a temperature sensor is set near the power tube of the electronic fuse to detect the temperature of the power tube, and the working state of the power tube is adjusted according to the feedback signal of the temperature sensor to implement over-temperature protection for the electronic fuse. However, there is a certain spatial interval between the position where the temperature sensor is set and the power tube, and there is a certain lag from the temperature sensor sensing the temperature change to its feedback electrical signal, which causes the detected temperature signal to deviate from the real-time temperature of the power tube. For occasions with a faster current change rate, a higher pulse current may generate huge heat and burn the power tube before the temperature sensor detects that the power tube is overheated, making it difficult to implement effective protection for it based on the real-time temperature of the power tube. Summary of the invention

[0003] In order to solve the problem that the signal of the temperature sensor lags behind the actual temperature of the power tube in the electronic fuse under the condition of a large current change rate, resulting in a delay in the over-temperature protection of the power tube, the present application provides the following technical solutions:

[0004] In a first aspect, an over-temperature protection circuit is provided, comprising: an operational amplifier module, a current source module, a thermal judgment module and a startup module;

[0005] The operational amplifier module has: a common-phase voltage input port, an inverting voltage input port, and a voltage output port;

[0006] The current source module has: a proportional voltage input port and a current output port;

[0007] The thermal judgment module has: a current input port, a first drive signal input port, a second drive signal input port and a control signal output port;

[0008] The startup module has: a current detection port, a first drive signal output port and a second drive signal output port;

[0009] The voltage output port is electrically connected to the proportional voltage input port and the current detection port, the current output port is electrically connected to the current input port, the first drive signal input port is electrically connected to the first drive signal output port, and the second drive signal input port is electrically connected to the second drive signal output port;

[0010] The over-temperature protection circuit is configured to determine an over-temperature protection signal according to a first voltage signal received by the in-phase voltage input port and a second voltage signal received by the inverting voltage input port, and output the over-temperature protection signal through a control signal output port.

[0011] Further, the operational amplifier module includes: a first resistor, a second resistor, a third resistor, a fourth resistor and an operational amplifier;

[0012] The operational amplifier has: a first non-inverting input terminal, a first inverting input terminal and a first output terminal;

[0013] A first resistor is connected in parallel between the first inverting input terminal and the first output terminal, one end of the second resistor is electrically connected to the first inverting input terminal, one end of the third resistor is electrically connected to the first non-inverting input terminal, one end of the fourth resistor is electrically connected to the first non-inverting input terminal, and the other end of the fourth resistor is grounded;

[0014] The other end of the second resistor is used as an inverting voltage input port, the other end of the third resistor is used as a non-inverting voltage input port, and the first output end is used as a voltage output port;

[0015] The operational amplifier module is configured to determine an operational amplifier output voltage according to the first voltage signal and the second voltage signal, and output the operational amplifier output voltage from the first output terminal.

[0016] Further, the current source module includes: a first transistor, a second transistor, a fifth resistor, a sixth resistor and a seventh resistor;

[0017] The first transistor comprises: a first transistor first electrode, a first transistor second electrode and a first transistor third electrode;

[0018] The second transistor comprises: a second transistor first electrode, a second transistor second electrode and a second transistor third electrode;

[0019] The first electrode of the first transistor is electrically connected to the second electrode of the first transistor and one end of the fifth resistor, the third electrode of the first transistor is connected in series with the sixth resistor and then grounded, the first electrode of the first transistor is also electrically connected to the first electrode of the second transistor, the second electrode of the second transistor is connected to the power supply voltage, and the third electrode of the second transistor is electrically connected to one end of the seventh resistor;

[0020] The other end of the fifth resistor is used as a proportional voltage input port, and the other end of the seventh resistor is used as a current output port;

[0021] The current source module is configured to: receive the operational amplifier output voltage through the proportional voltage input port, determine the current source output current according to the operational amplifier output voltage, and output the current source output current through the current output port.

[0022] Further, the first transistor and the second transistor are NPN bipolar transistors;

[0023] The first electrode of the first transistor is a base electrode, the second electrode of the first transistor is a collector, and the third electrode of the first transistor is an emitter electrode;

[0024] The first electrode of the second transistor is a base, the second electrode of the second transistor is a collector, and the third electrode of the second transistor is an emitter.

[0025] Further, the thermal determination module includes: a comparator, a third transistor, a fourth transistor and a capacitor;

[0026] The comparator has: a second non-inverting input port, a second inverting input port and a second output port;

[0027] The third transistor comprises: a third transistor first electrode, a third transistor second electrode and a third transistor third electrode;

[0028] The fourth transistor comprises: a fourth transistor first electrode, a fourth transistor second electrode and a fourth transistor third electrode;

[0029] The second inverting input port is connected in series with a capacitor and then grounded, the second non-inverting input port is connected to the first reference voltage, the second inverting input port is also electrically connected to the third electrode of the third transistor and the second electrode of the fourth transistor, and the third electrode of the fourth transistor is grounded;

[0030] The second output port is used as a control signal output port, the second electrode of the third transistor is used as a current input port, the first electrode of the third transistor is used as a second drive signal input port, and the first electrode of the fourth transistor is used as a first drive signal input port.

[0031] The thermal judgment module is configured as follows: controlling the third transistor to turn on according to the first drive signal received at the first drive signal input port, controlling the fourth transistor to turn off according to the second drive signal received at the second drive signal input port, and charging the capacitor using the current source output current received at the current input port; in response to the voltage across the capacitor being greater than the first reference voltage, outputting an over-temperature protection signal from the second output port.

[0032] Further, the startup module is configured to: in response to the current detection signal received by the current detection port being greater than the second reference voltage, the third output port outputs a low level as the first drive signal, and the inverter output terminal outputs a high level as the second drive signal.

[0033] In a second aspect, an electronic fuse is provided, the electronic fuse comprising: a switching transistor, a transistor control module and the over-temperature protection circuit described in the first aspect;

[0034] The switch transistor comprises: a first switch transistor electrode, a second switch transistor electrode and a third switch transistor electrode;

[0035] The transistor control module has: a first voltage input port, a second voltage input port, a switch signal output port, a control signal input port,

[0036] The over-temperature protection circuit has: a common-phase voltage input port, a reverse-phase voltage input port, and a control signal output port;

[0037] The first voltage input port is electrically connected to the second pole of the switching transistor and the in-phase voltage input port and then connected to the input voltage, the second voltage input port is electrically connected to the third pole of the switching transistor and the inverting voltage input port and then connected to the output voltage, the switch signal output port is electrically connected to the first pole of the switching transistor, and the control signal input port is electrically connected to the control signal output port.

[0038] In a third aspect, a circuit board is provided, including components and metal connecting wires;

[0039] At least part of the components and part of the metal connecting wires constitute the over-temperature protection circuit recorded in the first aspect.

[0040] In a fourth aspect, an over-temperature protection method is provided, the over-temperature protection method is applied to the over-temperature protection circuit described in the first aspect, the over-temperature protection circuit having: a common-phase voltage input port, a reverse-phase voltage input port, and a control signal output port;

[0041] Over-temperature protection methods include:

[0042] Acquire a first voltage signal and a second voltage signal;

[0043] Determine a voltage output signal according to the first voltage signal and the second voltage signal, and determine whether to enable an over-temperature protection circuit according to the voltage output signal;

[0044] In response to enabling the over-temperature protection circuit, determining a charging current according to the voltage output signal, and using the charging current to charge the capacitor in the over-temperature protection circuit;

[0045] In response to the amplitude of the voltage between the two plates of the capacitor exceeding the amplitude of the first reference voltage, an over-temperature protection signal is output, wherein the amplitude of the first reference voltage is used to measure the amplitude of the voltage between the two plates of the capacitor.

[0046] Further, determining a voltage output signal according to the first voltage signal and the second voltage signal, and judging whether to enable an over-temperature protection circuit according to the voltage output signal, includes:

[0047] according to Determine the voltage output signal, where U ois the amplitude of the voltage output signal, R 1 is the resistance of the first resistor, R 2 is the resistance of the second resistor, V IN is the amplitude of the input voltage, V OUT is the amplitude of the output voltage;

[0048] In response to the amplitude of the voltage output signal being greater than the amplitude of the second reference voltage, the over-temperature protection circuit is enabled, wherein the amplitude of the second reference voltage is used to measure the amplitude of the voltage output signal.

[0049] Further, determining the charging current according to the voltage output signal includes:

[0050] according to Determine the current value flowing through the proportional voltage input port, where I o is the current value flowing through the proportional voltage input port, U o is the amplitude of the voltage output signal, V BE1 is the voltage amplitude between the first electrode of the first transistor and the third electrode of the first transistor, R 5 is the resistance value of the fifth resistor, R 6 is the resistance value of the sixth resistor;

[0051] according to Determine the charging current, where I C is the charging current, R 7 is the resistance value of the seventh resistor.

[0052] The beneficial effects of the technical solution provided by the embodiment of the present application are:

[0053] By implementing the over-temperature protection circuit, electronic fuse and over-temperature protection method disclosed in the embodiments of the present application, it is possible to cooperate with the temperature sensor to estimate the heat generated by the power tube in advance under conditions where the current change rate is fast, thereby avoiding burning of the power tube due to delayed response of the temperature sensor signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0055] Figure 1 is a schematic diagram of an over-temperature protection circuit module provided in an embodiment of the present application;

[0056] Figure 2 is a circuit diagram of an operational amplifier module provided in an embodiment of the present application;

[0057] Figure 3 is a schematic diagram of a current source module circuit provided in an embodiment of the present application;

[0058] Figure 4 is a circuit diagram of a thermal determination module provided in an embodiment of the present application;

[0059] Figure 5 is a schematic diagram of a startup module circuit provided in an embodiment of the present application;

[0060] Figure 6 is a circuit diagram of an over-temperature protection circuit provided in an embodiment of the present application;

[0061] Figure 7 This is a schematic diagram of an electronic fuse module provided in an embodiment of the present application;

[0062] Figure 8 It is a schematic diagram of an over-temperature protection method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in the implementation mode of this application will be clearly and completely described below in conjunction with the drawings in the implementation mode of this application. Obviously, the described implementation mode is only a part of the embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0064] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure shall have the usual meanings understood by persons with ordinary skills in the field to which the present disclosure belongs. The words "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one", "one" or "the" do not indicate a quantity limitation, but indicate that there is at least one. The numbers in the drawings of the specification only indicate the distinction between various functional components or modules, and do not indicate the logical relationship between components or modules. Words such as "include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0065] Hereinafter, various embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that in the accompanying drawings, the same reference numerals are given to components having substantially the same or similar structures and functions, and repeated descriptions thereof will be omitted.

[0066] In view of the problem that when the current change rate of the electronic fuse is large, the signal of the temperature sensor lags behind the actual temperature of the power tube in the electronic fuse, resulting in a delay in the over-temperature protection of the power tube, the present application provides the following embodiments.

[0067] In some embodiments, Figure 1 As shown, an over-temperature protection circuit includes: an operational amplifier module 1, a current source module 2, a thermal judgment module 3 and a start-up module 4;

[0068] Operational amplifier module 1 has: common-phase voltage input port 1 i1 , Inverting voltage input port 1 i2 And voltage output port 1 vo ;

[0069] The current source module 2 has: proportional voltage input port 2 vi And current output port 2 io ;

[0070] The thermal judgment module 3 has: current input port 3 ii , first drive signal input port 3 i1 , the second drive signal input port 3 i2 And control signal output port 3 TS ;

[0071] The startup module 4 has: a current detection port 4 is , first drive signal output port 4 o1 And the second drive signal output port 4 o2 ;

[0072] Voltage output port 1 vo With proportional voltage input port 2 vi And current sensing port 4 is Electrical connection, current output port 2 io With current input port 3 ii Electrical connection, first drive signal input port 3 i1 The first drive signal output port 4 o1 Electrical connection, second drive signal input port 3 i2 The second drive signal output port 4 o2 Electrical connection;

[0073] The first voltage signal and the second voltage signal are differential signals. The over-temperature protection circuit is used to implement over-temperature protection for the switching transistor in the electronic fuse. For an N-channel metal-oxide-semiconductor field-effect transistor as a switching transistor, the in-phase voltage input port is electrically connected to the drain of the switching transistor, and the reverse voltage input port is electrically connected to the source of the switching transistor. The drain of the switching transistor is connected to the input voltage, and the source of the switching transistor is used to connect to the subsequent electrical appliance to supply power to the electrical appliance.

[0074] The first voltage signal is a drain voltage signal of the switching transistor; the second voltage signal is a source voltage signal of the switching transistor.

[0075] The over temperature protection circuit is configured as follows: according to the common-phase voltage input port 1 i1 The received first voltage signal and the inverted voltage are input to port 1 i2 The received second voltage signal determines the over-temperature protection signal, and the control signal output port 3 TS Output over-temperature protection signal.

[0076] Specifically, according to the first voltage signal and the second voltage signal, the op amp output voltage can be determined, and the op amp output voltage is output by the first output terminal, the proportional voltage input port receives the op amp output voltage, the current source output current is determined according to the op amp output voltage, and the current source output current is output by the current output port, the third transistor is controlled to be turned on according to the first drive signal received by the first drive signal input port, and the fourth transistor is controlled to be turned off according to the second drive signal received by the second drive signal input port, and the current source output current received by the current input port is used to charge the capacitor; in response to the voltage between the two plates of the capacitor being greater than the first reference voltage, the over-temperature protection signal is output by the second output port, and in response to the current detection signal received by the current detection port being greater than the second reference voltage, the third output port outputs a low level as the first drive signal, and the inverter output terminal outputs a high level as the second drive signal.

[0077] Specifically, the operational amplifier module 1 is as follows: Figure 2 As shown, it includes: a first resistor R 1 , the second resistor R 2 , the third resistor R 3 , the fourth resistor R 4 and an operational amplifier 10;

[0078] The operational amplifier 10 has a first non-inverting input terminal 10 i1 , the first inverting input terminal 10 i2 and the first output terminal 10 uo ;

[0079] The first resistor R 1Connected in parallel to the first reverse input terminal 10 i2 With the first output terminal 10 uo The second resistor R 2 One end of the first inverting input terminal 10 i2 Electrical connection, the third resistor R 3 One end of the first non-inverting input terminal 10 i1 Electrically connected, the fourth resistor R 4 One end of the first non-inverting input terminal 10 i1 Electrically connected, the fourth resistor R 4 The other end is grounded;

[0080] The second resistor R 2 The other end is used as the inverting voltage input port 1 i2 , the third resistor R 3 The other end is used as the common-phase voltage input port 1 i1 , the first output terminal 10 uo As voltage output port 1 vo ;

[0081] The operational amplifier module 1 is configured to: determine the operational amplifier output voltage according to the first voltage signal and the second voltage signal, and output the voltage from the first output terminal 10 uo Output op amp output voltage.

[0082] Using V IN Indicates the voltage amplitude of the forward voltage input port, V OUT Represents the voltage amplitude of the inverting voltage input port, we can get: as well as Among them, U + is the voltage of the first non-inverting input port, U- is the voltage of the first reverse input port, U o is the voltage value of the first output terminal, R 1 is the resistance of the first resistor, R 2 is the resistance of the second resistor, R 3 is the resistance of the third resistor, R 4 is the resistance value of the fourth resistor.

[0083]

[0084] On this basis, the resistance values ​​of the first resistor, the second resistor, the third resistor and the fourth resistor are set to: R 1 =R 4 and R 2 =R 3 , and then we get: So far, the first output terminal 10 is obtained. uo voltage.

[0085] When the electronic fuse is working normally, the switching transistor is fully turned on, and R dson is the on-resistance value of the switching transistor, I 1 is the current flowing through the drain and source of the switching transistor, we can get:

[0086]

[0087] It can be seen from this that: the voltage value of the first output terminal U o The current value I flowing between the drain and source of the switching transistor 1 There is a direct proportion between them.

[0088] Specifically, the current source module 2 is as follows: Figure 3 As shown, it includes: a first transistor T 1 , the second transistor T 2 , the fifth resistor R 5 , the sixth resistor R 6 And the seventh resistor R 7 ;

[0089] The first transistor T 1 Having: a first transistor first electrode T 11 , the second electrode T of the first transistor 12 and the third electrode T of the first transistor 13 ;

[0090] The second transistor T 2 Having: a first electrode T of a second transistor 21 , the second transistor second electrode T 22 and the third electrode T of the second transistor 23 ;

[0091] The first transistor first electrode T 11 The second electrode T of the first transistor 12 And the fifth resistor R 5 The first transistor is electrically connected to the third electrode T 13 The sixth resistor R is connected in series 6 The first transistor first electrode T 11 Also connected to the first electrode T of the second transistor 21 Electrically connected, the second transistor second electrode T 22 Connect to power supply voltage V CC , the third electrode of the second transistor T 23 With the seventh resistor R 7 One end of the device is electrically connected to the other end;

[0092] The fifth resistor R 5 The other end is used as proportional voltage input port 2 vi , the seventh resistor R 7The other end is used as the current output port 2 io ;

[0093] The current source module 2 is configured as follows: the proportional voltage input port 2 vi Receive the op amp output voltage, determine the current source output current based on the op amp output voltage, and output the current to the current output port 2 io Output Current Source Output current.

[0094] The first transistor T 1 and the second transistor T 2 It is an NPN bipolar transistor;

[0095] The first transistor first electrode T 11 is the base, the second electrode T of the first transistor 12 is the collector, the third electrode T of the first transistor 13 is the emitter;

[0096] The first electrode T of the second transistor 21 is the base, the second electrode T of the second transistor 22 is the collector, the third electrode T of the second transistor 23 For the emitter.

[0097] Take I o Represents the current value flowing through the proportional voltage input port, R 5 Represents the resistance value of the fifth resistor, R 6 Represents the resistance value of the sixth resistor, V BE1 represents the voltage amplitude between the first electrode of the first transistor and the third electrode of the first transistor, then we can get: I o ·(R 5 +R 6 )+V BE1 =U o , and then we get:

[0098] Typically, for bipolar transistors, the base-emitter voltage is constant, and since V BE1 The value is much smaller than the first output voltage value U o ,therefore:

[0099] Specifically, the thermal judgment module 3 is as follows: Figure 4 As shown, it includes: a comparator 30, a third transistor T 3 , the fourth transistor T 4 and a capacitor C;

[0100] The comparator 30 has a second non-inverting input port 30 i1 , the second inverting input port 30 i2 and the second output port 30uo ;

[0101] The third transistor T 3 Having: a first electrode T of a third transistor 31 , the second electrode T of the third transistor 32 and the third electrode T of the third transistor 33 ;

[0102] The fourth transistor T 4 Having: a first electrode T of a fourth transistor 41 , the second electrode T of the fourth transistor 42 and the third electrode T of the fourth transistor 43 ;

[0103] Second inverting input port 30 i2 The series capacitor C is connected to ground, and the second non-inverting input port 30 i1 Connect to the first reference voltage V ref1 , the second inverting input port 30 i2 Also connected to the third transistor third electrode T 33 and the second electrode T of the fourth transistor 42 Electrically connected, the third electrode T of the fourth transistor 43 Grounding;

[0104] Second output port 30 uo As control signal output port 3 TS , the second electrode T of the third transistor 32 As current input port 3 ii , the first electrode T of the third transistor 31 As the second drive signal input port 3 i2 , the first electrode T of the fourth transistor 41 As the first drive signal input port 3 i1 .

[0105] The thermal judgment module 3 is configured to: input the first drive signal to the port 3 i1 The received first driving signal controls the third transistor T 3 The second drive signal is input to port 3. i2 The received second driving signal controls the fourth transistor T 4 shutdown, using the current input port 3 ii The received current source output current is used to charge the capacitor C; in response to the voltage across the capacitor C being greater than the first reference voltage, the second output port 30 uo Output over-temperature protection signal.

[0106] The third transistor T 3 and the fourth transistor T 4is an N-channel metal-oxide-semiconductor field effect transistor, and the first electrode T 31 is the gate, the second electrode T of the third transistor 32 is the drain, the third electrode T of the third transistor 33 The first electrode T of the fourth transistor 41 is the gate, the second electrode T of the fourth transistor 42 is the drain, the third electrode T 43 For the source.

[0107] According to the above formula derivation and the working principle of proportional current source, we can know that: Among them, I C is the charging current for charging capacitor C.

[0108] When the third transistor is turned on and the fourth transistor is turned off, the charging current I C Charge the capacitor so that the voltage between the two plates of the capacitor is: changes, among which U d It represents the amplitude of the voltage between the two plates of the capacitor, C is the capacitance value, and t is the charging time.

[0109] According to the working characteristics of the N-channel metal-oxide-semiconductor field-effect transistor, when the switching transistor is fully turned on, its loss is mainly conduction loss, and the generated Joule heat is expressed as: Wherein, Q represents Joule heat. Based on the numerical relationship between the current flowing between the drain and source of the switching transistor and the charging current recorded above, the Joule heat of the switching transistor can be evaluated by the amplitude of the voltage between the two plates of the capacitor obtained by charging the capacitor. That is, when the amplitude of the voltage between the two plates of the capacitor exceeds the first reference voltage, the accumulated thermal effect of the switching transistor causes the temperature of the switching transistor to rise to the critical value of safe operation, and it should be turned off to protect the switching transistor. At this time, the second output port 30 uo Output over-temperature protection signal to turn off the switching transistor.

[0110] It should be noted that the working condition targeted here is the case where the current change rate on the switching transistor is high. For short-term heat accumulation, heat dissipation is negligible.

[0111] Specifically, the startup module 4 is as follows Figure 5 As shown, it includes: a second comparator 40 and an inverter 41; the second comparator 40 has: a third in-phase input port 40 i1 , the third inverting input port 40 i2 and the third output port 40 uo ; The inverter 41 has: an inverter input terminal 41 i and the inverter output terminal 41 o; The third non-inverting input port 40 i1 Connect to the second reference voltage V ref2 , the third output port 40 uo The inverter input terminal 41 i Electrical connection; third inverting input port 40 i2 As current sensing port 4 is , the third output port 40 uo Also serves as the first drive signal output port 4 o1 , inverter output 41 o As the second drive signal output port 4 o2 .

[0112] The startup module 4 is configured to: respond to the current detection port 4 is The received current detection signal is greater than the second reference voltage V ref2 , then the third output port 40 uo The low level is output as the first driving signal and is outputted by the inverter output terminal 41 o The high level is output as the second driving signal.

[0113] For the situation of a high current change rate on the switch transistor as described above, a judgment can be made through the startup module. The working condition of the switch transistor is judged by setting the amplitude of the second reference voltage. When the amplitude of the current detection port is greater than the amplitude of the second reference voltage, it indicates that the switch transistor is in a condition with a high current change rate; when the amplitude of the current detection port is less than the amplitude of the second reference voltage, it indicates that the switch transistor is not in a condition with a high current change rate.

[0114] When the switching transistor is not in a condition with a high current change rate, the third output port outputs a high level, so that the first drive signal output port outputs a high level, and the second drive signal output port outputs a low level. At this time, the first drive signal is at a high level and the second drive signal is at a low level. The third transistor is turned off under the action of the second drive signal, and the fourth transistor is turned on under the action of the first drive signal. The capacitor is in a discharge state, and the second output port does not output an over-temperature protection signal.

[0115] When the switching transistor is in a condition with a high current change rate, the current detection signal is greater than the second reference voltage, and the third output port outputs a low level, so that the first drive signal output port outputs a low level, and the second drive signal output port outputs a high level. At this time, the first drive signal is at a low level, and the second drive signal is at a high level. The third transistor is turned on by the second drive signal, and the fourth transistor is turned off by the first drive signal, and the capacitor is in a charging state. As the voltage between the two plates of the capacitor increases, when the voltage amplitude between the two plates of the capacitor exceeds the first reference voltage, the second output port 30 uoOutput an over-temperature protection signal to turn off the switching transistor.

[0116] Figure 6 A circuit diagram of an over-temperature protection circuit is shown, wherein the circuit implementation of each module has been introduced above and will not be repeated here.

[0117] In other embodiments, Figure 7 As shown, an electronic fuse includes: a switching transistor T 5 , a transistor control module 5 and the over-temperature protection circuit 0 described above;

[0118] Switching transistor T 5 Having: a first electrode T of a switching transistor 51 , the second electrode of the switching transistor T 52 And the third electrode T of the switching transistor 53 ;

[0119] The transistor control module 5 has: a first voltage input port 5 i1 , the second voltage input port 5 i2 , switch signal output port 503, control signal input port 504,

[0120] Over temperature protection circuit 0 has: common phase voltage input port 1 i1 , Inverting voltage input port 1 i2 And control signal output port 3 TS ;

[0121] First voltage input port 5 i1 The second electrode T of the switching transistor 52 And the same phase voltage input port 1 i1 After electrical connection, input voltage V IN , the second voltage input port 5 i2 The third electrode T of the switching transistor 53 And the inverting voltage input port 1 i2 After electrical connection, output voltage V OUT , the switch signal output port 503 is connected to the first electrode T of the switch transistor 51 Electrically connected, the control signal input port 504 and the control signal output port 3 TS Electrical connection.

[0122] The transistor control module is used to output a signal for controlling the on or off state of the switching transistor.

[0123] The electronic fuse also includes a temperature sensor 6, and the transistor control module 5 also has a temperature detection port 5 TS . Temperature detection port 5 TSIt is used to connect the temperature sensor 6, and the temperature sensor 6 is used to obtain the temperature sampling signal of the switching transistor.

[0124] When the switching transistor is not in a condition where the current change rate is relatively high, the transistor control module 5 controls the on or off state of the switching transistor through the temperature signal detected by the temperature sensor 6 .

[0125] In some other embodiments, a circuit board includes components and metal connecting wires;

[0126] At least part of the components and part of the metal connecting wires constitute the over-temperature protection circuit described above.

[0127] In some other embodiments, an over-temperature protection method, such as Figure 8 As shown, the over-temperature protection method is applied to the over-temperature protection circuit described above, and the over-temperature protection circuit has: a common-phase voltage input port 1 i1 , Inverting voltage input port 1 i2 And control signal output port 3 TS ;

[0128] Over-temperature protection methods include:

[0129] S100: Acquire a first voltage signal and a second voltage signal;

[0130] S200: determining a voltage output signal according to the first voltage signal and the second voltage signal, and judging whether to enable an over-temperature protection circuit according to the voltage output signal;

[0131] S300: In response to enabling the over-temperature protection circuit, determining a charging current according to the voltage output signal, and using the charging current to charge the capacitor in the over-temperature protection circuit;

[0132] S400: In response to the amplitude of the voltage between the two plates of the capacitor exceeding the amplitude of the first reference voltage, outputting an over-temperature protection signal, wherein the amplitude of the first reference voltage is used to measure the amplitude of the voltage between the two plates of the capacitor.

[0133] Specifically, S200: determining a voltage output signal according to the first voltage signal and the second voltage signal, and judging whether to enable the over-temperature protection circuit according to the voltage output signal, including:

[0134] S210: According to Determine the voltage output signal, where U o is the amplitude of the voltage output signal, R 1 is the resistance of the first resistor, R 2 is the resistance of the second resistor, V IN is the amplitude of the input voltage, V OUT is the amplitude of the output voltage;

[0135] S220: In response to the amplitude of the voltage output signal being greater than the amplitude of the second reference voltage V ref2 , the over-temperature protection circuit is enabled, wherein the amplitude of the second reference voltage is used to measure the amplitude of the voltage output signal.

[0136] Specifically, determining the charging current according to the voltage output signal includes:

[0137] S310: According to Determine the proportional voltage input port 2 vi The current value, where I o is the current value flowing through the proportional voltage input port, U o is the amplitude of the voltage output signal, V BE1 The first electrode T of the first transistor 11 The third electrode T of the first transistor 13 The voltage amplitude between R 5 is the resistance value of the fifth resistor, R 6 is the resistance value of the sixth resistor;

[0138] S320: According to Determine the charging current, where I C is the charging current, R 7 is the resistance value of the seventh resistor.

[0139] By implementing the over-temperature protection circuit, electronic fuse and over-temperature protection method disclosed in the embodiments of the present application, it is possible to cooperate with the temperature sensor to estimate the heat generated by the power tube in advance under conditions where the current change rate is fast, thereby avoiding burning of the power tube due to delayed response of the temperature sensor signal.

[0140] It should be understood that although Figure 8 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 8 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0141] All the above optional technical solutions can be arbitrarily combined to form optional embodiments of the present application, which will not be described one by one here.

[0142] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made to those skilled in the art without departing from the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may also include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. Over-temperature protection circuit, characterized in that, include: Operational amplifier module, current source module, thermal judgment module and startup module; The operational amplifier module has: a common-phase voltage input port, a reverse-phase voltage input port and a voltage output port; The current source module has: a proportional voltage input port and a current output port; The thermal judgment module has: a current input port, a first drive signal input port, a second drive signal input port and a control signal output port; The startup module has: a current detection port, a first drive signal output port and a second drive signal output port; The voltage output port is electrically connected to the proportional voltage input port and the current detection port, the current output port is electrically connected to the current input port, the first drive signal input port is electrically connected to the first drive signal output port, and the second drive signal input port is electrically connected to the second drive signal output port; The over-temperature protection circuit is configured to determine an over-temperature protection signal according to a first voltage signal received by the in-phase voltage input port and a second voltage signal received by the inverting voltage input port, and output the over-temperature protection signal through the control signal output port.

2. The over-temperature protection circuit according to claim 1, characterized in that: The operational amplifier module includes: a first resistor, a second resistor, a third resistor, a fourth resistor and an operational amplifier; The operational amplifier has: a first non-inverting input terminal, a first inverting input terminal and a first output terminal; The first resistor is connected in parallel between the first inverting input terminal and the first output terminal, one end of the second resistor is electrically connected to the first inverting input terminal, one end of the third resistor is electrically connected to the first non-inverting input terminal, one end of the fourth resistor is electrically connected to the first non-inverting input terminal, and the other end of the fourth resistor is grounded; The other end of the second resistor is used as the inverting voltage input port, the other end of the third resistor is used as the non-inverting voltage input port, and the first output end is used as the voltage output port; The operational amplifier module is configured to determine an operational amplifier output voltage according to the first voltage signal and the second voltage signal, and output the operational amplifier output voltage through the first output terminal.

3. The over-temperature protection circuit according to claim 1, characterized in that: The current source module includes: a first transistor, a second transistor, a fifth resistor, a sixth resistor and a seventh resistor; The first transistor comprises: a first transistor first electrode, a first transistor second electrode and a first transistor third electrode; The second transistor comprises: a second transistor first electrode, a second transistor second electrode and a second transistor third electrode; The first electrode of the first transistor is electrically connected to the second electrode of the first transistor and one end of the fifth resistor, the third electrode of the first transistor is connected in series with the sixth resistor and then grounded, the first electrode of the first transistor is also electrically connected to the first electrode of the second transistor, the second electrode of the second transistor is connected to a power supply voltage, and the third electrode of the second transistor is electrically connected to one end of the seventh resistor; The other end of the fifth resistor serves as the proportional voltage input port, and the other end of the seventh resistor serves as the current output port; The current source module is configured to: receive an operational amplifier output voltage through the proportional voltage input port, determine a current source output current according to the operational amplifier output voltage, and output the current source output current through the current output port.

4. The over-temperature protection circuit according to claim 3, characterized in that: The first transistor and the second transistor are NPN bipolar transistors; The first electrode of the first transistor is a base electrode, the second electrode of the first transistor is a collector electrode, and the third electrode of the first transistor is an emitter electrode; The first electrode of the second transistor is a base, the second electrode of the second transistor is a collector, and the third electrode of the second transistor is an emitter.

5. The over-temperature protection circuit according to claim 1, characterized in that: The thermal judgment module includes: a comparator, a third transistor, a fourth transistor and a capacitor; The comparator has: a second non-inverting input port, a second inverting input port and a second output port; The third transistor comprises: a third transistor first electrode, a third transistor second electrode and a third transistor third electrode; The fourth transistor comprises: a fourth transistor first electrode, a fourth transistor second electrode and a fourth transistor third electrode; The second inverting input port is connected in series with the capacitor and then grounded, the second non-inverting input port is connected to a first reference voltage, the second inverting input port is also electrically connected to the third electrode of the third transistor and the second electrode of the fourth transistor, and the third electrode of the fourth transistor is grounded; The second output port serves as the control signal output port, the second electrode of the third transistor serves as the current input port, the first electrode of the third transistor serves as the second drive signal input port, and the first electrode of the fourth transistor serves as the first drive signal input port. The thermal judgment module is configured to: control the third transistor to be turned on according to the first drive signal received by the first drive signal input port, control the fourth transistor to be turned off according to the second drive signal received by the second drive signal input port, and use the current source output current received by the current input port to charge the capacitor; in response to the voltage across the capacitor being greater than the first reference voltage, output the over-temperature protection signal from the second output port.

6. The over-temperature protection circuit according to claim 1, characterized in that: The startup module is configured to: in response to the current detection signal received by the current detection port being greater than the second reference voltage, the third output port outputs a low level as the first drive signal, and the inverter output terminal outputs a high level as the second drive signal.

7. An electronic fuse, characterized in that: The electronic fuse comprises: a switching transistor, a transistor control module and an over-temperature protection circuit according to any one of claims 1 to 6; The switch transistor comprises: a first switch transistor electrode, a second switch transistor electrode and a third switch transistor electrode; The transistor control module has: a first voltage input port, a second voltage input port, a switch signal output port, a control signal input port, The over-temperature protection circuit has: a common-phase voltage input port, a reverse-phase voltage input port and a control signal output port; The first voltage input port is electrically connected to the second pole of the switching transistor and the in-phase voltage input port and then connected to the input voltage, the second voltage input port is electrically connected to the third pole of the switching transistor and the inverting voltage input port and then connected to the output voltage, the switching signal output port is electrically connected to the first pole of the switching transistor, and the control signal input port is electrically connected to the control signal output port.

8. Over-temperature protection method, characterized in that, The method is applied to the over-temperature protection circuit according to any one of claims 1 to 6, wherein the over-temperature protection circuit has: a common-phase voltage input port, a reverse-phase voltage input port, and a control signal output port; The over-temperature protection method comprises: Acquire a first voltage signal and a second voltage signal; determining a voltage output signal according to the first voltage signal and the second voltage signal, and judging whether to enable the over-temperature protection circuit according to the voltage output signal; In response to enabling the over-temperature protection circuit, determining a charging current according to the voltage output signal, and using the charging current to charge the capacitor in the over-temperature protection circuit; In response to the amplitude of the voltage between the two plates of the capacitor exceeding the amplitude of the first reference voltage, an over-temperature protection signal is output, wherein the amplitude of the first reference voltage is used to measure the amplitude of the voltage between the two plates of the capacitor.

9. The over-temperature protection method according to claim 8, characterized in that: The step of determining a voltage output signal according to the first voltage signal and the second voltage signal, and judging whether to enable the over-temperature protection circuit according to the voltage output signal, comprises: according to Determine the voltage output signal, where U o is the amplitude of the voltage output signal, R1 is the resistance value of the first resistor, R2 is the resistance value of the second resistor, V IN is the amplitude of the input voltage, V OUT is the amplitude of the output voltage; In response to the amplitude of the voltage output signal being greater than the amplitude of a second reference voltage, the over-temperature protection circuit is enabled, wherein the amplitude of the second reference voltage is used to measure the amplitude of the voltage output signal.

10. The over-temperature protection method according to claim 8, characterized in that: The step of determining the charging current according to the voltage output signal comprises: according to Determine the current value flowing through the proportional voltage input port, where I o is the current value flowing through the proportional voltage input port, U o is the amplitude of the voltage output signal, V BE1 is the voltage amplitude between the first electrode of the first transistor and the third electrode of the first transistor, R5 is the resistance value of the fifth resistor, and R6 is the resistance value of the sixth resistor; according to Determine the charging current, where I C is the charging current, and R7 is the resistance of the seventh resistor.

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