Power protection circuit

Abstract

The application provides a power supply protection circuit, comprising: a power supply circuit, a protection circuit and a pull-down circuit; the power supply circuit is used for converting a received initial power supply voltage into a power supply; the protection circuit comprises a protection switch and a control circuit, the protection switch is connected in series on a signal transmission path of the power supply circuit; the control circuit is connected with a control end of the protection switch, and is used for outputting a first control signal in a first state to control the protection switch to be turned off if overcurrent and overvoltage are detected; otherwise, a first control signal in a second state is outputted to control the protection switch to be turned on; the pull-down circuit is connected with the control end of the protection switch, an output end of the protection switch and the control circuit, and is used for forming a transmission path between the control end of the protection switch and the output end of the protection switch when overcurrent and overvoltage occur, and blocking the transmission path when the protection switch is turned on. The circuit of the application provides multiple overcurrent and overvoltage protection modes, and improves the reliability of the circuit.

Description

Technical Field

[0001] This application relates to power protection technology, and more particularly to a power protection circuit. Background Technology

[0002] For DC power modules that convert from high voltage to low voltage, in order to prevent high voltage from entering the output terminal, an isolation scheme can be adopted, using a transformer to achieve electrical isolation between the input and output terminals, but there are certain losses in the transformer; alternatively, a non-isolated power supply scheme can be adopted, which reduces the risk of system damage caused by power failure by adding external protection circuitry.

[0003] In existing technologies, non-isolated power supply solutions often employ a controllable switch connected in series at the input of the power module, and a control module connected to the control terminal of the controllable switch. When overvoltage or overcurrent occurs, the control module generates a control signal through a chip to disconnect the controllable switch, thereby cutting off the power supply to the power module and achieving overvoltage and overcurrent protection.

[0004] In the above scheme, when the control module fails, it may be unable to control the controllable switch to disconnect, and the reliability of the overcurrent and overvoltage protection function is not strong. Summary of the Invention

[0005] This application provides a power protection circuit that can shut off the controllable switch connected in series in the power module when the control module fails, thereby improving the reliability of the overcurrent and overvoltage protection function.

[0006] On the one hand, this application provides a power protection circuit, including: a power supply circuit, a protection circuit, and a pull-down circuit;

[0007] The power supply circuit is used to convert the received initial power supply into voltage and output the power supply.

[0008] The protection circuit includes a protection switch and a control circuit. The protection switch is connected in series in the signal transmission path of the power supply circuit. The control circuit is connected to the control terminal of the protection switch and is used to output a first control signal in a first state to control the protection switch to open if overcurrent or overvoltage is detected; otherwise, it outputs a first control signal in a second state to control the protection switch to turn on.

[0009] The pull-down circuit is connected to the control terminal and output terminal of the protection switch and the control circuit. It is used to form a transmission path between the control terminal and the output terminal of the protection switch when the control circuit detects an overcurrent or overvoltage, and to block the transmission path between the control terminal and the output terminal of the protection switch when no overcurrent or overvoltage occurs.

[0010] In some examples, the pull-down circuit includes: a first transistor, a first resistor, a first diode, and a second transistor;

[0011] One end of the first transistor is connected to the control terminal of the protection switch, the other end of the first transistor is connected to the output terminal of the protection switch, the control terminal of the first transistor is connected to the positive terminal of the first diode, and the negative terminal of the first diode is connected to one end of the second transistor.

[0012] One end of the first resistor is connected to the other end of the first transistor, and the other end of the first resistor is connected to one end of the second transistor;

[0013] The other end of the second transistor is grounded, and the control terminal of the second transistor is connected to the control circuit. The control circuit is also used to output a second control signal in a third state to control the second transistor to turn on if overcurrent or overvoltage is detected; otherwise, it outputs a second control signal in a fourth state to control the second transistor to turn off.

[0014] In some examples, the pull-down circuit further includes: a second resistor, a third resistor, and a second diode;

[0015] One end of the second resistor is connected to one end of the first transistor, and the other end of the second resistor is connected to the control terminal of the first transistor and one end of the third resistor; the other end of the third resistor is connected to the positive terminal of the first diode.

[0016] The positive terminal of the second diode is connected to the other end of the first transistor, and the negative terminal of the second diode is connected to one end of the first resistor.

[0017] In some examples, the control circuit includes: a sampling circuit, a detection circuit, a processing circuit, and a self-locking circuit;

[0018] The sampling circuit is connected to the protection switch and is used to sample the current flowing through the protection switch and output a first detection signal reflecting the magnitude of the current.

[0019] The input terminal of the detection circuit is connected to the output terminal of the sampling circuit, and receives the voltage signal at the output terminal of the power supply circuit. Based on the first detection signal and the voltage signal, if overcurrent or overvoltage is detected, an indication signal in the fifth state is output; otherwise, an indication signal in the sixth state is output.

[0020] The input terminal of the self-locking circuit is connected to the output terminal of the detection circuit. The self-locking circuit is connected to the control terminal of the second transistor and the processing circuit. It is used to enter the self-locking state in response to the indication signal in the fifth state and maintain the output of the enable signal in the seventh state and the second control signal in the third state until a reset occurs, at which point it exits the self-locking state. When not in the self-locking state, it outputs the enable signal in the eighth state and the second control signal in the fourth state in response to the indication signal in the sixth state.

[0021] The processing circuit is connected to the control terminal of the protection switch. The processing circuit receives the enable signal and, in response to the enable signal in the seventh state, outputs the first control signal in the first state; and, in response to the enable signal in the eighth state, outputs the first control signal in the second state.

[0022] In some examples, the sampling circuit includes: a first processing chip, a sampling resistor, a fourth resistor, a fifth resistor, a first capacitor, and a second capacitor;

[0023] The sampling resistor is connected in series with the protection switch, one end of the fourth resistor is connected to one end of the sampling resistor, and the other end of the fourth resistor is connected to the first input terminal of the first processing chip and one end of the first capacitor.

[0024] One end of the fifth resistor is connected to the other end of the sampling resistor, and the other end of the fifth resistor is connected to the second input terminal of the first processing chip and the other end of the first capacitor.

[0025] One end of the second capacitor is connected to the output terminal of the first processing chip, and the other end of the second capacitor is connected to the ground terminal of the first processing chip and grounded; the output terminal of the first processing chip is used to output the first detection signal.

[0026] In some examples, the detection circuit includes: a second processing chip, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a third diode, a fourth diode, a fifth diode, a sixth diode, a third capacitor, a fourth capacitor, a fifth capacitor, and a sixth capacitor;

[0027] One end of the sixth resistor receives a first reference signal, and the other end of the sixth resistor is connected to the first input terminal of the second processing chip and the positive terminal of the third diode; the negative terminal of the third diode is connected to one end of the seventh resistor, and the other end of the seventh resistor is connected to one end of the eighth resistor and the first output terminal of the second processing chip; the other end of the eighth resistor receives a first high-level signal.

[0028] One end of the ninth resistor receives the voltage signal at the output terminal of the power supply circuit, the other end of the ninth resistor is connected to the second input terminal of the second processing chip and one end of the tenth resistor, and the other end of the tenth resistor is grounded.

[0029] One end of the eleventh resistor receives a second reference signal, and the other end of the eleventh resistor is connected to the third input terminal of the second processing chip, one end of the twelfth resistor, and the positive terminal of the sixth diode. The other end of the twelfth resistor is grounded. The negative terminal of the sixth diode is connected to one end of the thirteenth resistor, and the other end of the thirteenth resistor is connected to one end of the fourteenth resistor and the second output terminal of the second processing chip. The other end of the fourteenth resistor receives a second high-level signal.

[0030] The fourth input terminal of the second processing chip receives the first detection signal, the first output terminal of the second processing chip is connected to the negative terminal of the fourth diode, the second output terminal of the second processing chip is connected to the negative terminal of the fifth diode, the positive terminal of the fourth diode is connected to the positive terminal of the fifth diode, and the indication signal is output as the output terminal of the detection circuit.

[0031] One end of the third capacitor is connected to the first input terminal of the second processing chip, and the other end of the third capacitor is grounded; one end of the fourth capacitor is connected to the second input terminal of the second processing chip, and the other end of the fourth capacitor is grounded; one end of the fifth capacitor is connected to the fourth input terminal of the second processing chip, and the other end of the fifth capacitor is grounded; one end of the sixth capacitor is connected to the third input terminal of the second processing chip, and the other end of the sixth capacitor is grounded.

[0032] In some examples, the processing circuitry includes: a fifteenth resistor, a sixteenth resistor, and a third processing chip;

[0033] The fifteenth resistor receives a third high-level signal, and the other end of the fifteenth resistor is connected to the enable terminal of the third processing chip and one end of the sixteenth resistor, while the other end of the sixteenth resistor is grounded.

[0034] The enable terminal of the third processing chip receives the enable signal, and the output terminal of the third processing chip is connected to the control terminal of the protection switch.

[0035] In some examples, the self-locking circuit includes: a third transistor, a fourth transistor, a seventh diode, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, and a seventh capacitor;

[0036] One end of the seventeenth resistor is connected to one end of the twentieth resistor. One end of the seventeenth resistor receives a fourth high-level signal. The other end of the seventeenth resistor is connected to one end of the eighteenth resistor and one end of the third transistor for outputting the second control signal. The other end of the eighteenth resistor is grounded.

[0037] One end of the third transistor is connected to one end of the nineteenth resistor and the other end of the seventeenth resistor, and the other end of the third transistor is grounded. The control terminal of the third transistor is connected to the other end of the twentieth resistor, one end of the fourth transistor, and the negative terminal of the seventh diode, for receiving the indication signal; the positive terminal of the seventh diode is used to output the enable signal.

[0038] The control terminal of the fourth transistor is connected to one end of the seventh capacitor and the other end of the nineteenth resistor; the other end of the fourth transistor is connected to the other end of the seventh capacitor and the other end of the eighteenth resistor.

[0039] In some examples, the self-locking circuit further includes a reset switch;

[0040] One end of the reset switch is connected to one end of the eighteenth resistor, and the other end of the reset switch is connected to the other end of the eighteenth resistor.

[0041] In some examples, the power protection circuit further includes: a detection circuit and an isolation circuit;

[0042] The detection circuit is connected to the output terminal of the sampling circuit and the isolation circuit, and is used to output an isolation control signal, and to detect the protection circuit according to the isolation control signal and the first detection signal output by the sampling circuit;

[0043] One end of the isolation circuit receives the first control signal, and the other end of the isolation circuit is connected to the control terminal of the protection switch. The isolation circuit receives the isolation control signal and is used to turn on or off in response to the isolation control signal.

[0044] In some examples, the isolation circuit includes: an optocoupler, a twenty-first resistor, an eighth diode, a twenty-second resistor, and a twenty-third resistor;

[0045] One end of the 22nd resistor receives the third reference signal, and the other end of the 22nd resistor is connected to one end of the 23rd resistor; the other end of the 23rd resistor is connected to the negative input terminal of the optocoupler; the positive input terminal of the optocoupler is connected to the other end of the 22nd resistor, the negative input terminal of the optocoupler receives the isolation control signal, and the negative output terminal of the optocoupler is connected to the control terminal of the protection switch.

[0046] One end of the 21st resistor is connected to the positive output terminal of the optocoupler, and the other end of the 21st resistor receives the first control signal; the negative terminal of the 8th diode is connected to the other end of the 21st resistor, and the positive terminal of the 8th diode is connected to the control terminal of the protection switch.

[0047] In some examples, the power protection circuit further includes: a first Zener diode;

[0048] The positive terminal of the first Zener diode is connected to the output terminal of the protection switch, and the negative terminal of the first Zener diode is connected to the control terminal of the protection switch.

[0049] In some examples, the input terminal of the protection switch is connected to the positive input terminal of the power supply circuit, and the output terminal of the protection switch is connected to the positive output terminal of the power supply circuit.

[0050] The power protection circuit provided in this application includes a power supply circuit, a protection circuit, and a pull-down circuit. The power supply circuit converts the initial power supply to output the power supply. The protection circuit includes a control circuit and a protection switch, with the protection switch connected in series in the signal transmission path of the power supply circuit. The control circuit is connected to the control terminal of the protection switch and outputs a first control signal in a first state to open the protection switch if overcurrent or overvoltage is detected; otherwise, it outputs a first control signal in a second state to turn the protection switch on. The pull-down circuit is connected to the control terminal and output terminal of the protection switch, as well as the control circuit, to form a transmission path between the control terminal and output terminal of the protection switch when overcurrent or overvoltage occurs, and to block this transmission path when the protection switch is on. In the event of overcurrent or overvoltage, the protection switch can be opened and the power supply output cut off through both the control circuit and the pull-down circuit, providing multiple overcurrent and overvoltage protections and improving the reliability of the circuit. Attached Figure Description

[0051] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0052] Figure 1 This is a schematic diagram of a non-isolated power supply protection scheme as an example of this application;

[0053] Figure 2 This is a schematic diagram of the power protection circuit of an example of this application;

[0054] Figure 3 This is a schematic diagram of the structure of a pull-down circuit as an example of this application;

[0055] Figure 4 This is a schematic diagram of the control circuit of an example of this application;

[0056] Figure 5 This is a schematic diagram of the sampling circuit of an example in this application;

[0057] Figure 6 This is a schematic diagram of the detection circuit of an example in this application;

[0058] Figure 7 This is a schematic diagram of the structure of a self-locking circuit as an example of this application;

[0059] Figure 8 This is a schematic diagram of the processing circuit of an example of this application;

[0060] Figure 9 This is a schematic diagram of another power protection circuit as an example of this application;

[0061] Figure 10 This is a schematic diagram of another power protection circuit as an example of this application;

[0062] Figure 11 This is a schematic diagram of the structure of an example isolation circuit of this application;

[0063] Figure 12 This is a schematic diagram of another power protection circuit as an example of this application.

[0064] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0065] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0066] For DC power modules that convert from high voltage to low voltage, in order to prevent high voltage from entering the output terminal from the input terminal, an isolation scheme can be adopted, using a transformer to achieve electrical isolation between the input and output terminals, but there are certain losses in the transformer; alternatively, a non-isolation scheme can be adopted, which reduces the risk of system damage caused by power failure by adding external protection circuitry.

[0067] In existing technologies, non-isolated power supply solutions often employ a controllable switch connected in series at the input of the power module, and a control module containing a chip connected to the control terminal of the controllable switch. When overvoltage or overcurrent occurs, the control module generates a control signal through the chip to disconnect the controllable switch, thereby cutting off the power supply to the power module and achieving overvoltage and overcurrent protection.

[0068] Figure 1 This is a schematic diagram of a non-isolated power supply protection scheme as an example of this application, as shown below. Figure 1 As shown, taking a server DC-DC power module that steps down from 54V to 12V as an example, common protection measures for non-isolated power supply solutions may include:

[0069] A fuse connected in series at the input terminal is used to switch the current by melting itself when the current abnormally rises to a certain level and temperature.

[0070] A diode TVS1 connected in parallel to the input terminal is used to clamp the input voltage; and a diode TVS2 connected in parallel to the output terminal is used to clamp the output voltage.

[0071] The inductor L1 connected in series with the input terminal and the capacitor C1 connected in parallel with the input terminal are used to filter the input current signal and reduce the input ripple current.

[0072] A controllable switch Q1 is connected in series at the input terminal, and the control terminal of the controllable switch Q1 is connected to the hot-swap control module. The hot-swap control module receives the overvoltage and overcurrent detection results from the output overvoltage and overcurrent detection circuit, and controls the controllable switch Q1 to close when no overvoltage or overcurrent occurs; and controls the controllable switch Q1 to open when overvoltage or overcurrent occurs.

[0073] An inductor L2 connected in series at the output terminal, a capacitor C2 connected in parallel at the output terminal, and controllable switches Q2 and Q3 connected in series constitute a traditional buck converter circuit. Controllable switch Q3 is connected in parallel with the output terminal, and the control terminals of controllable switches Q2 and Q3 are connected to a DC-DC control module. The DC-DC control module receives overvoltage and overcurrent detection results from the output overvoltage and overcurrent detection circuits. When no overvoltage or overcurrent occurs, it controls controllable switches Q2 and Q3 to close, achieving a buck output. When overvoltage or overcurrent occurs, it controls controllable switches Q2 and Q3 to open.

[0074] In the above scheme, when the hot-swap control module fails, it may be unable to control the controllable switch to disconnect, and the reliability of the overcurrent and overvoltage protection function is not strong.

[0075] The technical solutions of this application are illustrated below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0076] Example 1

[0077] Figure 2 This is a schematic diagram of a power protection circuit as an example of this application. Figure 2 As shown, the power protection circuit includes: a power circuit 11, a protection circuit 12, and a pull-down circuit 13;

[0078] The power supply circuit 11 is used to convert the received initial power supply into voltage and output the power supply.

[0079] The protection circuit 12 includes a protection switch 121 and a control circuit 122. The protection switch 121 is connected in series in the signal transmission path of the power supply circuit 11. The control circuit 122 is connected to the control terminal of the protection switch 121 and is used to output a first control signal TURN_OFF2 in the first state if overcurrent or overvoltage is detected, so as to control the protection switch 121 to open; otherwise, it outputs a first control signal TURN_OFF2 in the second state, so as to control the protection switch 121 to turn on.

[0080] The pull-down circuit 13 is connected to the control terminal of the protection switch 121, the output terminal of the protection switch 121, and the control circuit 122. It is used to form a transmission path between the control terminal and the output terminal of the protection switch 121 when the control circuit 122 detects an overcurrent or overvoltage, and to block the transmission path between the control terminal and the output terminal of the protection switch 121 when the protection switch 121 is turned on.

[0081] Specifically, after receiving the initial power supply, the power supply circuit 11 performs a voltage conversion operation, which may include reducing the high voltage to a low voltage and outputting power to the load.

[0082] The protection switch 121 is connected in series in the signal transmission path of the power supply circuit 11. The control circuit 122 is connected to the control terminal of the protection switch 121 to detect whether overcurrent or overvoltage has occurred. When overcurrent or overvoltage is detected, the control circuit 122 outputs a first control signal TURN_OFF2 in the first state to the protection switch 121, controlling the protection switch 121 to open, thereby cutting off the signal transmission path of the power supply circuit 11. When no overcurrent or overvoltage is detected, the control circuit 122 outputs a first control signal TURN_OFF2 in the second state to the protection switch 121, controlling the protection switch 121 to close, thereby connecting the signal transmission path of the power supply circuit 11.

[0083] In practical applications, the protection switch 121 can be selected in various ways. For example, the protection switch 121 can be an N-MOSFET transistor. The control circuit 122 is connected to the gate of the protection switch 121. When overcurrent or overvoltage is detected, a first control signal TURN_OFF2 in a low-level state is output to the protection switch 121 to control the protection switch 121 to open. When no overcurrent or overvoltage is detected, a first control signal TURN_OFF2 in a high-level state is output to the protection switch 121 to control the protection switch 121 to close.

[0084] The pull-down circuit 13 is connected to the control terminal and output terminal of the protection switch 121 and the control circuit 122. When the control circuit 122 detects that an overcurrent or overvoltage has occurred, it forms a transmission path between the control terminal and the output terminal of the protection switch 121, causing the control terminal of the protection switch 121 to be in a low-level state and the protection switch 121 to be disconnected. When no overcurrent or overvoltage has occurred, it blocks the transmission path between the control terminal and the output terminal of the protection switch 121.

[0085] In the above technical solution, a protective switch is connected in series in the power supply circuit. The control circuit detects and controls the protective switch, causing it to disconnect in the event of overcurrent or overvoltage, thereby cutting off the transmission path between the input and output terminals of the power supply circuit. Furthermore, a pull-down circuit is added to the control circuit to quickly ground the control terminal of the protective switch in the event of overcurrent or overvoltage, causing the protective switch to disconnect. By controlling the protective switch to disconnect in the event of overcurrent or overvoltage using two methods, the effectiveness and reliability of overcurrent and overvoltage protection are improved.

[0086] The protective switch 121 can be located in various positions in the power supply circuit 11. In one example, the input terminal of the protective switch 121 is connected to the positive input terminal of the power supply circuit 11, and the output terminal of the protective switch 121 is connected to the positive output terminal of the power supply circuit 11.

[0087] Specifically, the power supply circuit 11 performs voltage conversion, converting the input voltage with a voltage value of U1 into an output voltage with a voltage value of U2. The protection switch 121 is connected in series with the positive terminal of the power supply circuit 11. The input terminal of the protection switch 121 is connected to the positive input terminal of the power supply circuit 11, and the output terminal of the protection switch 121 is connected to the positive output terminal of the power supply circuit 11. The remaining connections are as described above and will not be repeated here.

[0088] In the above technical solution, the protective switch is connected in series on the positive side of the power supply circuit, which can disconnect the circuit in the event of a circuit fault, ensuring circuit safety. In other examples, the protective switch can also be connected in series between the negative input terminal and the negative output terminal of the circuit.

[0089] In order to protect the protection switch 121, in one example, the power protection circuit also includes: a first Zener diode ZD11;

[0090] The positive terminal of the first Zener diode ZD11 is connected to the output terminal of the protection switch 121, and the negative terminal of the first Zener diode ZD11 is connected to the control terminal of the protection switch 121.

[0091] Specifically, the first Zener diode ZD11 acts as a clamp to prevent the driving voltage of the protection switch 121 from exceeding the specification.

[0092] In the above technical solution, a diode is placed between the control terminal and the output terminal of the protection switch to prevent the voltage at the control terminal of the protection switch from being too high and to prevent damage to the components.

[0093] In practical applications, there are multiple ways to implement the pull-down circuit 13. Figure 3 This is a schematic diagram of the structure of a pull-down circuit as an example of this application, as shown below. Figure 3 As shown, in one example, the pull-down circuit 13 includes: a first transistor Q12, a first resistor R15, a second transistor Q13, and a first diode D13;

[0094] One end of the first transistor Q12 is connected to the control terminal of the protection switch 121, the other end of the first transistor Q12 is connected to the output terminal of the protection switch 121, the control terminal of the first transistor Q12 is connected to the positive terminal of the first diode D13, and the negative terminal of the first diode D13 is connected to one end of the second transistor Q13.

[0095] One end of the first resistor R15 is connected to the other end of the first transistor Q12, and the other end of the first resistor R15 is connected to one end of the second transistor Q13.

[0096] The other end of the second transistor Q13 is grounded. The control terminal of the second transistor Q13 is connected to the control circuit 122. The control circuit 122 is also used to output a second control signal TURN_OFF3 in the third state if overcurrent or overvoltage is detected, so as to control the second transistor Q13 to turn on; otherwise, it outputs a second control signal TURN_OFF3 in the fourth state, so as to control the second transistor Q13 to turn off.

[0097] Specifically, the selection of the protection switch 121, the first transistor Q12, and the second transistor Q13 can vary. Here, we will use an N-MOSFET as the protection switch 121, a PNP transistor as the first transistor Q12, and an N-MOSFET as the second transistor Q13 as an example. When the control circuit 122 detects overcurrent or overvoltage, it outputs a second control signal TURN_OFF3 in the third state (i.e., a high-level second control signal TURN_OFF3), controlling the second transistor Q13 to turn on. When no overcurrent or overvoltage is detected, it outputs a second control signal TURN_OFF3 in the fourth state (i.e., a low-level second control signal TURN_OFF3), controlling the second transistor Q13 to turn off. In practical applications, the specific voltage values ​​for the high and low levels can be determined based on the model and specifications of the second transistor; these are not limited here.

[0098] When the second transistor Q13 is turned on, the negative voltage of the first diode D13 is pulled low to a low level, and the first diode D13 is forward-biased. The control terminal voltage (base voltage) of the first transistor Q12 is pulled low, and the first transistor Q12 is turned on. The control terminal voltage of the protection switch 121 is pulled low to the output terminal voltage of the protection switch 121, and the protection switch 121 is turned off. When the second transistor Q13 is turned off, the negative voltage of the first diode D13 is pulled high to a high level through the first resistor R15, and the first diode D13 is reverse-biased and cut off. The base voltage of the first transistor Q12 is high, and the first transistor Q12 is not turned on. The control terminal voltage of the protection switch 121 remains high, and the protection switch 121 is turned on. It should be noted that the figure is only an example of one implementation, and other possible implementations are not excluded. Figure 3 The function of the first Zener diode ZD11 is as described above and will not be repeated here. In practical applications, it is possible to choose whether to connect the first Zener diode ZD11 to the output terminal and the control terminal of the protection switch 121 according to production needs. There are no restrictions on this.

[0099] In the above technical solution, the control circuit controls the second transistor to conduct during overcurrent and overvoltage events, thereby conducting the first transistor and making the control terminal and output terminal of the protection switch conductive. The protection switch then disconnects due to the voltage drop at its control terminal. Conversely, the control circuit controls the second transistor to disconnect when no overcurrent or overvoltage event occurs, thereby disconnecting the first transistor, deconductively connecting the control terminal and output terminal of the protection switch, and closing the protection switch. By controlling the transistor, the protection switch can be quickly disconnected during overcurrent and overvoltage events, thus protecting the circuit.

[0100] In practical applications, certain measures need to be taken to prevent the first transistor Q12 in the pull-down circuit 13 from being mis-activated. In one example, it is still as follows: Figure 3As shown, the pull-down circuit 13 may also include: a second resistor R13, a third resistor R14, and a second diode D12;

[0101] One end of the second resistor R13 is connected to one end of the first transistor Q12, and the other end of the second resistor R13 is connected to the control terminal of the first transistor Q12 and one end of the third resistor R14; the other end of the third resistor R14 is connected to the positive terminal of the first diode D13.

[0102] The positive terminal of the second diode D12 is connected to the other end of the first transistor Q12, and the negative terminal of the second diode D12 is connected to one end of the first resistor R15.

[0103] Specifically, when the second transistor Q13 is off, there will be leakage current. This leakage current is released through the second resistor R13, the third resistor R14, the first diode D13, and the second transistor Q13, thereby preventing leakage current from flowing through the base of the first transistor Q12 and causing it to falsely turn on. The second diode D12 prevents the first transistor Q12 from conducting through the third resistor R14 and the first diode D13 to the output terminal of the protection switch 121, thus preventing the first transistor Q12 from being pulled low at its base voltage and falsely turning on. The first diode D13 prevents the base voltage of the transistor Q12 from becoming too high and causing component damage.

[0104] In the above technical solution, by setting a leakage current release path for the second transistor and blocking the current transmission path from the base of the first transistor to the output terminal of the protection switch, the first transistor is prevented from being mistakenly turned on.

[0105] The control circuit 122 is used to detect whether overcurrent or overvoltage has occurred, and to control the protection switch 121. It can be implemented in various ways; in one example... Figure 4 This is a schematic diagram of the control circuit of an example of this application, as shown below. Figure 4 As shown, the control circuit 122 includes: a sampling circuit 1221, a detection circuit 1222, a self-locking circuit 1223, and a processing circuit 1224;

[0106] The sampling circuit 1221 is connected to the protection switch 121 and is used to sample the current flowing through the protection switch 121 and output a first detection signal IMON that reflects the magnitude of the current.

[0107] The input terminal of the detection circuit 1222 is connected to the output terminal of the sampling circuit 1221, and receives the voltage signal OUTPUT at the output terminal of the power supply circuit 11. Based on the first detection signal IMON and the voltage signal OUTPUT, if overcurrent or overvoltage is detected, the circuit outputs the indicator signal TURN_OFF1 in the fifth state; otherwise, it outputs the indicator signal TURN_OFF1 in the sixth state.

[0108] The input terminal of the self-locking circuit 1223 is connected to the output terminal of the detection circuit 1222. The self-locking circuit 1223 is connected to the control terminal of the second transistor Q13 and the processing circuit 1224. It is used to enter the self-locking state in response to the indication signal TURN_OFF1 in the fifth state and maintain the output of the enable signal HOTSWAP_EN in the seventh state and the second control signal TURN_OFF3 in the third state until a reset occurs and then exits the self-locking state. When not in the self-locking state, in response to the indication signal TURN_OFF1 in the sixth state, it outputs the enable signal HOTSWAP_EN in the eighth state and the second control signal TURN_OFF3 in the fourth state.

[0109] The processing circuit 1224 is connected to the control terminal of the protection switch 121. The processing circuit 1224 receives the enable signal HOTSWAP_EN and outputs the first control signal TURN_OFF2 in the first state in response to the enable signal HOTSWAP_EN in the seventh state; and outputs the first control signal TURN_OFF2 in the second state in response to the enable signal HOTSWAP_EN in the eighth state.

[0110] Specifically, the sampling circuit 1221 is connected to the protection switch 121 and outputs a first detection signal IMON reflecting the magnitude of the current based on the current flowing through the protection switch 121. The detection circuit 1222 receives the first detection signal IMON output by the sampling circuit 1221 and the voltage signal OUTPUT at the output terminal of the power supply circuit 11. It determines whether an overcurrent has occurred based on the first detection signal IMON and whether an overvoltage has occurred based on the voltage signal OUTPUT at the output terminal of the power supply circuit 11. When an overcurrent or overvoltage occurs, it outputs an indication signal TURN_OFF1 in the fifth state to the self-locking circuit 1223. When no overcurrent or overvoltage occurs, it outputs an indication signal TURN_OFF1 in the sixth state to the self-locking circuit 1223. The self-locking circuit 1223 receives the indication signal TURN_OFF1 in the fifth state and enters the self-locking state. It then continuously outputs the enable signal HOTSWAP_EN in the seventh state to the processing circuit 1224. In response to the enable signal HOTSWAP_EN in the seventh state, the processing circuit 1224 outputs the first control signal TURN_OFF2 in the first state to the control terminal of the protection switch 121, causing the protection switch 121 to open. The self-locking circuit 1223 maintains the self-locking state until a reset occurs, at which point it exits the self-locking state. When not in the self-locking state, the self-locking circuit 1223 receives the indication signal TURN_OFF1 in the sixth state and outputs the enable signal HOTSWAP_EN in the eighth state to the processing circuit 1224. In response to the enable signal HOTSWAP_EN in the eighth state, the processing circuit 1224 outputs the first control signal TURN_OFF2 in the second state to the control terminal of the protection switch 121, causing the protection switch 121 to close. As an example, the second, third, sixth, and eighth states are high-level states, while the first, fourth, fifth, and seventh states are low-level states.

[0111] In the above technical solution, the sampling circuit samples the current flowing through the protection switch and outputs a first detection signal; the detection circuit receives the first detection signal and the voltage signal at the output of the power supply circuit, determines whether overcurrent or overvoltage has occurred, and outputs an indication signal; the self-locking circuit receives the indication signal, enters a self-locking state when overcurrent or overvoltage occurs, and exits the self-locking state only after a reset, effectively preventing the power supply circuit from repeatedly restarting, and outputs a corresponding enable signal and a second control signal in response to the indication signal; the processing circuit receives the enable signal, outputs a corresponding first control signal, controls the protection switch to be turned on or off, thereby realizing the control of the protection switch.

[0112] The sampling circuit 1221 can have various circuit configurations. Figure 5 This is a schematic diagram of the sampling circuit of an example of this application, as shown below. Figure 5As shown, in one example, the sampling circuit 1221 includes: a first processing chip U91, a sampling resistor R_SENSE, a fourth resistor R91, a fifth resistor R92, a first capacitor C91, and a second capacitor C93;

[0113] The sampling resistor R_SENSE is connected in series with the protection switch 121. One end of the fourth resistor R91 is connected to one end of the sampling resistor R_SENSE. The other end of the fourth resistor R91 is connected to the first input terminal IN_P of the first processing chip U91 and one end of the first capacitor C91.

[0114] One end of the fifth resistor R92 is connected to the other end of the sampling resistor R_SENSE, and the other end of the fifth resistor R92 is connected to the second input terminal IN_N of the first processing chip U91 and the other end of the first capacitor C91.

[0115] One end of the second capacitor C93 is connected to the output terminal OUT of the first processing chip U91, and the other end of the second capacitor C93 is connected to the ground terminal GND of the first processing chip U91 and grounded; the output terminal OUT of the first processing chip U91 is used to output the first detection signal IMON.

[0116] Specifically, the sampling resistor R_SENSE is connected in series with the protection switch 121. The IN_P terminal of the first processing chip U91 receives the voltage signal after the voltage drop across one end of the sampling resistor R_SENSE through the fourth resistor R91, and the IN_N terminal of the first processing chip U91 receives the voltage signal after the voltage drop across the other end of the sampling resistor R_SENSE through the fifth resistor R92, thereby obtaining the current value Iout flowing through the sampling resistor R_SENSE. After a certain amplification factor, the first processing chip U91 outputs the induced voltage IMON as the first detection signal reflecting the magnitude of the current. The formula for calculating the induced voltage IMON is as follows:

[0117]

[0118] Where A is the amplification factor of the first processing chip U91, and r_sense is the resistance value of the sampling resistor. The VS terminal of the first processing chip U91 receives the driving power supply VCC1, and the GND terminal of the first processing chip U91 is grounded. Preferably, capacitors C91, C92, and C93 serve as filters.

[0119] In the above technical solution, the first processing chip detects the voltage drop across the sampling resistor, obtains the magnitude of the current flowing through the sampling resistor, that is, the magnitude of the current flowing through the protection switch, and outputs a first detection signal that reflects the magnitude of the current.

[0120] The detection circuit 1222 is used to detect whether overcurrent or overvoltage has occurred. Figure 6 This is a schematic diagram of the detection circuit of an example of this application, as shown below. Figure 6 As shown, the detection circuit 1222 includes: a second processing chip U81, a sixth resistor R81, a seventh resistor R82, an eighth resistor R83, a ninth resistor R84, a tenth resistor R85, an eleventh resistor R86, a twelfth resistor R87, a thirteenth resistor R88, a fourteenth resistor R89, a third diode D81, a fourth diode D83, a fifth diode D84, a sixth diode D86, a third capacitor C81, a fourth capacitor C83, a fifth capacitor C84, and a sixth capacitor C85;

[0121] One end of the sixth resistor R81 receives the first reference signal REF1, and the other end of the sixth resistor R81 is connected to the first input terminal INA_P of the second processing chip U81 and the positive terminal of the third diode D81; the negative terminal of the third diode D81 is connected to one end of the seventh resistor R82, and the other end of the seventh resistor R82 is connected to one end of the eighth resistor R83 and the first output terminal OUTA of the second processing chip U81; the other end of the eighth resistor R83 receives the first high-level signal VIH1.

[0122] One end of the ninth resistor R84 receives the voltage signal OUTPUT at the output terminal of the power supply circuit 11. The other end of the ninth resistor R84 is connected to the second input terminal INA_N of the second processing chip U81 and one end of the tenth resistor R85. The other end of the tenth resistor R85 is grounded.

[0123] One end of the eleventh resistor R86 receives the second reference signal REF2, and the other end of the eleventh resistor R86 is connected to the third input terminal INB_P of the second processing chip U81. One end of the twelfth resistor R87 is connected to the positive terminal of the sixth diode D86, and the other end of the twelfth resistor R87 is grounded. The negative terminal of the sixth diode D86 is connected to one end of the thirteenth resistor R88, and the other end of the thirteenth resistor R88 is connected to one end of the fourteenth resistor R89 ​​and the second output terminal OUTB of the second processing chip U81. The other end of the fourteenth resistor R89 ​​receives the second high-level signal VIH2.

[0124] The fourth input terminal INB_N of the second processing chip U81 receives the first detection signal IMON. The first output terminal OUTA of the second processing chip U81 is connected to the negative terminal of the fourth diode D83. The second output terminal OUTB of the second processing chip U81 is connected to the negative terminal of the fifth diode D84. The positive terminal of the fourth diode D83 is connected to the positive terminal of the fifth diode D84, and serves as the output terminal of the detection circuit 1222 to output the indicator signal TURN_OFF1.

[0125] One end of the third capacitor C81 is connected to the first input terminal INA_P of the second processing chip U81, and the other end of the third capacitor C81 is grounded; one end of the fourth capacitor C83 is connected to the second input terminal INA_N of the second processing chip U81, and the other end of the fourth capacitor C83 is grounded; one end of the fifth capacitor C84 is connected to the fourth input terminal INB_N of the second processing chip U81, and the other end of the fifth capacitor C84 is grounded; one end of the sixth capacitor C85 is connected to the third input terminal INB_P of the second processing chip U81, and the other end of the sixth capacitor C85 is grounded.

[0126] Specifically, the VDD terminal of the second processing chip U81 receives the driving voltage VCC2, and the sixth resistor R81 introduces the first reference signal REF1 to the first input terminal INA_P of the second processing chip U81. The ninth resistor R84 receives the voltage signal OUTPUT at the output terminal of the power supply circuit 11, and this voltage signal is transmitted to the second input terminal INA_N of the second processing chip U81 after being divided by the tenth resistor R85. The second processing chip U81 compares the input signal at the first input terminal INA_P with the input signal at the second input terminal INA_N. If the input signal value at the first input terminal INA_P is greater than or equal to the input signal value at the second input terminal INA_N, it is determined that no overvoltage has occurred. The first output terminal OUTA of the second processing chip U81 is at a high level, the fourth diode D83 is reverse-biased and cut off, and the eighth resistor R83 introduces the first high-level signal VIH1 to pull the indicator signal TURN_OFF1 high, which serves as the indicator signal TURN_OFF1 in the sixth state. If the input signal value at the first input terminal INA_P is less than the input signal value at the second input terminal INA_N, it is determined that an overvoltage has occurred. The first output terminal OUTA of the second processing chip U81 is pulled low, the fourth diode D83 is forward-biased and the indicator signal TURN_OFF1 is pulled low, which serves as the indicator signal TURN_OFF1 in the fifth state. The third diode D81 is forward-biased, and the seventh resistor R82 and the sixth resistor R81 divide the voltage to pull the input signal value at the first input terminal INA_P low to prevent bouncing.

[0127] The eleventh resistor R86 receives the second reference signal REF2. After being divided by the twelfth resistor R87, the second reference signal REF2 is transmitted to the third input terminal INB_P of the second processing chip U81. The fourth input terminal INB_N of the second processing chip U81 receives the first detection signal IMON. The second processing chip U81 compares the input signal at the third input terminal INB_P with the input signal at the fourth input terminal INB_N. If the input signal at the third input terminal INB_P is greater than or equal to the input signal at the fourth input terminal INB_N, it is determined that no overcurrent has occurred, the second output terminal OUTB of the second processing chip U81 is at a high level, the fifth diode D84 is reverse-biased and cut off, the fourteenth resistor R89 ​​introduces the second high-level signal VIH2, pulling the indicator signal TURN_OFF1 high, serving as the indicator signal TURN_OFF1 for the sixth state; if the... If the input signal at the third input terminal INB_P is less than the input signal at the fourth input terminal INB_N, an overcurrent is detected. The second output terminal OUTB of the second processing chip U81 is pulled low, the fifth diode D84 is forward-biased, and the indicator signal TURN_OFF1 is pulled low as the indicator signal for the fifth state. The sixth diode D86 is forward-biased. The thirteenth resistor R88 and the twelfth resistor R87 are connected in parallel and then divided by the eleventh resistor R86 to pull the input signal value of the third input terminal INB_P low, thus preventing bouncing.

[0128] In practical applications, the magnitude of each signal and the specifications of the components can be set as needed. In one example, the voltage value of the first reference signal REF1 can be 3.3V, the voltage value of the second reference signal REF2 can be 3.3V, the voltage value of the first high-level signal VIH1 can be 12V, the voltage value of the second high-level signal VIH2 can be 12V, the resistance value of the sixth resistor R81 can be 10kΩ, the resistance value of the seventh resistor R82 can be 10kΩ, the resistance value of the eighth resistor R83 can be 10kΩ, the resistance value of the ninth resistor R84 can be 10kΩ, and the tenth resistor... The resistance of resistor R85 can be 3kΩ, the resistance of the eleventh resistor R86 can be 10kΩ, the resistance of the twelfth resistor R87 can be 26.1kΩ, the resistance of the thirteenth resistor R88 can be 10kΩ, the resistance of the fourteenth resistor R89 ​​can be 10kΩ, the capacitance of the third capacitor C81 can be 2.2NF, the capacitance of the fourth capacitor C83 can be 220pF, the capacitance of the fifth capacitor C84 can be 220pF, and the capacitance of the sixth capacitor C85 can be 2.2NF.

[0129] Preferably, the third capacitor C81, the fourth capacitor C83, the fifth capacitor C84, and the sixth capacitor C85 serve as filters. A capacitor C82 is connected in parallel between the VDD terminal of the second processing chip U81 and ground.

[0130] In the above technical solution, the detection circuit compares the voltage signal at the output of the power supply circuit and the current flowing through the protection switch with preset values ​​through the second processing chip to determine whether overcurrent or overvoltage has occurred. When overcurrent or overvoltage occurs, the indicator signal is pulled low to a low level as the indicator signal for the fifth state; when no overcurrent or overvoltage occurs, the indicator signal is pulled high to a high level as the indicator signal for the sixth state.

[0131] The commonly used fault protection method is hiccup mode. To add a fault lockout function, Figure 7 Here is a schematic diagram of the structure of a self-locking circuit as an example of this application, as shown below. Figure 7 As shown, in one example, the self-locking circuit 1223 includes:

[0132] The components are: third transistor Q71, fourth transistor Q72, seventh diode D85, seventeenth resistor R71, eighteenth resistor R72, nineteenth resistor R73, twentieth resistor R74, and seventh capacitor C71.

[0133] One end of the seventeenth resistor R71 is connected to one end of the twentieth resistor R74. One end of the seventeenth resistor R71 receives the fourth high-level signal VIH4. The other end of the seventeenth resistor R71 is connected to one end of the eighteenth resistor R72 and one end of the third transistor Q71 to output the second control signal TURN_OFF3. The other end of the eighteenth resistor R72 is grounded.

[0134] One end of the third transistor Q71 is connected to one end of the nineteenth resistor R73 and the other end of the seventeenth resistor R71. The other end of the third transistor Q71 is grounded. The control terminal of the third transistor Q71 is connected to the other end of the twentieth resistor R74, one end of the fourth transistor Q72, and the cathode of the seventh diode D85, and is used to receive the indication signal TURN_OFF1. The anode of the seventh diode D85 is used to output the enable signal HOTSWAP_EN.

[0135] The control terminal of the fourth transistor Q72 is connected to one end of the seventh capacitor C71 and the other end of the nineteenth resistor R73; the other end of the fourth transistor Q72 is connected to the other end of the seventh capacitor C71 and the other end of the eighteenth resistor R72.

[0136] Specifically, after the fourth high-level signal VIH4 is powered on, the nineteenth resistor R73 and the seventh capacitor C71 form an RC delay circuit, which makes the third transistor Q71 turn on before the fourth transistor Q72. At this time, the indicator signal TURN_OFF1 is pulled up to the high level by the twentieth resistor R74, and the transmission path between the second control signal TURN_OFF3 and ground is opened and pulled down to the low level.

[0137] When overcurrent or overvoltage occurs, the indicator signal TURN_OFF1 is in its fifth state (low level). The third transistor Q71 is not conducting, and the transmission path between the second control signal TURN_OFF3 and ground is broken, causing it to go high, thus becoming the second control signal TURN_OFF3 in its third state. After the voltage of the seventh capacitor C71 increases, the fourth transistor Q72 conducts, opening the transmission path between the indicator signal TURN_OFF1 and ground, pulling it low. At this time, the indicator signal TURN_OFF1 remains low, and the second control signal TURN_OFF3 remains high, achieving self-locking. The seventh diode D85 is forward-biased, pulling the enable signal HOTSWAP_EN low. The self-locking circuit 1223 can be reset by disconnecting the high-level signal and then powering on again.

[0138] When no overcurrent or overvoltage occurs and the self-locking circuit 1223 is not self-locked, the indicator signal TURN_OFF1 is in the sixth state, i.e., the high level state, the third transistor Q71 is turned on, and the transmission path between the second control signal TURN_OFF3 and ground is turned on and pulled low to the low level, which is the second control signal TURN_OFF3 in the fourth state.

[0139] In the above technical solution, when overcurrent or overvoltage occurs, the third transistor remains non-conducting, the transmission path between the second control signal and ground remains disconnected and remains at a high level, the fourth transistor remains conducting, the transmission path between the indicator signal and ground remains conducting, the enable signal remains pulled low until it is reset and exits the current self-locking state, thereby achieving fault lockout and avoiding repeated restarts of the power supply circuit.

[0140] To facilitate the reset of the self-locking circuit 1223, it is still as follows Figure 7 As shown, the self-locking circuit 1223 also includes: a reset switch K;

[0141] One end of the reset switch K is connected to one end of the eighteenth resistor R72, and the other end of the reset switch K is connected to the other end of the eighteenth resistor R72.

[0142] Specifically, the initial state of the reset switch K is open. When resetting the self-locking circuit 1223, the reset switch can be closed, the transmission path between the second control signal TURN_OFF3 and ground is connected, and it is pulled low; the fourth transistor Q72 is not turned on, the transmission path between the indicator signal TURN_OFF1 and ground is disconnected, and it is pulled high by the twentieth resistor R74, the third transistor Q71 is turned on, and thus the self-locking circuit 1223 exits the self-locking state. After the self-locking circuit 1223 exits the self-locking state, the reset switch K is opened.

[0143] In the above technical solution, the second control signal is pulled low by the reset switch, so that the fourth transistor is not turned on, the third transistor is turned on, the indicator signal becomes high level, and the second control signal becomes low level, thereby restoring the initial state.

[0144] Figure 8 This is a schematic diagram of the processing circuit of an example of this application, as shown below. Figure 8 As shown, in one example, the processing circuit 1224 includes: a fifteenth resistor R1, a sixteenth resistor R2, and a third processing chip U71;

[0145] One end of the fifteenth resistor R1 receives the third high-level signal, and the other end of the fifteenth resistor R1 is connected to the enable terminal UVLO / EN of the third processing chip U71 and one end of the sixteenth resistor R2. The other end of the sixteenth resistor R2 is grounded. The enable terminal UVLO / EN of the third processing chip U71 receives the enable signal HOTSWAP_EN, and the output terminal GATE of the third processing chip U71 is connected to the control terminal of the protection switch 121.

[0146] In this example, one end of the fifteenth resistor R1 is connected to one end of the protection switch 121, and the input voltage of the protection switch 121 is used as the third high-level signal. In practical applications, the fifteenth resistor R1 can also be connected to a high-level power supply, and there is no restriction on this.

[0147] Specifically, the sixteenth resistor R2 and the fifteenth resistor R1 divide the voltage to provide a voltage signal to the enable terminal UVLO / EN of the third processing chip U71. When overcurrent or overvoltage occurs, the enable terminal UVLO / EN of the third processing chip U71 receives the enable signal HOTSWAP_EN in the seventh state (low level). This means the voltage value of the enable terminal UVLO / EN of the third processing chip U71 is pulled low by the self-locking circuit 1223. In response to this low-level enable signal HOTSWAP_EN, the third processing chip U71 outputs the first control signal TURN_OFF2 in the first state (low level), preventing the protection switch 121 from conducting. When no overcurrent or overvoltage occurs, the enable terminal UVLO / EN of the third processing chip U71 receives the enable signal HOTSWAP_EN in the eighth state (high level). This means the voltage value of the enable terminal UVLO / EN of the third processing chip U71 is pulled high by the fifteenth resistor R1. In response to this high-level enable signal HOTSWAP_EN, the third processing chip U71 outputs the first control signal TURN_OFF2 in the second state (high level), turning on the protection switch 121. Preferably, the GND terminal of the third processing chip U71 is grounded, and the PGD terminal of the third processing chip U71 receives the operating voltage VDD through resistor R3.

[0148] In the above technical solution, the third processing chip responds to the enable signal in the seventh state by outputting a first control signal in the first state, and responds to the enable signal in the eighth state by outputting a first control signal in the second state to control the protection switch.

[0149] In practical applications, to improve circuit safety, the operating status of protection circuit 12 can be monitored. Figure 9 Here is a schematic diagram of another power protection circuit as an example of this application, such as Figure 9 As shown, in one example, the power protection circuit also includes: a detection circuit 14 and an isolation circuit 15;

[0150] The detection circuit 14 is connected to the output terminal of the sampling circuit 1221 and the isolation circuit 15, and is used to output the isolation control signal PIN, and to detect the protection circuit 12 according to the isolation control signal PIN and the first detection signal IMON output by the sampling circuit 1221.

[0151] One end of the isolation circuit 15 receives the first control signal TURN_OFF2, and the other end of the isolation circuit 15 is connected to the control terminal of the protection switch. The isolation circuit 15 receives the isolation control signal PIN and is used to turn on or off in response to the isolation control signal PIN.

[0152] Specifically, when there is no overcurrent or overvoltage, the detection circuit 14 outputs an isolation control signal PIN to the isolation circuit 15, causing the isolation circuit 15 to turn on or off in response to the isolation control signal PIN. This disconnects or opens the first control signal TURN_OFF2 from the control protection switch 121, and checks whether the protection circuit 12 is functioning correctly based on the isolation control signal PIN and the received first detection signal IMON. For example, if the detection circuit 14 outputs an isolation control signal PIN to the isolation circuit 15 to prevent it from turning on, the isolation circuit 15 responds by not turning on the isolation control signal PIN. The first control signal TURN_OFF2 is then disconnected from the control protection switch 121, and the protection switch 121 does not turn on. Simultaneously, the first detection signal IMON received by the detection circuit 14 is 5V, meaning the current through the protection switch 121 is not zero. Since the protection switch 121 has not properly opened, the protection circuit 12 is determined to be faulty.

[0153] In practical applications, a microcontroller unit (MCU) and a complex programmable logic device (CPLD) or a baseboard management controller (BMC) can be selected as components of the detection circuit 14, or other devices can be selected, without any restrictions.

[0154] For example, Figure 10 Here is a schematic diagram of another power protection circuit as an example of this application, as shown below. Figure 10 As shown, when no overcurrent or overvoltage occurs, the BMC issues a protection circuit detection command. The MCU receives this command and determines whether the current flowing through the protection switch 121 is abnormal based on the first detection signal IMON. If the current value fed back by the first detection signal IMON is abnormal, the detection is terminated, the fault status word is updated, and an alarm signal is given. If the previous step determines that the protection circuit 121 is not abnormal, the MCU outputs an isolation control signal PIN to control the isolation circuit 15 to disconnect, causing the protection switch 121 to disconnect. The MCU then determines whether the protection switch 121 is properly closed based on the current value fed back by the first detection signal IMON. If the current value is abnormal, the protection circuit 12 is determined to be faulty. The isolation control signal PIN for controlling the isolation circuit 15 to conduct is re-outputted, the detection is terminated, the fault status word is updated, and an alarm signal is issued. If the previous step determined that the protection circuit 12 is not faulty, the isolation control signal PIN for controlling the isolation circuit 15 to conduct is output, the protection switch 121 is turned on, and the current value fed back by the first detection signal IMON is used to determine whether the protection switch 121 is conducting normally. If the current value is normal, the protection switch 121 is in a normal conducting state; otherwise, the protection circuit 12 is determined to be faulty, the detection is terminated, the fault status word is updated, and an alarm signal is issued. The BMC determines whether the protection circuit 12 is normal by reading the fault status word or alarm signal from the corresponding register of the MCU and sends a signal to notify human intervention to troubleshoot the fault.

[0155] In the above technical solution, the detection circuit controls the isolation circuit to isolate or not isolate the first control signal from the protection switch, and receives the first detection signal output by the sampling circuit. Based on the current magnitude when the protection switch is not conducting or conducting, the health status of the protection circuit is determined.

[0156] The isolation circuit 15 is used to isolate or not isolate the first control signal TURN_OFF2, and its specific structure is not limited. Figure 11 This is a schematic diagram of the isolation circuit of an example of this application, as shown below. Figure 11 As shown, in one example, the isolation circuit 15 includes: optocoupler U111, 21st resistor R11, 8th diode D11, 22nd resistor R111, and 23rd resistor R112;

[0157] One end of the twenty-second resistor R111 receives the third reference signal REF3, and the other end of the twenty-second resistor R111 is connected to one end of the twenty-third resistor R112; the other end of the twenty-third resistor R112 is connected to the negative input terminal CATHODE of the optocoupler U111; the positive input terminal ANODE of the optocoupler U111 is connected to the other end of the twenty-second resistor R111, the negative input terminal CATHODE of the optocoupler U111 receives the isolation control signal PIN, and the negative output terminal EMITTER of the optocoupler U111 is connected to the control terminal of the protection switch 121.

[0158] One end of the twenty-first resistor R111 is connected to the positive output terminal COLLECTOR of the optocoupler U111, and the other end of the twenty-first resistor R11 receives the first control signal TURN_OFF2; the negative terminal of the eighth diode D11 is connected to the other end of the twenty-first resistor R11, and the positive terminal of the eighth diode D11 is connected to the control terminal of the protection switch 121.

[0159] Specifically, when optocoupler U111 receives a low-level isolation control signal PIN, it conducts, and the first control signal TURN_OFF2 drives the protection switch 121 to turn on through the twenty-first resistor R11; when optocoupler U111 receives a high-level isolation control signal PIN, it does not conduct, and the protection switch 121 does not conduct. The leakage current of the isolation control signal PIN can be released through the twenty-third resistor R112, preventing it from flowing through optocoupler U111 and causing false turn-on, thus serving as a bypass.

[0160] Preferably, as Figure 11 As shown, the power protection circuit may also include a twenty-fourth resistor R12. One end of the twenty-fourth resistor R12 is connected to the output terminal of the protection switch 121, and the other end of the twenty-fourth resistor R12 is connected to the control terminal of the protection switch 121. When the optocoupler U111 is not conducting, the driving voltage of the protection switch 121 is released through the twenty-fourth resistor R12, and the protection switch 121 is not conducting.

[0161] In the above technical solution, the optocoupler responds to the isolation control signal to control the protection switch to be turned on or off, so that the detection circuit can obtain the current value corresponding to the protection switch being turned on and off, and perform protection circuit detection.

[0162] In practical applications, the number of protection switch 121, first Zener diode ZD11, twenty-fourth resistor R12, sampling circuit 1221, pull-down circuit 13, and isolation circuit 15 can be multiple. Figure 12 Here is a schematic diagram of another power protection circuit as an example of this application, as shown below. Figure 12As shown, assuming the power protection circuit includes two protection switches 121, the circuit can be divided into two branches. Correspondingly, each protection switch 121 is connected to a sampling circuit 1221 and an isolation circuit 15. The first detection signal IMON output by the two sampling circuits 1221 is input to a common detection circuit 1222. The detection circuit 1222 outputs an indication signal TURN_OFF1 to the common self-locking circuit 1223. In response to the indication signal TURN_OFF1, the self-locking circuit 1223 outputs an enable signal HOTSWAP_EN to the common processing circuit 1224. The enable circuit 1224 outputs a first control signal TURN_OFF2 to the isolation circuit 15 corresponding to each protection switch 121. The isolation circuit 15 receives the isolation control signal PIN output by the common detection circuit 14, and is turned on or off. At the same time, the pull-down circuit 13 corresponding to each protection switch 121 receives the second control signal TURN_OFF3 output by the common self-locking circuit 1223 to control the protection switch 121. The output terminal of each protection switch 121 is connected to the positive terminal of a first Zener diode ZD11 and one end of a twenty-fourth resistor R12, and the control terminal of each protection switch 121 is connected to the negative terminal of a first Zener diode ZD11 and the other end of a twenty-fourth resistor R12. The specific structure of each circuit is as described above and will not be repeated here. Furthermore, in the different pull-down circuits 13, the second transistor Q13 can be shared, while the other components are not shared and are connected to the shared second transistor Q13. By dividing the protection switches 121 into two groups, the health status of the protection circuit 12 can be detected by alternating switching, achieving uninterrupted detection without affecting the normal operation of the circuit.

[0163] In the above technical solution, by setting multiple sets of parallel protection switches and a first Zener diode, a twenty-fourth resistor, a sampling circuit, a pull-down circuit and an isolation circuit connected to each protection switch, the health status of the protection circuit can be detected without power failure through alternating switching.

[0164] The power protection circuit provided in this embodiment includes a power supply circuit, a protection circuit, and a pull-down circuit. The power supply circuit converts the initial power supply to output the power supply. The protection circuit includes a control circuit and a protection switch, with the protection switch connected in series in the signal transmission path of the power supply circuit. The control circuit is connected to the control terminal of the protection switch and outputs a first control signal in a first state to open the protection switch if overcurrent or overvoltage is detected; otherwise, it outputs a first control signal in a second state to turn the protection switch on. The pull-down circuit is connected to the control terminal and output terminal of the protection switch, as well as the control circuit, and forms a transmission path between the control terminal and output terminal of the protection switch when overcurrent or overvoltage occurs, and blocks this transmission path when the protection switch is on. In the event of overcurrent or overvoltage, the protection switch can be opened using both the control circuit and the pull-down circuit, cutting off the power supply output and providing multiple overcurrent and overvoltage protections, thus improving the reliability of the circuit.

[0165] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0166] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A power supply protection circuit, characterized in that, include: Power supply circuit, protection circuit, and pull-down circuit; The power supply circuit is used to convert the received initial power supply into voltage and output the power supply. The protection circuit includes a protection switch and a control circuit. The protection switch is connected in series in the signal transmission path of the power supply circuit. The control circuit is connected to the control terminal of the protection switch and is used to output a first control signal in a first state if an overcurrent or overvoltage is detected, so as to control the protection switch to open. Otherwise, the first control signal in the second state is output to control the protection switch to be turned on; The pull-down circuit is connected to the control terminal and output terminal of the protection switch and the control circuit, and is used to form a transmission path between the control terminal and the output terminal of the protection switch when the control circuit detects an overcurrent or overvoltage, and to block the transmission path between the control terminal and the output terminal of the protection switch when no overcurrent or overvoltage occurs. The pull-down circuit includes: a first transistor, a first resistor, a first diode, and a second transistor; One end of the first transistor is connected to the control terminal of the protection switch, the other end of the first transistor is connected to the output terminal of the protection switch, the control terminal of the first transistor is connected to the positive terminal of the first diode, and the negative terminal of the first diode is connected to one end of the second transistor. One end of the first resistor is connected to the other end of the first transistor, and the other end of the first resistor is connected to one end of the second transistor; The other end of the second transistor is grounded, and the control terminal of the second transistor is connected to the control circuit. The control circuit is also used to output a second control signal in the third state to control the second transistor to turn on if overcurrent or overvoltage is detected; otherwise, it outputs a second control signal in the fourth state to control the second transistor to turn off. The control circuit includes: a sampling circuit, a detection circuit, a processing circuit, and a self-locking circuit; The sampling circuit is connected to the protection switch and is used to sample the current flowing through the protection switch and output a first detection signal reflecting the magnitude of the current. The input terminal of the detection circuit is connected to the output terminal of the sampling circuit, and receives the voltage signal at the output terminal of the power supply circuit. Based on the first detection signal and the voltage signal, if overcurrent or overvoltage is detected, an indication signal in the fifth state is output; otherwise, an indication signal in the sixth state is output. The input terminal of the self-locking circuit is connected to the output terminal of the detection circuit. The self-locking circuit is connected to the control terminal of the second transistor and the processing circuit. It is used to enter the self-locking state in response to the indication signal in the fifth state and maintain the output of the enable signal in the seventh state and the second control signal in the third state until a reset occurs, at which point it exits the self-locking state. When not in the self-locking state, it outputs the enable signal in the eighth state and the second control signal in the fourth state in response to the indication signal in the sixth state. The processing circuit is connected to the control terminal of the protection switch. The processing circuit receives the enable signal and, in response to the enable signal in the seventh state, outputs the first control signal in the first state; and, in response to the enable signal in the eighth state, outputs the first control signal in the second state.

2. The power protection circuit according to claim 1, characterized in that, The pull-down circuit also includes: a second resistor, a third resistor, and a second diode; One end of the second resistor is connected to one end of the first transistor, and the other end of the second resistor is connected to the control terminal of the first transistor and one end of the third resistor; the other end of the third resistor is connected to the positive terminal of the first diode. The positive terminal of the second diode is connected to the other end of the first transistor, and the negative terminal of the second diode is connected to one end of the first resistor.

3. The power protection circuit according to claim 1, characterized in that, The sampling circuit includes: a first processing chip, a sampling resistor, a fourth resistor, a fifth resistor, a first capacitor, and a second capacitor; The sampling resistor is connected in series with the protection switch, one end of the fourth resistor is connected to one end of the sampling resistor, and the other end of the fourth resistor is connected to the first input terminal of the first processing chip and one end of the first capacitor. One end of the fifth resistor is connected to the other end of the sampling resistor, and the other end of the fifth resistor is connected to the second input terminal of the first processing chip and the other end of the first capacitor. One end of the second capacitor is connected to the output terminal of the first processing chip, and the other end of the second capacitor is connected to the ground terminal of the first processing chip and grounded; the output terminal of the first processing chip is used to output the first detection signal.

4. The power protection circuit according to claim 1, characterized in that, The detection circuit includes: a second processing chip, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a third diode, a fourth diode, a fifth diode, a sixth diode, a third capacitor, a fourth capacitor, a fifth capacitor, and a sixth capacitor; One end of the sixth resistor receives a first reference signal, and the other end of the sixth resistor is connected to the first input terminal of the second processing chip and the positive terminal of the third diode; the negative terminal of the third diode is connected to one end of the seventh resistor, and the other end of the seventh resistor is connected to one end of the eighth resistor and the first output terminal of the second processing chip; the other end of the eighth resistor receives a first high-level signal. One end of the ninth resistor receives the voltage signal at the output terminal of the power supply circuit, the other end of the ninth resistor is connected to the second input terminal of the second processing chip and one end of the tenth resistor, and the other end of the tenth resistor is grounded. One end of the eleventh resistor receives a second reference signal, and the other end of the eleventh resistor is connected to the third input terminal of the second processing chip, one end of the twelfth resistor, and the positive terminal of the sixth diode. The other end of the twelfth resistor is grounded. The negative terminal of the sixth diode is connected to one end of the thirteenth resistor, and the other end of the thirteenth resistor is connected to one end of the fourteenth resistor and the second output terminal of the second processing chip. The other end of the fourteenth resistor receives a second high-level signal. The fourth input terminal of the second processing chip receives the first detection signal, the first output terminal of the second processing chip is connected to the negative terminal of the fourth diode, the second output terminal of the second processing chip is connected to the negative terminal of the fifth diode, the positive terminal of the fourth diode is connected to the positive terminal of the fifth diode, and the indication signal is output as the output terminal of the detection circuit. One end of the third capacitor is connected to the first input terminal of the second processing chip, and the other end of the third capacitor is grounded; one end of the fourth capacitor is connected to the second input terminal of the second processing chip, and the other end of the fourth capacitor is grounded; one end of the fifth capacitor is connected to the fourth input terminal of the second processing chip, and the other end of the fifth capacitor is grounded; one end of the sixth capacitor is connected to the third input terminal of the second processing chip, and the other end of the sixth capacitor is grounded.

5. The power protection circuit according to claim 1, characterized in that, The processing circuit includes: a fifteenth resistor, a sixteenth resistor, and a third processing chip; The fifteenth resistor receives a third high-level signal, and the other end of the fifteenth resistor is connected to the enable terminal of the third processing chip and one end of the sixteenth resistor, while the other end of the sixteenth resistor is grounded. The enable terminal of the third processing chip receives the enable signal, and the output terminal of the third processing chip is connected to the control terminal of the protection switch.

6. The power protection circuit according to claim 1, characterized in that, The self-locking circuit includes: a third transistor, a fourth transistor, a seventh diode, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, and a seventh capacitor; One end of the seventeenth resistor is connected to one end of the twentieth resistor. One end of the seventeenth resistor receives the fourth high-level signal. The other end of the seventeenth resistor is connected to one end of the eighteenth resistor and one end of the third transistor for outputting the second control signal. The other end of the eighteenth resistor is grounded. One end of the third transistor is connected to one end of the nineteenth resistor and the other end of the seventeenth resistor, and the other end of the third transistor is grounded. The control terminal of the third transistor is connected to the other end of the twentieth resistor, one end of the fourth transistor, and the negative terminal of the seventh diode, respectively, for receiving the indication signal; the positive terminal of the seventh diode is used to output the enable signal. The control terminal of the fourth transistor is connected to one end of the seventh capacitor and the other end of the nineteenth resistor; the other end of the fourth transistor is connected to the other end of the seventh capacitor and the other end of the eighteenth resistor.

7. The power protection circuit according to claim 6, characterized in that, The self-locking circuit further includes: a reset switch; One end of the reset switch is connected to one end of the eighteenth resistor, and the other end of the reset switch is connected to the other end of the eighteenth resistor.

8. The power protection circuit according to claim 1, characterized in that, The power protection circuit also includes: a detection circuit and an isolation circuit; The detection circuit is connected to the output terminal of the sampling circuit and the isolation circuit, and is used to output an isolation control signal, and to detect the protection circuit according to the isolation control signal and the first detection signal output by the sampling circuit; One end of the isolation circuit receives the first control signal, and the other end of the isolation circuit is connected to the control terminal of the protection switch. The isolation circuit receives the isolation control signal and is used to turn on or off in response to the isolation control signal.

9. The power protection circuit according to claim 8, characterized in that, The isolation circuit includes: an optocoupler, a twenty-first resistor, an eighth diode, a twenty-second resistor, and a twenty-third resistor; One end of the 22nd resistor receives the third reference signal, and the other end of the 22nd resistor is connected to one end of the 23rd resistor; the other end of the 23rd resistor is connected to the negative input terminal of the optocoupler; the positive input terminal of the optocoupler is connected to the other end of the 22nd resistor, the negative input terminal of the optocoupler receives the isolation control signal, and the negative output terminal of the optocoupler is connected to the control terminal of the protection switch. One end of the 21st resistor is connected to the positive output terminal of the optocoupler, and the other end of the 21st resistor receives the first control signal; the negative terminal of the 8th diode is connected to the other end of the 21st resistor, and the positive terminal of the 8th diode is connected to the control terminal of the protection switch.

10. The power protection circuit according to claim 1, characterized in that, The power protection circuit further includes: a first Zener diode; The positive terminal of the first Zener diode is connected to the output terminal of the protection switch, and the negative terminal of the first Zener diode is connected to the control terminal of the protection switch.

11. The power protection circuit according to any one of claims 1-10, characterized in that, The input terminal of the protection switch is connected to the positive input terminal of the power supply circuit, and the output terminal of the protection switch is connected to the positive output terminal of the power supply circuit.

Images