Peripheral interface power supply circuit

Abstract

The embodiment of the utility model provides a peripheral interface power supply circuit, an overvoltage protection circuit is arranged between a level conversion circuit and an interface circuit of the peripheral interface power supply circuit, and the overvoltage protection circuit comprises a voltage limiting circuit and a switching circuit. The voltage limiting circuit determines that the power supply electric signal meets the safety standard when the power supply electric signal obtained at the first end is smaller than a preset voltage value, controls the switching circuit to be switched on, and transmits the power supply electric signal output by the level conversion circuit to the interface circuit to supply power to external equipment. The voltage limiting circuit determines that the power supply electric signal does not meet the safety standard when the power supply electric signal obtained at the first end is greater than or equal to a preset voltage value, and outputs a disconnection signal to turn off the switching circuit and stop transmission of the power supply electric signal; therefore, transmission of the power supply electric signal can be interrupted through the overvoltage protection circuit when the level conversion circuit is not regulated and controlled in time based on the sampling signal, so that external equipment is prevented from being damaged, and the reliability of the external interface power supply circuit is guaranteed.

Description

Technical Field

[0001] The embodiments of this application relate to the field of protection system technology, and more particularly to a peripheral interface power supply circuit. Background Technology

[0002] The peripheral interface power supply circuit is a circuit in the electronic device that provides a power signal to the external device to maintain its normal operation when the external device is connected to the peripheral interface of the electronic device. After receiving the mains power, the peripheral interface power supply circuit rectifies, filters, and performs level conversion on the mains power before outputting the power signal required for the operation of the external device.

[0003] During the level conversion process of the peripheral interface power supply circuit, its output voltage is sampled. Based on the sampled signal, the output voltage is adjusted to maintain a stable voltage range. When an overvoltage signal is output, the power supply signal output can be terminated in a timely manner to protect the electrically connected external devices. When a single fault exists in the level conversion circuit, it may be unable to adjust the power supply signal voltage value in response to the output overvoltage signal, resulting in the output of an overvoltage signal that does not meet safety standards. Utility Model Content

[0004] This application provides a peripheral interface power supply circuit to solve the technical problem of poor reliability of the overvoltage protection function of the peripheral interface power supply circuit.

[0005] This application provides a peripheral interface power supply circuit, including a level conversion circuit, an overvoltage protection circuit, and an interface circuit that are sequentially connected.

[0006] The overvoltage protection circuit includes:

[0007] A voltage limiting circuit, the first terminal of which is electrically connected to the output terminal of the level conversion circuit, is configured to output a circuit breaking signal from its output terminal when the voltage value of the power supply signal provided by the level conversion circuit is greater than or equal to a preset voltage limit value.

[0008] The voltage limiting circuit is further configured to not output the circuit breaking signal when the voltage value of the power supply signal is less than the preset voltage limit value; the preset voltage limit value is greater than the power supply standard voltage and less than the safety standard voltage.

[0009] A switching circuit, whose first terminal is electrically connected to the output terminal of the level conversion circuit and whose control terminal is electrically connected to the output terminal of the voltage limiting circuit, is configured to obtain the power supply signal from its first terminal and output the power supply signal to the interface circuit when the control terminal does not obtain the circuit break signal.

[0010] The switching circuit is further configured to stop outputting the power supply signal to the interface circuit when it receives the circuit break signal at its control terminal.

[0011] In the above technical solution, an overvoltage protection circuit is provided between the level conversion circuit and the interface circuit of the peripheral interface power supply circuit. The overvoltage protection circuit includes a voltage limiting circuit and a switching circuit. When the power supply signal obtained by the voltage limiting circuit at its first terminal is less than the preset voltage value, it determines that the power supply signal meets the safety standard, controls the switching circuit to conduct, and transmits the power supply signal output by the level conversion circuit to the interface circuit to supply power to the external device. When the power supply signal obtained by the voltage limiting circuit at its first terminal is greater than or equal to the preset voltage value, it determines that the power supply signal does not meet the safety standard, outputs a circuit breaking signal to turn off the switching circuit and stop the transmission of the power supply signal. This ensures that even if the level conversion circuit fails to adjust in time based on the sampling signal, the transmission of the power supply signal can be interrupted by the overvoltage protection circuit to prevent damage to the external device and ensure the reliability of the peripheral interface power supply circuit.

[0012] In one feasible implementation, the first preset voltage value includes the Zener diode turn-on voltage value;

[0013] The voltage limiting sub-circuit includes:

[0014] The first resistor, the first end of which serves as the first terminal of the voltage limiting sub-circuit;

[0015] A Zener diode, whose first terminal serves as the second terminal of the voltage limiting sub-circuit and is electrically connected to the second terminal of the first resistor, and whose second terminal is grounded, is configured to conduct when the voltage value at its first terminal is greater than or equal to the Zener diode's on-state voltage value, and output a regulated electrical signal as the first level signal;

[0016] The Zener diode is further configured to not conduct when the voltage at its first terminal is less than the Zener diode's turn-on voltage, and to output the power supply signal as the second level signal.

[0017] In one feasible implementation, the switching sub-circuit includes:

[0018] The second resistor has its first end serving as the control terminal of the switch sub-circuit.

[0019] The first switching device has a first terminal as the first terminal of the switching sub-circuit, a control terminal and a second terminal of the second resistor electrically connected, and a second terminal as the second terminal of the switching sub-circuit. It is configured to obtain the first level signal from its control terminal and the power supply signal from its first terminal. It is turned on when the voltage value of the power supply signal is greater than or equal to the preset voltage limit value, and outputs the power supply signal from its second terminal as the circuit breaker signal.

[0020] The first switching device is further configured to receive the first level signal from its control terminal, receive the power supply signal from its first terminal, turn off when the voltage value of the power supply signal is less than the preset voltage limit value, and not output the power supply signal from its second terminal.

[0021] The first switching device is further configured to turn off when it receives the second level signal from its control terminal, and not output the power supply signal from its second terminal;

[0022] A third resistor, whose first end is electrically connected to the second end of the first switching device and whose second end is grounded, is configured to output a ground signal when the first switching device does not output the circuit breaker signal.

[0023] In one feasible implementation, the preset voltage limit value is equal to the sum of the on-state voltage of the first switching device and the on-state voltage of the Zener diode.

[0024] In the above technical solution, a Zener diode is set in the voltage limiting sub-circuit, and a first switching device is set in the switching sub-circuit. The sum of the Zener diode's on-state voltage and the first switching device's on-state voltage is controlled as a preset voltage limit value. When the voltage value of the power supply signal output by the level conversion circuit is greater than or equal to the preset voltage limit value, the overvoltage protection circuit controls the Zener diode to provide the Zener diode's on-state voltage to the first switching device and controls the first switching device to turn on. This causes the first switching device to output a circuit breaker signal, turn off the switching circuit, and interrupt the overvoltage protection circuit's output of the power supply signal, thereby protecting external devices and ensuring the stability of the peripheral interface power supply circuit.

[0025] In one feasible implementation, the voltage limiting sub-circuit includes:

[0026] The voltage divider circuit has a first terminal as the first terminal of the voltage limiting sub-circuit, a second terminal grounded, and is configured to obtain the power supply signal from its first terminal and output the voltage divider signal from its third terminal.

[0027] The control circuit has its first terminal electrically connected to the first terminal of the voltage divider circuit, its second terminal grounded, its control terminal electrically connected to the third terminal of the voltage divider circuit, and its output terminal serving as the second terminal of the voltage limiting sub-circuit. It is configured to conduct when the voltage divider signal is greater than or equal to a preset threshold voltage and output a ground signal as the second level signal.

[0028] The control circuit is also configured to turn off when the voltage divider signal is less than the preset threshold voltage and output a power supply signal as the first level signal.

[0029] The preset threshold voltage is the product of the preset voltage limit value and the voltage division ratio.

[0030] In one feasible implementation, the preset threshold voltage includes the turn-on voltage of the second switching device;

[0031] The control circuit includes:

[0032] The second switching device, whose first terminal serves as the output terminal of the control circuit, whose second terminal serves as the second terminal of the control circuit, and whose control terminal serves as the control terminal of the control circuit, is configured to conduct when the voltage divider signal is greater than or equal to its conduction voltage, and output the ground signal.

[0033] The second switching device is further configured to turn off when the voltage divider signal is less than its on-state voltage;

[0034] The seventh resistor, whose first end serves as the first end of the control circuit, outputs the power supply signal when the second switching device is turned off.

[0035] In one feasible implementation, the switching sub-circuit includes:

[0036] The eighth resistor, the first end of which serves as the control terminal of the switch sub-circuit;

[0037] The ninth resistor, the first end of which serves as the first end of the switch sub-circuit;

[0038] The third switching device has its control terminal electrically connected to the second terminal of the eighth resistor, its first terminal electrically connected to the second terminal of the ninth resistor, and its second terminal grounded. It is configured to turn on when it receives the power supply signal at its control terminal and output a ground signal.

[0039] The third switching device is also configured to turn off when it receives the ground signal at its control terminal;

[0040] The tenth resistor has its first end electrically connected to the second end of the ninth resistor and the first end of the third switching device. Its second end serves as the second end of the switching sub-circuit and is configured to output the power supply signal as the circuit breaker signal when the third switching device is turned off.

[0041] In the above technical solution, a voltage divider circuit, a third switching device, and a fourth switching device are set in the level conversion circuit and interface circuit of the peripheral interface power supply circuit. The preset threshold voltage is adjusted to be the product of the preset voltage limit value and the voltage division ratio. When the power supply signal obtained by the overvoltage protection circuit is greater than or equal to the preset voltage value, the voltage value obtained by the control terminal of the third switching device is greater than or equal to its corresponding preset threshold voltage. The third switching device is turned on to pull down the potential value of the control terminal of the fourth switching device, thereby turning off the fourth switching signal. This allows the control terminal of the switching circuit to obtain an open circuit signal, interrupting the transmission of the power signal to prevent damage to the external device and ensuring the reliability of the peripheral interface power supply circuit.

[0042] This application provides a peripheral interface power supply circuit. An overvoltage protection circuit is provided between the level conversion circuit and the interface circuit of the peripheral interface power supply circuit. The overvoltage protection circuit includes a voltage limiting circuit and a switching circuit. When the power supply signal obtained by the voltage limiting circuit at its first terminal is less than a preset voltage value, it determines that the power supply signal meets safety standards and controls the switching circuit to conduct, transmitting the power supply signal output by the level conversion circuit to the interface circuit to supply power to the external device. When the power supply signal obtained by the voltage limiting circuit at its first terminal is greater than or equal to the preset voltage value, it determines that the power supply signal does not meet safety standards and outputs a circuit breaker signal to turn off the switching circuit and stop the transmission of the power supply signal. This ensures that even if the level conversion circuit fails to adjust in time based on the sampling signal, the transmission of the power supply signal can be interrupted through the overvoltage protection circuit to prevent damage to the external device and ensure the reliability of the peripheral interface power supply circuit. Attached Figure Description

[0043] 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.

[0044] Figure 1 This is a schematic diagram of the structure of an electronic device provided according to an exemplary embodiment of this application;

[0045] Figure 2 This is a circuit diagram of a peripheral interface power supply circuit provided in an exemplary embodiment of this application;

[0046] Figure 3 This is a circuit diagram of a peripheral interface power supply circuit provided in another exemplary embodiment of this application;

[0047] Figure 4 This is a circuit diagram of a peripheral interface power supply circuit provided in another exemplary embodiment of this application;

[0048] Figure 5 This is a circuit diagram of a peripheral interface power supply circuit provided in another exemplary embodiment of this application;

[0049] Figure 6 This is a circuit diagram of a peripheral interface power supply circuit provided in another exemplary embodiment of this application;

[0050] Figure 7 This is a schematic diagram of the peripheral interface power supply circuit provided in another exemplary embodiment of this application.

[0051] The accompanying drawings have illustrated 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 specific embodiments. Detailed Implementation

[0052] 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.

[0053] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, components, features, and elements with the same names in different embodiments of this application may have the same meaning or different meanings, the specific meaning of which must be determined by its interpretation in that specific embodiment or further in conjunction with the context of that specific embodiment. It should be further understood that the terms "comprising" or "including" indicate the presence of features, steps, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups.

[0054] In the description of this disclosure, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "multiple" means two or more, unless otherwise expressly specified. The terms "or" and "and / or" are interpreted as inclusive, or mean any one or any combination thereof. Therefore, "A, B, or C" or "A, B, and / or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A, B, and C." Exceptions to this definition occur only when combinations of elements, functions, steps, or operations are inherently mutually exclusive in some manner.

[0055] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0056] Figure 1 A schematic diagram of the structure of an electronic device provided in an exemplary embodiment of this application, as shown below. Figure 1 As shown, the electronic device includes:

[0057] The power supply circuit 10 is configured to provide power signals to various power-consuming circuits within the electronic device.

[0058] In some embodiments, the power supply circuit 10 is also configured to provide a power signal to an external device electrically connected to the electronic device via an interface.

[0059] The power supply equipment 10 provides power signals with different voltage and / or current values ​​for different power circuits and external devices.

[0060] The electronic device also includes at least one processor 11, which includes, but is not limited to, a video processor, an audio processor, and a graphics processor. The at least one processor 11 is configured to acquire signals from external sources or other circuits within the electronic device, process the signals, and store and / or output the processing results.

[0061] In some embodiments, the signal includes data to be processed. For example, at least one processor 11 acquires display data, generates a drive signal based on the display data, and transmits the drive signal to a display electrically connected thereto for display.

[0062] In other embodiments, at least one processor 11 includes a storage unit and is further configured to fetch instructions from external or other circuits within an electronic device, respond to the instructions based on various software control programs stored in the storage unit, and store, output, and / or adjust state information of the response results.

[0063] For example, at least one processor 11 obtains the user's gesture image data, and based on the command corresponding to the gesture in the gesture image data (such as the start play command), calls the corresponding program to perform the corresponding operation.

[0064] The electronic device also includes an external device interface 12, which is electrically connected to at least one processor 11. The external device interface 12 includes at least one type of interface circuit, including but not limited to one or more interfaces such as a high-definition multimedia interface (HDMI), an analog or data high-definition component input interface (component), a composite video input interface (CVBS), a USB input interface (USB), and an RGB port.

[0065] The external device interface 12 is configured to acquire signals or data from the electronic device and / or transmit signals or data to the electronic device after an external device is connected to the electronic device through any interface circuit.

[0066] In some embodiments, external devices do not have independent power supply circuits and require electronic devices to provide power signals to ensure the normal operation of the external devices. For example, after a USB device is connected to a USB port, the power supply circuit in the electronic device needs to provide power signals to the power pins of the USB port to power on and operate the USB device.

[0067] Figure 2 A circuit diagram of a peripheral interface power supply circuit provided in an embodiment of this application is shown below. Figure 2 As shown, the power supply circuit 10 for the peripheral interface includes:

[0068] The pre-stage voltage processing circuit 00 is configured to obtain mains power, process the mains power signal, and output a DC signal at a preset level.

[0069] In some embodiments, the front-end voltage processing circuit 00 includes a lightning protection circuit configured to receive mains power and discharge the lightning current surge energy and operational surge energy contained in the mains power.

[0070] In some embodiments, the front-end voltage processing circuit 00 includes a rectifier circuit whose input terminal is electrically connected to the output terminal of the surge protection circuit. The rectifier circuit is configured to obtain mains power and convert the mains power into a first DC signal.

[0071] The external devices include those electrically connected to the external device interface 12, including but not limited to: external displays, external electronic devices, storage devices, audio equipment, and communication equipment. Each of these external devices is electrically connected to the electronic device through its corresponding interface type.

[0072] In some embodiments, the pre-stage voltage processing circuit 00 includes a filter circuit whose input terminal is electrically connected to the output terminal of the rectifier circuit, and the filter circuit is configured to filter out the ripple in the voltage of the first DC signal output by the rectifier circuit.

[0073] The following explanation uses a USB external device as an example to illustrate the power supply circuit of an external device.

[0074] The power supply circuit 10 of the peripheral interface also includes a level conversion circuit 01. The input terminal of the level conversion circuit 01 is electrically connected to the output terminal of the pre-stage voltage processing circuit 00 and is configured to convert the level of the first DC signal into the power supply voltage required by the USB external device 03.

[0075] In one embodiment, the voltage value of the first DC signal output by the pre-stage voltage processing circuit 00 is 12V, and the power supply voltage value of the USB external device 03 is 5V. Therefore, the level conversion circuit 01 corresponding to the USB external device is a 12V to 5V DC-DC circuit.

[0076] refer to Figure 2 The level conversion circuit 01 includes a level conversion chip U1, a filter inductor L1, a first sampling resistor R06, and a second sampling resistor R05.

[0077] The level conversion chip U1 has an input terminal VIN, an output terminal SW, and a feedback terminal FB. The input terminal VIN is electrically connected to the output terminal of the pre-stage voltage processing circuit 00. The output terminal SW is electrically connected to the first terminal of the filter inductor L1. The second terminal of the filter inductor L1 serves as the output terminal of the level conversion circuit 01 and is electrically connected to the power supply terminal of the interface circuit 02.

[0078] The first terminal of the first sampling resistor R06 is electrically connected to the second terminal of the filter inductor L1. The second terminal of the first sampling resistor R06 is electrically connected to the first terminal of the second sampling resistor R05. The second terminal of the second sampling resistor R05 is electrically connected to the feedback terminal FB of the level conversion chip U1.

[0079] The level conversion chip U1 is configured to convert the level of a first DC signal received at its input terminal and output a second DC signal. The voltage value of the second DC signal is the operating voltage of the USB external device 03.

[0080] In some embodiments, the level conversion chip U1 is further configured to obtain the sampled voltage value of the second DC signal through the first sampling resistor R06 and the second sampling resistor R05, and to regulate the currently output second DC signal based on the sampled voltage value of the second DC signal so that it varies within a preset level fluctuation range.

[0081] For example, if the power supply voltage required by the USB external device 03 is 5V and its allowable fluctuation range is ±5%, then the level conversion chip U1 controls the fluctuation of the second DC signal between 4.75 and 5.25V based on the sampled voltage value of the second DC signal.

[0082] In some embodiments, the level conversion chip U1 is further configured to interrupt the current output of the power supply signal when it detects that the sampled voltage value of the second DC signal is continuously greater than the maximum value of the allowable fluctuation range of the USB external device 03, and adjust its level conversion process based on the sampled voltage value to reduce the voltage value of the second DC signal, thereby protecting the USB external device 03 from damage by the overvoltage signal.

[0083] When the level conversion circuit 01 has a single fault (e.g., the sampling resistor is damaged or the resistance value is inaccurate), it will cause the sampling voltage to be abnormal. The level conversion chip U1 may adjust the voltage value of the second DC signal output based on the abnormal sampling voltage, which may be overvoltage. However, the level conversion chip U1 cannot detect this, which leads to abnormal voltage regulation process and continuous output of overvoltage signal. This does not meet safety standards, and the overvoltage power supply signal will damage the USB external device 03.

[0084] Therefore, improving the reliability of overvoltage protection function of peripheral interface power supply circuits has become the focus of this application.

[0085] To address the aforementioned problems, this application provides a peripheral interface power supply circuit. The technical concept of this application is as follows: an overvoltage protection circuit is provided between the level conversion circuit and the interface circuit of the peripheral interface power supply circuit. The overvoltage protection circuit includes a voltage limiting circuit and a switching circuit. When the power supply signal obtained at its first terminal does not meet safety standards, the voltage limiting circuit outputs a circuit breaker signal to shut down the switching circuit and stop the transmission of the power supply signal. This ensures that even if the level conversion circuit fails to adjust in time based on the sampling signal, the overvoltage protection circuit can interrupt the transmission of the power supply signal, preventing damage to external devices and ensuring the reliability of the peripheral interface power supply circuit.

[0086] The peripheral interface power supply circuit proposed in this application will be explained in detail below.

[0087] Figure 3 This is a circuit diagram of a peripheral interface power supply circuit provided in an exemplary embodiment of this application, such as... Figure 3 As shown, the peripheral interface power supply circuit 10 includes a front-end voltage processing circuit 00, a level conversion circuit 01, an overvoltage protection circuit 04, and an interface circuit 02, which are connected in sequence.

[0088] The overvoltage protection circuit 04 includes a voltage limiting circuit 041. The first terminal D of the voltage limiting circuit 041 is electrically connected to the output terminal of the level conversion circuit 01. It is configured to output a circuit breaking signal from its output terminal when the voltage value of the power supply signal provided by the level conversion circuit 01 is greater than or equal to a preset voltage limit value.

[0089] The voltage limiting circuit 041 is also configured to not output a circuit breaker signal when the voltage value of the power supply signal is less than the preset voltage limit value; the preset voltage limit value is greater than the power supply standard voltage and less than the safety standard voltage.

[0090] In some embodiments, the standard power supply voltage is the voltage required for the operation of the external device connected to the interface circuit 02. When there is an allowable fluctuation range in the voltage required for the operation of the external device, the standard power supply voltage is the voltage value within the fluctuation range.

[0091] For example, when repairing a USB external device, if the required operating voltage is 5V, then the standard power supply voltage is 5V. When there is an allowable fluctuation range for this voltage, if the fluctuation range is ±5%, the standard power supply voltage is a voltage value between 4.75V and 5.25V. The preset voltage limit is greater than the standard power supply voltage, that is, the preset voltage limit is greater than 5.25V.

[0092] In some embodiments, to increase the margin, the preset voltage limit is set to the sum of the maximum value of the standard supply voltage and the preset voltage difference.

[0093] In some embodiments, the safety standard voltage is the maximum voltage value applied to the external device.

[0094] For example, if the power supply voltage of a USB external device is 5V, the safety standard in Region A requires that when a single fault occurs in the USB power supply circuit, the voltage increase of the power supply signal it provides should not exceed the larger of 3V or 10% (i.e., 8V). In accordance with the safety standard, 8V will be set as the safety standard voltage, and the output voltage of the peripheral interface power supply circuit should not exceed the safety standard voltage. Therefore, the preset voltage difference is 2.75V.

[0095] The overvoltage protection circuit 04 also includes a switching circuit 042. The first terminal of the switching circuit 042 and the output terminal of the level conversion circuit 041 are electrically connected to point L. Its control terminal and the output terminal of the voltage limiting circuit 041 are electrically connected to point M. It is configured to obtain a power supply signal from its first terminal and output a power supply signal to the interface circuit 02 when no circuit break signal is obtained at its control terminal.

[0096] The switching circuit 042 is also configured to stop outputting power supply signals to the interface circuit 02 when it receives a circuit break signal at its control terminal.

[0097] Voltage limiting circuit 041 includes:

[0098] The voltage limiting circuit 0411, whose first terminal and the output terminal of the level conversion circuit 01 are electrically connected at point D, is configured to output a first level signal from its second terminal (point N) when the voltage value of the power supply signal is greater than or equal to a first preset voltage value.

[0099] The voltage limiting circuit 0411 is also configured to output a second level signal from its second terminal (point N) when the voltage value of the power supply signal is less than the first preset voltage value.

[0100] The first terminal of the switch sub-circuit 0412 is electrically connected to the first terminal of the voltage limiting sub-circuit 0411 and the output terminal of the level conversion circuit 01 at point D. Its second terminal serves as the output terminal of the voltage limiting circuit 041 and is electrically connected to the control terminal of the switch circuit 042 at point M. Its control terminal and the second terminal of the voltage limiting sub-circuit are electrically connected to point N. It is configured to obtain a power supply signal from its first terminal, obtain a first level signal from its control terminal, and output a circuit breaker signal from its second terminal when the voltage value of the power supply signal is greater than or equal to a preset voltage limit value.

[0101] The switch sub-circuit 0412 is also configured to not output a circuit breaker signal from its second terminal when it receives a first level signal at its control terminal and the power supply signal is less than a preset voltage limit, or when it receives a second level signal at its control terminal.

[0102] The overvoltage protection circuit provided in this application includes multiple specific circuit structures, each of which will be explained below.

[0103] In one embodiment, the specific circuit structure of the overvoltage protection circuit 04 is as follows: Figure 3 As shown.

[0104] Among them, the voltage limiting sub-circuit 0411 includes a first resistor R1, the first end of which serves as the first end (point D) of the voltage limiting sub-circuit 0411;

[0105] Zener diode D1, whose first terminal serves as the second terminal (N point) of voltage limiting sub-circuit 0411, is electrically connected to the second terminal of the first resistor R1. Its second terminal is grounded or electrically connected to the power supply terminal that provides a stable level signal.

[0106] When the second terminal of Zener diode D1 is grounded, the first preset voltage value is the Zener diode's on-state voltage value; when the second terminal of Zener diode D1 is electrically connected to the power supply terminal that provides a stable level signal, the first preset voltage value is the sum of the Zener diode's on-state voltage value and the voltage value of the stable level signal.

[0107] Zener diode D1 is configured to conduct when the voltage at its first terminal is greater than or equal to the Zener diode's turn-on voltage, outputting a regulated electrical signal as the first level signal.

[0108] The voltage value of the first level signal is the Zener diode's on-state voltage.

[0109] Zener diode D1 is also configured to not conduct when the voltage at its first terminal is less than the Zener diode's turn-on voltage, and to output a power supply signal as a second-level signal.

[0110] The voltage limiting sub-circuit 0411 also includes a first resistor R1, which is configured to limit the current passing through the Zener diode D1 when it is turned on.

[0111] The switch sub-circuit 0412 includes a second resistor R2, the first end of which serves as the control terminal (point N) of the switch sub-circuit 0412;

[0112] The switch sub-circuit 0412 also includes a first switch device Q1, whose first terminal serves as the first terminal (point D) of the switch sub-circuit 0412, and its control terminal is electrically connected to the second terminal of the second resistor R2. Its second terminal serves as the second terminal (point M) of the switch sub-circuit 0412, and is configured to obtain a first level signal from its control terminal and a power supply signal from its first terminal. When the voltage value of the power supply signal is greater than or equal to a preset voltage limit value, it is turned on, and the power supply signal is output from its second terminal as a circuit breaker signal.

[0113] The first switching device Q1 is also configured to receive a first level signal from its control terminal, receive a power supply signal from its first terminal, turn off when the voltage value of the power supply signal is less than a preset voltage limit, and not output a power supply signal from its second terminal.

[0114] The first switching device Q1 is also configured to turn off when it receives a second level signal from its control terminal, and not to output a power supply signal from its second terminal.

[0115] In one embodiment, the first switching device Q1 is a PNP transistor. When the difference between the voltage value of the emitter and the voltage value of the base of the transistor is greater than or equal to the conduction voltage difference, the emitter and collector of the transistor are turned on, and the electrical signal obtained by the emitter is transmitted to the collector.

[0116] When the difference between the voltage at the emitter and the voltage at the base of a transistor is less than its turn-on voltage, the transistor is turned off from the emitter to the collector, and the potential at the collector is determined by other devices electrically connected to it.

[0117] The switching sub-circuit 0412 also includes a third resistor R3, whose first terminal is electrically connected to the second terminal of the first switching device Q1, and whose second terminal is grounded. It is configured to output a ground signal when the first switching device Q1 does not output an open-circuit signal. Therefore, when the transistor is turned off, the voltage at its collector is 0V.

[0118] Based on the above circuit structure, the preset voltage limit is set as the sum of the on-state voltage of the first switching device Q1 and the on-state voltage of the Zener diode.

[0119] The switching circuit 042 includes a fourth switching device Q2, whose first terminal serves as the first terminal (point L) of the switching circuit 042, its second terminal serves as the output terminal (point E) of the switching circuit 042, and its control terminal serves as the control terminal (point M) of the switching circuit 042.

[0120] The fourth switching device Q2 is configured to receive a power supply signal from its first terminal, turn off when it receives a circuit breaker signal at its control terminal, and stop outputting a power supply signal.

[0121] The fourth switching device Q2 is also configured to turn on and output a power supply signal when it does not receive an open circuit signal at its control terminal.

[0122] The switching circuit 042 also includes a third resistor R3, whose first end is electrically connected to the control end of the fourth switching device Q2, and whose second end is electrically connected to the second end of the Zener diode D1.

[0123] In one embodiment, the fourth switching device Q2 is a P-type MOS transistor, which is turned on when Vgs is less than or equal to its on-state voltage drop and turned off when Vgs is greater than its on-state voltage drop. Here, Vgs represents the voltage difference between the gate and source of the MOS transistor, the gate is the control terminal of the fourth switching device Q2, and the source is the first terminal of the fourth switching device Q2.

[0124] When the MOSFET receives a turn-off signal, Vgs is greater than its on-state voltage drop, so the MOSFET turns off and stops outputting the power supply signal obtained from its first terminal from its second terminal. When the MOSFET does not receive a turn-off signal, the voltage value at its control terminal is the same as the voltage value at the second terminal of the third resistor R3. Since the on-state voltage value of the Zener diode is much greater than the on-state voltage drop of the MOSFET, Vgs is less than its on-state voltage drop, so the MOSFET turns on and outputs the power supply signal from its second terminal.

[0125] The following example illustrates the operation of the circuit structure described above. In this example, the preset voltage limit is set to 5.9V, the Zener diode D1's on-state voltage is 5.6V, the PNP transistor's on-state voltage difference is 0.3V, and the fourth switching device Q2's on-state voltage difference is -0.5V.

[0126] In one scenario, when the output voltage of the level conversion circuit 01 is less than 5.6V (e.g., 5V), the voltage at the first terminal of the Zener diode D1 is 5.6V. Since the Zener diode's on-state voltage is 5.6V, the Zener diode D1 is not conducting.

[0127] Since the Zener diode D1 is not conducting, the base voltage of transistor Q1 is the same as the voltage value of the power supply signal obtained at the first terminal of the first resistor R1.

[0128] Since the voltage at the emitter of transistor Q1 is the same as the voltage of the power supply signal obtained at the first terminal of the first resistor, the voltage difference between the emitter and base of transistor Q1 is 0V. Even considering the voltage loss generated on the first resistor R1 and the second resistor R2, the voltage difference between the two terminals is much smaller than the conduction voltage difference of the transistor, which is 0.3V. Therefore, the collector and emitter of transistor Q1 are turned off, and the voltage at the control terminal of the fourth switching device Q2 is the same as the voltage at the second terminal of the third resistor R3, which is 0V.

[0129] Since the potential value of the first terminal of the fourth switching device Q2 is 5V and the potential value of the control terminal is 0V, the voltage difference between its control terminal and the first terminal is -5V, which is much smaller than its conduction voltage difference of -0.5V. Therefore, the fourth switching device Q2 is turned on, and the power supply signal obtained from its first terminal is output from its second terminal.

[0130] In another case, when the output voltage of the level conversion circuit 01 is greater than or equal to 5.6V and less than 5.9V (e.g., 5.7V), the Zener diode D1 is turned on, and the voltage at its first terminal is 5.6V.

[0131] Since the base of transistor Q1 is electrically connected to the first terminal of Zener diode D1 through the second resistor R2, the voltage at the base of transistor Q1 is 5.6V. Since the voltage at the emitter of transistor Q1 is 5.7V, the voltage difference between its two terminals is 0.1V, which is less than its conduction voltage difference of 0.3V. Therefore, transistor Q1 remains in the off state.

[0132] Then the state of the fourth switching device Q2 is the same as in the previous case, it is still in the on state, and it outputs the power supply signal.

[0133] In another case, when the output voltage of the level conversion circuit 01 is greater than or equal to 5.9V (e.g., 6V), the Zener diode D1 is turned on, and the voltage at its first terminal is 5.6V.

[0134] Since the base of transistor Q1 is electrically connected to the first terminal of Zener diode D1 through the second resistor R2, the base voltage of transistor Q1 is 5.6V. Since the emitter voltage of transistor Q1 is 6V, the voltage difference between its two terminals is 0.4V, which is greater than its conduction voltage difference of 0.3V. Therefore, transistor Q1 is turned on, and the collector voltage is equal to the supply voltage of 6V.

[0135] Since the control terminal of the fourth switching device Q2 is electrically connected to the collector of the transistor Q1, the voltage value of its control terminal is 6V, the voltage value of its first terminal is also 6V, and the voltage difference between its two terminals is 0V, which is greater than the conduction voltage difference of the fourth switching device Q2. Therefore, the fourth switching device Q2 is turned off, and the output of the power supply signal is stopped.

[0136] In another embodiment, the specific circuit structure of the overvoltage protection circuit is as follows: Figure 4 As shown.

[0137] The voltage limiting sub-circuit 0411 includes a voltage divider circuit 0413. Its first terminal serves as the first terminal (point D) of the voltage limiting sub-circuit 0411, and its second terminal is grounded. It is configured to obtain a power supply signal from its first terminal and output a voltage divider signal from its third terminal (point O).

[0138] The voltage limiting sub-circuit 0411 also includes a control circuit 0414, whose first terminal and the first terminal of the voltage divider circuit 0413 are electrically connected to point D, and whose second terminal is grounded or electrically connected to the power supply terminal that provides a stable level signal. Its control terminal and the third terminal of the voltage divider circuit 0413 are electrically connected to point O, and its output terminal serves as the second terminal (point N) of the voltage limiting sub-circuit 0411. It is configured to conduct when the voltage divider signal is greater than or equal to a preset threshold voltage, and output a ground signal as the second level signal.

[0139] The control circuit 0414 is also configured to turn off when the voltage divider signal is less than a preset threshold voltage and output a power supply signal as the first level signal.

[0140] When the second terminal of voltage divider circuit 0413 is grounded, the preset threshold voltage is the product of the preset voltage limit value and the voltage division ratio;

[0141] The second terminal of the voltage divider circuit 0413 is electrically connected to the power supply terminal that provides a stable level signal. The preset threshold voltage is the sum of the product of the preset limit voltage and the voltage difference of the power supply terminal and the voltage division ratio, and the voltage of the power supply terminal.

[0142] The voltage divider circuit 0413 includes a fourth resistor R4, the first end of which serves as the first terminal (point D) of the voltage divider circuit 0413.

[0143] The voltage divider circuit 0413 also includes a fifth resistor R5, whose first end is electrically connected to the second end of the fourth resistor R4, and the second end serves as the second end of the voltage divider circuit 0413.

[0144] The voltage divider circuit 0413 also includes a sixth resistor R6, whose first end is electrically connected to the second end of the fourth resistor R4, and the second end serves as the third end (point O) of the voltage divider circuit.

[0145] When the power supply signal is received at the first terminal of the fourth resistor R4, the voltage at the first terminal of the sixth resistor R6 is the voltage division of the fifth resistor R5 and the fourth resistor R4.

[0146] When the second terminal of the fourth resistor R4 is grounded, the voltage across the first terminal of the sixth resistor R6 is [value missing]. When the second terminal of the fourth resistor R4 is electrically connected to the power supply terminal VSS, which provides a stable level signal, the voltage at the first terminal of the sixth resistor R6 is [value missing].

[0147] Among them, V D R5 represents the voltage value of the power supply signal, R4 represents the voltage value of the fifth resistor, and VSS represents the voltage value of the fourth resistor. VSS is the voltage value of the power supply terminal electrically connected to the second terminal of the fourth resistor R4.

[0148] The control circuit 0414 includes a second switching device Q3, whose first terminal serves as the output terminal of the control circuit 0414, its second terminal serves as the second terminal of the control circuit 0414, and its control terminal serves as the control terminal of the control circuit 0414. It is configured to conduct when the voltage divider signal is greater than or equal to its conduction voltage and output a ground signal.

[0149] The second switching device Q3 is also configured to turn off when the voltage divider signal is less than its turn-on voltage; wherein, when the second terminal of the second switching device Q3 is grounded, its turn-on voltage is a preset threshold voltage; and when the second terminal of the second switching device Q3 is electrically connected to a power supply terminal that provides a stable level signal, the sum of its turn-on voltage and the voltage value of the power supply terminal is the preset threshold voltage.

[0150] The control circuit 0414 includes a seventh resistor R7, the first end of which serves as the first terminal of the control circuit and outputs a power supply signal when the second switching device Q3 is turned off.

[0151] The switch sub-circuit 0412 includes an eighth resistor R8, the first end of which serves as the control terminal (point N) of the switch sub-circuit 0412;

[0152] The switch sub-circuit 0412 includes a ninth resistor R9, the first end of which serves as the first terminal (point D) of the switch sub-circuit 0412.

[0153] The switch sub-circuit 0412 includes a third switch device Q4, whose control terminal is electrically connected to the second terminal of the eighth resistor R8, its first terminal is electrically connected to the second terminal of the ninth resistor R9, and its second terminal is grounded or electrically connected to the power supply terminal that provides a stable level signal.

[0154] When the second terminal of the third switching device Q4 is grounded, it is configured to turn on when it receives a power supply signal at its control terminal and output a ground signal, and turn off when it receives a ground signal at its control terminal.

[0155] When the second terminal of the third switching device Q4 is electrically connected to the power supply terminal that provides a stable level signal, it is configured to conduct when the voltage difference between its control terminal and its second terminal is greater than or equal to its conduction voltage difference, and output the voltage value of the power supply terminal. When its control terminal obtains the voltage value of the power supply terminal connected to its second terminal, it is turned off.

[0156] The switch sub-circuit 0412 includes a tenth resistor R10, whose first end is electrically connected to the second end of the ninth resistor R9 and the first end of the third switching device Q4. Its second end serves as the second end of the switch sub-circuit 0412 and is configured to output a power supply signal as a circuit breaker signal when the third switching device Q4 is turned off.

[0157] When the first terminal of the fourth switching device Q2 receives a power supply signal, it turns off and stops outputting the power supply signal when it receives a circuit break signal at its control terminal, i.e., when it receives a power supply signal. When it does not receive a short circuit signal at its control terminal, the signal it receives at its control terminal is either a ground signal or a power supply signal electrically connected to the second terminal of the third switching device Q4. In this case, the fourth switching device Q2 turns on and outputs the power supply signal.

[0158] In one embodiment, the second switching device Q3 and the third switching device Q4 are NPN transistors. When the difference between the voltage value at their base (control terminal) and the voltage value at their emitter (second terminal) is greater than or equal to their on-state voltage drop, their collector (first terminal) and their emitter are connected; when the difference between the voltage value at their base and the voltage value at their emitter is less than their on-state voltage drop, their collector and their emitter are turned off.

[0159] The following example illustrates the operation of the circuit structure described above. In this example, the preset voltage limit is set to 6.6V. The second switching device Q3 and the third switching device Q4 are both NPN transistors, with their second terminals grounded. The conduction voltage difference of these transistors is 0.6V. The conduction voltage difference of the fourth switching device Q2 is -0.5V. The resistance ratio of the fourth resistor R4 to the fifth resistor R5 is 5:1.

[0160] In one scenario, when the output voltage of the level conversion circuit 01 is less than 6.6V (e.g., 5V), the voltage at the first terminal of the fifth resistor R5 is 0.5V, which means the voltage at the control terminal of the second switching device Q3 is 0.5V.

[0161] Since the voltage at the control terminal of the second switching device Q3 is 0.5V and the voltage at its second terminal is 0V, the voltage difference between its two terminals is 0.5V, which is less than its conduction voltage difference of 0.6V. Therefore, the second switching device Q3 is turned off, and the voltage at its first terminal is the voltage value of the power supply signal, which is 5V.

[0162] Since the voltage at the first terminal of the second switching device Q3 is 5V, the voltage at the control terminal of the third switching device Q4 is also 5V. Since the voltage at the second terminal of the third switching device Q4 is 0V, the voltage difference between its two terminals is 5V, which is greater than its conduction voltage difference. Therefore, the third switching device Q4 is turned on, and the voltage at its first terminal is 0V.

[0163] Since the first terminal of the third switching device Q4 is electrically connected to the control terminal of the fourth switching device Q2 through the tenth resistor R10, the voltage value of the control terminal of the fourth switching device Q2 is 0V. Since the voltage value of the first terminal of the fourth switching device Q2 is the voltage value of the power supply signal, which is 5V, the voltage difference between its two terminals is -5V, which is less than its conduction voltage value of -0.5V. Therefore, the fourth switching device Q2 is turned on and will output the power supply signal from its second terminal.

[0164] In another case, when the output voltage of the level conversion circuit 01 is greater than or equal to 6.6V (e.g., 7V), the voltage at the first terminal of the fifth resistor R5 is 0.7V, which means the voltage at the control terminal of the second switching device Q3 is 0.7V.

[0165] Since the voltage at the control terminal of the second switching device Q3 is 0.7V and the voltage at its second terminal is 0V, the voltage difference between its two terminals is 0.7V, which is greater than its conduction voltage difference of 0.6V. Therefore, the second switching device Q3 is turned on, and the voltage at its first terminal is 0V.

[0166] Since the voltage at the first terminal of the second switching device Q3 is 0V, the voltage at the control terminal of the third switching device Q4 is also 0V. Since the second terminal of the third switching device Q4 is 0V, the voltage difference between its two terminals is 0V, which is less than its conduction voltage difference. Therefore, the third switching device Q4 is turned off, and the voltage at its first terminal is the voltage of the power supply signal, which is 7V.

[0167] Since the first terminal of the third switching device Q4 is electrically connected to the control terminal of the fourth switching device Q2 through the tenth resistor R10, the voltage value of the control terminal of the fourth switching device Q2 is 7V. Since the voltage value of the first terminal of the fourth switching device Q2 is the voltage value of the power supply signal, which is 7V, the voltage difference between its two terminals is 0V, which is greater than its conduction voltage value of -0.5V. Therefore, the fourth switching device Q2 is turned off and stops outputting the power supply signal from its second terminal.

[0168] In the circuit structure shown above, the circuit structure of interface circuit 02 in one embodiment is as follows: Figure 7 As shown, the interface circuit 02 includes an interface chip U3, which has differential signal terminals D+ and D-, a power supply terminal VCC, a ground terminal GND, and interface terminals.

[0169] In one embodiment, the power supply terminal VCC of the interface chip U3 is electrically connected to the output terminal of the overvoltage protection circuit 04, the differential signal terminals D+ and D- are electrically connected to the signal transmission terminal of the electronic device, and the interface terminals are used for electrical connection with external devices.

[0170] The interface chip U3 is configured to power on when it receives a power supply signal at its power supply terminal VCC. When an external device is connected to the interface terminal, the electronic device interacts with the external device or transmits information or data in one direction through the differential signal terminals D+ and D-.

[0171] In some embodiments, a current limiting switch circuit 05 is connected in series between the output of the overvoltage protection circuit 04 and the input of the interface circuit 02, and is configured to limit the current value of the electrical signal output by the level conversion circuit 01.

[0172] In some embodiments, the current limiting switch circuit 05 includes a fuse FU, and its circuit structure diagram is shown below. Figure 5 As shown.

[0173] The fuse FU is configured to blow when the current value of the electrical signal output by the overvoltage protection circuit 04 continuously exceeds the rated current of the fuse FU and the duration exceeds the preset duration.

[0174] In some other embodiments, the current limiting switch circuit 05 includes a current limiting switch device U2, the circuit structure of which is shown in the figure below. Figure 6 As shown.

[0175] The input terminal VIN of the current limiting switch chip U2 is electrically connected to the output terminal of the overvoltage protection circuit 04, and its output terminal OUT is electrically connected to the input terminal of the interface circuit 02.

[0176] The current limiting switch U2 is configured to, when enabled, maintain the conduction between its input terminal VIN and output terminal OUT when the current value of the electrical signal obtained at its input terminal is less than the preset current value, and output the electrical signal obtained at its input terminal from its output terminal; when the current value of the electrical signal obtained at its input terminal is greater than or equal to the preset current value, interrupt the conduction loop between its input terminal VIN and output terminal OUT, and interrupt the output of the electrical signal.

[0177] In some embodiments, the current limiting switch circuit 05 further includes a first capacitor C1, configured to filter the electrical signal output by the overvoltage protection circuit 04.

[0178] In general, the current limiting switch is electrically connected to the back side of the overvoltage protection circuit to prevent the current limiting switch U2 from being burned out by excessive voltage.

[0179] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the utility models 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.

[0180] 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 circuit for a peripheral interface, characterized in that, This includes a level conversion circuit, an overvoltage protection circuit, and an interface circuit for sequential electrical connections; The overvoltage protection circuit includes: A voltage limiting circuit, the first terminal of which is electrically connected to the output terminal of the level conversion circuit, is configured to output a circuit breaking signal from its output terminal when the voltage value of the power supply signal provided by the level conversion circuit is greater than or equal to a preset voltage limit value. The voltage limiting circuit is further configured to not output the circuit breaking signal when the voltage value of the power supply signal is less than the preset voltage limit value; the preset voltage limit value is greater than the power supply standard voltage and less than the safety standard voltage. A switching circuit, whose first terminal is electrically connected to the output terminal of the level conversion circuit and whose control terminal is electrically connected to the output terminal of the voltage limiting circuit, is configured to obtain the power supply signal from its first terminal and output the power supply signal to the interface circuit when the control terminal does not obtain the circuit break signal. The switching circuit is further configured to stop outputting the power supply signal to the interface circuit when it receives the circuit break signal at its control terminal.

2. The peripheral interface power supply circuit according to claim 1, characterized in that, The voltage limiting circuit includes: A voltage limiting circuit, whose first terminal is electrically connected to the output terminal of the level conversion circuit, is configured to output a first level signal from its second terminal when the voltage value of the power supply signal is greater than or equal to a first preset voltage value; The voltage limiting sub-circuit is further configured to output a second level signal from its second terminal when the voltage value of the power supply signal is less than the first preset voltage value; A switching sub-circuit, whose first terminal is electrically connected to the first terminal of the voltage limiting sub-circuit, whose second terminal is electrically connected to the control terminal of the switching circuit, and whose control terminal is electrically connected to the second terminal of the voltage limiting sub-circuit, is configured to obtain the power supply signal from its first terminal and the first level signal from its control terminal, and output the circuit breaking signal from its second terminal when the voltage value of the power supply signal is greater than or equal to the preset voltage limit value. The switch sub-circuit is further configured to, when it receives the first level signal at its control terminal and the power supply signal is less than the preset voltage limit, or when it receives the second level signal at its control terminal, not output the circuit breaker signal from its second terminal.

3. The peripheral interface power supply circuit according to claim 2, characterized in that, The first preset voltage value includes the Zener diode's on-state voltage; The voltage limiting sub-circuit includes: The first resistor, the first end of which serves as the first terminal of the voltage limiting sub-circuit; A Zener diode, whose first terminal serves as the second terminal of the voltage limiting sub-circuit and is electrically connected to the second terminal of the first resistor, and whose second terminal is grounded, is configured to conduct when the voltage value at its first terminal is greater than or equal to the Zener diode's on-state voltage value, and output a regulated electrical signal as the first level signal; The Zener diode is further configured to not conduct when the voltage at its first terminal is less than the Zener diode's turn-on voltage, and to output the power supply signal as the second level signal.

4. The peripheral interface power supply circuit according to claim 2 or 3, characterized in that, The switching sub-circuit includes: The second resistor has its first end serving as the control terminal of the switch sub-circuit. The first switching device has a first terminal as the first terminal of the switching sub-circuit, a control terminal and a second terminal of the second resistor electrically connected, and a second terminal as the second terminal of the switching sub-circuit. It is configured to obtain the first level signal from its control terminal and the power supply signal from its first terminal. It is turned on when the voltage value of the power supply signal is greater than or equal to the preset voltage limit value, and outputs the power supply signal from its second terminal as the circuit breaker signal. The first switching device is further configured to receive the first level signal from its control terminal, receive the power supply signal from its first terminal, turn off when the voltage value of the power supply signal is less than the preset voltage limit value, and not output the power supply signal from its second terminal. The first switching device is further configured to turn off when it receives the second level signal from its control terminal, and not output the power supply signal from its second terminal; A third resistor, whose first end is electrically connected to the second end of the first switching device and whose second end is grounded, is configured to output a ground signal when the first switching device does not output the circuit breaker signal.

5. The peripheral interface power supply circuit according to claim 4, characterized in that, The preset voltage limit is equal to the sum of the on-state voltage of the first switching device and the on-state voltage of the Zener diode.

6. The peripheral interface power supply circuit according to claim 2, characterized in that, The voltage limiting sub-circuit includes: The voltage divider circuit has a first terminal as the first terminal of the voltage limiting sub-circuit, a second terminal grounded, and is configured to obtain the power supply signal from its first terminal and output the voltage divider signal from its third terminal. The control circuit has its first terminal electrically connected to the first terminal of the voltage divider circuit, its second terminal grounded, its control terminal electrically connected to the third terminal of the voltage divider circuit, and its output terminal serving as the second terminal of the voltage limiting sub-circuit. It is configured to conduct when the voltage divider signal is greater than or equal to a preset threshold voltage and output a ground signal as the second level signal. The control circuit is also configured to turn off when the voltage divider signal is less than the preset threshold voltage and output a power supply signal as the first level signal. The preset threshold voltage is the product of the preset voltage limit value and the voltage division ratio.

7. The peripheral interface power supply circuit according to claim 6, characterized in that, The voltage divider circuit includes: The fourth resistor has its first end serving as the first end of the voltage divider circuit. The fifth resistor has its first end electrically connected to the second end of the fourth resistor, and its second end serves as the second end of the voltage divider circuit. The sixth resistor has its first end electrically connected to the second end of the fourth resistor, and the second end serves as the third end of the voltage divider circuit.

8. The peripheral interface power supply circuit according to claim 6 or 7, characterized in that, The preset threshold voltage includes the turn-on voltage of the second switching device; The control circuit includes: The second switching device, whose first terminal serves as the output terminal of the control circuit, whose second terminal serves as the second terminal of the control circuit, and whose control terminal serves as the control terminal of the control circuit, is configured to conduct when the voltage divider signal is greater than or equal to its conduction voltage, and output the ground signal. The second switching device is further configured to turn off when the voltage divider signal is less than its on-state voltage; The seventh resistor, whose first end serves as the first end of the control circuit, outputs the power supply signal when the second switching device is turned off.

9. The peripheral interface power supply circuit according to any one of claims 2, 6, or 7, characterized in that, The switching sub-circuit includes: The eighth resistor, the first end of which serves as the control terminal of the switch sub-circuit; The ninth resistor, the first end of which serves as the first end of the switch sub-circuit; The third switching device has its control terminal electrically connected to the second terminal of the eighth resistor, its first terminal electrically connected to the second terminal of the ninth resistor, and its second terminal grounded. It is configured to turn on when it receives the power supply signal at its control terminal and output a ground signal. The third switching device is also configured to turn off when it receives the ground signal at its control terminal; The tenth resistor has its first end electrically connected to the second end of the ninth resistor and the first end of the third switching device. Its second end serves as the second end of the switching sub-circuit and is configured to output the power supply signal as the circuit breaker signal when the third switching device is turned off.

10. The peripheral interface power supply circuit according to claim 1, characterized in that, The switching circuit includes: The fourth switching device, whose first terminal serves as the first terminal of the switching circuit, whose second terminal serves as the output terminal of the switching circuit, and whose control terminal serves as the control terminal of the switching circuit, is configured to receive the power supply signal from its first terminal, and to turn off and stop outputting the power supply signal when the circuit breaker signal is received at its control terminal. The fourth switching device is also configured to turn on and output the power supply signal when it does not receive the circuit breaker signal at its control terminal.

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