Power supply output protection circuit

Abstract

The invention discloses a power supply output protection circuit. The power supply output protection circuit comprises a first-stage output protection module and a second-stage output protection module, the first-stage output protection module comprises a first switch connected between the input end and the output end; the first-stage output protection module is used for controlling the first switch to be switched on or switched off according to the voltage and / or current output by the power supply; the second-stage output protection module comprises a second switch connected between the input end and the output end, and the second-stage output protection module is used for controlling the second switch to be switched on or switched off according to the voltage and / or current output by the first-stage output protection module; wherein after the first switch is switched from a turn-off state to a turn-on state, the output end of the first-stage output protection module is powered on, and the second-stage output protection module is further used for controlling the second switch to be turned on in a delayed mode according to the power-on voltage of the output end of the first-stage output protection module. The reliability of the power supply output protection circuit is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power supplies, and in particular to a power supply output protection circuit. Background Art

[0002] Intrinsically safe electrical equipment is increasingly being used underground in coal mines. For example, sensors and instruments are used in automation systems like communications and monitoring systems, playing a vital role in mine safety. To ensure the stable operation of communications and monitoring systems, the proper functioning of intrinsically safe electrical equipment within these systems is essential. A stable power supply is crucial for ensuring the continued reliable operation of these devices.

[0003] In the prior art, power supply output protection circuits have a self-recovery function. This means that when the protection circuit detects a fault, it shuts off the power supply output, then automatically reopens after a delay to determine whether the fault has been resolved, repeating this cycle. However, the fault detection time and shutdown delay of this protection circuit are proportional, and these two times cannot be adjusted independently. As the speed of fault detection increases, the switching transistors in the power supply output protection circuit also shut down more frequently, potentially causing them to overheat and damage, rendering the entire power supply output protection circuit inoperable. This means that the prior art power supply output protection circuit suffers from low reliability. Summary of the Invention

[0004] The present invention provides a power supply output protection circuit to solve the problem of low reliability of the power supply output protection circuit.

[0005] According to one aspect of the present invention, a power supply output protection circuit is provided, the power supply output protection circuit comprising a first-stage output protection module and a second-stage output protection module;

[0006] The input end of the first-stage output protection module is connected to a power supply, and the output end of the first-stage output protection module is connected to the input end of the second-stage output protection module;

[0007] The first-stage output protection module includes a first switch connected between the input terminal and the output terminal; the first-stage output protection module is used to control the first switch to be turned on or off according to the voltage and / or current output by the power supply;

[0008] The second-stage output protection module includes a second switch connected between the input end and the output end, and the second-stage output protection module is used to control the second switch to be turned on or off according to the voltage and / or current of the output of the first-stage output protection module; wherein, after the first switch is switched from the off state to the on state, the output end of the first-stage output protection module is powered on, and the second-stage output protection module is further used to control the second switch to be turned on according to the power-on voltage delay of the output end of the first-stage output protection module.

[0009] The technical solution of the embodiments of the present invention extends the shutdown delay of the power supply output protection circuit by delaying the second switch in the second-stage output protection module to turn on according to the power-on voltage at the output terminal of the first-stage output protection module. This reduces the switching frequency of the first and second switches, thereby increasing the service life of the first and second switches. Furthermore, the second-stage output protection module can also provide a backup for the first-stage output protection module. This improves the reliability of the power supply output protection circuit.

[0010] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0012] Figure 1 A schematic structural diagram of a power output protection circuit provided by an embodiment of the present invention;

[0013] Figure 2 A schematic structural diagram of another power supply output protection circuit provided by an embodiment of the present invention;

[0014] Figure 3 A schematic diagram of the structure of another power supply output protection circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0015] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0016] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0017] Figure 1 This is a schematic diagram of the structure of a power output protection circuit provided by an embodiment of the present invention. This embodiment is applicable to protecting the power output of intrinsically safe electrical equipment. Figure 1 As shown, the power supply output protection circuit includes: a first-stage output protection module 110 and a second-stage output protection module 210. The input of the first-stage output protection module 110 is connected to the power supply 310, and the output of the first-stage output protection module 110 is connected to the input of the second-stage output protection module 210. The first-stage output protection module 110 includes a first switch connected between the input and output terminals. The first-stage output protection module 110 is configured to control the first switch to be turned on or off based on the voltage and / or current output by the power supply 310. The second-stage output protection module 210 includes a second switch connected between the input and output terminals. The second-stage output protection module 210 is configured to control the second switch to be turned on or off based on the voltage and / or current output by the first-stage output protection module 110. When the first switch switches from the off state to the on state, the output of the first-stage output protection module 110 is powered on. The second-stage output protection module 210 is further configured to control the second switch to be turned on with a delay based on the power-on voltage at the output of the first-stage output protection module 110.

[0018] The output voltage / current of power supply 310 passes through first-stage output protection module 110 and second-stage output protection module 210 before being output to the load. Specifically, first-stage output protection module 110 is a circuit module used to provide preliminary protection for the output of power supply 310. It is directly connected to the output terminal of power supply 310 and is responsible for detecting and handling common faults such as overcurrent, overvoltage, and undervoltage to protect subsequent circuits. Second-stage output protection module 210 is a circuit module used to provide further protection for the output of power supply 310. It is located after first-stage output protection module 110 and operates based on the voltage and current at the output terminal of first-stage output protection module 110.

[0019] The first switch refers to the electronic component in the first-stage output protection module 110 that controls the on / off state of the circuit. Exemplarily, the first switch can be a transistor such as a MOSFET or IGBT, or an electronic component such as a relay. The second switch refers to the electronic component in the second-stage output protection module 210 that controls the on / off state of the circuit. Exemplarily, the second switch can be a transistor such as a MOSFET or IGBT, or an electronic component such as a relay. The power-on voltage refers to the voltage value reached at the output end of the first-stage output protection module 110 at the moment the first switch switches from the off state to the on state.

[0020] In an embodiment of the present invention, the first-stage output protection module 110 provides preliminary protection for the output of the power supply 310. If a fault such as overcurrent, overvoltage, or undervoltage occurs at the output of the power supply 310, the first switch in the first-stage output protection module 110 is turned off. When the first switch transitions from the off state to the on state, the second-stage output protection module 210 can delay its operation based on the power-up voltage at the output of the first-stage output protection module 110. When the power-up voltage rises to the activation voltage of the second-stage output protection module 210, the second switch turns on, thereby extending the shutdown delay of the power supply output protection circuit. Furthermore, the second-stage output protection module 210 can also provide a backup for the first-stage output protection module 110. For example, if the first-stage output protection module 110 fails to operate due to a fault or other reason in the event of a power supply 310 output fault, the second-stage output protection module 210 can provide a backup and activate promptly to ensure the reliability of the power supply 310 output.

[0021] For example, the output terminal of the first-stage output protection module 110 can be connected to the first output terminal 410, and the input terminal of the second-stage output protection module 210 can be connected to the first output terminal 410. That is, the first-stage output protection module 110 and the second-stage output protection module 210 are connected via the first output terminal 410. This connection has the advantage that a detection circuit can be provided at the output terminal of the first-stage output protection module 110 to detect the output voltage of the first-stage output protection module 110. Furthermore, a detection circuit can also be provided at the output terminal of the second-stage output protection module 210 to detect the output voltage of the second-stage output protection module 210.

[0022] The technical solution of the embodiments of the present invention extends the shutdown delay of the power supply output protection circuit by delaying the second switch in the second-stage output protection module to turn on according to the power-on voltage at the output terminal of the first-stage output protection module. This reduces the switching frequency of the first and second switches, thereby increasing the service life of the first and second switches. Furthermore, the second-stage output protection module can also provide a backup for the first-stage output protection module. This improves the reliability of the power supply output protection circuit.

[0023] Figure 2 This is a structural diagram of another power output protection circuit provided by an embodiment of the present invention. Based on the above embodiments, Figure 2 As shown, the first-stage output protection module 110 optionally further includes: a first control unit 120, a first overvoltage sampling circuit 130, a first undervoltage sampling circuit 140, and a first current sampling circuit 150. A first terminal of the first overvoltage sampling circuit 130 is connected to the power supply 310, a second terminal of the first overvoltage sampling circuit 130 is connected to the first terminal of the first control unit 120, and a third terminal of the first overvoltage sampling circuit 130 is connected to the ground terminal. The first overvoltage sampling circuit 130 is configured to detect the voltage output by the power supply 310 and output a first voltage. A first terminal of the first undervoltage sampling circuit 140 is connected to the power supply 310, a second terminal of the first undervoltage sampling circuit 140 is connected to the second terminal of the first control unit 120, and a third terminal of the first undervoltage sampling circuit 140 is connected to the ground terminal. The first undervoltage sampling circuit 140 is configured to detect the output voltage of the power supply 310 and output a second voltage. The first current sampling circuit 150 is connected between the power supply 310 and the first switch 111. The output terminal of the first current sampling circuit 150 is connected to the third terminal of the first control unit 120. The first current sampling circuit 150 is configured to detect the current at the output terminal of the power supply 310 and output a first current. The fourth terminal of the first control unit 120 is connected to the control terminal of the first switch 111. The first control unit 120 sends a shutdown signal to the control terminal of the first switch 111 when the first voltage is greater than a first preset voltage, the second voltage is less than a second preset voltage, and / or the first current is greater than the first preset current.

[0024] Specifically, the first overvoltage sampling circuit 130 refers to a circuit for detecting the voltage output by the power supply 310. For example, sampling can be achieved by means of a resistor divider. The first voltage refers to the voltage signal output by the first overvoltage sampling circuit 130, which can reflect the magnitude of the output voltage of the power supply 310 and is primarily used to determine whether the voltage output by the power supply 310 is overvoltage. The first undervoltage sampling circuit 140 refers to another circuit for detecting the voltage output by the power supply 310. For example, sampling can be achieved by means of a resistor divider. The second voltage refers to the voltage signal output by the first undervoltage sampling circuit 140, which can reflect the magnitude of the output voltage of the power supply 310 and is primarily used to determine whether the voltage output by the power supply 310 is undervoltage. The first current sampling circuit 150 refers to a circuit for measuring the current flowing between the output end of the power supply 310 and the first switch 111. For example, the first current sampling circuit 150 can measure the voltage drop across the sampling resistor and then calculate the current according to Ohm's law. The first current refers to the current signal output by the first current sampling circuit 150 , which can reflect the magnitude of the current between the power source 310 and the first switch 111 and is mainly used to determine whether the current output by the power source 310 is overcurrent.

[0025] The first control unit 120 is a control circuit or module that receives the first voltage, second voltage, and first current outputted by the first overvoltage sampling circuit 130, the first undervoltage sampling circuit 140, and the first current sampling circuit 150, and controls the operation of the first switch 111 based on these signals. The first preset voltage is a pre-set voltage value used to determine whether the voltage outputted by the power supply 310 is overvoltage. If the first voltage is greater than the first preset voltage, the voltage outputted by the power supply 310 is overvoltage. The second preset voltage is a pre-set voltage value used to determine whether the voltage outputted by the power supply 310 is undervoltage. If the second voltage is less than the second preset voltage, the voltage outputted by the power supply 310 is undervoltage. The first preset current is a pre-set current value used to determine whether the voltage outputted by the power supply 310 is overcurrent. If the first current is greater than the first preset current, the current outputted by the power supply 310 is overcurrent. The shutdown signal is a signal used to control the shutdown of the first switch 111 or the second switch 211. For example, the shutdown signal can be a high-level signal or a low-level signal.

[0026] In this embodiment of the present invention, the first overvoltage sampling circuit 130 and the first undervoltage sampling circuit 140 respectively detect the voltage output by the power supply 310 and output a first voltage and a second voltage. The first current sampling circuit 150 samples the current at the output terminal of the power supply 310 and outputs a first current. When the first voltage is greater than a first preset voltage, the second voltage is less than the second preset voltage, and the first current is greater than the first preset current, the first control unit 120 sends a shutdown signal to the control terminal of the first switch 111, causing the first switch 111 to turn off, thereby disconnecting the power supply 310 from the subsequent circuits, preventing damage to the circuits caused by overvoltage, undervoltage, or overcurrent, and thus achieving a protective function.

[0027] On the basis of the above embodiments, continue to refer to Figure 2 Optionally, the second-stage output protection module 210 further includes: a second overvoltage sampling circuit 230, a second undervoltage sampling circuit 240, a second current sampling circuit, a second control unit 220, and a delayed start circuit 270. A first terminal of the second overvoltage sampling circuit 230 is connected to the output terminal of the first-stage output protection module, a second terminal of the second overvoltage sampling circuit 230 is connected to the first terminal of the second control unit 220, and a third terminal of the second overvoltage sampling circuit 230 is connected to the ground terminal. The second overvoltage sampling circuit 230 detects the voltage at the output terminal of the first-stage output protection module and outputs a third voltage. A first terminal of the second undervoltage sampling circuit 240 is connected to the output terminal of the first-stage output protection module, an output terminal of the second undervoltage sampling circuit 240 is connected to the second terminal of the second control unit 220, and a third terminal of the second undervoltage sampling circuit 240 is connected to the ground terminal. The second undervoltage sampling circuit 240 is configured to detect the voltage at the output terminal of the first-stage output protection module and output a fourth voltage. The second current sampling circuit is connected between the first-stage output protection module and the second switch 211. The output of the second current sampling circuit is connected to the third terminal of the second control unit 220. The second current sampling circuit is configured to detect the current at the output of the first-stage output protection module and output a second current. A first terminal of a delayed start circuit 270 is connected to the output of the first-stage output protection module, a second terminal of the delayed start circuit 270 is connected to the output of the second undervoltage sampling circuit 240, and a third terminal of the delayed start circuit 270 is connected to ground. The delayed start circuit is configured to delay the rise of the voltage output by the second undervoltage sampling circuit 240 to a stable voltage based on the power-up voltage at the output of the first-stage output protection module. The fourth terminal of the second control unit 220 is connected to the control terminal of the second switch 211. The second control unit 220 is configured to send a shutdown signal to the control terminal of the second switch 211 when the third voltage is greater than the third preset voltage, the fourth voltage is less than the fourth preset voltage, and / or the second current is greater than the first preset current.

[0028] Specifically, the second overvoltage sampling circuit 230 is a circuit for detecting the voltage output by the first-stage output protection module 110. Exemplarily, sampling can be achieved through resistor voltage division. The third voltage is a voltage signal output by the second overvoltage sampling circuit 230, which reflects the magnitude of the output voltage of the first-stage output protection module 110 and is primarily used to determine whether the voltage output by the first-stage output protection module 110 is overvoltage. The second undervoltage sampling circuit 240 is another circuit for detecting the voltage output by the first-stage output protection module 110. Exemplarily, sampling can be achieved through resistor voltage division. The fourth voltage is a voltage signal output by the second undervoltage sampling circuit 240, which reflects the magnitude of the output voltage of the first-stage output protection module 110 and is primarily used to determine whether the voltage output by the first-stage output protection module 110 is undervoltage. The second current sampling circuit 250 is a circuit for measuring the current flowing between the output terminal of the first-stage output protection module 110 and the second switch 211. Exemplarily, the second current sampling circuit 250 can measure the voltage drop across the sampling resistor and then calculate the current according to Ohm's law. The second current refers to the current signal output by the second current sampling circuit 250 , which can reflect the magnitude of the current between the first-stage output protection module 110 and the second switch 211 , and is mainly used to determine whether the current output by the first-stage output protection module 110 is overcurrent.

[0029] In some examples, the delayed start circuit 270 is a circuit configured to delay the turning-on of the second switch 211 for a period of time after the turning-on of the first switch 111. In an embodiment of the present invention, when the first switch 111 in the first-stage output protection module is just turned on, due to the effect of the delayed start circuit 270, the output voltage of the second undervoltage sampling circuit 240 does not immediately reach a stable voltage, but instead rises to a stable voltage after a delay. Consequently, the second control unit 220 continuously detects the undervoltage signal during this period, and the second control unit 220 controls the second switch 211 to remain in an off state until the second voltage output by the second undervoltage sampling circuit 240 reaches a stable voltage, at which point the second control unit 220 controls the second switch 211 to turn on.

[0030] In some examples, the second control unit 220 refers to a control circuit or module that receives the third voltage, fourth voltage, and second current outputted by the second overvoltage sampling circuit 230, the second undervoltage sampling circuit 240, and the second current sampling circuit 250, and controls the operation of the second switch 211 based on these signals. The third preset voltage refers to a preset voltage value used to determine whether the voltage outputted by the first-stage output protection module 110 is overvoltage. If the third voltage is greater than the third preset voltage, the voltage outputted by the first-stage output protection module 110 is overvoltage. The fourth preset voltage refers to a preset voltage value used to determine whether the voltage outputted by the first-stage output protection module 110 is undervoltage. If the fourth voltage is less than the fourth preset voltage, the voltage outputted by the first-stage output protection module 110 is undervoltage. The second preset current refers to a preset current value used to determine whether the voltage outputted by the first-stage output protection module 110 is overcurrent. If the second current is greater than the second preset current, the current outputted by the first-stage output protection module 110 is overcurrent.

[0031] In this embodiment of the present invention, the second overvoltage sampling circuit 230 and the second undervoltage sampling circuit 240 respectively detect the voltage output by the first-stage output protection module 110 and output a third voltage and a fourth voltage. The second current sampling circuit 250 samples the current at the output of the power supply 310 and outputs a second current. When the third voltage is greater than the third preset voltage, the fourth voltage is less than the fourth preset voltage, and the second current is greater than the second preset current, the second control unit 220 sends a shutdown signal to the control terminal of the second switch 211, causing the second switch 211 to turn off, thereby disconnecting the power supply 310 from the subsequent circuits and preventing damage to the circuits caused by overvoltage, undervoltage, or overcurrent, thereby achieving a protective function. When the first switch 111 is turned on, the delayed startup circuit 270 in the second-stage output protection module 210 delays the voltage output by the second undervoltage sampling circuit 240 from rising to a stable voltage. This delays the second switch 211 from turning on until a certain period of time after the first switch 111 turns on, thereby extending the shutdown delay of the power output protection circuit.

[0032] The technical solution of the embodiment of the present invention delays the voltage output by the second undervoltage sampling circuit to a stable voltage based on the power-on voltage at the output end of the first-stage output protection module through a delayed start-up circuit, thereby delaying the conduction of the second switch of the second-stage output protection module. The embodiment of the present invention can extend the shutdown delay time of the power output protection circuit, thereby extending the shutdown delay time of the entire power output protection circuit. Therefore, for short-term voltage fluctuations, the protection circuit will not respond immediately, but will wait for a period of time to determine whether the voltage can recover on its own. If the voltage returns to normal within the delay time, the protection circuit will not shut down the output, thereby reducing the switching frequency of the first switch and the second switch, and preventing them from being damaged due to excessive temperature. In other words, the present invention improves the reliability of the power output protection circuit.

[0033] Figure 3 This is a structural diagram of another power output protection circuit provided by an embodiment of the present invention. Based on the above embodiments, Figure 3 As shown, optionally, the first overvoltage sampling circuit 130 includes a first resistor 131 and a second resistor 132 connected in series, with the connection point between the first resistor 131 and the second resistor 132 connected to the first terminal of the first control unit 120. The first undervoltage sampling circuit 140 includes a third resistor 141 and a fourth resistor 142 connected in series, with the connection point between the third resistor 141 and the fourth resistor 142 connected to the second terminal of the first control unit 120. The first current sampling circuit 150 includes a fifth resistor 151 connected in series between the output terminal of the power supply and the first terminal of the first switch 111, with the first terminal of the fifth resistor 151 connected to the third terminal of the first control unit 120. The second terminal of the first switch is connected to the output terminal of the first-stage output protection module 110, and the control terminal of the first switch 111 is connected to the fourth terminal of the first control unit 120.

[0034] In an embodiment of the present invention, the first overvoltage sampling circuit 130 includes a first resistor 131 and a second resistor 132 connected in series. When the output voltage of the power supply 310 increases, the output voltage is distributed between the first resistor 131 and the second resistor 132. The voltage at the connection point between the two resistors reflects the magnitude of the output voltage of the power supply 310. This connection point is connected to a first terminal of the first control unit 120. The first control unit 120 monitors a first voltage at the connection point. If the first voltage exceeds a first preset voltage, the first control unit 120 sends a signal to trigger a protective measure, such as closing the first switch 111. The first undervoltage sampling circuit 140 includes a third resistor 141 and a fourth resistor 142 connected in series. Similar to the first overvoltage sampling circuit 130, when the output voltage of the power supply 310 decreases, the output voltage is also distributed between the third resistor 141 and the fourth resistor 142. The second voltage at the connection point between the two resistors reflects the actual output voltage of the power supply 310. This connection point is connected to the second terminal of the first control unit 120. The first control unit 120 monitors the second voltage. If the second voltage is lower than a second preset voltage, the first control unit 120 outputs a control signal to turn off the first switch 111. The first current sampling circuit 150 includes a fifth resistor 151, which is connected in series between the output terminal of the power supply 310 and the first terminal of the first switch 111. When the current output by the power supply 310 flows through the fifth resistor 151, a voltage drop is generated across it. According to Ohm's law, this voltage drop is proportional to the first current flowing through the fifth resistor 151. The first terminal of the fifth resistor 151 is connected to the third terminal of the first control unit 120. The first control unit 120 monitors the first current signal. If the first current exceeds a first preset current, which is an overcurrent threshold, the first control unit 120 triggers a protection mechanism to turn off the first switch 111.

[0035] On the basis of the above embodiments, continue to refer to Figure 3 Optionally, the second overvoltage sampling circuit 230 includes a sixth resistor 231 and a seventh resistor 232, which are connected in series. The connection point between the sixth resistor 231 and the seventh resistor 232 is connected to the first terminal of the second control unit 220. The second undervoltage sampling circuit 240 includes an eighth resistor 241 and a ninth resistor 242, which are connected in series. The connection point between the eighth resistor 241 and the ninth resistor 242 is connected to the second terminal of the second control unit 220. The second current sampling circuit 250 includes a tenth resistor 251, which is connected in series between the output terminal of the first-stage output protection module 110 and the first terminal of the second switch 211. The first terminal of the tenth resistor 251 is connected to the third terminal of the second control unit 220. The second terminal of the second switch 211 is connected to the output terminal of the second-stage output protection module 210, and the control terminal of the second switch 211 is connected to the fourth terminal of the second control unit 220.

[0036] In this embodiment of the present invention, the second overvoltage sampling circuit 230 includes a sixth resistor 231 and a seventh resistor 232 connected in series. When the output voltage of the first-stage output protection module 110 increases, the output voltage is distributed between the sixth resistor 231 and the seventh resistor 232. The third voltage at the connection point between the two resistors reflects the magnitude of the output voltage of the first-stage output protection module 110. This connection point is connected to the first terminal of the first control unit 120. The first control unit 120 monitors the third voltage at the connection point. If the third voltage exceeds a third preset voltage, the first control unit 120 sends a signal to trigger a protective measure, such as closing the second switch 211. The second undervoltage sampling circuit 240 includes an eighth resistor 241 and a ninth resistor 242 connected in series. Similar to the second overvoltage sampling circuit 230, when the output voltage of the first-stage output protection module 110 decreases, the output voltage is also distributed between the eighth resistor 241 and the ninth resistor 242. The fourth voltage at the connection point between the two resistors reflects the actual output voltage of the first-stage output protection module 110. This connection point is connected to the second terminal of the first control unit 120. The first control unit 120 monitors the fourth voltage. If the fourth voltage is lower than the fourth preset voltage, the first control unit 120 sends a signal to turn off the second switch 211. The second current sampling circuit 250 includes a tenth resistor 251, which is connected in series between the output terminal of the first-stage output protection module 110 and the first terminal of the second switch 211. When the current output by the first-stage output protection module 110 flows through the tenth resistor 251, a voltage drop is generated across it. According to Ohm's law, this voltage drop is proportional to the second current flowing through the tenth resistor 251. The first terminal of the tenth resistor 251 is connected to the third terminal of the second control unit 220. The second control unit 220 monitors the second current signal. If the second current exceeds the second preset current, the second control unit 220 triggers a protection mechanism to turn off the second switch 211.

[0037] On the basis of the above embodiments, continue to refer to Figure 2 Optionally, the first-stage output protection module 110 further includes: a first fast discharge circuit 160; a first end of the first fast discharge circuit 160 is connected to the fourth end of the first control unit 120, a second end of the first fast discharge circuit 160 is connected to the output end of the first-stage output protection module 110, and a third end of the first fast discharge circuit 160 is connected to the ground end; the first fast discharge circuit 160 is configured to charge when the first control unit 120 sends a turn-on signal to the control end of the first switch 111, and discharge when an off signal is sent.

[0038] Specifically, the first fast discharge circuit 160 refers to a circuit for slowly turning on the load and quickly releasing excess charge at the control end of the first switch 111. In an embodiment of the invention, when the first control unit 120 sends a turn-on signal to the first switch 111, the first fast discharge circuit 160 is charged and the first switch 111 is slowly turned on to avoid false protection caused by excessive startup current of the capacitive load; when the first control unit 120 sends a turn-off signal to the first switch 111, the first fast discharge circuit 160 can discharge quickly. At the same time, the electrical energy stored in the junction capacitance of the control end of the first switch 111 is quickly released. That is, the first fast discharge circuit 160 can provide a stable leakage path when the first switch 111 is repeatedly restarted.

[0039] For example, the first fast discharge circuit 160 may include a capacitor, and the shutdown signal may be a low-level signal. When the first control unit 120 sends a turn-on signal to the control terminal of the first switch 111, the capacitor is charged, enabling a slow startup of the output of the first control unit 120. When the first control unit 120 sends a turn-off signal to the control terminal of the first switch 111, the first fast discharge circuit 160 can be quickly turned on, thereby providing a low-impedance path. The energy stored in the capacitor of the first fast discharge circuit 160 is quickly released to prepare for the next slow startup. Furthermore, due to the presence of the junction capacitance of the first switch 111, when the first control unit 120 sends a low-level signal to the first switch 111, the voltage at the control terminal of the first switch 111 does not immediately drop to a low level. The first fast discharge circuit 160 provides a stable leakage path, allowing the voltage at the control terminal of the first switch 111 to drop rapidly, thereby ensuring that the first switch 111 can be quickly shut down and preventing voltage damage to subsequent circuits. In addition, by quickly discharging excess voltage, the first fast discharging circuit 160 can prevent equipment damage caused by overvoltage, thereby enhancing the safety and reliability of the power output protection circuit.

[0040] On the basis of the above embodiments, continue to refer to Figure 2 Optionally, the second-stage output protection module 210 further includes: a second fast discharge circuit 260; a first end of the second fast discharge circuit 260 is connected to the fourth end of the second control unit 220, a second end of the second fast discharge circuit 260 is connected to the output end of the second-stage output protection module 210, and a third end of the second fast discharge circuit 260 is connected to the ground end; the second fast discharge circuit 260 is configured to charge when the second control unit 220 sends a turn-on signal to the control end of the first switch 211, and discharge when an off signal is sent.

[0041] Specifically, the second fast discharge circuit 260 refers to a circuit for slowly turning on the load and quickly releasing excess charge at the control end of the second switch 211. In an embodiment of the invention, when the second control unit 220 sends a turn-on signal to the second switch 211, the second fast discharge circuit 260 is charged and the second switch 211 is slowly turned on to avoid false protection caused by excessive startup current of the capacitive load; when the second control unit 220 sends a turn-off signal to the second switch 211, the second fast discharge circuit 260 can discharge quickly. At the same time, the electrical energy stored in the junction capacitance of the control end of the second switch 211 is quickly released. That is, the second fast discharge circuit 260 can provide a stable leakage path when the second switch 211 is repeatedly restarted.

[0042] Exemplarily, the second fast discharge circuit 260 may include a capacitor, and the shutdown signal may be a low-level signal. When the second control unit 220 sends a turn-on signal to the control terminal of the second switch 211, the capacitor is charged, enabling a slow startup of the output of the second control unit 220. When the second control unit 220 sends a turn-off signal to the control terminal of the second switch 211, the second fast discharge circuit 260 can be quickly turned on, thereby providing a low-impedance path. The energy stored in the capacitor of the second fast discharge circuit 260 is quickly released to prepare for the next slow startup. Furthermore, due to the junction capacitance of the second switch 211, when the second control unit 220 sends a low-level signal to the second switch 211, the voltage at the control terminal of the second switch 211 does not immediately drop to a low level. The second fast discharge circuit 260 provides a stable leakage path, allowing the voltage at the control terminal of the second switch 211 to drop rapidly, thereby ensuring that the second switch 211 can be quickly shut down and preventing voltage damage to subsequent circuits. In addition, by quickly discharging excess voltage, the second fast discharging circuit 260 can prevent damage to equipment due to overvoltage, thereby enhancing the safety and reliability of the power output protection circuit.

[0043] The technical solution of the embodiments of the present invention prevents the power supply output protection circuit from misactivating by utilizing the slow startup function of the first and second fast discharge circuits. Furthermore, the first and second fast discharge circuits ensure that the first and second switches are quickly turned off upon receiving a shutdown signal, thereby preventing damage to subsequent circuits caused by overvoltage, undervoltage, or overcurrent, effectively improving the safety and reliability of the power supply output protection circuit.

[0044] On the basis of the above embodiments, continue to refer to Figure 3Optionally, the first fast discharge circuit 160 includes: an eleventh resistor 161, a twelfth resistor 162, a third switch 163, a first capacitor 164, and a first diode 165. The eleventh resistor 161 is connected between the fourth terminal of the first control unit 120 and the control terminal of the third switch 163; the first terminal of the first diode 165 is connected to the fourth terminal of the first control unit 120, and the second terminal of the first diode 165 is connected to the first terminal of the third switch 163; the second terminal of the third switch 163 is connected to the ground terminal; the twelfth resistor 162 is connected between the second terminal of the first diode 165 and the output terminal of the first-stage output protection module 110; and the first capacitor 164 is connected between the first and second terminals of the third switch 163. The second fast discharge circuit 260 includes: a thirteenth resistor 261, a fourteenth resistor 262, a fourth switch 263, a second capacitor 264, and a second diode 265. The thirteenth resistor 261 is connected between the fourth end of the second control unit 220 and the control end of the fourth switch 263; the first end of the second diode 265 is connected to the fourth end of the second control unit 220, and the second end of the second diode 265 is connected to the first end of the fourth switch 263; the second end of the fourth switch 263 is connected to the ground end; the fourteenth resistor 262 is connected between the second end of the second diode 265 and the output end of the second-stage output protection module 210; the second capacitor 264 is connected between the first end and the second end of the fourth switch 263.

[0045] In an embodiment of the present invention, illustratively, when the first control unit 120 sends a turn-on signal to the control terminal of the first switch, and the turn-on signal is a high-level signal, the high-level signal can be transmitted through the first diode 165 to charge the first capacitor 164, causing the first control unit 120 to send the turn-on signal to the control terminal of the first switch to slow down. Therefore, the opening speed of the first switch 111 slows down until the first capacitor 164 is fully charged. The slow opening speed of the first switch 111 can reduce the risk of false protection caused by excessive output current of the first-stage output protection module 110 during the startup of the capacitive load. When the first control unit 120 sends a turn-off signal to the control terminal of the first switch 111, and the turn-off signal is a low-level signal, the low-level signal can be transmitted to the control terminal of the third switch 163, causing the third switch 163 to be driven to conduct, and the first capacitor 164 discharges to the ground terminal through the third switch 163, preparing for the next startup. The first diode 165 can ensure that the current in the first capacitor 164 does not flow back to reversely charge the first control unit 120. In the case of repeated restarts, when the output of the first control unit 120 is quickly pulled low, the twelfth resistor 162 provides a stable leakage path for the pin of the first control unit 120 .

[0046] Exemplarily, when the second control unit 220 sends a turn-on signal to the control end of the second switch, and the turn-on signal is a high-level signal, the high-level signal can be transmitted to the second capacitor 264 through the second diode 265 to charge, so that the second control unit 220 slows down the speed of sending the turn-on signal to the control end of the second switch. Therefore, the opening speed of the second switch 211 slows down until the second capacitor 264 is fully charged. The slow opening speed of the first switch 111 can reduce the risk of false protection caused by excessive output current of the second-stage output protection module 210 when the capacitive load is started. When the second control unit 220 sends a turn-off signal to the control end of the second switch, and the turn-off signal is a low-level signal, the low-level signal can be transmitted to the control end of the fourth switch 263, so that the fourth switch 263 is driven to turn on, and the second capacitor 264 flows to the ground end through the fourth switch 263 to discharge, preparing for the next startup. The second diode 265 can ensure that the current in the second capacitor 264 does not flow back to reversely charge the second control unit 220. In the case of repeated restarts, when the output of the second control unit 220 is quickly pulled low, the fourteenth resistor 262 provides a stable leakage path for the pin of the second control unit 220 .

[0047] On the basis of the above embodiments, continue to refer to Figure 3 Optionally, the delayed start circuit 270 includes: a third capacitor 272 and a third diode 271; the third capacitor 272 is connected between the second end of the second control unit 220 and the ground end; the first end of the third diode 271 is connected to the second end of the second control unit 220, and the second end of the third diode 271 is connected to the input end of the second output protection module 210.

[0048] In this embodiment of the present invention, when the first switch 111 in the first-stage output protection module 110 is turned on, the input terminal of the second-stage output protection module 210 is powered, and the third capacitor 272 begins charging. Before the voltage across the third capacitor 272 reaches the rated voltage, the fourth voltage monitored by the second undervoltage sampling circuit 240 remains below the fourth preset voltage. The second control unit 220 controls the second switch 211 to remain off until the third capacitor 272 is fully charged and the fourth voltage is greater than or equal to the fourth preset voltage, at which point the second switch 211 is turned on. This achieves a delayed turn-on of the second switch 211 of the second-stage output protection module 210.

[0049] On the basis of the above embodiments, continue to refer to Figure 3Optionally, the first control unit 120 further includes: a fourth capacitor 121; the fourth capacitor 121 is connected between the fifth terminal of the first control unit 120 and the ground terminal, and the fourth capacitor 121 is used to set the duration of time that the first control unit 120 monitors that the first current is greater than the first preset current. The second control unit 220 further includes: a fifth capacitor 221; the fifth capacitor 221 is connected between the fifth terminal of the second control unit 220 and the ground terminal, and the fifth capacitor 221 is used to set the duration of time that the second control unit 220 monitors that the second current is greater than the second preset current.

[0050] In an embodiment of the present invention, the fourth capacitor 121 is connected between the fifth end of the first control unit 120 and the ground end, and when the first current flows through the first control unit 120, the fourth capacitor 121 is charged according to the magnitude of the current. When the fourth capacitor 121 is fully charged, if the first current still exceeds the first preset current, the first control unit 120 deems that the first current output by the power supply 310 is overcurrent. The fifth capacitor 221 is connected between the fifth end of the second control unit 220 and the ground end, and when the second current flows through the second control unit 220, the fifth capacitor 221 is charged according to the magnitude of the current. When the fifth capacitor 221 is fully charged, if the second current still exceeds the second preset current, the second control unit 220 deems that the second current output by the first-level output protection module 110 is overcurrent.

[0051] The technical solution of the embodiments of the present invention uses a fourth capacitor and a fifth capacitor to respectively set the duration of overcurrent monitoring performed by the first and second control units on the first and second currents. This invention effectively reduces malfunctions caused by transient current fluctuations, thereby improving the reliability and safety of the entire power supply output protection circuit.

[0052] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0053] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A power output protection circuit, characterized in that: The power output protection circuit includes a first-level output protection module and a second-level output protection module; The input end of the first-stage output protection module is connected to a power supply, and the output end of the first-stage output protection module is connected to the input end of the second-stage output protection module; The first-stage output protection module includes a first switch connected between the input terminal and the output terminal; The first-stage output protection module is used to control the first switch to be turned on or off according to the voltage and / or current output by the power supply; The second-stage output protection module includes a second switch connected between the input end and the output end, and the second-stage output protection module is used to control the second switch to be turned on or off according to the voltage and / or current of the output of the first-stage output protection module; wherein, after the first switch is switched from the off state to the on state, the output end of the first-stage output protection module is powered on, and the second-stage output protection module is further used to control the second switch to be turned on according to the power-on voltage delay of the output end of the first-stage output protection module.

2. The power output protection circuit according to claim 1, wherein: The first-stage output protection module further includes: a first control unit, a first overvoltage sampling circuit, a first undervoltage sampling circuit, and a first current sampling circuit; A first end of the first overvoltage sampling circuit is connected to the power supply, a second end of the first overvoltage sampling circuit is connected to the first end of the first control unit, and a third end of the first overvoltage sampling circuit is connected to the ground end. The first overvoltage sampling circuit is used to detect the voltage output by the power supply and output a first voltage; A first end of the first undervoltage sampling circuit is connected to the power supply, an output end of the first undervoltage sampling circuit is connected to a second end of the first control unit, a third end of the first undervoltage sampling circuit is connected to the ground end, and the first undervoltage sampling circuit is used to detect the output voltage of the power supply and output a second voltage; The first current sampling circuit is connected between the power supply and the first switch, and an output terminal of the first current sampling circuit is connected to a third terminal of the first control unit. The first current sampling circuit is used to detect a current at the output terminal of the power supply and output a first current. The fourth end of the first control unit is connected to the control end of the first switch, and the first control unit sends a shutdown signal to the control end of the first switch when the first voltage is greater than a first preset voltage, the second voltage is less than a second preset voltage and / or the first current is greater than a first preset current.

3. The power output protection circuit according to claim 1, wherein: The second-stage output protection module further includes: a second overvoltage sampling circuit, a second undervoltage sampling circuit, a second current sampling circuit, a second control unit and a delayed start circuit; A first end of the second overvoltage sampling circuit is connected to the output end of the first-stage output protection module, a second end of the second overvoltage sampling circuit is connected to the first end of the second control unit, and a third end of the second overvoltage sampling circuit is connected to the ground end. The second overvoltage sampling circuit detects the voltage at the output end of the first-stage output protection module and outputs a third voltage. A first end of the second undervoltage sampling circuit is connected to the output end of the first-stage output protection module, the output end of the second undervoltage sampling circuit is connected to the second end of the second control unit, a third end of the second undervoltage sampling circuit is connected to the ground end, and the second undervoltage sampling circuit is used to detect the voltage of the output end of the first-stage output protection module and output a fourth voltage; The second current sampling circuit is connected between the first-stage output protection module and the second switch, and the output end of the second current sampling circuit is connected to the third end of the second control unit. The second current sampling circuit is used to detect the current at the output end of the first-stage output protection module and output a second current; A first end of the delayed start circuit is connected to the output end of the first-stage output protection module, a second end of the delayed start circuit is connected to the output end of the second undervoltage sampling circuit, and a third end of the delayed start circuit is connected to the ground end. The delayed start circuit is configured to delay the rise of the voltage output by the second undervoltage sampling circuit to a stable voltage according to the power-on voltage of the output end of the first-stage output protection module; The fourth end of the second control unit is connected to the control end of the second switch, and the second control unit is used to send a shutdown signal to the control end of the second switch when the third voltage is greater than the third preset voltage, the fourth voltage is less than the fourth preset voltage and / or the second current is greater than the first preset current.

4. The power output protection circuit according to claim 2, wherein: The first overvoltage sampling circuit includes a first resistor and a second resistor, the first resistor and the second resistor are connected in series, and a connection point between the first resistor and the second resistor is connected to a first end of the first control unit; The first undervoltage sampling circuit includes a third resistor and a fourth resistor, the third resistor and the fourth resistor are connected in series, and the connection point between the third resistor and the fourth resistor is connected to the second end of the first control unit; The first current sampling circuit includes a fifth resistor, the fifth resistor is connected in series between the output terminal of the power supply and the first terminal of the first switch, and the first terminal of the fifth resistor is connected to the third terminal of the first control unit; The second end of the first switch is connected to the output end of the first-level protection output module, and the control end of the first switch is connected to the fourth end of the first control unit.

5. The power output protection circuit according to claim 3, wherein: The second overvoltage sampling circuit includes a sixth resistor and a seventh resistor, the sixth resistor and the seventh resistor are connected in series, and a connection point between the sixth resistor and the seventh resistor is connected to the first end of the second control unit; The second undervoltage sampling circuit includes an eighth resistor and a ninth resistor, the eighth resistor and the ninth resistor are connected in series, and a connection point between the eighth resistor and the ninth resistor is connected to the second end of the second control unit; The second current sampling circuit includes a tenth resistor, the tenth resistor is connected in series between the output terminal of the first-stage output protection module and the first terminal of the second switch, and the first terminal of the tenth resistor is connected to the third terminal of the second control unit; The second end of the second switch is connected to the output end of the second-stage output protection module, and the control end of the second switch is connected to the fourth end of the second control unit.

6. The power output protection circuit according to claim 2, wherein: The first-stage output protection module further includes: a first fast discharge circuit; A first end of the first fast discharge circuit is connected to a fourth end of the first control unit, a second end of the first fast discharge circuit is connected to an output end of the first-stage output protection module, and a third end of the first fast discharge circuit is connected to the ground end. The first fast discharge circuit is configured to charge when the first control unit sends an on signal to the control end of the first switch, and discharge when the first control unit sends an off signal.

7. The power output protection circuit according to claim 3, wherein: The second-stage output protection module further includes: a second fast discharge circuit; A first end of the second fast discharge circuit is connected to a fourth end of the second control unit, a second end of the second fast discharge circuit is connected to the output end of the second-stage output protection module, and a third end of the second fast discharge circuit is connected to the ground end. The second fast discharge circuit is configured to charge when the second control unit sends an on signal to the control end of the second switch, and discharge when the second control unit sends an off signal.

8. The power output protection circuit according to claim 6 or claim 7, characterized in that: The first fast discharge circuit includes: an eleventh resistor, a twelfth resistor, a third switch, a first capacitor and a first diode; The eleventh resistor is connected between the fourth terminal of the first control unit and the control terminal of the third switch; the first terminal of the first diode is connected to the fourth terminal of the first control unit, and the second terminal of the first diode is connected to the first terminal of the third switch; the second terminal of the third switch is connected to the ground terminal; the twelfth resistor is connected between the second terminal of the first diode and the output terminal of the first-stage output protection module; and the first capacitor is connected between the first terminal and the second terminal of the third switch; The second fast discharge circuit includes: a thirteenth resistor, a fourteenth resistor, a fourth switch, a second capacitor and a second diode; The thirteenth resistor is connected between the fourth end of the second control unit and the control end of the fourth switch; the first end of the second diode is connected to the fourth end of the second control unit, and the second end of the second diode is connected to the first end of the fourth switch; the second end of the fourth switch is connected to the ground end; the fourteenth resistor is connected between the second end of the second diode and the output end of the second-stage output protection module; and the second capacitor is connected between the first end and the second end of the fourth switch.

9. The power output protection circuit according to claim 7, wherein: The delayed start circuit includes: a third capacitor and a third diode; The third capacitor is connected between the second terminal of the second control unit and the ground terminal; A first end of the third diode is connected to a second end of the second control unit, and a second end of the third diode is connected to an input end of the second output protection module.

10. The power output protection circuit according to claim 4 or claim 5, characterized in that: The first control unit further includes: a fourth capacitor; the fourth capacitor is connected between the fifth terminal of the first control unit and the ground terminal, and the fourth capacitor is used to set the duration of the first control unit monitoring that the first current is greater than the first preset current; The second control unit further includes: a fifth capacitor; the fifth capacitor is connected between the fifth end of the second control unit and the ground end, and the fifth capacitor is used to set the duration for which the second control unit monitors that the second current is greater than the second preset current.

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