Load decoupling circuit and power supply circuit

Abstract

The utility model discloses a load decoupling circuit and a power supply circuit, and relates to the technical field of power supply, the load decoupling circuit comprises a first switch circuit, a second switch circuit and a fault detection circuit; in a closed-loop circuit formed by the secondary winding of the transformer, the load, the first switching circuit and the second switching circuit, the fault detection circuit can judge whether the load has a short-circuit fault or not according to the voltage at the two ends of the secondary winding. When the load has a short-circuit fault, the fault detection circuit automatically controls the first switching circuit and the second switching circuit to disconnect a bidirectional current transmission channel between the secondary winding of the transformer and the load, thereby realizing automatic decoupling of the load. And when the load returns to a normal state, the first switching circuit and the second switching circuit can be automatically controlled through the fault detection circuit to recover the connection between the transformer and the load. The circuit can be prevented from being damaged by current generated by a load fault, quick automatic coupling can be realized when the load is recovered, and the maintenance cost and the time cost are saved.

Description

Technical Field

[0001] This application relates to the field of power supply technology, and in particular to a load decoupling circuit and a power supply circuit. Background Technology

[0002] In existing technologies, for scenarios requiring high-to-low voltage conversion, an isolated power supply topology is typically used. This involves coupling the DC chopper circuit to the load via a transformer. If a short-circuit fault occurs in the load of the downstream circuit, excessive current will be generated in the downstream circuit. Due to the transformer coupling, this excessive current will also affect the upstream circuit, potentially damaging both the upstream circuit and the transformer in severe cases.

[0003] Typically, a switching device is placed between the load and the secondary winding of the transformer. The electrical connection between the two is controlled by adjusting the on / off state of this switching device. However, common switching devices, such as MOSFETs, have a body diode connected in reverse parallel in their design, which means they cannot completely cut off the current transmission between positive and negative polarities. Therefore, when a short-circuit fault occurs in the load and the polarity of the transformer's secondary winding changes, the decoupling between the transformer and the load cannot be completed in a timely and effective manner, and the resulting current can still damage the upstream circuitry and the transformer. Utility Model Content

[0004] The main objective of this application is to provide a load decoupling circuit and a power supply circuit, which aims to solve the technical problem of how to automatically decouple the transformer from the load when a short circuit occurs in the load connected to the transformer, and how to automatically couple the transformer from the load when the load returns to normal.

[0005] To achieve the above objectives, embodiments of this application provide a load decoupling circuit, which includes: a first switching circuit, a second switching circuit, and a fault detection circuit;

[0006] The first input terminal of the fault detection circuit is connected to the first terminal of the load and the first terminal of the secondary winding of the transformer, respectively. The output terminal of the fault detection circuit is connected to the control terminal of the first switching circuit and the control terminal of the second switching circuit, respectively. The input terminal of the first switching circuit is connected to the second terminal of the secondary winding of the transformer. The output terminal of the first switching circuit is connected to the output terminal of the second switching circuit and the second input terminal of the fault detection circuit. The input terminal of the second switching circuit is connected to the second terminal of the load.

[0007] The fault detection circuit is used to determine whether the load has failed based on the voltage across the secondary winding, and to shut off the first switching circuit and the second switching circuit when the load fails, thereby disconnecting the connection between the load and the transformer; and / or, to turn on the first switching circuit and the second switching circuit when the load recovers from a fault state to a normal state, thereby restoring the connection between the load and the transformer.

[0008] In one embodiment, the load decoupling circuit further includes: a controller;

[0009] The controller is connected to the enable terminal of the fault detection circuit. When the number of times the load fails within a preset time exceeds a preset number of failures, the controller pulls the enable signal of the fault detection circuit low, thereby keeping the load disconnected from the transformer.

[0010] In one embodiment, the controller is further configured to adjust the enable signal of the fault detection circuit when receiving an externally transmitted control command, so as to keep the load and the transformer in a conducting state or in a disconnected state.

[0011] In one embodiment, the fault detection circuit includes: a first resistor and a second resistor;

[0012] The first end of the first resistor is connected to the first end of the load and the first end of the secondary winding of the transformer, respectively. The second end of the first resistor is connected to the first end of the second resistor, the control terminal of the first switching circuit and the control terminal of the second switching circuit, respectively. The second end of the second resistor is connected to the output terminal of the first switching circuit and the output terminal of the second switching circuit, respectively.

[0013] In one embodiment, the fault detection circuit further includes: a first diode;

[0014] The anode of the first diode is connected to the first terminal of the load and the first terminal of the secondary winding of the transformer, respectively, and the cathode of the first diode is connected to the first terminal of the first resistor.

[0015] In one embodiment, the first switching circuit includes: a first NMOS transistor;

[0016] The gate of the first NMOS transistor is connected to the control terminal of the second switching circuit and the output terminal of the fault detection circuit. The source of the first NMOS transistor is connected to the second input terminal of the fault detection circuit and the output terminal of the second switching circuit. The drain of the first NMOS transistor is connected to the second terminal of the secondary winding of the transformer.

[0017] In one embodiment, the second switching circuit includes: a second NMOS transistor;

[0018] The gate of the second NMOS transistor is connected to the control terminal of the first switching circuit and the output terminal of the fault detection circuit. The source of the second NMOS transistor is connected to the second input terminal of the fault detection circuit and the output terminal of the first switching circuit. The drain of the second NMOS transistor is connected to the second terminal of the load.

[0019] In addition, to achieve the above objectives, this application also provides a power supply circuit, which includes: a DC chopper circuit, a transformer, and a load decoupling circuit as described above;

[0020] The output terminal of the DC chopper circuit is connected to the primary winding of the transformer, the input terminal of the load decoupling circuit is connected to the secondary winding of the transformer, and the output terminal of the load decoupling circuit is connected to the load.

[0021] The load decoupling circuit is used to determine whether the load has failed based on the voltage across the secondary winding, and disconnect the connection between the load and the transformer when the load fails; and / or, to restore the connection between the load and the transformer when the load is detected to have recovered from a fault state to a normal state.

[0022] Furthermore, in this embodiment, the power supply circuit further includes multiple load decoupling circuits, and the transformer further includes multiple secondary windings:

[0023] The input terminal of each load decoupling circuit is connected to a corresponding secondary winding, and the output terminal of each load decoupling circuit is connected to a corresponding load.

[0024] This application provides a load decoupling circuit and a power supply circuit. The load decoupling circuit includes a first switching circuit, a second switching circuit, and a fault detection circuit. The first input terminal of the fault detection circuit is connected to a first terminal of the load and a first terminal of the secondary winding of a transformer. The output terminal of the fault detection circuit is connected to the control terminal of the first switching circuit and the control terminal of the second switching circuit. The input terminal of the first switching circuit is connected to the second terminal of the secondary winding of the transformer. The output terminal of the first switching circuit is connected to the output terminal of the second switching circuit and the second input terminal of the fault detection circuit. The input terminal of the second switching circuit is connected to the second terminal of the load. The fault detection circuit is used to determine whether the load has failed based on the voltage across the secondary winding. When the load fails, it shuts off the first switching circuit and the second switching circuit to disconnect the connection between the load and the transformer. And / or, it is used to turn on the first switching circuit and the second switching circuit when the load recovers from a fault state to a normal state to restore the connection between the load and the transformer.

[0025] In a closed-loop circuit consisting of the transformer's secondary winding, load, first switching circuit, and second switching circuit, the fault detection circuit can determine whether a short-circuit fault has occurred in the load based on the voltage across the secondary winding. If a short-circuit fault occurs in the load, the fault detection circuit automatically controls the first and second switching circuits to disconnect the bidirectional current transmission path between the transformer's secondary winding and the load, achieving automatic decoupling of the load. Furthermore, when the load returns to normal operation, the fault detection circuit automatically controls the first and second switching circuits to restore the connection between the transformer and the load. This prevents current damage to the circuit caused by load faults and allows for rapid and automatic coupling upon load recovery, saving maintenance costs and time. Attached Figure Description

[0026] 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.

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a structural connection diagram provided for Embodiment 1 of the load decoupling circuit of this application;

[0029] Figure 2 This is a circuit connection diagram provided for Embodiment 2 of the load decoupling circuit of this application;

[0030] Figure 3 This is a circuit connection diagram provided for Embodiment 3 of the load decoupling circuit of this application;

[0031] Figure 4 The circuit connection diagram provided for Embodiment 1 of the power supply circuit of this application.

[0032] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0033] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0034] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0035] This application presents a load decoupling circuit according to a first embodiment. Please refer to [link / reference]. Figure 1 The load 40 decoupling circuit includes: a first switching circuit 10, a second switching circuit 20, and a fault detection circuit 30;

[0036] The first input terminal of the fault detection circuit 30 is connected to the first terminal of the load 40 and the first terminal of the secondary winding of the transformer, respectively. The output terminal of the fault detection circuit 30 is connected to the control terminal of the first switching circuit 10 and the control terminal of the second switching circuit 20, respectively. The input terminal of the first switching circuit 10 is connected to the second terminal of the secondary winding of the transformer. The output terminal of the first switching circuit 10 is connected to the output terminal of the second switching circuit 20 and the second input terminal of the fault detection circuit 30. The input terminal of the second switching circuit 20 is connected to the second terminal of the load 40.

[0037] The fault detection circuit 30 is used to determine whether the load 40 has failed based on the voltage across the secondary winding, and to shut off the first switching circuit 10 and the second switching circuit 20 when the load 40 fails, thereby disconnecting the connection between the load 40 and the transformer; and / or, to turn on the first switching circuit 10 and the second switching circuit 20 when the load 40 recovers from the fault state to the normal state, thereby restoring the connection between the load 40 and the transformer.

[0038] It should be noted that, in this embodiment, both the first switching circuit 10 and the second switching circuit 20 refer to circuits with switching devices that can control the on / off state of a current transmission channel in a single direction. More specifically, the first switching circuit 10 can control the current transmission from its input terminal to its output terminal. When the voltage received at the control terminal of the first switching circuit 10 is lower than a voltage threshold, it can prevent current from flowing from its input terminal to its output terminal without affecting the current transmission from its output terminal to its input terminal. Correspondingly, the second switching circuit 20 can also control the current transmission from its input terminal to its output terminal. When the voltage received at the control terminal of the second switching circuit 20 is lower than a voltage threshold, it can also prevent current from flowing from its input terminal to its output terminal without affecting the current transmission from its output terminal to its input terminal.

[0039] It is easy to understand that in this embodiment, the secondary winding of the transformer and the load 40 form a closed loop, allowing the secondary winding of the transformer to transfer electrical energy to the load 40. This energy transfer can typically be represented as a current formed by the superposition of direct current (DC) and alternating current (AC). The current during the positive half-cycle of both DC and AC can be considered the first current, flowing from the first end of the transformer's secondary winding to the first end of the load 40 (the second end of the load 40 flows to the second end of the secondary winding); the current during the negative half-cycle of AC can be considered the second current, flowing from the first end of the load 40 to the second end of the transformer's secondary winding (the second end of the secondary winding flows to the second end of the load 40).

[0040] It should be noted that in this embodiment, the first switching circuit 10 and the second switching circuit 20 are connected in series between the second end of the secondary winding and the second end of the load 40. This means that the on / off state of the first switching circuit 10 and the second switching circuit 20 can be controlled to control the flow of two currents (the first current and the second current) between the second end of the secondary winding and the second end of the load 40. In the series structure formed by the first switching circuit 10 and the second switching circuit 20, the output terminals of the first switching circuit 10 and the second switching circuit 20 are connected. Therefore, if both the first switching circuit 10 and the second switching circuit 20 are simultaneously turned off, neither the first current nor the second current, as described above, can be transmitted between the secondary winding of the transformer and the load 40.

[0041] It is easy to understand that in this embodiment, the fault detection circuit 30 can collect the voltage difference between its first input terminal and second input terminal, determine the current operating state of the load 40 based on the magnitude of the collected voltage difference, and control the on / off state of the first switching circuit 10 and the second switching circuit 20 according to the determination result. When the voltage difference between the first input terminal and the second input terminal is higher than the voltage threshold, it can be determined that the current load 40 is in a normal state, and the first switching circuit 10 and the second switching circuit 20 are controlled to enter the conducting state accordingly; when the voltage difference between the first input terminal and the second input terminal is not higher than the voltage threshold, it can be determined that the current load 40 is in a fault state, and the first switching circuit 10 and the second switching circuit 20 are controlled to enter the off state accordingly. When the load 40 is in a normal state, the fault detection circuit 30 controls both the first switching circuit 10 and the second switching circuit 20 to be in the conducting state. Therefore, it can be considered that the first input terminal and the second input terminal of the fault detection circuit 30 are respectively connected to the first and second terminals of the secondary winding (or the first and second terminals of the load 40). At this time, the voltage collected by the fault detection circuit 30 can be regarded as the voltage across the secondary winding (or the voltage across the load 40).

[0042] In practical implementation, if a short-circuit fault occurs on the load 40 side, the voltage across the secondary winding (voltage across the load 40) will drop sharply, and the voltage difference collected by the fault detection circuit 30 will also drop sharply below the voltage threshold. At this time, the fault detection circuit 30 automatically controls the first switching circuit 10 and the second switching circuit 20 to enter the off state. The first switching circuit 10 will shut off the current transmission path from its input terminal to its output terminal, that is, shut off the first current transmission path corresponding to the second terminal of the transformer's secondary winding to the second terminal of the load 40, so as to prevent the transmission of a second current between the transformer's secondary winding and the load 40; at the same time, the second switching circuit 20 will shut off the current transmission path from its input terminal to its output terminal, that is, shut off the second current transmission path corresponding to the second terminal of the load 40 to the second terminal of the transformer's secondary winding, so as to prevent the transmission of a first current between the load 40 and the transformer's secondary winding. At this point, since the bidirectional current transmission path between the transformer's secondary winding and the load 40 is cut off, neither the first nor the second current can be transmitted between the transformer's secondary winding and the load 40. This can also be understood as neither alternating current nor direct current being able to be transmitted between the transformer's secondary winding and the load 40, thus decoupling is achieved between the transformer and the load 40. The transformer's secondary winding will not receive excessive transient current due to the short circuit in the load 40, thereby protecting the transformer's safety and ensuring the safety of the entire power supply circuit.

[0043] It is worth noting that in this embodiment, when the first switching circuit 10 enters the off state, it does not prevent current from flowing from its output to its input. At this time, the secondary winding can form a connection loop with the fault detection circuit 30 and the first switching circuit 10, and the fault detection circuit 30 can still detect the voltage across the secondary winding. When the fault detection circuit 30 detects that the voltage across the secondary winding has recovered to above the voltage threshold, it can be determined that the current load 40 has recovered from the fault state to the normal state. Then, the fault detection circuit 30 can also control the first switching circuit 10 and the second switching circuit 20 to re-enter the conducting state to restore the connection between the transformer's secondary winding and the load 40, realize the automatic coupling between the transformer and the load 40, quickly restore the power supply to the load 40, and enable the load 40 to work normally.

[0044] This application provides a load decoupling circuit, comprising: a first switching circuit, a second switching circuit, and a fault detection circuit; the first input terminal of the fault detection circuit is connected to a first terminal of the load and a first terminal of the secondary winding of a transformer, the output terminal of the fault detection circuit is connected to the control terminal of the first switching circuit and the control terminal of the second switching circuit, the input terminal of the first switching circuit is connected to the second terminal of the secondary winding of the transformer, the output terminal of the first switching circuit is connected to the output terminal of the second switching circuit and the second input terminal of the fault detection circuit, and the input terminal of the second switching circuit is connected to the second terminal of the load; the fault detection circuit is used to determine whether the load has failed based on the voltage across the secondary winding, and to shut off the first and second switching circuits when the load fails, thereby disconnecting the connection between the load and the transformer; and / or, to turn on the first and second switching circuits when the load recovers from a fault state to a normal state, thereby restoring the connection between the load and the transformer. In a closed-loop circuit formed by the secondary winding of the transformer, the load, the first switching circuit, and the second switching circuit, the fault detection circuit can determine whether the load has experienced a short-circuit fault based on the voltage across the secondary winding. When a short-circuit fault occurs in the load, the fault detection circuit automatically controls the first and second switching circuits to disconnect the bidirectional current transmission path between the transformer secondary winding and the load, achieving automatic decoupling of the load. Furthermore, when the load returns to normal operation, the fault detection circuit automatically controls the first and second switching circuits to restore the connection between the transformer and the load. This prevents current damage to the circuit caused by load faults and allows for rapid automatic coupling upon load recovery, saving maintenance and time costs.

[0045] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in Embodiment 1 above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 2 The load 40 decoupling circuit further includes: a controller 50;

[0046] The controller 50 is connected to the enable terminal of the fault detection circuit 30. When the number of times the load 40 fails within a preset time exceeds a preset number of failures, the controller pulls the enable signal of the fault detection circuit 30 low, so that the load 40 and the transformer remain disconnected.

[0047] It should be noted that, in this embodiment, the enable terminal of the fault detection circuit 30 can also be the output terminal of the fault detection circuit 30, both of which are used to output an electrical signal representing the magnitude of the voltage across the secondary winding. The electrical signal output by the enable terminal can be understood as the enable signal described above.

[0048] In practical implementation, the controller 50 can integrate a timer and a counter. The controller 50 can collect the enable signal output from the enable terminal of the fault detection circuit 30 and record the number of times the voltage of the enable signal changes below the voltage threshold, i.e., the number of times the load 40 fails, through the internally integrated counter. If the number of failures recorded by the counter exceeds the preset number of failures within the preset time period, it can be considered that the current fault of the load 40 is unrecoverable. Correspondingly, a low-level electrical signal can be applied to the enable terminal of the fault detection circuit 30, forcing the enable terminal of the fault detection circuit 30 to be in a low-level state. When the enable terminal of the fault detection circuit 30 is in a low-level state, its output terminal will also be in a low-level state. At this time, both the first switching circuit 10 and the second switching circuit 20 will be forcibly controlled to be in a turned-off state, keeping the connection between the load 40 and the transformer disconnected and no longer automatically recovering.

[0049] Furthermore, in this embodiment, the controller 50 is also used to adjust the enable signal of the fault detection circuit 30 when receiving an externally transmitted control command, so that the load 40 and the transformer are kept in a conducting state or a disconnected state.

[0050] It should be noted that in this embodiment, the controller 50 can also be connected to an external device with control functions (not shown in the figure) to receive control commands sent by the external device and adjust the enable signal of the fault detection circuit 30 according to the control commands. This allows the controller to actively control the on / off state of the first switching circuit 10 and the second switching circuit 20 through the fault detection circuit 30, i.e., control the connection state between the load 40 and the transformer.

[0051] For example, when the load 40 is not required to operate, the controller 50 can, based on the received corresponding control command, force the enable signal of the enable terminal of the fault detection circuit 30 to enter a low-level state. At this time, the output terminal of the fault detection circuit 30 also enters a low-level state, causing the first switch circuit 10 and the second switch circuit 20 to enter a turn-off state, ultimately interrupting the connection between the load 40 and the transformer. When the load 40 is required to operate, the controller 50 can, based on the received corresponding control command, force the enable signal of the enable terminal of the fault detection circuit 30 to enter a high-level state. At this time, the output terminal of the fault detection circuit 30 also enters a high-level state, causing the first switch circuit 10 and the second switch circuit 20 to enter a conduction state, ultimately restoring the connection between the load 40 and the transformer.

[0052] Furthermore, in this embodiment, the fault detection circuit 30 includes: a first resistor R1 and a second resistor R2;

[0053] The first end of the first resistor R1 is connected to the first end of the load 40 and the first end of the secondary winding of the transformer, respectively. The second end of the first resistor R1 is connected to the first end of the second resistor R2, the control terminal of the first switching circuit 10 and the control terminal of the second switching circuit 20, respectively. The second end of the second resistor R2 is connected to the output terminal of the first switching circuit 10 and the output terminal of the second switching circuit 20, respectively.

[0054] It should be noted that, in this embodiment, when both the first switching circuit 10 and the second switching circuit 20 are on, the voltage divider structure formed by the first resistor R1 and the second resistor R2 can divide the voltage difference across the secondary winding. The voltage divided across the second resistor R2 is the voltage output to the control terminals of the first switching circuit 10 and the second switching circuit 20. The resistance values ​​of the first resistor R1 and the second resistor R2 can be adjusted to change the voltage division ratio, so that when the load 40 does not experience a short circuit fault, the voltage output by the fault detection circuit 30 can keep the first switching circuit 10 and the second switching circuit 20 on. In this way, the first switching circuit 10 and the second switching circuit 20 can conduct a bidirectional current transmission channel between the second terminal of the load 40 and the second terminal of the transformer's secondary winding, thereby enabling the transformer's secondary winding to normally provide power to the load 40.

[0055] Furthermore, in this embodiment, the fault detection circuit 30 further includes: a first diode D1;

[0056] The anode of the first diode D1 is connected to the first terminal of the load 40 and the first terminal of the secondary winding of the transformer, respectively, and the cathode of the first diode D1 is connected to the first terminal of the first resistor R1.

[0057] It should be understood that in this embodiment, at certain moments, such as the instant when the transformer is coupled to the load 40, a spike current may be generated, causing the instantaneous voltage difference between the first resistor R1 and the second resistor R2 to be negative. The voltage applied to the control terminals of the first switching circuit 10 and the second switching circuit 20 will also become negative, which may cause the first switching circuit 10 and the second switching circuit 20 to mistakenly enter the off state, cutting off the bidirectional current transmission channel between the secondary winding of the transformer and the load 40.

[0058] It is easy to understand that, in this embodiment, a first diode D1 can also be set between the first end of the first resistor R1 and the first end of the load 40 and the first end of the secondary winding. The cathode of the first diode D1 is connected to the first end of the first resistor R1 to prevent a second current, such as a spike current, from affecting the voltage difference value collected by the fault detection circuit 30. At this time, the normal range of the voltage difference value collected by the first resistor R1 and the second resistor R2 is above the voltage threshold. When the load 40 is short-circuited, the collected voltage difference value is 0V, so that the voltage output to the first switching circuit 10 and the second switching circuit 20 can only be 0V (the first switching circuit 10 and the second switching circuit 20 will not be turned on), thereby ensuring that it will precisely cut off the bidirectional current transmission channel between the secondary winding and the load 40 only when the load 40 is open-circuited, thus achieving decoupling of the faulty load 40.

[0059] Furthermore, the fault detection circuit 30 also includes: a first capacitor C1;

[0060] The first end of the first capacitor C1 is connected to the second end of the first resistor R1, the first end of the second resistor R2, the control terminal of the first switching circuit 10, and the control terminal of the second switching circuit 20, respectively. The second end of the first capacitor C1 is connected to the second end of the second resistor R2, the output terminal of the first switching circuit 10, and the output terminal of the second switching circuit 20, respectively.

[0061] It should be noted that in this embodiment, since there is AC power transmission between the secondary winding of the transformer and the load 40, even if the first diode D1 filters out the second current, the voltage output by the voltage divider structure of the first resistor R1 and the second resistor R2 will fluctuate to a certain extent, which may result in a low output voltage that prevents the first switching circuit 10 and the second switching circuit 20 from entering the conduction state.

[0062] It is easy to understand that, in this embodiment, a first capacitor C1 can be connected in parallel across the second resistor R2 to make the output voltage more stable through the charging and discharging characteristics of the first capacitor C1.

[0063] In practical implementation, when the load 40 is not short-circuited, the first capacitor C1 can be charged first. After the first capacitor C1 is fully charged, the output voltage can stably keep the first switching circuit 10 and the second switching circuit 20 in a conducting state. The first switching circuit 10 and the second switching circuit 20 can conduct the bidirectional current transmission channel between the secondary winding of the transformer and the load 40. When the load 40 is short-circuited, the characteristic that the output terminal to the input terminal of the first switching circuit 10 is always conducting can be used to discharge the first capacitor C1. After the first capacitor C1 is fully discharged, the voltage across the first capacitor C1 is 0V. Therefore, the voltage output of the voltage divider structure of the first resistor R1 and the second resistor R2 also stabilizes to 0V, causing the first switching circuit 10 and the second switching circuit 20 to enter the off state, cutting off the bidirectional current transmission channel between the secondary winding of the transformer and the load 40.

[0064] It is worth noting that in this embodiment, the charging and discharging characteristics of the first capacitor C1 are utilized so that the load 40 is automatically decoupled only when the short circuit duration of the load 40 reaches a certain time, avoiding misjudgments caused by sudden current changes. Specifically, the charging and discharging time of the first capacitor C1 can be controlled by adjusting its capacitance value.

[0065] Based on the first and / or second embodiments of this application, in the third embodiment of this application, the content that is the same as or similar to that in embodiments one and two above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 3 The first switching circuit 10 includes: a first NMOS transistor Qn1;

[0066] The gate of the first NMOS transistor Qn1 is connected to the control terminal of the second switching circuit 20 and the output terminal of the fault detection circuit 30. The source of the first NMOS transistor Qn1 is connected to the second input terminal of the fault detection circuit 30 and the output terminal of the second switching circuit 20. The drain of the first NMOS transistor Qn1 is connected to the second end of the secondary winding of the transformer.

[0067] It should be noted that, in this embodiment, the first switching circuit 10 can be a simple circuit composed solely of a switching transistor with unidirectional conduction control function, or a more complex circuit composed of a switching transistor with the same function combined with other devices.

[0068] As an example, a single NMOS transistor Qn1 can be used as the first switching circuit 10. The gate of the first NMOS transistor Qn1 is used as the control terminal of the first switching circuit 10, and is connected to the control terminal of the second switching circuit 20 and the output terminal of the fault detection circuit 30, respectively. The source of the first NMOS transistor Qn1 is used as the output terminal of the first switching circuit 10, and is connected to the output terminal of the second switching circuit 20. The drain of the first NMOS transistor Qn1 is used as the input terminal of the first switching circuit 10, and is connected to the second terminal of the secondary winding. When the gate of the first NMOS transistor Qn1 is turned on due to a voltage not lower than the turn-on threshold, the current can flow from the drain to the source or from the source to the drain. However, when the gate of the first NMOS transistor Qn1 is turned off due to a voltage lower than the turn-on threshold, the current cannot flow from the drain to the source, but can only flow from the source to the drain through its internal body diode.

[0069] Furthermore, in this embodiment, the second switching circuit 20 includes: a second NMOS transistor Qn2;

[0070] The gate of the second NMOS transistor Qn2 is connected to the control terminal of the first switching circuit 10 and the output terminal of the fault detection circuit 30. The source of the second NMOS transistor Qn2 is connected to the second input terminal of the fault detection circuit 30 and the output terminal of the first switching circuit 10. The drain of the second NMOS transistor Qn2 is connected to the second terminal of the load 40.

[0071] It should be noted that, in this embodiment, similar to the case of the first switch circuit 10, the second switch circuit 20 can be a simple circuit composed solely of a switch transistor with unidirectional conduction control function, or a more complex circuit composed of a switch transistor with the same function combined with other devices.

[0072] As an example, a second NMOS transistor Qn2 can be used as a single device as the second switching circuit 20. The gate of the second NMOS transistor Qn2 is used as the control terminal of the second switching circuit 20, and is connected to the control terminal of the first switching circuit 10 and the output terminal of the fault detection circuit 30, respectively. The source of the second NMOS transistor Qn2 is used as the output terminal of the second switching circuit 20, and is connected to the output terminal of the first switching circuit 10. The drain of the second NMOS transistor Qn2 is used as the input terminal of the second switching circuit 20, and is connected to the second terminal of the load 40. When the gate of the second NMOS transistor Qn2 is turned on due to a voltage not lower than the turn-on threshold, the current can flow from the drain to the source or from the source to the drain. However, when the gate of the second NMOS transistor Qn2 is turned off due to a voltage lower than the turn-on threshold, the current cannot flow from the drain to the source, but can only flow from the source to the drain through its internal body diode.

[0073] Furthermore, to achieve the above objectives, this application also proposes a power supply circuit, please refer to... Figure 4 The power supply circuit includes: a DC chopper circuit 200, a transformer, and a load decoupling circuit 100 as described above;

[0074] The output terminal of the DC chopper circuit 200 is connected to the primary winding of the transformer, the input terminal of the load decoupling circuit 100 is connected to the secondary winding of the transformer, and the output terminal of the load decoupling circuit 100 is connected to the load 40.

[0075] The load decoupling circuit 100 is used to determine whether the load 40 has failed based on the voltage across the secondary winding, and to disconnect the connection between the load 40 and the transformer when the load 40 fails; and / or, to restore the connection between the load 40 and the transformer when the load 40 is detected to have recovered from a fault state to a normal state.

[0076] It should be understood that when a load of 40V is short-circuited, the voltage across its terminals will drop rapidly to 0V, while the current will rise sharply. Excessive current will cause the transformer windings to experience significant stress, potentially leading to winding deformation or breakage. Simultaneously, excessive current will also cause the winding temperature to rise sharply. Increased transformer temperature reduces insulation, potentially causing damage due to overheating. Furthermore, the resulting excessive current will also impact the upstream circuitry, affecting its performance.

[0077] It should be noted that in this embodiment, the DC chopper circuit 200, the transformer, and the load 40 can form an isolated DC chopper topology. The DC chopper circuit 200, after stepping up or stepping down the voltage through the transformer, supplies power to the load 40 connected to the downstream stage. A load decoupling circuit 100, as described above, is provided between the transformer and the load 40. The load decoupling circuit 100 can detect whether a short circuit fault has occurred on the load 40 side by detecting the voltage across the secondary winding. When the voltage across the secondary winding is detected to be 0V (or below the voltage threshold), it can be determined that a short circuit has occurred in the load 40. Then, the first switching circuit 10 and the second switching circuit 20 internally disconnect the first current transmission channel and the second current transmission channel between the transformer and the load 40, automatically decoupling the transformer from the load 40. Through this mechanism, it can be ensured that the load 40 can be quickly decoupled from the transformer after a short circuit fault occurs, preventing excessive current from damaging the transformer and the upstream circuit (DC chopper circuit 200), thus improving the safety of the entire power supply circuit.

[0078] It is worth noting that the load decoupling circuit 100 can continue to detect the voltage across the secondary winding after disconnecting the load 40 from the secondary winding, and when the voltage across the secondary winding is detected to recover (not lower than the voltage threshold), it can restore the first current transmission channel and the second current transmission channel between the transformer and the load 40, thereby enabling the transformer to supply power to the load 40 again.

[0079] Furthermore, in this embodiment, the power supply circuit further includes multiple load decoupling circuits 100, and the transformer further includes multiple secondary windings:

[0080] The input terminal of each load decoupling circuit 100 is connected to a corresponding secondary winding, and the output terminal of each load decoupling circuit 100 is connected to a corresponding load 40.

[0081] It should be noted that in this embodiment, the DC chopper circuit 200 is connected to the primary winding of the transformer. The transformer can have multiple secondary windings, and each secondary winding can be connected to a load 40 through a load decoupling circuit 100 to achieve multiple outputs of the DC chopper circuit 200. When any load 40 experiences a short-circuit fault, the corresponding load decoupling circuit 100 can quickly decouple only the faulty load 40 from the transformer to prevent excessive current generated by a short circuit in a single branch of the load 40 from impacting the upper-level circuit (DC chopper circuit 200) and other lower-level circuits (loads 40 connected to other secondary windings).

[0082] It is worth noting that in this embodiment, the load decoupling circuit 100 of each branch can be connected to the controller 50. The controller 50 can also be connected to each secondary winding and collect the voltage at both ends of each secondary winding (not shown in the figure). Therefore, the controller 50 can control the load decoupling circuit 100 of each branch to change the connection state between the transformer and the load 40 connected to it.

[0083] Furthermore, to achieve the above objectives, the power supply circuit proposed in this application adopts all embodiments of the load decoupling circuit described above. Compared with the prior art, the other beneficial effects of the power supply circuit provided in this application are the same as those of the load decoupling circuit provided in the above embodiments, and the other technical features of the power supply circuit are the same as those disclosed in the various embodiments of the above load decoupling circuit, and will not be repeated here.

[0084] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent scope of this application.

Claims

1. A load decoupling circuit, characterized in that, The load decoupling circuit includes: a first switching circuit, a second switching circuit, and a fault detection circuit; The first input terminal of the fault detection circuit is connected to the first terminal of the load and the first terminal of the secondary winding of the transformer, respectively. The output terminal of the fault detection circuit is connected to the control terminal of the first switching circuit and the control terminal of the second switching circuit, respectively. The input terminal of the first switching circuit is connected to the second terminal of the secondary winding of the transformer. The output terminal of the first switching circuit is connected to the output terminal of the second switching circuit and the second input terminal of the fault detection circuit. The input terminal of the second switching circuit is connected to the second terminal of the load. The fault detection circuit is used to determine whether the load has failed based on the voltage across the secondary winding, and to shut off the first switching circuit and the second switching circuit when the load fails, thereby disconnecting the connection between the load and the transformer; and / or, to turn on the first switching circuit and the second switching circuit when the load recovers from a fault state to a normal state, thereby restoring the connection between the load and the transformer.

2. The load decoupling circuit as described in claim 1, characterized in that, The load decoupling circuit further includes: a controller; The controller is connected to the enable terminal of the fault detection circuit. When the number of times the load fails within a preset time exceeds a preset number of failures, the controller pulls the enable signal of the fault detection circuit low, thereby keeping the load disconnected from the transformer.

3. The load decoupling circuit as described in claim 2, characterized in that, The controller is also configured to adjust the enable signal of the fault detection circuit when receiving an externally transmitted control command, so as to keep the load and the transformer in a conducting state or in a disconnected state.

4. The load decoupling circuit as described in claim 1, characterized in that, The fault detection circuit includes: a first resistor and a second resistor; The first end of the first resistor is connected to the first end of the load and the first end of the secondary winding of the transformer, respectively. The second end of the first resistor is connected to the first end of the second resistor, the control terminal of the first switching circuit and the control terminal of the second switching circuit, respectively. The second end of the second resistor is connected to the output terminal of the first switching circuit and the output terminal of the second switching circuit, respectively.

5. The load decoupling circuit as described in claim 4, characterized in that, The fault detection circuit further includes: a first diode; The anode of the first diode is connected to the first terminal of the load and the first terminal of the secondary winding of the transformer, respectively, and the cathode of the first diode is connected to the first terminal of the first resistor.

6. The load decoupling circuit as described in claim 4, characterized in that, The fault detection circuit further includes: a first capacitor; The first end of the first capacitor is connected to the second end of the first resistor, the first end of the second resistor, the control terminal of the first switching circuit, and the control terminal of the second switching circuit, respectively. The second end of the first capacitor is connected to the second end of the second resistor, the output terminal of the first switching circuit, and the output terminal of the second switching circuit, respectively.

7. The load decoupling circuit as described in claim 1, characterized in that, The first switching circuit includes: a first NMOS transistor; The gate of the first NMOS transistor is connected to the control terminal of the second switching circuit and the output terminal of the fault detection circuit. The source of the first NMOS transistor is connected to the second input terminal of the fault detection circuit and the output terminal of the second switching circuit. The drain of the first NMOS transistor is connected to the second terminal of the secondary winding of the transformer.

8. The load decoupling circuit as described in claim 1, characterized in that, The second switching circuit includes: a second NMOS transistor; The gate of the second NMOS transistor is connected to the control terminal of the first switching circuit and the output terminal of the fault detection circuit. The source of the second NMOS transistor is connected to the second input terminal of the fault detection circuit and the output terminal of the first switching circuit. The drain of the second NMOS transistor is connected to the second terminal of the load.

9. A power supply circuit, characterized in that, The power supply circuit includes: a DC chopper circuit, a transformer, and a load decoupling circuit as described in any one of claims 1-8; The output terminal of the DC chopper circuit is connected to the primary winding of the transformer, the input terminal of the load decoupling circuit is connected to the secondary winding of the transformer, and the output terminal of the load decoupling circuit is connected to the load. The load decoupling circuit is used to determine whether the load has failed based on the voltage across the secondary winding, and disconnect the connection between the load and the transformer when the load fails; and / or, to restore the connection between the load and the transformer when the load is detected to have recovered from a fault state to a normal state.

10. The power supply circuit as described in claim 9, characterized in that, The power supply circuit also includes multiple load decoupling circuits, and the transformer also includes multiple secondary windings: The input terminal of each load decoupling circuit is connected to a corresponding secondary winding, and the output terminal of each load decoupling circuit is connected to a corresponding load.

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