Turn-off circuit and rectification circuit

Abstract

The utility model relates to a turn-off circuit and a rectification circuit. The circuit comprises a first switch piece arranged in a target circuit and a turn-off driving circuit of the first switch piece, the turn-off driving circuit comprises a level pull-down circuit, a bleeder circuit and a switch piece control circuit, the level pull-down circuit comprises a second power supply and a second switch piece, one end of the second switch piece is connected with the second power supply, and the other end of the second switch piece is connected with the bleeder circuit. The other end is connected with the bleeder circuit; the level pull-down circuit comprises a level pull-down point, and the level pull-down point is connected with the first switch piece; the switch piece control circuit is connected with the second switch piece and the turn-off driving signal source, and can output a first level signal to the second switch piece when the turn-off driving signal source outputs the first level signal, so that the second switch piece is turned on. By adopting the method, the first switch piece can be quickly turned off.

Description

Technical Field

[0001] The present application relates to the field of circuit control, and in particular to a shutdown circuit and a rectifier circuit. Background Art

[0002] A switch is an electronic component that acts as a switch in a circuit. It can control the conduction and closure of the circuit. When the circuit is on, current is allowed to flow through. When the circuit is off, current is not allowed to flow through. In a switching power supply, a switch can be used for synchronous rectification. When using a switch for rectification, the switch can be placed on the high side, i.e., the positive pole of the power supply, for rectification control.

[0003] However, when a switch is currently placed on the high side for rectification control, when the power is cut off, due to the parasitic current inside the switch, the switch needs to delay for a period of time before turning off, which may affect the shutdown timeliness of the circuit and cause the circuit to fail to cut off the power in time. Summary of the invention

[0004] Based on this, it is necessary to provide a shut-off circuit and a rectifier circuit that can quickly shut down the switch element in order to solve the above technical problems.

[0005] In a first aspect, the present application provides a shutdown circuit, comprising:

[0006] A first switch element, wherein the first switch element is disposed in a target circuit to be shut down, the target circuit includes a first power source and a target load, and the first switch element is connected to the first power source and the target load respectively;

[0007] A shutdown drive circuit, the shutdown drive circuit comprising a level-lowering circuit, a discharge circuit and a switch component control circuit;

[0008] The level-lowering circuit includes a second power supply and a second switch, one end of the second switch is connected to the second power supply, and the other end is connected to the discharge circuit, and the level-lowering circuit includes a level-lowering point, and the level-lowering point is connected to the first switch;

[0009] The switch element control circuit is connected to the second switch element and the shutdown drive signal source respectively, and can output a first level signal to the second switch element when the shutdown drive signal source outputs a first level signal to turn on the second switch element.

[0010] In one embodiment, the switch element control circuit includes a first control branch, one end of the first control branch is connected to the second power supply, the other end of the first control branch is grounded, the first control branch includes a third switch element, a first end of the third switch element is connected to the second switch element;

[0011] When the shutdown driving signal source outputs a first level signal, the first control branch outputs a first level signal to the second switch element to turn on the second switch element.

[0012] In one embodiment, the switch element control circuit includes a second control branch, one end of the second control branch is connected to a third power source, the other end of the second control branch is grounded, the second control branch includes a fourth switch element, a first end of the fourth switch element is connected to the third switch element;

[0013] When the shutdown driving signal source outputs a first level signal, the second control branch outputs a second level signal to the third switch element to turn on the third switch element.

[0014] In one embodiment, the level-lowering circuit further includes a first resistor, a first end of the first resistor is connected to the second power supply, a second end of the first resistor is connected to the first end of the second switch, and the connection point is located at the level-lowering point.

[0015] In one embodiment, the first control branch further includes a second resistor and a third resistor;

[0016] The first end of the second resistor is connected to the first end of the third switch element, and the second end of the second resistor is connected to the second switch element;

[0017] A first end of the third resistor is connected to the second switch element, and a second end of the third resistor is connected to the level-lowering point.

[0018] In one embodiment, the second control branch further includes a fourth resistor and a fifth resistor;

[0019] A first end of the fourth resistor is connected to the third power supply, and a second end of the fourth resistor is connected to the third switch element;

[0020] A first end of the fifth resistor is connected to the third switch element, and a second end of the fifth resistor is grounded.

[0021] In one embodiment, the switch element control circuit further includes a sixth resistor and a seventh resistor;

[0022] A first end of the sixth resistor is connected to the shutdown drive signal source, and a second end of the sixth resistor is connected to the fourth switch element;

[0023] A first end of the seventh resistor is connected to the fourth switch element, and a second end of the seventh resistor is grounded.

[0024] In one embodiment, the level-lowering circuit further includes a fifth switch element, a first end of the fifth switch element is connected to the second power source, and a second end of the fifth switch element is connected to the first resistor;

[0025] The fifth switch element is connected to a conduction drive signal.

[0026] In one embodiment, one end of the discharge circuit is connected to the second switch element, and the other end of the discharge circuit is grounded.

[0027] In a second aspect, the present application further provides a rectifier circuit, comprising a shutdown circuit as described in any one of the first aspects above.

[0028] The above-mentioned shutdown circuit and rectification circuit include a first switch element arranged in the target circuit and a shutdown drive circuit of the first switch element, the shutdown drive circuit includes a level pull-down circuit, a discharge circuit and a switch element control circuit, wherein the level pull-down circuit includes a second power supply and a second switch element, one end of the second switch element is connected to the second power supply, and the other end is connected to the discharge circuit; the level pull-down circuit includes a level pull-down point, and the level pull-down point is connected to the first switch element; the switch element control circuit is respectively connected to the second switch element and the shutdown drive signal source, and can output a first level signal to the second switch element when the shutdown drive signal source outputs a first level signal to turn on the second switch element. In this way, when the shutdown drive signal source outputs the first level signal, the switch component control circuit outputs the first level signal to the second switch component, so that the second switch component is turned on. After the second switch component is turned on, the level pull-down point is pulled down to a low level. At this time, the first switch component is turned off. At the same time, the parasitic capacitance of the first switch component can be quickly discharged through the discharge circuit, shortening the delay time when the first switch component is turned off, so that the first switch component can be turned off quickly, avoiding the failure of the target circuit due to untimely power-off protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] FIG1 is a circuit structure block diagram of a shutdown circuit in one embodiment;

[0031] FIG2 is a circuit structure block diagram of a switch element control circuit in another embodiment;

[0032] FIG3 is a circuit structure block diagram of a switch element control circuit in another embodiment;

[0033] FIG4 is a circuit structure block diagram of a switch element control circuit in another embodiment;

[0034] FIG5 is a circuit structure block diagram of a level-lowering circuit in another embodiment;

[0035] FIG6 is a circuit structure block diagram of a shutdown circuit in one embodiment;

[0036] FIG7 is a schematic diagram of simulation results of an embodiment in which no switch is added to turn off the circuit;

[0037] FIG8 is a schematic diagram of simulation results of adding a switch to shut down the circuit in one embodiment;

[0038] FIG9 is a circuit structure block diagram of a DCDC full-bridge rectifier circuit in one embodiment;

[0039] FIG10 is a circuit block diagram of a flyback circuit in one embodiment;

[0040] FIG. 11 is a circuit structure block diagram of a synchronous BUCK circuit in one embodiment.

[0041] Description of main component numbers:

[0042] A first switch element 11; a shut-off drive circuit 12; a first power supply 13;

[0043] Level pull-down circuit 121; discharge circuit 122; switch element control circuit 123;

[0044] A second power source 1211; a second switch 1212; a first resistor 1213;

[0045] A first control branch 20; a third switch 21; a second resistor 22; a third resistor 23;

[0046] A second control branch 30; a third power supply 31; a fourth switch 32; a fourth resistor 33; a fifth resistor 34;

[0047] A sixth resistor 41; a seventh resistor 42;

[0048] a fifth switch element 50 and a sixth switch element 60 . DETAILED DESCRIPTION

[0049] In order to make the purpose, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0050] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0051] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0052] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0053] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0054] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0055] A switch is an electronic component that acts as a switch in a circuit. It can control the conduction and closure of the circuit. When the circuit is on, current is allowed to flow through. When the circuit is off, current is not allowed to flow through. In a switching power supply, a switch can be used for synchronous rectification. When using a switch for rectification, the switch can be placed on the high side, i.e., the positive pole of the power supply, for rectification control.

[0056] However, when a switch is currently placed on the high side for rectification control, when the power is cut off, due to the parasitic current inside the switch, the switch needs to delay for a period of time before turning off, which may affect the shutdown timeliness of the circuit and cause the circuit to fail to cut off the power in time.

[0057] In view of this, the present application provides a shutdown circuit. When the shutdown drive signal source outputs a first level signal, the switch device control circuit outputs a first level signal to the second switch device, so that the second switch device is turned on. After the second switch device is turned on, the level pull-down point is pulled down to a low level. At this time, the first switch device is turned off. At the same time, the parasitic capacitance of the first switch device can be quickly discharged through the discharge circuit, thereby shortening the delay time when the first switch device is turned off.

[0058] In an embodiment of the present application, as shown in FIG. 1 , a shutdown circuit 10 is provided, comprising: a first switch element 11 arranged in a target circuit; a shutdown drive circuit 12 of the first switch element, the shutdown drive circuit 12 comprising a level-lowering circuit 121 , a discharge circuit 122 and a switch element control circuit 123 .

[0059] The target circuit is a circuit to be shut down, and the target circuit includes a first power source 13 and a target load, and the first switch 11 is connected to the first power source 13 and the target load respectively;

[0060] The level-lowering circuit 121 includes a second power supply 1211 and a second switch 1212, one end of the second switch 1212 is connected to the second power supply 1211, and the other end is connected to the discharge circuit 122; the level-lowering circuit 121 includes a level-lowering point a, and the level-lowering point a is connected to the first switch 11;

[0061] The switch element control circuit 123 is connected to the second switch element 1212 and the shutdown driving signal source respectively, and can output a first level signal to the second switch element 1212 to turn on the second switch element 1212 when the shutdown driving signal source outputs a first level signal.

[0062] Among them, the first switch element 11 can be a switch tube, which is a transistor that acts as a switch in the circuit, and can include different types of transistors such as triodes, field effect tubes or thyristors, such as MOS (MOSFET, metal-oxide semiconductor field effect transistor) switch tubes. The first switch element 11 can be set at the high side of the target circuit. Optionally, the target circuit includes a first power supply 13 and a target load. The high side is also the positive end of the first power supply. The first switch element 11 can be used to control the on and off of the target circuit. The control end of the first switch element 11 is connected to the level pull-down point a, the first end of the first switch element 11 is connected to the target load, and the second end of the first switch element 11 is connected to the output end of the first power supply 13 in the target circuit. The shutdown drive circuit 12 is used to control the shutdown of the first switch element 11. Since there is a parasitic capacitor Ciss inside the first switch element 11, when the first switch element 11 is turned off, the stored electricity in the parasitic capacitor Ciss needs to be released before the target circuit can be powered off.

[0063] Optionally, one end of the discharge circuit 122 is connected to the second switch 1212, and the other end of the discharge circuit 122 is grounded. The discharge circuit 122 includes a discharge resistor.

[0064] Optionally, the second power supply 1211 is a high-side drive power supply, the second switch 1212 may be a PNP transistor, the size of the discharge resistor in the discharge circuit 122 may be 5 ohms, one end of the second switch 1212 is connected to the second power supply 1211, and the other end is connected to the discharge circuit 122, and the other end of the discharge circuit 122 is grounded. The switch control circuit 123 is a control circuit of the second switch 1212, one end of the switch control circuit 123 is connected to the control end of the second switch 1212, and the other end of the switch control circuit 123 is connected to the shutdown drive signal source, wherein the shutdown drive signal may be a control signal sent by a device such as a DSP (Digital Signal Processing, digital signal processing technology), which is low level effective, and the first level signal may be a low level signal. When the shutdown drive signal source outputs a low level signal, the switch control circuit 123 outputs a low level signal to the control end of the second switch 1212. Since the second switch 1212 is a PNP transistor, the second switch 1212 is turned on at this time. Therefore, the level of the level-lowering point a in Figure 1 is pulled down. Since the level-lowering point a is connected to the control end of the first switch element 11, the level of point a is pulled down, and the first switch element 11 is turned off. At the same time, the parasitic capacitor Ciss in the first switch element 11 forms a loop with the second switch element 1212 and the discharge circuit 122, and can be discharged through the discharge circuit 122. Since the resistance of the discharge resistor in the discharge circuit 122 is small, the discharge speed is fast, and the first switch element 11 can be quickly turned off.

[0065] Optionally, please continue to refer to FIG. 1 , the level-lowering circuit 121 further includes a first resistor 1213 , and the first resistor 1213 is disposed between the second power source 1211 and the level-lowering point a.

[0066] The resistance of the first resistor 1213 may be 1 kilo-ohm. Since the resistance of the discharge resistor is smaller than that of the first resistor 1213 , when the second switch 1212 is turned on, the voltage at the level-lowering point a is pulled down to a low level.

[0067] In the above embodiment, a first switch element and a shutdown drive circuit of the first switch element are provided in the target circuit, and the shutdown drive circuit includes a level pull-down circuit, a discharge circuit and a switch element control circuit, wherein the level pull-down circuit includes a second power supply and a second switch element, one end of the second switch element is connected to the second power supply, and the other end is connected to the discharge circuit; the level pull-down circuit 121 includes a level pull-down point a, and the level pull-down point a is connected to the first switch element 11; the switch element control circuit is connected to the second switch element and the shutdown drive signal source, respectively, and can output a first level signal to the second switch element when the shutdown drive signal source outputs a first level signal, so that the second switch element is turned on. In this way, when the shutdown drive signal source outputs a low level signal, the switch element control circuit outputs a low level signal to the second switch element, so that the second switch element is turned on, and after the second switch element is turned on, the level pull-down point is pulled down to a low level, and at this time, the first switch element is turned off, and at the same time, the parasitic capacitance of the first switch element can be quickly discharged through the discharge circuit, shortening the delay time when the first switch element is turned off.

[0068] In the embodiment of the present application, as shown in FIG2 , the switch element control circuit 123 includes a first control branch 20, one end of the first control branch 20 is connected to the second power supply 1211, the other end of the first control branch 20 is grounded, and the first control branch 20 includes a third switch element 21, and a first end of the third switch element 21 is connected to the control end of the second switch element 1212. When the first control branch 20 turns off the drive signal source to output the first level signal, it outputs the first level signal to the control end of the second switch element 1212 to turn on the second switch element 1212.

[0069] Optionally, one end of the first control branch 20 is connected to the second power supply 1211 via a level-lowering point a, and the third switch element 21 may be an NPN transistor.

[0070] In one embodiment, please continue to refer to Figure 2, the first control branch 20 also includes a second resistor 22 and a third resistor 23; the first end of the second resistor 22 is connected to the first end of the third switch element 311, and the second end of the second resistor 22 is connected to the control end of the second switch element 1212; the first end of the third resistor 23 is connected to the control end of the second switch element 1212, and the second end of the third resistor is connected to the level pull-down point a.

[0071] The resistance values ​​of the second resistor 22 and the third resistor 23 may be 1 kilo-ohm, and the second resistor 22 and the third resistor 23 may be used for current limiting and voltage division.

[0072] In one embodiment, as shown in Figure 3, the switch element control circuit 123 includes a second control branch 30, one end of the second control branch 30 is connected to the third power supply 31, and the other end of the second control branch 30 is grounded, and the second control branch 30 includes a fourth switch element 32, and the first end of the fourth switch element 32 is connected to the control end of the third switch element 21.

[0073] When the driving signal source is turned off to output the first level signal, the second control branch 30 outputs a second level signal to the control end of the third switch element 21 to turn on the third switch element 21 .

[0074] Among them, the first level signal can be a low level signal, the second level signal can be a high level signal, the fourth switch element 32 can be an NPN transistor, and the control end of the fourth switch element 32 can be connected to the fast shutdown drive signal source. When the fast drive signal outputs a low level, the fourth switch element 32 is in the off state, and the first end of the fourth switch element 32 is connected to the control end of the third switch element 21. When the fourth switch element 32 is turned off, the control end of the third switch element 21 is a high level, so the third switch element 21 is turned on.

[0075] Optionally, please continue to refer to Figure 3, the second control branch 30 also includes a fourth resistor 33 and a fifth resistor 34; the first end of the fourth resistor 33 is connected to the third power supply 31, and the second end of the fourth resistor 33 is connected to the control end of the third switch element; the first end of the fifth resistor 34 is connected to the control end of the third switch element, and the second end of the fifth resistor 34 is grounded.

[0076] The resistance values ​​of the fourth resistor 33 and the fifth resistor 34 may be 10 kilo-ohms, and the fourth resistor 33 and the fifth resistor 34 may play the role of voltage division and current limiting.

[0077] In one embodiment, as shown in Figure 4, the switch element control circuit 123 also includes a sixth resistor 41 and a seventh resistor 42; the first end of the sixth resistor 41 is connected to the shutdown drive signal source, and the second end of the sixth resistor 41 is connected to the control end of the fourth switch element 32; the first end of the seventh resistor 42 is connected to the control end of the fourth switch element 32, and the second end of the seventh resistor 42 is grounded.

[0078] The resistance values ​​of the sixth resistor 41 and the seventh resistor 42 may be 10 kilo-ohms. The sixth resistor 41 is used for current limiting and voltage division. When the shutdown drive signal is at a low level, the fourth switch element 32 is turned off through the sixth resistor 41 to the fourth switch element 32 .

[0079] In one embodiment, as shown in Figure 5, the level pull-down circuit 121 also includes a fifth switch element 50, the first end of the fifth switch element 50 is connected to the second power supply 1211, and the second end of the fifth switch element 50 is connected to the first resistor 1213; the control end of the fifth switch element 50 is connected to the conduction drive signal.

[0080] As shown in FIG. 5 , when the conduction driving signal is at a high level, the fifth switch element 50 is controlled to be in a conduction state through the conduction driving circuit. After the fifth switch element 50 is turned on, the first switch element 11 is turned on.

[0081] Among them, the fifth switch element 50 can be a PNP type transistor, and the conduction drive signal can be a control signal sent by a device such as a DSP, which is used to control the conduction of the first switch element 11. The conduction drive signal can be high level valid. When the output is high level, the fifth switch element 50 is turned on and the first switch element 11 is turned on accordingly.

[0082] In the embodiment of the present application, as shown in Figure 6, it is an overall structural block diagram of the switch element shutdown circuit provided in the embodiment of the present application. Among them, the conduction drive circuit is shown in Figure 6, including the sixth switch element 60 and multiple resistors, and the resistance value of each resistor is shown in the figure. When the conduction drive signal outputs a high level, the sixth switch element 60 of the conduction drive circuit is turned on, thereby controlling the fifth switch element 50 to be turned on, and then controlling the first switch element 11 to be turned on, and the target circuit is turned on. When the first switch element 11 is turned on, when the shutdown drive signal outputs a low level, that is, the first switch element 11 needs to be turned off, the fourth switch element 32 is turned off, and is connected to the control end of the third switch element 21 through the second control branch 30, so that the third switch element 21 is turned on, and then connected to the second switch element 1212 through the first control branch 20, so that the second switch element 1212 is turned on. At this time, the level pull-down point a is pulled down to a low level, and the first switch element 11 is turned off. At the same time, the parasitic capacitance Ciss of the first switch element can be quickly discharged through the discharge circuit 122, so that the first switch element 11 can be quickly turned off.

[0083] Optionally, the above-mentioned shutdown circuit is simulated by simulation software. When the first switch element 11 is controlled to be shut down without adding the above-mentioned switch element shutdown circuit, as shown in Figure 7, the delay time for shutting down the first switch element 11 is 60us. When the above-mentioned switch element shutdown circuit is added to control the shutdown of the first switch element 11, when the first switch element 11 is turned off, as shown in Figure 8, the shutdown delay time is 200ns. It can be seen that after adding the switch element shutdown circuit, the shutdown delay time is reduced.

[0084] In the above embodiment, the first switch element can be quickly shut down by turning off the circuit through the switch element, thereby preventing the target circuit from failing due to untimely circuit shutdown protection. At the same time, only the second power supply and the third power supply are required to be quickly shut down without isolation, and the control method is simple and the cost is low.

[0085] In one embodiment, the present application further provides a rectifier circuit, comprising a shutdown circuit as in the above method embodiment.

[0086] Optionally, the shutdown circuit can also be used in a DCDC (direct current-direct current) full-bridge rectifier circuit as shown in FIG9 . The application module in the gray part of FIG9 is the shutdown circuit described in the above embodiment. By connecting the shutdown circuit application module to the high side of the DCDC full-bridge rectifier circuit, the DCDC full-bridge circuit can be quickly shut down. It can also be used in a flyback circuit as shown in FIG10 , or in a synchronous BUCK circuit as shown in FIG11 . The flyback circuit or the synchronous BUCK circuit can be quickly shut down by the shutdown circuit application module.

[0087] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A shutdown circuit, characterized in that: The shutdown circuit comprises: a first switch element, wherein the first switch element is disposed in a target circuit to be shut down, the target circuit comprising a first power source and a target load, and the first switch element is connected to the first power source and the target load respectively; A shutdown drive circuit of the first switch element, the shutdown drive circuit comprising a level-lowering circuit, a discharge circuit and a switch element control circuit; The level-lowering circuit includes a second power supply and a second switch, one end of the second switch is connected to the second power supply, and the other end is connected to the discharge circuit, and the level-lowering circuit includes a level-lowering point, and the level-lowering point is connected to the first switch; The switch element control circuit is connected to the second switch element and the shutdown drive signal source respectively, and can output a first level signal to the second switch element when the shutdown drive signal source outputs a first level signal to turn on the second switch element.

2. The shutdown circuit according to claim 1, characterized in that: The switch element control circuit comprises a first control branch, one end of the first control branch is connected to the second power supply, the other end of the first control branch is grounded, the first control branch comprises a third switch element, a first end of the third switch element is connected to the second switch element; When the shutdown driving signal source outputs a first level signal, the first control branch outputs a first level signal to the second switch element to turn on the second switch element.

3. The shutdown circuit according to claim 2, characterized in that: The switch element control circuit comprises a second control branch, one end of the second control branch is connected to a third power source, the other end of the second control branch is grounded, the second control branch comprises a fourth switch element, a first end of the fourth switch element is connected to the third switch element; When the shutdown driving signal source outputs a first level signal, the second control branch outputs a second level signal to the third switch element to turn on the third switch element.

4. The shutdown circuit according to claim 1, characterized in that: The level-lowering circuit further includes a first resistor, a first end of the first resistor is connected to the second power supply, a second end of the first resistor is connected to the first end of the second switch, and a connection point is located at the level-lowering point.

5. The shutdown circuit according to claim 2, characterized in that: The first control branch also includes a second resistor and a third resistor; The first end of the second resistor is connected to the first end of the third switch element, and the second end of the second resistor is connected to the second switch element; A first end of the third resistor is connected to the second switch element, and a second end of the third resistor is connected to the level-lowering point.

6. The shutdown circuit according to claim 3, characterized in that: The second control branch further includes a fourth resistor and a fifth resistor; A first end of the fourth resistor is connected to the third power supply, and a second end of the fourth resistor is connected to the third switch element; A first end of the fifth resistor is connected to the third switch element, and a second end of the fifth resistor is grounded.

7. The shutdown circuit according to claim 3, characterized in that: The switch element control circuit further includes a sixth resistor and a seventh resistor; A first end of the sixth resistor is connected to the shutdown drive signal source, and a second end of the sixth resistor is connected to the fourth switch element; A first end of the seventh resistor is connected to the fourth switch element, and a second end of the seventh resistor is grounded.

8. The shutdown circuit according to claim 4, characterized in that: The level-lowering circuit further includes a fifth switch element, a first end of the fifth switch element is connected to the second power source, and a second end of the fifth switch element is connected to the first resistor; The fifth switch element is connected to a conduction driving signal source.

9. The shutdown circuit according to claim 1, characterized in that: One end of the discharge circuit is connected to the second switch element, and the other end of the discharge circuit is grounded.

10. A rectifier circuit, characterized in that: The rectifier circuit comprises a shutdown circuit as described in any one of claims 1-9.

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