Constant current discharge circuit and protection device

Abstract

The present application provides a constant current discharge circuit and protection device, including: a switch circuit, an absorption circuit, a constant current source circuit, a voltage stabilizing circuit and a control switch circuit. The first end of the switch circuit is used to electrically connect the first end of the capacitor and the power supply respectively. The first end of the absorption circuit is electrically connected to the second end of the switch circuit. The second end of the absorption circuit and the second end of the capacitor are both grounded. The first end of the constant current source circuit is electrically connected to the first end of the switch circuit. The second end of the constant current source circuit is electrically connected to the third end of the switch circuit. The first end of the voltage stabilizing circuit is electrically connected to the third end of the switch circuit. The second end of the voltage stabilizing circuit is electrically connected to the second end of the capacitor. The first end of the control switch circuit is electrically connected to the second end of the constant current source circuit. The second end of the control switch circuit is electrically connected to the second end of the voltage stabilizing circuit.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a constant current discharge circuit and a protection device. Background Art

[0002] In high-power electronic system modules, there will be large-capacity energy storage capacitors as energy sources for large pulse currents. Generally, such functional modules will be plugged in and out of the entire system. If the module's own capacitor discharge time is long, it may cause life-threatening physical contact, as well as the risk of damaging the device when the module itself is plugged in and out while powered on. Therefore, it is necessary to quickly discharge the charge of the energy storage capacitor after shutdown, usually within 2S to 10S.

[0003] In order to discharge the charge of the large-capacity energy storage capacitor, the current method is to connect a high-power resistor in parallel at both ends of the capacitor and connect a normally closed relay in series in the resistor branch. After power is turned on, the relay switch is disconnected, and the power resistor has no power consumption; after power is turned off, the relay switch is closed, and the charge is discharged through the power resistor. The above method makes the relay contacts easily damaged, posing a safety hazard. Summary of the invention

[0004] Based on this, it is necessary to use a relay in combination with a high-power resistor to discharge the charge of the energy storage capacitor, which makes the relay contacts easily damaged and poses a safety hazard. A constant current discharge circuit and protection device are provided.

[0005] A constant current discharge circuit, comprising:

[0006] a switch circuit, wherein a first end of the switch circuit is used to electrically connect a first end of the capacitor and a power source respectively;

[0007] an absorption circuit, wherein a first end of the absorption circuit is electrically connected to a second end of the switch circuit, and a second end of the absorption circuit and a second end of the capacitor are both grounded;

[0008] a constant current source circuit, wherein a first end of the constant current source circuit is electrically connected to a first end of the switch circuit, and a second end of the constant current source circuit is electrically connected to a third end of the switch circuit;

[0009] a voltage stabilizing circuit, wherein a first end of the voltage stabilizing circuit is electrically connected to a third end of the switch circuit, and a second end of the voltage stabilizing circuit is electrically connected to a second end of the capacitor; and

[0010] A control switch circuit, wherein a first end of the control switch circuit is electrically connected to a second end of the constant current source circuit, and a second end of the control switch circuit is electrically connected to a second end of the voltage stabilizing circuit.

[0011] In one of the embodiments, when the control switch circuit is powered on, the switch circuit is in an off state;

[0012] When the control switch circuit is powered off and disconnected, the switch circuit is in an on state.

[0013] In one embodiment, the switch circuit comprises:

[0014] A first switch tube, wherein the first end of the first switch tube is electrically connected to the first end of the capacitor and the power supply respectively, the second end of the first switch tube is electrically connected to the first end of the absorption circuit, and the control end of the first switch tube is electrically connected to the second end of the constant current source circuit, the first end of the voltage stabilizing circuit and the first end of the control switch circuit respectively.

[0015] In one embodiment, the constant current source circuit comprises:

[0016] a second switch tube, wherein a first end of the second switch tube is electrically connected to a first end of the switch circuit, and a control end of the second switch tube is electrically connected to a third end of the switch circuit;

[0017] A first resistor, wherein a first end of the first resistor is electrically connected to a second end of the second switch tube, and a second end of the first resistor is electrically connected to a third end of the switch circuit.

[0018] In one embodiment, the voltage stabilizing circuit comprises:

[0019] A voltage stabilizing diode, wherein a cathode of the voltage stabilizing diode is electrically connected to the second end of the constant current source circuit, and an anode of the voltage stabilizing diode is electrically connected to the second end of the capacitor.

[0020] In one embodiment, the control switch circuit includes:

[0021] A relay switch, wherein the first input end of the relay switch is electrically connected to the second end of the constant current source circuit, the second input end of the relay switch is used to electrically connect to a power supply, and the first output end and the second output end of the relay switch are both electrically connected to the second end of the voltage stabilizing circuit.

[0022] In one embodiment, the constant current discharge circuit further includes:

[0023] A voltage divider circuit, wherein a first end of the voltage divider circuit is electrically connected to a first end of the constant current source circuit and a first end of the capacitor respectively, and a second end of the voltage divider circuit is electrically connected to a first end of the switch circuit.

[0024] In one embodiment, the voltage divider circuit includes:

[0025] A voltage-dividing resistor, wherein a first end of the voltage-dividing resistor is electrically connected to a first end of the constant current source circuit, and a second end of the voltage-dividing resistor is electrically connected to a first end of the switch circuit.

[0026] In one embodiment, the absorption circuit includes:

[0027] A second resistor, wherein a first end of the second resistor is electrically connected to a second end of the switch circuit, and a second end of the second resistor is grounded.

[0028] A protection device comprises the constant current discharge circuit described in any one of the above embodiments.

[0029] Compared with the prior art, in the above-mentioned constant current discharge circuit and protection device, when the system loses power, the control switch circuit is disconnected. At this time, the constant current source circuit cooperates with the voltage stabilizing circuit to output a stable voltage to drive the switch circuit to turn on, and cooperates with the absorption circuit to form a constant current discharge circuit, thereby discharging the charge stored in the capacitor to the ground at a constant current, thereby improving the safety and reliability of discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A principle block diagram of a constant current discharge circuit provided in one embodiment of the present application;

[0031] Figure 2 A circuit diagram of a constant current discharge circuit provided in one embodiment of the present application;

[0032] Figure 3 A circuit diagram of a protection device provided in one embodiment of the present application.

[0033] 10 Constant current discharge circuit

[0034] 100 switch circuit

[0035] 101 Capacitor

[0036] 102 Power Supply

[0037] 110 First switch tube

[0038] 20 Protective devices

[0039] 200 Absorption Circuit

[0040] 210 Second resistor

[0041] 300 constant current source circuit

[0042] 310 Second switch tube

[0043] 320 first resistor

[0044] 400 voltage regulator circuit

[0045] 410 Zener diode

[0046] 500 control switch circuit

[0047] 510 relay switch

[0048] 600 voltage divider circuit

[0049] 610 voltage divider resistor DETAILED DESCRIPTION

[0050] In order to make the above-mentioned purposes, 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 implementation disclosed below.

[0051] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate 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 an intermediate element at the same time.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0053] See also Figure 1, an embodiment of the present application provides a constant current discharge circuit 10, comprising: a switch circuit 100, an absorption circuit 200, a constant current source circuit 300, a voltage stabilizing circuit 400, and a control switch circuit 500. The first end of the switch circuit 100 is used to electrically connect the first end of the capacitor 101 and the power supply 102 respectively. The first end of the absorption circuit 200 is electrically connected to the second end of the switch circuit 100. The second end of the absorption circuit 200 and the second end of the capacitor 101 are both grounded. The first end of the constant current source circuit 300 is electrically connected to the first end of the switch circuit 100. The second end of the constant current source circuit 300 is electrically connected to the third end of the switch circuit 100. The first end of the voltage stabilizing circuit 400 is electrically connected to the third end of the switch circuit 100. The second end of the voltage stabilizing circuit 400 is electrically connected to the second end of the capacitor 101. The first end of the control switch circuit 500 is electrically connected to the second end of the constant current source circuit 300. The second end of the control switch circuit 500 is electrically connected to the second end of the voltage stabilizing circuit 400.

[0054] It can be understood that the specific circuit structure of the switch circuit 100 is not limited, as long as it has a stable voltage conduction based on the output of the constant current source circuit 300. The specific circuit structure of the switch circuit 100 can be selected according to actual needs. In one embodiment, the switch circuit 100 can be an IGBT (Insulated Gate Bipolar Transistor). In one embodiment, the switch circuit 100 can also be a MOS tube.

[0055] It can be understood that the specific circuit structure of the absorption circuit 200 is not limited, as long as it has the function of cooperating with the switch circuit 100 to form a constant current discharge circuit. In one embodiment, the absorption circuit 200 can be a high-power resistor. In one embodiment, the absorption circuit 200 can also be a nonlinear resistance element (such as a varistor, etc.).

[0056] It can be understood that the specific circuit structure of the constant current source circuit 300 is not limited, as long as it has the function of cooperating with the voltage stabilizing circuit 400 to output a stable voltage to drive the switch circuit 100 to turn on. In one embodiment, the constant current source circuit 300 can be a constant current source. In one embodiment, the constant current source circuit 300 can also be formed by a depletion-type MOS tube with a resistor. When the system is powered off, the constant current source circuit 300 outputs a constant current as the excitation current of the voltage stabilizing circuit 400, so that the constant current source circuit 300 cooperates with the voltage stabilizing circuit 400 to generate a stable voltage to drive the switch circuit 100 to turn on, and cooperates with the absorption circuit 200 to discharge the charge stored in the capacitor 101 at a constant current, thereby improving the safety and reliability of the discharge.

[0057] It can be understood that the specific circuit structure of the voltage stabilizing circuit 400 is not limited, as long as it has the function of cooperating with the constant current source circuit 300 to generate a stable voltage to drive the switch circuit 100 to conduct. In one embodiment, the voltage stabilizing circuit 400 can be a voltage stabilizer. In one embodiment, the voltage stabilizing circuit 400 can also be other voltage stabilizing devices such as a voltage stabilizing diode.

[0058] It can be understood that the circuit structure of the control switch circuit 500 is not limited, as long as it has the function of turning on the control switch circuit 500 when the system is powered on and turning off the control switch circuit 500 when the system is powered off. In one embodiment, the control switch circuit 500 can adopt a relay switch with an isolation function (such as an electromagnetic relay, a photorelay, etc.). In one embodiment, the control switch circuit 500 can also be a switch tube such as a triode.

[0059] Specifically, when the system is powered on (i.e., the power supply 102 is working normally), the control switch circuit 500 is closed and turned on, and the switch circuit 100 is in an open state. At the same time, the absorption circuit 200 and the voltage stabilizing circuit 400 do not work, and the constant current source circuit 300 is short-circuited to the ground by the control switch circuit 500. When the system is powered off (i.e., the power supply 102 is powered off), the control switch circuit 500 is automatically disconnected, and the voltage stabilizing circuit 400 works at this time, and cooperates with the constant current source circuit 300 to generate a stable voltage, and outputs the voltage to the switch circuit 100. The switch circuit 100 is turned on, and the absorption circuit 200 works at this time. Through the cooperation of the absorption circuit 200 and the switch circuit 100, the charge stored in the capacitor 101 can be discharged with a constant current, thereby improving the safety and reliability of the discharge.

[0060] In this embodiment, when the system loses power, the control switch circuit 500 is disconnected. At this time, the constant current source circuit 300 cooperates with the voltage stabilizing circuit 400 to output a stable voltage to drive the switch circuit 100 to turn on, and cooperates with the absorption circuit 200 to form a constant current discharge circuit, thereby discharging the charge stored in the capacitor 101 to the ground at a constant current, thereby improving the safety and reliability of the discharge.

[0061] See also Figure 2 In one embodiment, the switch circuit 100 includes: a first switch tube 110. The first end of the first switch tube 110 is electrically connected to the first end of the capacitor 101 and the power supply 102 respectively. The second end of the first switch tube 110 is electrically connected to the first end of the absorption circuit 200. The control end of the first switch tube 110 is electrically connected to the second end of the constant current source circuit 300, the first end of the voltage stabilizing circuit 400 and the first end of the control switch circuit 500 respectively.

[0062] In one embodiment, the first switch tube 110 may be an IGBT tube or a MOS tube. In one embodiment, the control end (i.e., the gate) of the first switch tube 110 is turned on based on the stable voltage generated by the constant current source circuit 300 and the voltage stabilizing circuit 400 when the system is powered off, so that the charge stored in the capacitor 101 can be discharged along the absorption circuit 200 with a constant current, thereby improving the safety and reliability of discharge.

[0063] In one embodiment, the constant current source circuit 300 includes: a second switch tube 310 and a first resistor 320. The first end of the second switch tube 310 is electrically connected to the first end of the switch circuit 100. The control end of the second switch tube 310 is electrically connected to the third end of the switch circuit 100. The first end of the first resistor 320 is electrically connected to the second end of the second switch tube 310. The second end of the first resistor 320 is electrically connected to the third end of the switch circuit 100.

[0064] In one embodiment, the second switch tube 310 can be a depletion type MOS tube. In one embodiment, the second switch tube 310 can also be other switch tubes (such as triodes, IGBT tubes, etc.). In one embodiment, the first resistor 320 can be a fixed resistance resistor. When the system is powered off, the second switch tube 310, the first resistor 320 and the voltage stabilizing circuit 400 cooperate to generate a stable voltage to drive the switch circuit 100 to properly conduct, and cooperate with the absorption circuit 200 to form a constant current discharge circuit, so that the charge stored in the capacitor 101 is discharged at a constant current.

[0065] In one embodiment, the voltage stabilizing circuit 400 includes: a voltage stabilizing diode 410. The cathode of the voltage stabilizing diode 410 is electrically connected to the second end of the constant current source circuit 300. The anode of the voltage stabilizing diode 410 is electrically connected to the second end of the capacitor 101. In one embodiment, the voltage stabilizing diode 410 can be replaced with other voltage stabilizing devices, such as a voltage stabilizer. By cooperating with the constant current source circuit 300, the voltage stabilizing diode 410 can generate a stable voltage to drive the switch circuit 100 to properly conduct, and cooperate with the absorption circuit 200 to form a constant current discharge circuit, so that the charge stored in the capacitor 101 is discharged with a constant current.

[0066] In one embodiment, the control switch circuit 500 includes: a relay switch 510. The first input end of the relay switch 510 is electrically connected to the second end of the constant current source circuit 300. The second input end of the relay switch 510 is used to electrically connect the power supply 102. The first output end and the second output end of the relay switch 510 are both electrically connected to the second end of the voltage stabilizing circuit 400. In one embodiment, the relay switch 510 can be a photorelay or other types of relays (such as electromagnetic relays, etc.). In one embodiment, the power supply 102 can be a power supply that is disconnected synchronously with the relay switch 510. That is, when the system loses power, the power supply 102 is also disconnected synchronously. In one embodiment, the relay switch 510 and the capacitor 101 can also share a power supply, that is, the power supply 102 can supply power to the relay switch 510 and the capacitor 101 at the same time.

[0067] In one embodiment, the constant current discharge circuit 10 further includes: a voltage divider circuit 600. A first end of the voltage divider circuit 600 is electrically connected to a first end of the constant current source circuit 300 and a first end of the capacitor 101. A second end of the voltage divider circuit 600 is electrically connected to a first end of the switch circuit 100.

[0068] It is understood that the specific circuit structure of the voltage divider circuit 600 is not limited, as long as it has the function of voltage division. In one embodiment, the voltage divider circuit 600 may include: a voltage divider resistor 610. Specifically, the first end of the voltage divider resistor 610 is electrically connected to the first end of the constant current source circuit 300. The second end of the voltage divider resistor 610 is electrically connected to the first end of the switch circuit 100. The voltage divider resistor 610 can provide voltage division to the constant current source circuit 300 when the system is powered off to avoid damage.

[0069] In one embodiment, the absorption circuit 200 includes: a second resistor 210. A first end of the second resistor 210 is electrically connected to a second end of the switch circuit 100. A second end of the second resistor 210 is grounded. In one embodiment, the second resistor 210 may be a fixed resistance resistor. In one implementation, the second resistor 210 may also be a nonlinear resistor element (such as a varistor, etc.).

[0070] In one embodiment, the number of the second resistors 210 may be multiple. That is, the absorption circuit 200 may include multiple second resistors 210 connected in series. The second resistors 210 cooperate with the first switch tube 110 to form a constant current discharge circuit, so that the capacitor 101 can discharge its remaining charge with a constant current when the power is off, thereby improving the safety and reliability of the discharge.

[0071] See also Figure 3 , an embodiment of the present application provides a protection device 20, comprising the constant current discharge circuit 10 described in any of the above embodiments. The protection device 20 described in this embodiment can control the switch circuit 500 to be disconnected when the system loses power. At this time, the constant current source circuit 300 cooperates with the voltage stabilizing circuit 400 to output a stable voltage to drive the switch circuit 100 to turn on, and cooperates with the absorption circuit 200 to form a constant current discharge circuit, so as to discharge the charge stored in the capacitor 101 to the ground with a constant current, thereby improving the safety and reliability of discharge.

[0072] To summarize, in the present application, when the system loses power, the control switch circuit 500 is disconnected. At this time, the constant current source circuit 300 cooperates with the voltage stabilizing circuit 400 to output a stable voltage to drive the switch circuit 100 to turn on, and cooperates with the absorption circuit 200 to form a constant current discharge circuit, thereby discharging the charge stored in the capacitor 101 to the ground at a constant current, thereby improving the safety and reliability of the discharge.

[0073] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0074] The above-mentioned 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 invention patent. 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 patent of the present application shall be subject to the attached claims.

Claims

1. A constant current discharge circuit, characterized in that: include: A switch circuit (100), wherein a first end of the switch circuit (100) is used to electrically connect a first end of a capacitor (101) and a power source (102) respectively; An absorption circuit (200), the absorption circuit (200) comprising a second resistor (210), a first end of the second resistor (210) being electrically connected to a second end of the switch circuit (100), and a second end of the second resistor (210) being grounded; A constant current source circuit (300), wherein a first end of the constant current source circuit (300) is electrically connected to a first end of the switch circuit (100), and a second end of the constant current source circuit (300) is electrically connected to a third end of the switch circuit (100); A voltage stabilizing circuit (400), wherein a first end of the voltage stabilizing circuit (400) is electrically connected to a third end of the switch circuit (100), and a second end of the voltage stabilizing circuit (400) is electrically connected to a second end of the capacitor (101); as well as A control switch circuit (500), wherein a first end of the control switch circuit (500) is electrically connected to a second end of the constant current source circuit (300), and a second end of the control switch circuit (500) is electrically connected to a second end of the voltage stabilizing circuit (400); The power supply (102) supplies power to the controlled switch circuit (500) and the capacitor (101) at the same time, and when the power supply (102) is powered off, the controlled switch circuit (500) is automatically disconnected.

2. The constant current discharge circuit according to claim 1, characterized in that: When the control switch circuit (500) is powered on, the switch circuit (100) is in an off state; When the control switch circuit (500) is powered off and disconnected, the switch circuit (100) is in an on state.

3. The constant current discharge circuit according to claim 1, characterized in that: The switch circuit (100) comprises: A first switch tube (110), wherein a first end of the first switch tube (110) is electrically connected to a first end of the capacitor (101) and the power source (102) respectively, a second end of the first switch tube (110) is electrically connected to a first end of the absorption circuit (200), and a control end of the first switch tube (110) is electrically connected to a second end of the constant current source circuit (300), a first end of the voltage stabilizing circuit (400), and a first end of the control switch circuit (500) respectively.

4. The constant current discharge circuit according to claim 1, characterized in that: The constant current source circuit (300) comprises: a second switch tube (310), wherein a first end of the second switch tube (310) is electrically connected to a first end of the switch circuit (100), and a control end of the second switch tube (310) is electrically connected to a third end of the switch circuit (100); A first resistor (320), wherein a first end of the first resistor (320) is electrically connected to a second end of the second switch tube (310), and a second end of the first resistor (320) is electrically connected to a third end of the switch circuit (100).

5. The constant current discharge circuit according to claim 1, characterized in that: The voltage stabilizing circuit (400) comprises: A voltage stabilizing diode (410), wherein a cathode of the voltage stabilizing diode (410) is electrically connected to a second end of the constant current source circuit (300), and an anode of the voltage stabilizing diode (410) is electrically connected to a second end of the capacitor (101).

6. The constant current discharge circuit according to claim 1, characterized in that: The control switch circuit (500) comprises: A relay switch (510), wherein a first input end of the relay switch (510) is electrically connected to a second end of the constant current source circuit (300), a second input end of the relay switch (510) is used to electrically connect to a power source (102), and a first output end and a second output end of the relay switch (510) are both electrically connected to a second end of the voltage stabilizing circuit (400).

7. The constant current discharge circuit according to claim 1, characterized in that: Also includes: A voltage divider circuit (600), wherein a first end of the voltage divider circuit (600) is electrically connected to a first end of the constant current source circuit (300) and a first end of the capacitor (101), respectively, and a second end of the voltage divider circuit (600) is electrically connected to a first end of the switch circuit (100).

8. The constant current discharge circuit according to claim 7, characterized in that: The voltage divider circuit (600) comprises: A voltage-dividing resistor (610), wherein a first end of the voltage-dividing resistor (610) is electrically connected to a first end of the constant current source circuit (300), and a second end of the voltage-dividing resistor (610) is electrically connected to a first end of the switch circuit (100).

9. The constant current discharge circuit according to any one of claims 1 to 8, characterized in that: The absorption circuit (200) comprises: A second resistor (210), wherein a first end of the second resistor (210) is electrically connected to a second end of the switch circuit (100), and a second end of the second resistor (210) is grounded.

10. A protection device, characterized in that: It comprises a constant current discharge circuit (10) as claimed in any one of claims 1 to 8.

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