Disclosure of Invention
Therefore, the constant-current discharge circuit and the protection device are provided for solving the problems that the relay contact is easy to damage and has potential safety hazards by adopting a mode that a relay is matched with a high-power resistor aiming at the charge discharge of the energy storage capacitor.
A constant current discharge circuit comprising:
the first end of the switch circuit is used for being electrically connected with the first end of the capacitor and a power supply respectively;
the first end of the absorption circuit is electrically connected with the second end of the switch circuit, and 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 with the first end of the switch circuit, and the second end of the constant current source circuit is electrically connected with the third end of the switch circuit;
the first end of the voltage stabilizing circuit is electrically connected with the third end of the switch circuit, and the second end of the voltage stabilizing circuit is electrically connected with the second end of the capacitor; and
and the first end of the control switch circuit is electrically connected with the second end of the constant current source circuit, and the second end of the control switch circuit is electrically connected with the second end of the voltage stabilizing circuit.
In one embodiment, when the control switch circuit is powered on, the switch circuit is in an off state;
and when the control switch circuit is switched off in a power failure mode, the switch circuit is in a conducting state.
In one embodiment, the switching circuit includes:
the first end of the first switch tube is electrically connected with the first end of the capacitor and the power supply respectively, the second end of the first switch tube is electrically connected with the first end of the absorption circuit, and the control end of the first switch tube is electrically connected with 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.
In one embodiment, the constant current source circuit includes:
a first end of the second switching tube is electrically connected with a first end of the switching circuit, and a control end of the second switching tube is electrically connected with a third end of the switching circuit;
and a first end of the first resistor is electrically connected with a second end of the second switch tube, and a second end of the first resistor is electrically connected with a third end of the switch circuit.
In one embodiment, the voltage stabilizing circuit comprises:
and the cathode of the voltage stabilizing diode is electrically connected with the second end of the constant current source circuit, and the anode of the voltage stabilizing diode is electrically connected with the second end of the capacitor.
In one embodiment, the control switch circuit includes:
and a first input end of the relay switch is electrically connected with a second end of the constant current source circuit, a second input end of the relay switch is used for electrically connecting a power supply, and a first output end and a second output end of the relay switch are electrically connected with a second end of the voltage stabilizing circuit.
In one embodiment, the constant current discharge circuit further includes:
and the first end of the voltage division circuit is electrically connected with the first end of the constant current source circuit and the first end of the capacitor respectively, and the second end of the voltage division circuit is electrically connected with the first end of the switch circuit.
In one embodiment, the voltage divider circuit includes:
and the first end of the divider resistor is electrically connected with the first end of the constant current source circuit, and the second end of the divider resistor is electrically connected with the first end of the switch circuit.
In one embodiment, the absorption circuit includes:
and a first end of the second resistor is electrically connected with a second end of the switch circuit, and a second end of the second resistor is grounded.
A protection device comprising the constant current discharge circuit of any one of the above embodiments.
Compared with the prior art, the constant current discharge circuit and the protection device control the switch circuit to be switched off when the system is powered off, and the constant current source circuit is matched with the voltage stabilizing circuit to output stable voltage to drive the switch circuit to be switched on and is matched with the absorption circuit to form the constant current discharge circuit, so that charges stored in the capacitor are discharged to the ground at constant current, and the discharge safety and reliability are improved.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and those skilled in the art will be able to make similar modifications without departing from the spirit of the application and it is therefore not intended to be limited to the embodiments disclosed below.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Referring to fig. 1, an embodiment of the present application provides a constant current discharge circuit 10, including: a switching circuit 100, an absorption circuit 200, a constant current source circuit 300, a voltage stabilizing circuit 400, and a control switching circuit 500. The first terminal of the switch circuit 100 is electrically connected to the first terminal of the capacitor 101 and the power source 102, respectively. A first terminal of the snubber circuit 200 is electrically connected to a second terminal of the switch circuit 100. The second terminal of the absorption circuit 200 and the second terminal of the capacitor 101 are both grounded. A first terminal of the constant current source circuit 300 is electrically connected to a first terminal of the switch circuit 100. A second terminal of the constant current source circuit 300 is electrically connected to a third terminal of the switching circuit 100. The first terminal of the voltage stabilizing circuit 400 is electrically connected to the third terminal of the switching circuit 100. The second end of the voltage stabilizing circuit 400 is electrically connected to the second end of the capacitor 101. A first terminal of the control switch circuit 500 is electrically connected to a second terminal of the constant current source circuit 300. The second terminal of the control switch circuit 500 is electrically connected to the second terminal of the voltage stabilizing circuit 400.
It is to be understood that the specific circuit configuration of the switching circuit 100 is not limited as long as there is a stable voltage conduction based on the output of the constant current source circuit 300. The specific circuit structure of the switching circuit 100 can be selected according to actual requirements. In one embodiment, the switching circuit 100 may be an IGBT (Insulated Gate bipolar transistor). In one embodiment, the switching circuit 100 may also be a MOS transistor.
It is understood that the specific circuit structure of the snubber circuit 200 is not limited as long as it has the function of forming a constant current discharge circuit in cooperation with the switch circuit 100. In one embodiment, the absorption circuit 200 may be a high power resistor. In one embodiment, the absorption circuit 200 may also be a non-linear resistive element (e.g., a varistor, etc.).
It is understood that the specific circuit structure of the constant current source circuit 300 is not limited as long as it has a function of outputting a stable voltage to drive the switching circuit 100 to be turned on in cooperation with the voltage stabilizing circuit 400. In one embodiment, the constant current source circuit 300 may be a constant current source. In one embodiment, the constant current source circuit 300 may also be formed by a depletion type MOS transistor with a resistor. When the system is powered off, the constant current source circuit 300 outputs a constant current as an excitation current of the voltage stabilizing circuit 400, so that the constant current source circuit 300 is matched with the voltage stabilizing circuit 400 to generate a stable voltage to drive the switching circuit 100 to be conducted, and is matched with the absorption circuit 200 to enable the charges stored in the capacitor 101 to be discharged in a constant current manner, thereby improving the safety and reliability of discharging.
It is understood that the specific circuit structure of the voltage stabilizing circuit 400 is not limited as long as the voltage stabilizing circuit has the function of generating a stable voltage to drive the switching circuit 100 to be turned on in cooperation with the constant current source circuit 300. In one embodiment, the voltage stabilizing circuit 400 may be a voltage regulator. In one embodiment, the voltage regulating circuit 400 may also be other voltage regulating devices such as a zener diode.
It is understood that the circuit structure of the control switch circuit 500 is not limited, as long as the control switch circuit 500 is turned on when the system is powered on, and the control switch circuit 500 is turned off when the system is powered off. In one embodiment, the control switch circuit 500 may employ a relay switch (e.g., an electromagnetic relay, an optical relay, etc.) having an isolation function. In one embodiment, the control switch circuit 500 may also be a transistor or the like.
Specifically, when the system is powered on (i.e., the power source 102 works normally), the control switch circuit 500 is turned on, and the switch circuit 100 is in an off state. While the absorption circuit 200 and the stabilizing circuit 400 are not operated, the constant current source circuit 300 is shorted 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 turned off, and at this time, the voltage stabilizing circuit 400 operates, and cooperates with the constant current source circuit 300 to generate a stable voltage, and outputs the voltage to the switch circuit 100. The switching circuit 100 is turned on, and the snubber circuit 200 operates. Through the matching of the absorption circuit 200 and the switch circuit 100, the charges stored in the capacitor 101 can be discharged at a constant current, so that the safety and reliability of discharge can be improved.
In this embodiment, when the system is powered down, the control switch circuit 500 is turned off, and 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 be turned on, and cooperates with the absorption circuit 200 to form a constant current discharge circuit, so that the charges stored in the capacitor 101 are discharged to the ground at a constant current, and the safety and reliability of discharge are further improved.
Referring to fig. 2, in one embodiment, the switching circuit 100 includes: a first switch tube 110. 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. 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.
In one embodiment, the first switch tube 110 may adopt an IGBT tube or an MOS tube. In one embodiment, the control terminal (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 in cooperation when the system is powered down, so that the charges stored in the capacitor 101 are discharged at a constant current along the snubber circuit 200, and thus, the safety and reliability of discharging can be improved.
In one embodiment, the constant current source circuit 300 includes: a second switch tube 310 and a first resistor 320. A first end of the second switch tube 310 is electrically connected to a first end of the switch circuit 100. The control terminal of the second switch tube 310 is electrically connected to the third terminal of the switch circuit 100. A first end of the first resistor 320 is electrically connected to a second end of the second switch tube 310. The second terminal of the first resistor 320 is electrically connected to the third terminal of the switch circuit 100.
In one embodiment, the second switch tube 310 may adopt a depletion type MOS tube. In one embodiment, the second switch tube 310 may also adopt other switch tubes (such as a triode, an IGBT tube, etc.). In one embodiment, the first resistor 320 may be a fixed-value resistor. When the system is powered off, the second switching tube 310, the first resistor 320 and the voltage stabilizing circuit 400 cooperate to generate a stable voltage to drive the switching circuit 100 to be properly conducted, and cooperate with the absorption circuit 200 to form a constant current discharge circuit, so that the charges stored in the capacitor 101 are subjected to constant current discharge.
In one embodiment, the stabilizing circuit 400 includes: a zener diode 410. The cathode of the zener diode 410 is electrically connected to the second terminal of the constant current source circuit 300. The anode of the zener diode 410 is electrically connected to the second terminal of the capacitor 101. In one embodiment, the zener diode 410 may be replaced with other voltage stabilizing devices, such as a voltage regulator, etc. Through the zener diode 410 cooperating with the constant current source circuit 300, a stable voltage can be generated to drive the switching circuit 100 to be properly conducted, and cooperate with the absorption circuit 200 to form a constant current discharge circuit, so that the charges stored in the capacitor 101 are subjected to constant current discharge.
In one embodiment, the control switch circuit 500 includes: a relay switch 510. A first input terminal of the relay switch 510 is electrically connected to a second terminal of the constant current source circuit 300. A second input of the relay switch 510 is used for electrically connecting the power supply 102. The first output terminal and the second output terminal of the relay switch 510 are electrically connected to the second terminal of the voltage stabilizing circuit 400. In one embodiment, the relay switch 510 may be an optical relay, or may be another type of relay (e.g., an electromagnetic relay). In one embodiment, the power source 102 may be a power source that is synchronously disconnected from the relay switch 510. I.e., when the system is powered down, the power supply 102 is also synchronously turned off. In one embodiment, the relay switch 510 and the capacitor 101 may share a power source, i.e., the power source 102 may simultaneously supply power to the relay switch 510 and the capacitor 101.
In one embodiment, the constant current discharge circuit 10 further includes: a voltage divider circuit 600. A first end of the voltage dividing 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. A second terminal of the voltage divider circuit 600 is electrically connected to the first terminal of the switch circuit 100.
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: the voltage dividing resistor 610. Specifically, a first end of the voltage dividing resistor 610 is electrically connected to a first end of the constant current source circuit 300. A second terminal of the voltage dividing resistor 610 is electrically connected to the first terminal of the switch circuit 100. The voltage dividing resistor 610 can provide voltage division for the constant current source circuit 300 when the system is powered down, so that damage is avoided.
In one embodiment, the absorption circuit 200 includes: a second resistor 210. A first terminal of the second resistor 210 is electrically connected to a second terminal of the switching circuit 100. A second terminal of the second resistor 210 is grounded. In one embodiment, the second resistor 210 may be a fixed-value resistor. In one implementation, the second resistor 210 may also be a non-linear resistive element (e.g., a voltage dependent resistor, etc.).
In one embodiment, the number of the second resistors 210 may be plural. That is, the absorption circuit 200 may include a plurality of the second resistors 210 connected in series in sequence. The second resistor 210 and the first switch tube 110 cooperate to form a constant current discharge circuit, so that when the capacitor 101 is powered down, the remaining charges of the capacitor can be subjected to constant current discharge, and the safety and reliability of the discharge are improved.
Referring to fig. 3, an embodiment of the present application provides a protection device 20, which includes the constant current discharge circuit 10 according to any one of the embodiments. The protection device 20 of this embodiment can control the switch circuit 500 to be turned off when the system is powered down, and 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 be turned on, and cooperates with the absorption circuit 200 to form a constant current discharge circuit, so that the charges stored in the capacitor 101 are discharged to the ground at a constant current, and the safety and reliability of discharge are further improved.
To sum up, when the system is powered down, the control switch circuit 500 is turned off, and at this time, the constant current source circuit 300 is matched with the voltage stabilizing circuit 400 to output stable voltage to drive the switch circuit 100 to be conducted, and is matched with the absorption circuit 200 to form a constant current discharge circuit, so that the charges stored in the capacitor 101 are discharged to the ground at a constant current, and the safety and reliability of discharge are improved.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.