CN112636583A - Filter circuit and bridge rectifier circuit - Google Patents
Filter circuit and bridge rectifier circuit Download PDFInfo
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- CN112636583A CN112636583A CN202011519851.9A CN202011519851A CN112636583A CN 112636583 A CN112636583 A CN 112636583A CN 202011519851 A CN202011519851 A CN 202011519851A CN 112636583 A CN112636583 A CN 112636583A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
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Abstract
The invention provides a filter circuit which comprises a first filter capacitor, a voltage detection module, a second filter capacitor, a third filter capacitor, a control module and a fourth filter capacitor, wherein the first filter capacitor is connected with the voltage detection module; the voltage detection module is used for detecting an output signal of the circuit to be filtered to obtain a detection signal and sending the detection signal to the control module; the control module is used for receiving the detection signal, controlling the second filter capacitor and the third filter capacitor to form a parallel relation when the detection signal is a low-voltage signal, and controlling the second filter capacitor and the third filter capacitor to form a series relation when the detection signal is a high-voltage signal, so that the size of the used capacitor is effectively reduced under the condition of ensuring high withstand voltage and large capacity, and the problems that the size of the filter capacitor is overlarge and the finished bridge rectifier circuit is overlarge when the alternating-current input voltage range of the existing bridge rectifier circuit is large are solved.
Description
Technical Field
The invention relates to the technical field of electronics, in particular to a filter circuit and a bridge rectifier circuit.
Background
In the prior art, a filter capacitor is adopted to shape a rectified waveform output by a bridge rectifier circuit, so that smooth direct current is obtained. The withstand voltage of the filter capacitor is determined by the alternating-current input voltage, and the capacity of the filter capacitor is determined by the output power. The higher the AC input voltage is, the higher the withstand voltage of the filter capacitor is, and the lower the AC input voltage is, the larger the capacitance of the filter capacitor is. When the variation range of the alternating-current input voltage is large, the withstand voltage of the filter capacitor is very high and the capacity of the filter capacitor is very large, so that the size of the filter capacitor is very large, and further the finished product of the bridge rectifier circuit is very large.
Disclosure of Invention
The invention provides a filter circuit and a bridge rectifier circuit, which are used for solving the problems that when the AC input voltage range of the conventional bridge rectifier circuit is large, the size of a filter capacitor is overlarge and the finished product of the bridge rectifier circuit is overlarge.
The present invention is achieved as such, and a filter circuit includes:
the voltage detection module is connected with the first filter capacitor, the second filter capacitor, the third filter capacitor, the control module and the fourth filter capacitor;
a common joint point among the anode of the first filter capacitor, the first end of the voltage detection module, the anode of the second filter capacitor and the first end of the control module is used as the first end of the filter circuit;
the second end of the voltage detection module is connected with the second end of the control module;
the negative electrode of the second filter capacitor is connected with the third end of the control module;
a fourth end of the control module is connected with the anode of the third filter capacitor, and a fifth end of the control module is connected with the first end of the fourth filter capacitor;
a common junction point among the negative electrode of the first filter capacitor, the third end of the voltage detection module, the negative electrode of the third filter capacitor, the second end of the fourth filter capacitor and the sixth end of the control module is used as the second end of the filter circuit;
the first end of the filter circuit is used for connecting the output end of the circuit to be filtered, and the second end of the filter circuit is used for grounding;
the voltage detection module is used for detecting an output signal of the circuit to be filtered to obtain a detection signal and sending the detection signal to the control module; the control module is used for receiving the detection signal, controlling the second filter capacitor and the third filter capacitor to form a parallel relation when the detection signal is a low-voltage signal, and controlling the second filter capacitor and the third filter capacitor to form a series relation when the detection signal is a high-voltage signal.
Optionally, the first filter capacitor is a high withstand voltage low capacity electrolytic capacitor, and the second filter capacitor and the third filter capacitor are low voltage electrolytic capacitors.
Optionally, the control module comprises:
the device comprises a control unit, a first switching tube, a second switching tube and a third switching tube;
a first end of the control unit is used as a second end of the control module, the second end of the control unit is connected with a first end of the first switching tube, a third end of the control unit is connected with a first end of the third switching tube, a fourth end of the control unit is connected with a first end of the second switching tube, and a fifth end of the control unit is used as a fifth end of the control module;
a common joint between the second end of the first switching tube and the second end of the third switching tube is used as a third end of the control module; a common joint between the third end of the first switch tube and the sixth end of the control unit is used as the sixth end of the control module;
the second end of the second switch tube is used as the first end of the control module; a common junction point between the third end of the second switching tube and the third end of the third switching tube is used as a fourth end of the control module;
the control unit is used for receiving the detection signal, controlling the first switch tube and the second switch tube to be conducted when the detection signal is a low-voltage signal so as to enable the second filter capacitor and the third filter capacitor to form a parallel connection relation, and controlling the third switch tube to be conducted when the detection signal is a high-voltage signal so as to enable the second filter capacitor and the third filter capacitor to form a series connection relation.
Optionally, the first switching tube, the second switching tube and the third switching tube are NMOS tubes respectively;
the grid electrode of the first switching tube is connected with the second end of the control unit, the grid electrode of the second switching tube is connected with the fourth end of the control unit, and the grid electrode of the third switching tube is connected with the third end of the control unit;
a common joint point between the drain electrode of the first switching tube and the drain electrode of the third switching tube is used as a third end of the control module; a common joint point between the source electrode of the first switch tube and the sixth end of the control unit is used as the sixth end of the control module;
the drain electrode of the second switching tube is used as the first end of the control module, and the common junction point between the source electrode of the second switching tube and the source electrode of the third switching tube is used as the fourth end of the control module.
Optionally, the voltage detection circuit is composed of a plurality of resistors connected in series with each other;
the first end of the first resistor is used as the first end of the voltage detection module, the second end of the last resistor is used as the third end of the voltage detection module, and any serial connection point between the resistors is used as the second end of the voltage detection module.
Optionally, the voltage detection module includes a first resistor, a second resistor, and a third resistor;
the first resistor is used as a first end of the voltage detection module, a second section of the first resistor is connected with a first end of the second resistor, and a common joint between a second end of the second resistor and a first end of the third resistor is used as a second end of the voltage detection module; and the second end of the third resistor is used as the third end of the voltage detection module.
A bridge rectifier circuit comprising a rectifier bridge and a filter circuit as claimed in any one of the preceding claims;
the first end of the rectifier bridge is connected with the live wire, the second end of the rectifier bridge is connected with the zero line, the third end of the rectifier bridge is connected with the first end of the filter circuit, and the fourth end of the rectifier bridge and the second end of the filter circuit are connected to the ground in a shared mode.
Optionally, the maximum withstand voltage value of the first filter capacitor is 400V, the capacity of the first filter capacitor is 27 μ F, and the size of the first filter capacitor is 10 × 17mm, and the maximum withstand voltage values of the second filter capacitor and the third filter capacitor are 200V, the capacity of the second filter capacitor is 47 μ F, and the size of the second filter capacitor is 10 × 17 mm.
The invention provides a filter circuit, which comprises a first filter capacitor, a voltage detection module, a second filter capacitor, a third filter capacitor, a control module and a fourth filter capacitor, wherein the first filter capacitor is connected with the voltage detection module; a common joint point among the anode of the first filter capacitor, the first end of the voltage detection module, the anode of the second filter capacitor and the first end of the control module is used as the first end of the filter circuit; the second end of the voltage detection module is connected with the second end of the control module; the negative electrode of the second filter capacitor is connected with the third end of the control module; a fourth end of the control module is connected with the anode of the third filter capacitor, and a fifth end of the control module is connected with the first end of the fourth filter capacitor; a common junction point among the negative electrode of the first filter capacitor, the third end of the voltage detection module, the negative electrode of the third filter capacitor, the second end of the fourth filter capacitor and the sixth end of the control module is used as the second end of the filter circuit; the first end of the filter circuit is used for connecting the output end of the circuit to be filtered, and the second end of the filter circuit is used for grounding; the voltage detection module is used for detecting an output signal of the circuit to be filtered to obtain a detection signal and sending the detection signal to the control module; the control module is used for receiving the detection signal, controlling the second filter capacitor and the third filter capacitor to form a parallel connection relation when the detection signal is a low-voltage signal, and controlling the second filter capacitor and the third filter capacitor to form a series connection relation when the detection signal is a high-voltage signal; thereby effectively reducing the size of the capacitor used while ensuring high withstand voltage and large capacity.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
FIG. 1 is a schematic diagram of a filter circuit according to an embodiment of the invention;
FIG. 2 is a diagram illustrating a control module in a filter circuit according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a filter circuit according to another embodiment of the present invention;
fig. 4 is a schematic diagram of a bridge rectifier circuit according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The filter circuit provided by the invention comprises a first filter capacitor, a voltage detection module, a second filter capacitor, a third filter capacitor, a control module and a fourth filter capacitor, wherein the voltage detection module is used for detecting an output signal of a circuit to be filtered, and the control module is used for changing the connection relationship between the second filter capacitor and the third filter capacitor into a parallel relationship or a series relationship according to the height of a detection signal, so that the size of the used capacitor is effectively reduced under the condition of ensuring high withstand voltage and large capacity.
Fig. 1 is a schematic diagram of a filter circuit 1 according to an embodiment of the present invention. As shown in fig. 1, the filter circuit 1 includes:
the voltage detection circuit comprises a first filter capacitor EC1, a voltage detection module 10, a second filter capacitor EC2, a third filter capacitor EC3, a control module 20 and a fourth filter capacitor C1;
a common junction point between the anode of the first filter capacitor EC1, the first terminal of the voltage detection module 10, the anode of the second filter capacitor EC2 and the first terminal p1 of the control module 20 serves as a first terminal of the filter circuit 1;
the second end of the voltage detection module 10 is connected with the second end p2 of the control module 20;
the negative electrode of the second filter capacitor EC2 is connected with the third terminal p3 of the control module 20;
the fourth terminal p4 of the control module 20 is connected to the positive electrode of the third filter capacitor EC3, and the fifth terminal p5 is connected to the first terminal of the fourth filter capacitor C1;
a common junction point among a cathode of the first filter capacitor EC1, a third terminal of the voltage detection module 10, a cathode of the third filter capacitor EC3, a second terminal of the fourth filter capacitor C1 and a sixth terminal p6 of the control module 20 is used as a second terminal of the filter circuit 1;
the first end of the filter circuit 1 is used for connecting the output end of a circuit to be filtered, and the second end of the filter circuit 1 is used for grounding GND;
the voltage detection module 10 is configured to detect an output signal of the circuit to be filtered, obtain a detection signal, and send the detection signal to the control module 20; the control module 20 is configured to receive the detection signal, control the second filter capacitor EC2 and the third filter capacitor EC3 to form a parallel connection when the detection signal is a low-voltage signal, and control the second filter capacitor EC2 and the third filter capacitor EC3 to form a series connection when the detection signal is a high-voltage signal.
In the embodiment of the invention, the first filter capacitor EC1 is a high-withstand voltage low-capacity electrolytic capacitor, and the second filter capacitor EC2 and the third filter capacitor EC3 are low-voltage electrolytic capacitors. The embodiment of the invention divides the filter capacitor used in the prior art into two low-voltage electrolytic capacitors and 1 high-voltage-withstanding low-capacity electrolytic capacitor. The voltage signal output by the circuit to be filtered is firstly filtered by a first filter capacitor EC1, and then is detected by the voltage detection module 10 to obtain a detection signal of the output signal of the circuit to be filtered, and the detection signal is sent to the control module 20; the connection relationship between the second filter capacitor EC2 and the third filter capacitor EC3 is changed to be a parallel relationship or a series relationship according to the high-low of the detection signal by the control module 20. The fourth filter capacitor C1 is used as the control module 20 supply filter.
When the detection signal is a low-voltage signal, the control module 20 controls the second filter capacitor EC2 and the third filter capacitor EC3 to form a parallel relationship, at this time, the first filter capacitor EC1, the second filter capacitor EC2 and the third filter capacitor EC3 form a parallel relationship, and the total capacity of the filter circuit 1 is the sum of the capacities of the first filter capacitor EC1, the second filter capacitor EC2 and the third filter capacitor EC3, that is, C3General assemblyThe withstand voltage of the filter circuit 1 is the withstand voltage of the second filter capacitor EC2 or the third filter capacitor EC3, so that the requirement for the large capacity of the filter capacitor is effectively met.
When the detection signal is a high-voltage signal, the control module 20 controls the second filter capacitor EC2 and the third filter capacitor EC3 to form a series connection relationship, at this time, the second filter capacitor EC2 and the third filter capacitor EC3 form a series connection relationship, and the total capacity of the filter circuit 1 is the sum of the series capacity of the second filter capacitor EC2 and the third filter capacitor EC3 and the capacity of the first filter capacitor EC1, that is, CGeneral assemblyThe withstand voltage of the filter circuit 1 is the sum of the withstand voltages of the second filter capacitor EC2 and the third filter capacitor EC3 ═ EC1+ (EC2 × EC3)/(EC2+ EC 3). In the embodiment of the invention, the second filter capacitor EC2 and the third filter capacitor EC3 are both low-voltage electrolytic capacitors, and the size of a single low-voltage electrolytic capacitor is smaller, and usually only 1/4 of a high-withstand-voltage high-capacity electrolytic capacitor is used, so that the problem that the size of the filter capacitor is too large under the condition of high withstand voltage and high capacity is effectively solved.
Optionally, as an implementation example of the present invention, as shown in fig. 2, the control module 20 includes:
a control unit 21, a first switch tube 22, a second switch tube 23 and a third switch tube 24;
the first end d1 of the control unit 21 serves as the second end p2 of the control module 20, the second end d2 is connected to the first end of the first switch tube 22, the third end d3 is connected to the first end of the third switch tube 24, the fourth end d4 is connected to the first end of the second switch tube 23, and the fifth end d5 serves as the fifth end p5 of the control module 20;
a common junction point between the second end of the first switching tube 22 and the second end of the third switching tube 24 is used as a third end p3 of the control module 20; a common point between the third terminal of the first switch tube 22 and the sixth terminal d6 of the control unit 21 is used as a sixth terminal p6 of the control module 20;
the second end of the second switch tube 23 is used as the first end p1 of the control module 20; a common junction point between the third terminal of the second switching tube 23 and the third terminal of the third switching tube 24 serves as a fourth terminal p4 of the control module 20;
the control unit is configured to receive the detection signal, control the first switch tube 22 and the second switch tube 23 to be turned on when the detection signal is a low-voltage signal, so that the second filter capacitor EC2 and the third filter capacitor EC3 form a parallel relationship, and control the third switch tube 24 to be turned on when the detection signal is a high-voltage signal, so that the second filter capacitor EC2 and the third filter capacitor EC3 form a series relationship.
In the embodiment of the present invention, first ends of the first switch tube 22, the second switch tube 23, and the third switch tube 24 are respectively used as control ends of the first switch tube 22, the second switch tube 23, and the third switch tube 24, and are connected to the control unit 21. The control unit 21 receives the detection signal through the first end d1, and determines the high and low voltages of the detection signal.
When the detection signal is a low-voltage signal, the control unit 21 generates a conduction signal of the first switch tube 22 and the second switch tube 23 to make the first switch tube 22 and the second switch tube 23 conduct; when the first switch tube 22 and the second switch tube 23 are conducted, the second filter capacitor EC2 and the third filter capacitor EC3 form a parallel connection relationship. At this time, the first filter capacitor EC1, the second filter capacitor EC2 and the third filter capacitor EC3 are connected in parallel, and the total capacity of the filter circuit 1 is the sum of the capacities of the first filter capacitor EC1, the second filter capacitor EC2 and the third filter capacitor EC3, that is, CGeneral assemblyThe withstand voltage of the filter circuit 1 is the withstand voltage of the second filter capacitor EC2 or the third filter capacitor EC3, so that the requirement for the large capacity of the filter capacitor is effectively met.
When the detection signal is a high-voltage signal, the control unit 21 generates a conduction signal of the third switch tube 24 to make the third switch tube 24 conduct; when the third switch tube 24 is turned on, the second filter capacitor EC2 and the third filter capacitor EC3 form a series relationship. At this time, the second filter capacitor EC2 and the third filter capacitor EC3 are connected in series and then connected in parallel with the first filter capacitor EC1, and the total capacity of the filter circuit 1 is the sum of the series capacity of the second filter capacitor EC2 and the third filter capacitor EC3 and the capacity of the first filter capacitor EC1, that is, CGeneral assemblyThe withstand voltage of the filter circuit 1 is the sum of the withstand voltages of the second filter capacitor EC2 and the third filter capacitor EC3 ═ EC1+ (EC2 × EC3)/(EC2+ EC 3). In the embodiment of the invention, the second filter capacitor EC2 and the third filter capacitor EC3 are both low-voltage electrolytic capacitors, and the size of a single low-voltage electrolytic capacitor is smaller, and usually only 1/4 of a high-withstand-voltage high-capacity electrolytic capacitor is used, so that the problem that the size of the filter capacitor is too large under the condition of high withstand voltage and high capacity is effectively solved.
Optionally, as a preferred example of the present invention, as shown in fig. 2, the first switching tube 22, the second switching tube 23, and the third switching tube 24 are NMOS tubes respectively;
the gate G of the first switching tube 22 is connected to the second end d2 of the control unit 21, the gate G of the second switching tube 23 is connected to the fourth end d4 of the control unit 21, and the gate G of the third switching tube 24 is connected to the third end d3 of the control unit 21;
a common junction point between the drain electrode D of the first switching tube 22 and the drain electrode D of the third switching tube 24 is used as a third end p3 of the control module 20; a common node between the source S of the first switch tube 22 and the sixth terminal d6 of the control unit 21 is used as the sixth terminal p6 of the control module 20;
the drain D of the second switching tube 23 serves as the first end p1 of the control module 20, and the common node between the source S of the second switching tube 23 and the source S of the third switching tube 24 serves as the fourth end p4 of the control module 20.
Here, the control unit 21 receives the detection signal through the first end d1, and determines high and low voltages of the detection signal. When the detection signal is a low voltage signal, the control circuit 21 provides a high level to the first switch tube 22 and the second switch tube 23, so that the first switch tube 22 and the second switch tube 23 are turned on; when the first switch tube 22 and the second switch tube 23 are conducted, the second filter capacitor EC2 and the third filter capacitor EC3 form a parallel connection relationship.
When the detection signal is a high-voltage signal, the control circuit 21 provides a high level to the third switch tube 24, so that the third switch tube 24 is turned on; when the third switch tube 24 is turned on, the second filter capacitor EC2 and the third filter capacitor EC3 form a series relationship.
Alternatively, as a preferred example of the present invention, the voltage detection circuit 10 is composed of several resistors connected in series;
a first end of the first resistor is used as a first end of the voltage detection module 10, a second end of the last resistor is used as a third end of the voltage detection module 10, and any series connection point between the resistors is used as a second end of the voltage detection module 10.
For convenience of understanding, the voltage detection module 10 will be described below by taking an example in which 3 resistors are connected in series with each other. As shown in fig. 3, the voltage detection module includes a first resistor R1, a second resistor R2, and a third resistor R3; the first resistor R1 serves as a first end of the voltage detection module 10, and receives an output signal of the circuit to be filtered; a second end of the first resistor R2 is connected to a first end of the second resistor R2, and a common node between a second end of the second resistor R2 and a first end of the third resistor R3 serves as a second end of the voltage detection module 10, and outputs a detection signal to the control module 20; the second end of the third resistor R3 is used as the third end of the voltage detection module 10, and the second end of the circuit to be filtered and the third end are connected to the ground.
Here, after the output signal of the circuit to be filtered is divided by the first resistor R1, the second resistor R2, and the third resistor R3, a voltage drop is formed across the third resistor R3, and the divided signal across the third resistor R3 is used as a detection signal and provided to the following control module 20 in the embodiment of the present invention.
The embodiment of the present invention further provides a bridge rectifier circuit, as shown in fig. 4, the bridge rectifier circuit includes a rectifier bridge 2 and the filter circuit 1;
the first end of the rectifier bridge 2 is connected with the live wire L, the second end is connected with the zero line N, the third end is connected with the first end of the filter circuit 1, and the fourth end and the second end of the filter circuit 1 are connected to the ground GND in a shared mode.
In the embodiment of the present invention, the filter circuit 1 is configured to filter an output signal of the rectifier bridge 2. Specifically, the voltage detection module 10 detects an output signal of the rectifier bridge 2 to obtain a detection signal, and then the control module 20 changes the connection relationship between the second filter capacitor EC2 and the third filter capacitor EC3 to be a parallel relationship or a series relationship according to the level of the detection signal.
When the ac input signal is low, the output signal of the rectifier bridge 2 is a low-voltage signal, the control module 20 controls the second filter capacitor EC2 and the third filter capacitor EC3 to form a parallel relationship, at this time, the first filter capacitor EC1, the second filter capacitor EC2 and the third filter capacitor EC3 form a parallel relationship, and the total capacity of the filter circuit 1 is the sum of the capacities of the first filter capacitor EC1, the second filter capacitor EC2 and the third filter capacitor EC3, that is, CGeneral assemblyThe withstand voltage of the filter circuit 1 is the withstand voltage of the second filter capacitor EC2 or the third filter capacitor EC3, so that the requirement on the large capacity of the filter capacitor is effectively met; when the ac input signal is high, the output signal of the rectifier bridge 2 is a high-voltage signal, the control module 20 controls the second filter capacitor EC2 and the third filter capacitor EC3 to form a series connection relationship, at this time, the second filter capacitor EC2 and the third filter capacitor EC3 form a series connection relationship, and the total capacity of the filter circuit 1 is the series capacity of the second filter capacitor EC2 and the third filter capacitor EC3 and the first filter capacitor EC 3538The sum of the capacities of the filter capacitors EC1, i.e. CGeneral assemblyThe withstand voltage of the filter circuit 1 is the sum of the withstand voltages of the second filter capacitor EC2 and the third filter capacitor EC3 ═ EC1+ (EC2 × EC3)/(EC2+ EC 3). In the embodiment of the invention, the second filter capacitor EC2 and the third filter capacitor EC3 are both low-voltage electrolytic capacitors, and the size of a single low-voltage electrolytic capacitor is smaller, and usually only 1/4 of a high-withstand-voltage high-capacity electrolytic capacitor is used, so that the problem that the size of the filter capacitor is too large under the condition of high withstand voltage and high capacity is effectively solved.
Optionally, as a preferred example of the present invention, taking a 65W flyback switching power supply as an example, the input voltage range of the rectifier bridge 2 is 100-240 Vac, the selection type of the filter capacitor in the prior art is 400V120uF, the size of the filter capacitor is 18 × 32mm, and the volume of the filter capacitor is 8138mm 3. According to the filter circuit provided by the embodiment of the invention, the first filter capacitor EC1 can be a high-withstand-voltage low-capacity electrolytic capacitor with a maximum withstand voltage value of 400V, a capacity of 27 μ F and a size of 10 × 17mm, the second filter capacitor EC2 and the third filter capacitor EC3 can be a low-voltage electrolytic capacitor with a maximum withstand voltage value of 200V, a capacity of 47 μ F and a size of 10 × 17mm, and the size of the first filter capacitor EC1, the size of the second filter capacitor EC2 and the size of the third filter capacitor EC3 are 1334 × 3-4002 mm3, which is reduced by about 50% compared with the size of the high-withstand-voltage high-capacity electrolytic capacitor, so that the size of the filter capacitor used by the rectifier bridge 2 is effectively reduced, and the problems that the size of the filter capacitor is too large and the finished bridge rectifier is too large when the ac input voltage range of the existing bridge rectifier circuit is large are solved.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.
Claims (8)
1. A filter circuit, comprising:
the voltage detection module is connected with the first filter capacitor, the second filter capacitor, the third filter capacitor, the control module and the fourth filter capacitor;
a common joint point among the anode of the first filter capacitor, the first end of the voltage detection module, the anode of the second filter capacitor and the first end of the control module is used as the first end of the filter circuit;
the second end of the voltage detection module is connected with the second end of the control module;
the negative electrode of the second filter capacitor is connected with the third end of the control module;
a fourth end of the control module is connected with the anode of the third filter capacitor, and a fifth end of the control module is connected with the first end of the fourth filter capacitor;
a common junction point among the negative electrode of the first filter capacitor, the third end of the voltage detection module, the negative electrode of the third filter capacitor, the second end of the fourth filter capacitor and the sixth end of the control module is used as the second end of the filter circuit;
the first end of the filter circuit is used for connecting the output end of the circuit to be filtered, and the second end of the filter circuit is used for grounding;
the voltage detection module is used for detecting an output signal of the circuit to be filtered to obtain a detection signal and sending the detection signal to the control module; the control module is used for receiving the detection signal, controlling the second filter capacitor and the third filter capacitor to form a parallel relation when the detection signal is a low-voltage signal, and controlling the second filter capacitor and the third filter capacitor to form a series relation when the detection signal is a high-voltage signal.
2. The filter circuit according to claim 1, wherein the first filter capacitor is a high withstand voltage low capacity electrolytic capacitor, and the second filter capacitor and the third filter capacitor are low voltage electrolytic capacitors.
3. The filter circuit of claim 2, wherein the control module comprises:
the device comprises a control unit, a first switching tube, a second switching tube and a third switching tube;
a first end of the control unit is used as a second end of the control module, the second end of the control unit is connected with a first end of the first switching tube, a third end of the control unit is connected with a first end of the third switching tube, a fourth end of the control unit is connected with a first end of the second switching tube, and a fifth end of the control unit is used as a fifth end of the control module;
a common joint between the second end of the first switching tube and the second end of the third switching tube is used as a third end of the control module; a common joint between the third end of the first switch tube and the sixth end of the control unit is used as the sixth end of the control module;
the second end of the second switch tube is used as the first end of the control module; a common junction point between the third end of the second switching tube and the third end of the third switching tube is used as a fourth end of the control module;
the control unit is used for receiving the detection signal, controlling the first switch tube and the second switch tube to be conducted when the detection signal is a low-voltage signal so as to enable the second filter capacitor and the third filter capacitor to form a parallel connection relation, and controlling the third switch tube to be conducted when the detection signal is a high-voltage signal so as to enable the second filter capacitor and the third filter capacitor to form a series connection relation.
4. The filter circuit according to claim 3, wherein the first switch tube, the second switch tube and the third switch tube are NMOS tubes respectively;
the grid electrode of the first switching tube is connected with the second end of the control unit, the grid electrode of the second switching tube is connected with the fourth end of the control unit, and the grid electrode of the third switching tube is connected with the third end of the control unit;
a common joint point between the drain electrode of the first switching tube and the drain electrode of the third switching tube is used as a third end of the control module; a common joint point between the source electrode of the first switch tube and the sixth end of the control unit is used as the sixth end of the control module;
the drain electrode of the second switching tube is used as the first end of the control module, and the common junction point between the source electrode of the second switching tube and the source electrode of the third switching tube is used as the fourth end of the control module.
5. Filter circuit according to one of claims 1 to 4, characterized in that the voltage detection circuit is formed by several resistors connected in series with each other;
the first end of the first resistor is used as the first end of the voltage detection module, the second end of the last resistor is used as the third end of the voltage detection module, and any serial connection point between the resistors is used as the second end of the voltage detection module.
6. The filter circuit of claim 5, wherein the voltage detection module comprises a first resistor, a second resistor, a third resistor;
the first resistor is used as a first end of the voltage detection module, a second section of the first resistor is connected with a first end of the second resistor, and a common joint between a second end of the second resistor and a first end of the third resistor is used as a second end of the voltage detection module; and the second end of the third resistor is used as the third end of the voltage detection module.
7. A bridge rectifier circuit, comprising a rectifier bridge and a filter circuit according to any one of claims 1 to 6;
the first end of the rectifier bridge is connected with the live wire, the second end of the rectifier bridge is connected with the zero line, the third end of the rectifier bridge is connected with the first end of the filter circuit, and the fourth end of the rectifier bridge and the second end of the filter circuit are connected to the ground in a shared mode.
8. The bridge rectifier circuit according to claim 7 wherein said first filter capacitor has a maximum withstand voltage of 400V, a capacity of 27 μ F, and a size of 10 x 17mm, and said second filter capacitor and said third filter capacitor have a maximum withstand voltage of 200V, a capacity of 47 μ F, and a size of 10 x 17 mm.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011519851.9A CN112636583A (en) | 2020-12-21 | 2020-12-21 | Filter circuit and bridge rectifier circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011519851.9A CN112636583A (en) | 2020-12-21 | 2020-12-21 | Filter circuit and bridge rectifier circuit |
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| CN112636583A true CN112636583A (en) | 2021-04-09 |
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| CN202011519851.9A Pending CN112636583A (en) | 2020-12-21 | 2020-12-21 | Filter circuit and bridge rectifier circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113381492A (en) * | 2021-07-12 | 2021-09-10 | 深圳市助尔达电子科技有限公司 | High power density intelligent charger |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113381492A (en) * | 2021-07-12 | 2021-09-10 | 深圳市助尔达电子科技有限公司 | High power density intelligent charger |
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