CN115333346A - Filter circuit, implementation method thereof and filter device - Google Patents

Filter circuit, implementation method thereof and filter device Download PDF

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Publication number
CN115333346A
CN115333346A CN202210881307.1A CN202210881307A CN115333346A CN 115333346 A CN115333346 A CN 115333346A CN 202210881307 A CN202210881307 A CN 202210881307A CN 115333346 A CN115333346 A CN 115333346A
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China
Prior art keywords
voltage
switch
resistor
capacitor
electrically connected
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Chinese (zh)
Inventor
高瑞
张建洪
李志坚
程娟
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Zhuhai Ruite Photoelectric Technology Co ltd
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Zhuhai Ruite Photoelectric Technology Co ltd
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Priority to CN202210881307.1A priority Critical patent/CN115333346A/en
Publication of CN115333346A publication Critical patent/CN115333346A/en
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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
    • H02M1/14—Arrangements for reducing ripples from dc input or output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/04—Arrangements for preventing response to transient abnormal conditions, e.g. to lightning or to short duration over voltage or oscillations; Damping the influence of dc component by short circuits in ac networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Power Conversion In General (AREA)

Abstract

The invention discloses a filter circuit, an implementation method thereof and a filter device, and relates to the technical field of filtering. The filter circuit comprises a signal filtering unit, an active filter unit, a clamping unit, a voltage input end and a voltage output end; the output voltage flows into the signal filtering unit through the voltage input end, and the signal filtering unit is used for filtering high-frequency small signal interference of the input voltage; the active filter unit is used for filtering ripples and instantaneous surges of input voltage to form direct-current output voltage; the clamping unit is used for clamping the direct current output voltage at a fixed value and outputting the direct current output voltage through the voltage output end; the signal filtering unit, the active filtering unit and the clamping unit are electrically connected in sequence and are arranged between the voltage input end and the voltage output end. According to the filter circuit provided by the embodiment of the invention, the signal filtering unit can filter high-frequency small signal interference; the active filtering unit can filter out ripples and instantaneous surges; the clamping unit can clamp the DC output voltage at a fixed value.

Description

Filter circuit, implementation method thereof and filter device
Technical Field
The invention relates to the technical field of filtering, in particular to a filtering circuit, an implementation method thereof and a filtering device.
Background
The existing high-voltage direct-current power supply circuit generally filters a power supply through a capacitor, an LC filter circuit consisting of a capacitor and an inductor, an RC filter circuit consisting of a capacitor and a resistor and other filter circuits. However, these filter circuits inevitably require the use of a high-voltage capacitor with a high withstand voltage, and the filter capacitors with high voltage and large capacity have high cost and large volume.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a filter circuit, an implementation method thereof and a filter device, which can effectively filter ripples and restrain instantaneous surge.
In one aspect, a filter circuit according to an embodiment of the present invention includes: the signal filtering unit is used for filtering high-frequency small signal interference of the input voltage; the active filter unit is used for filtering ripples and instantaneous surges of input voltage to form direct-current output voltage; the clamping unit is used for clamping the direct current output voltage at a fixed value; the filter circuit is provided with a voltage input end and a voltage output end, and the signal filtering unit, the active filter unit and the clamping unit are electrically connected in sequence and are arranged between the voltage input end and the voltage output end.
According to some embodiments of the present invention, the signal filtering unit includes a filter capacitor, a first end of the filter capacitor is electrically connected to the voltage input terminal, and a second end of the filter capacitor is grounded.
According to some embodiments of the invention, the active filtering unit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor, a first switch and a second switch; a first end of the third resistor is electrically connected with the voltage input end, a second end of the third resistor is electrically connected with a first end of the fourth resistor, and a second end of the fourth resistor is grounded; the first capacitor is connected with the third resistor in parallel, the first end of the second capacitor is electrically connected with the voltage input end, and the second end of the second capacitor is electrically connected with the controlled end of the first switch; a first end of the second resistor is electrically connected with the voltage input end, a second end of the second resistor is electrically connected with a first end of the first switch, and a second end of the first switch is electrically connected with a connection point between a second end of the third resistor and a first end of the fourth resistor; a first end of the first resistor is electrically connected with a connection point between the voltage input end and the controlled end of the first switch, and a second end of the first resistor is electrically connected with a connection point between a second end of the second resistor and the first end of the first switch; the controlled end of the second switch is electrically connected with a connection point between the second end of the second resistor and the first end of the first switch, the first end of the second switch is electrically connected with a connection point between the voltage input end and the voltage output end, and the second end of the second switch is electrically connected with a connection point between the second end of the third resistor and the first end of the fourth resistor.
According to some embodiments of the invention, the first switch is a triode, the controlled terminal of the first switch is a base of the first switch, the first terminal of the first switch is a collector of the first switch, and the second terminal of the first switch is an emitter of the first switch; the second switch is a triode, the controlled end of the second switch is the base electrode of the second switch, the first end of the second switch is the collector electrode of the second switch, and the second end of the second switch is the emitter electrode of the second switch.
According to some embodiments of the invention, the clamping unit comprises a voltage dependent resistor, a first end of the voltage dependent resistor is electrically connected with a second end of the first capacitor, and a second end of the voltage dependent resistor is grounded.
According to some embodiments of the invention, the power supply further comprises a load resistor, a first end of the load resistor is electrically connected with the voltage output end, and a second end of the load resistor is grounded.
On the other hand, the implementation method of the filter circuit according to the embodiment of the invention comprises the following steps:
the input voltage is sent to the signal filtering unit through the voltage input end;
filtering high-frequency small signal interference of the input voltage by the signal filtering unit;
filtering ripples and instantaneous surges of the input voltage through an active filtering unit to form direct-current output voltage;
and clamping the direct current output voltage at a fixed value through a clamping unit, and outputting the direct current output voltage through a voltage output end.
According to some embodiments of the invention, the ripple and instantaneous surge of the input voltage are filtered out by an active filtering unit to form a direct current output voltage; the method includes clamping the dc output voltage at a fixed value by a clamping unit, and outputting the dc output voltage through a voltage output terminal, and specifically includes:
when the input voltage formed by superposing the direct-current voltage and the alternating-current interference signal is larger than a preset value, the voltage value at two ends of the piezoresistor is larger than the voltage stabilizing value of the piezoresistor, the impedance at two ends of the piezoresistor is reduced, and the first capacitor is charged through a loop formed by the first capacitor and the piezoresistor; at this time, the second switch is in an amplifying state, the base current of the second switch is increased, the output equivalent resistance between the collector and the emitter of the second switch is reduced, and the charging current of a loop formed by the first capacitor and the piezoresistor is increased, so that ripples and instantaneous surges of the input voltage are filtered, and the direct-current output voltage is formed;
when the input voltage formed by superposing alternating-current interference signals on direct-current voltage is smaller than the preset value, the first capacitor discharges through a loop formed by the first capacitor and the third resistor, a loop formed by the first capacitor, the second resistor and the first switch, a loop formed by the first capacitor, the second resistor and the second switch and a loop formed by the first capacitor and the second switch, so that ripples and instantaneous surges of the input voltage are filtered, and the direct-current output voltage is formed;
and clamping the direct current output voltage at a fixed value through the clamping unit, and outputting the direct current output voltage through the voltage output end.
On the other hand, the filtering apparatus according to the embodiment of the present invention includes the filtering circuit according to the embodiment of the above aspect of the present invention.
The filter circuit, the implementation method thereof and the filter device provided by the embodiment of the invention at least have the following beneficial effects: the signal filtering unit can filter the high-frequency small signal interference generated by the outside and the circuit; the active filter unit can effectively filter ripples output by the high-voltage direct-current power supply and restrain larger instantaneous current; the clamping unit can clamp the direct current output voltage at a fixed value; the filter circuit can increase the equivalent capacitance of the filter circuit without adopting a high withstand voltage value capacitor, can effectively filter ripples and high-frequency interference output by a high-voltage direct-current power supply, inhibits larger instantaneous current and enhances the loading capacity of the power supply.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic circuit diagram of a filter circuit according to an embodiment of the present invention;
FIG. 2 is a flow chart of steps of a method for implementing a filter circuit according to an embodiment of the present invention;
reference numerals:
the signal filtering unit 100, the active filtering unit 200, and the clamping unit 300.
Detailed Description
Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.
In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number. If there is a description of first and second for the purpose of distinguishing technical features only, this is not to be understood as indicating or implying a relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of technical features indicated.
In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.
On one hand, as shown IN fig. 1, the filter circuit according to the embodiment of the present invention includes a signal filtering unit 100, an active filter unit 200, a clamping unit 300, a voltage input terminal HV _ IN, and a voltage output terminal HV _ OUT; the output voltage flows into the signal filtering unit 100 through the voltage input terminal HV _ IN, and the signal filtering unit 100 is used for filtering high-frequency small signal interference of the input voltage; the active filter unit 200 is configured to filter ripples and instantaneous surges of the input voltage to form a dc output voltage; the clamping unit 300 is configured to clamp the dc output voltage at a fixed value, and output the dc output voltage through the voltage output terminal HV _ OUT; the signal filtering unit 100, the active filtering unit 200 and the clamping unit 300 are electrically connected IN sequence and are disposed between the voltage input terminal HV _ IN and the voltage output terminal HV _ OUT.
According to the filter circuit of the embodiment of the invention, the signal filtering unit 100 can filter the external and high-frequency small signal interference generated by the circuit; the active filter unit 200 can effectively filter ripples output by the high-voltage direct-current power supply, suppress large instantaneous current and enhance the load capacity of the power supply; the clamping unit 300 can clamp the dc output voltage at a fixed value, so as to provide a stable and high-voltage dc power supply with high load capability for the subsequent circuit.
Specifically, as shown IN fig. 1, IN some embodiments of the present invention, the signal filtering unit 100 includes a filter capacitor C64, a first end of the filter capacitor C64 is electrically connected to the voltage input terminal HV _ IN, a second end of the filter capacitor C64 is grounded, and the filter capacitor C64 can filter the external and high-frequency small signal interference generated by the circuit itself.
As shown in fig. 1, in some embodiments of the present invention, the active filtering unit 200 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, a first switch Q1, and a second switch Q2; a first end of the third resistor R3 is electrically connected to the voltage input terminal HV _ IN, a second end of the third resistor R3 is electrically connected to a first end of the fourth resistor R4, and a second end of the fourth resistor R4 is grounded; the first capacitor C1 is connected with the third resistor R3 IN parallel, the first end of the second capacitor C2 is electrically connected with the voltage input end HV _ IN, and the second end of the second capacitor C2 is electrically connected with the controlled end of the first switch Q1; a first end of the second resistor R2 is electrically connected with the voltage input end HV _ IN, a second end of the second resistor R2 is electrically connected with a first end of the first switch Q1, and a second end of the first switch Q1 is electrically connected with a connection point between a second end of the third resistor R3 and a first end of the fourth resistor R4; a first end of the first resistor R1 is electrically connected with a connection point between the voltage input end HV _ IN and the controlled end of the first switch Q1, and a second end of the first resistor R1 is electrically connected with a connection point between a second end of the second resistor R2 and the first end of the first switch Q1; the controlled terminal of the second switch Q2 is electrically connected to a connection point between the second terminal of the second resistor R2 and the first terminal of the first switch Q1, the first terminal of the second switch Q2 is electrically connected to a connection point between the voltage input terminal HV _ IN and the voltage output terminal HV _ OUT, and the second terminal of the second switch Q2 is electrically connected to a connection point between the second terminal of the third resistor R3 and the first terminal of the fourth resistor R4.
The first switch Q1 and the second switch Q2 can adopt components such as a triode, a field effect transistor, a thyristor, an operational amplifier, a comparator and the like; when the first switch Q1 and the second switch Q2 adopt triodes, the controlled end of the first switch Q1 is the base electrode of the first switch Q1, the first end of the first switch Q1 is the collector electrode of the first switch Q1, and the second end of the first switch Q1 is the emitter electrode of the first switch Q1; the controlled end of the second switch Q2 is a base electrode of the second switch Q2, the first end of the second switch Q2 is a collector electrode of the second switch Q2, and the second end of the second switch Q2 is an emitter electrode of the second switch Q2.
The clamping unit 300 includes a voltage dependent resistor TVS1, a first end of the voltage dependent resistor TVS1 is electrically connected to a second end of the first capacitor C1, and a second end of the voltage dependent resistor TVS1 is grounded. Note that, the clamping unit 300 may be a varistor, a TVS diode, or the like. In addition to the filtering effect, the clamping unit 300 also clamps the dc output voltage to a fixed value.
In some embodiments of the present invention, the dc output voltage is clamped to a fixed value, and then the load resistor RL is used to provide a stable high-voltage dc voltage for the subsequent circuit.
According to the active filter unit 200 of the embodiment of the present invention, 400V (or other values) high voltage direct current can be divided by the first resistor R1 and the second resistor R2, and a terminal voltage Vab =10V is formed at two points a and b; the Q1 and the Q2 can adopt NPN triodes with the same type and the current amplification factor of more than 60. Meanwhile, in order to make the amplification factors of Q1 and Q2 small and almost close to zero under the condition of direct current, the resistance value of the fourth resistor R4 needs to be large enough, such as 2M Ω or other reasonable values.
As shown in fig. 1, when an interference-free signal is input and the voltage is a dc voltage of 400V, since the voltage across the first capacitor C1 cannot suddenly change, the third resistor R3 is equivalent to a short circuit, the voltage across the varistor TVS1 is 400V, and the voltage-stabilizing value of the varistor TVS1 is 390V, when the two terminals of the TVS1 are subjected to reverse transient impact, it can change the high impedance between the two terminals thereof to a low impedance at a very fast speed; at this time, the first capacitor C1 is charged through a loop formed by the first capacitor C1 and the voltage dependent resistor TVS1 and a loop formed by the first capacitor C1 and the fourth resistor R4, and reaches a stable value of 10V.
When the input voltage formed by superposing the direct-current voltage and the alternating-current interference signal is greater than 400V, on one hand, the voltage value at the two ends of the voltage dependent resistor TVS1 exceeds 390V because the voltage at the two ends of the C1 cannot change suddenly, and the two ends of the TVS1 are subjected to reverse transient impact, so that the high impedance between the two ends of the TVS1 is changed into low impedance at a very high speed; at this time, the first capacitor C1 is charged through the first capacitor C1 and the TVS1 loop, and at the same time, Q1 and Q2 are changed from the off state to the amplification state, the base current of Q2 is increased, the output equivalent resistance between the collector and the emitter is decreased, the charging current of the loop formed by C1 and TVS1 is increased, the output ripple of the voltage is reduced through the equivalent transformation of the current source and the voltage source, and the transient surge is suppressed.
When the input voltage formed by superposing the direct current voltage and the alternating current interference signal is less than 400V, the base current of Q2 is increased and the output equivalent resistance between the collector and the emitter is reduced due to the fact that C1 discharges through a loop formed by C2 and Q1, the loop formed by C1 and R3, the loop formed by C1, R2 and Q1 and the loop formed by C1, R2 and Q2, particularly the loop formed by C1 and Q2 discharges rapidly, for a point a, according to the kirchhoff current law, the output current is increased through C1 release, the surge current is restrained, and the output ripple of the voltage is reduced through the equivalent transformation of a current source and a voltage source.
Therefore, according to the filter circuit provided by the embodiment of the invention, the equivalent capacitance of the high-voltage direct-current power supply filter circuit is effectively increased, a high-voltage-withstanding-value capacitor is not required, and only a low-voltage-withstanding-value capacitor is suitable, so that the cost and the volume are reduced; moreover, the circuit can effectively filter ripples and high-frequency small signal interference output by the high-voltage direct-current power supply, restrain larger instantaneous current and enhance the loading capacity of the power supply.
On the other hand, according to the filter device provided by the embodiment of the invention, by adopting the filter circuit, a stable high-voltage output power supply can be provided, the product performance is greatly improved, and the service life of the product is prolonged. For example, the filter circuit is applied to a laser radar (or other devices), and a stable high-voltage direct-current power supply can be output, so that the distance measurement precision is improved, and the service life of components is prolonged.
On the other hand, as shown in fig. 2, the implementation method of the filter circuit according to the embodiment of the present invention includes the following steps:
the input voltage is transmitted to the signal filtering unit 100 through the voltage input terminal HV _ IN;
the signal filtering unit 100 filters the high-frequency small signal interference of the input voltage;
the ripple and the instantaneous surge of the input voltage are filtered by the active filter unit 200 to form a direct current output voltage;
the dc output voltage is clamped at a fixed value by the clamping unit 300 and is output through the voltage output terminal HV _ OUT.
Specifically, after the input voltage is sent to the signal filtering unit 100 through the voltage input terminal HV _ IN, the high-frequency small signal interference generated by the outside and the circuit itself is filtered through the filter capacitor C64; meanwhile, the input voltage is sent to the active filter unit 200, when the input voltage formed by superimposing the ac interference signal with the dc voltage is greater than a preset value (for example, 400V or other values), the voltage value at both ends of the varistor TVS1 is greater than the regulated voltage value thereof, the impedance at both ends of the varistor TVS1 is reduced, and the first capacitor C1 is charged through a loop formed by the first capacitor C1 and the varistor TVS 1; at this time, the second switch Q2 is in an amplifying state, the base current of the second switch Q2 is increased, the output equivalent resistance between the collector and the emitter of the second switch Q2 is reduced, and the charging current of a loop formed by the first capacitor C1 and the voltage dependent resistor TVS1 is increased, so that ripples and instantaneous surges of input voltage are filtered, and direct current output voltage is formed; when the input voltage formed by superposing the direct-current voltage with the alternating-current interference signal is smaller than a preset value, the first capacitor C1 discharges through a loop formed by the first capacitor C1 and the third resistor R3, a loop formed by the first capacitor C1, the second resistor R2 and the first switch Q1, a loop formed by the first capacitor C1, the second resistor R2 and the second switch Q2 and a loop formed by the first capacitor C1 and the second switch Q2, so that ripples and instantaneous surges of the input voltage are filtered, and the direct-current output voltage is formed; finally, the dc output voltage is clamped at a fixed value by the clamping unit 300 and is output through the voltage output terminal HV _ OUT.
According to the implementation method of the filter circuit, the equivalent capacitance of the high-voltage direct-current power supply filter circuit is effectively increased, the capacitor with a high withstand voltage value is not needed, and only the capacitor with a low withstand voltage value is applicable, so that the cost and the volume are reduced; moreover, the circuit can effectively filter ripples and high-frequency small signal interference output by the high-voltage direct-current power supply, restrain larger instantaneous current and enhance the loading capacity of the power supply.
In the description herein, references to the description of "one embodiment," "a further embodiment," "some specific embodiments," or "some examples," etc., mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims (9)

1. A filter circuit, comprising:
the signal filtering unit is used for filtering high-frequency small signal interference of the input voltage;
the active filter unit is used for filtering ripples and instantaneous surges of input voltage to form direct-current output voltage;
the clamping unit is used for clamping the direct current output voltage at a fixed value;
the filter circuit is provided with a voltage input end and a voltage output end, and the signal filtering unit, the active filter unit and the clamping unit are electrically connected in sequence and are arranged between the voltage input end and the voltage output end.
2. The filter circuit according to claim 1, wherein the signal filtering unit comprises a filter capacitor, a first end of the filter capacitor is electrically connected to the voltage input end, and a second end of the filter capacitor is grounded.
3. The filter circuit according to claim 1, wherein the active filter unit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor, a first switch, and a second switch; a first end of the third resistor is electrically connected with the voltage input end, a second end of the third resistor is electrically connected with a first end of the fourth resistor, and a second end of the fourth resistor is grounded; the first capacitor is connected with the third resistor in parallel, the first end of the second capacitor is electrically connected with the voltage input end, and the second end of the second capacitor is electrically connected with the controlled end of the first switch; a first end of the second resistor is electrically connected with the voltage input end, a second end of the second resistor is electrically connected with a first end of the first switch, and a second end of the first switch is electrically connected with a connection point between a second end of the third resistor and a first end of the fourth resistor; a first end of the first resistor is electrically connected with a connection point between the voltage input end and the controlled end of the first switch, and a second end of the first resistor is electrically connected with a connection point between a second end of the second resistor and the first end of the first switch; the controlled end of the second switch is electrically connected with a connection point between the second end of the second resistor and the first end of the first switch, the first end of the second switch is electrically connected with a connection point between the voltage input end and the voltage output end, and the second end of the second switch is electrically connected with a connection point between the second end of the third resistor and the first end of the fourth resistor.
4. The filter circuit according to claim 3, wherein the first switch is a triode, the controlled terminal of the first switch is the base of the first switch, the first terminal of the first switch is the collector of the first switch, and the second terminal of the first switch is the emitter of the first switch; the second switch is a triode, the controlled end of the second switch is the base electrode of the second switch, the first end of the second switch is the collector electrode of the second switch, and the second end of the second switch is the emitter electrode of the second switch.
5. The filter circuit according to claim 3, wherein the clamping unit comprises a voltage dependent resistor, a first end of the voltage dependent resistor is electrically connected to the second end of the first capacitor, and a second end of the voltage dependent resistor is grounded.
6. The filter circuit of claim 1, further comprising a load resistor, wherein a first end of the load resistor is electrically connected to the voltage output terminal, and a second end of the load resistor is grounded.
7. A method for realizing a filter circuit is characterized by comprising the following steps:
the input voltage is sent to the signal filtering unit through the voltage input end;
filtering high-frequency small signal interference of the input voltage by the signal filtering unit;
filtering ripples and instantaneous surges of the input voltage through an active filtering unit to form direct-current output voltage;
and clamping the direct current output voltage at a fixed value through a clamping unit, and outputting the direct current output voltage through a voltage output end.
8. The method according to claim 7, wherein the ripple and the transient surge of the input voltage are filtered by an active filter unit to form a dc output voltage; the method includes clamping the dc output voltage at a fixed value by a clamping unit, and outputting the dc output voltage through a voltage output terminal, and specifically includes:
when the input voltage formed by superposing the direct-current voltage and the alternating-current interference signal is larger than a preset value, the voltage value at two ends of the piezoresistor is larger than the voltage stabilizing value of the piezoresistor, the impedance at two ends of the piezoresistor is reduced, and the first capacitor is charged through a loop formed by the first capacitor and the piezoresistor; at this time, the second switch is in an amplifying state, the base current of the second switch is increased, the output equivalent resistance between the collector and the emitter of the second switch is reduced, and the charging current of a loop formed by the first capacitor and the piezoresistor is increased, so that ripples and instantaneous surges of the input voltage are filtered, and the direct-current output voltage is formed;
when the input voltage formed by superposing alternating-current interference signals on direct-current voltage is smaller than the preset value, the first capacitor discharges through a loop formed by the first capacitor and the third resistor, a loop formed by the first capacitor, the second resistor and the first switch, a loop formed by the first capacitor, the second resistor and the second switch and a loop formed by the first capacitor and the second switch, so that ripples and instantaneous surges of the input voltage are filtered, and the direct-current output voltage is formed;
and clamping the direct current output voltage at a fixed value through the clamping unit, and outputting the direct current output voltage through the voltage output end.
9. A filter arrangement, comprising a filter circuit according to any one of claims 1-6.
CN202210881307.1A 2022-07-22 2022-07-22 Filter circuit, implementation method thereof and filter device Pending CN115333346A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210881307.1A CN115333346A (en) 2022-07-22 2022-07-22 Filter circuit, implementation method thereof and filter device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210881307.1A CN115333346A (en) 2022-07-22 2022-07-22 Filter circuit, implementation method thereof and filter device

Publications (1)

Publication Number Publication Date
CN115333346A true CN115333346A (en) 2022-11-11

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CN202210881307.1A Pending CN115333346A (en) 2022-07-22 2022-07-22 Filter circuit, implementation method thereof and filter device

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