Filtering device for high-voltage power supply
By designing filter devices for active resistor units and filter capacitor units in high-voltage power supplies, using NPN type transistors and resistors, the problems of complex structure and high cost in the prior art are solved, and high-efficiency filtering in high-voltage and high current situations are realized Effective and reliable performance.
Patent Information
- Application Number
- CN202421015911.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-11
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-05-11
AI Technical Summary
The prior art has problems such as complex structure, high cost, and inappropriate high current scenarios in reducing the output ripple of piezoelectric driving circuit power supply, and it is difficult to provide an active high-voltage filter circuit with simple structure and reliable performance.
Design a filtering device including an active resistor unit and a filter capacitor unit, using NPN type transistor and resistor to form an active resistor, electrolytic capacitor and ceramic capacitor to form a filter capacitor, connected in series at the output end of the high-voltage switching power supply and the input end of the piezoelectric driver Between, the filtering effect is achieved between the active resistor output terminal and the common ground.
In high voltage and high current situations, the voltage drop of the filter circuit is small and not affected by load current, the components are easy to select, the circuit structure is simple, the performance is reliable and stable, which reduces ripple and reduces costs.
Smart Images
Figure CN222262480U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a filtering device for a high voltage power supply. Background Art
[0002] In the field of precision positioning technology, the power supply voltage of the piezoelectric drive circuit is as high as hundreds of volts. The power supply is usually a switching power supply, and its output voltage contains ripples related to the switching frequency. The frequency is generally tens of kilohertz or higher, and the peak-to-peak value can reach tens of millivolts or even hundreds of millivolts. The output ripple of the piezoelectric drive circuit power supply directly affects the accuracy of the positioning system. In order to ensure the accuracy of the positioning system, the output ripple of the piezoelectric drive circuit power supply needs to be reduced to a reasonable range before the piezoelectric drive circuit can be powered.
[0003] At present, there are several methods to reduce the output ripple of switching power supplies:
[0004] The first method is to connect an LDO in series at the output end of the switching power supply to reduce the output ripple. However, the supply voltage of the piezoelectric drive circuit is as high as hundreds of volts. There are very few LDOs that can withstand such a high input voltage, and they are expensive.
[0005] The second method is to connect multiple large-capacity electrolytic capacitors in parallel at the output end of the switching power supply. Although this has a certain effect on reducing ripple, the ripple will not decrease linearly with the increase of capacitance. When the capacitance reaches a certain level, the effect of further increasing the capacitance on improving the ripple will become less obvious, and as the capacitance increases, it will bring about problems such as rising costs and excessive surge current when powering on.
[0006] The third method is to connect a passive RC filter circuit in series at the output end of the switching power supply. This method has a certain effect, but a voltage drop will occur on the filter resistor, and it cannot be used in scenarios with large load currents.
[0007] The fourth method is to build a discrete LDO and connect it in series at the output end of the switching power supply. This method has a very good filtering effect, but the circuit structure is relatively complicated.
[0008] In order to solve the above problems, it is necessary to design an active high-voltage filter circuit with simple structure and reliable performance. Utility Model Content
[0009] The purpose of the utility model is to overcome the shortcomings of the prior art and provide a filtering device for a high voltage power supply.
[0010] The purpose of the utility model is achieved through the following technical solutions:
[0011] The invention discloses a filtering device for a high voltage power supply, which is characterized in that it comprises an active resistance unit and a filtering capacitor unit, wherein the active resistance unit is connected in series between the output end of the high voltage switching power supply and the input end of the piezoelectric driver, and the filtering capacitor unit is connected in parallel between the output end of the active resistance unit and a common ground.
[0012] Further, the above-mentioned filtering device for high-voltage power supply, wherein the active resistance unit includes a transistor, a resistor and a diode, the filtering capacitor unit includes a first capacitor and a second capacitor, the positive electrode of the high-voltage switching power supply is connected to the collector of the transistor, and the negative electrode of the high-voltage switching power supply is connected to the common ground; the positive electrode of the diode is connected to the emitter of the transistor, and the negative electrode of the diode is connected to the collector of the transistor; the base of the transistor is connected to the first end of the resistor, the collector of the transistor is connected to the second end of the resistor and the negative electrode of the diode, the emitter of the transistor is connected to the positive electrode of the first capacitor and the positive electrode of the diode, and the negative electrode of the first capacitor is connected to the common ground; the first end of the second capacitor is connected to the positive electrode of the first capacitor, and the second end of the second capacitor is connected to the common ground; the positive electrode of the piezoelectric driver is connected to the emitter of the transistor, and the negative electrode of the piezoelectric driver is connected to the common ground.
[0013] Furthermore, in the above-mentioned filtering device for high-voltage power supply, the transistor is an NPN transistor.
[0014] Furthermore, in the above-mentioned filtering device for high-voltage power supply, the transistor is an NPN-type Darlington transistor.
[0015] Furthermore, in the above-mentioned filtering device for high-voltage power supply, the first capacitor is an electrolytic capacitor.
[0016] Furthermore, in the above-mentioned filtering device for high-voltage power supply, the second capacitor is a ceramic capacitor.
[0017] Furthermore, in the above-mentioned filtering device for high-voltage power supply, the resistance value of the resistor is 1 ohm to 900 ohms.
[0018] Compared with the prior art, the present invention has significant advantages and beneficial effects, which are specifically embodied in the following aspects:
[0019] The utility model is based on the active resistor and capacitor of the triode to form a power filter device. The high-voltage-resistant triode and filter capacitor are used in the filter circuit for high-voltage and high-current applications. The voltage drop of the filter circuit is very small and is not affected by the load current. The components are easy to select, the circuit structure is simple, and the performance is reliable and stable.
[0020] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by implementing the specific implementation of the utility model. The purpose and other advantages of the utility model can be achieved and obtained by the structures specifically pointed out in the written description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.
[0022] Figure 1 : Schematic diagram of the principle of the filter device of the utility model
[0023] Figure 2 : Schematic diagram of the circuit structure of the utility model filtering device. DETAILED DESCRIPTION
[0024] The technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, rather than all the embodiments. The components of the embodiment of the utility model generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiment of the utility model provided in the drawings is not intended to limit the scope of the utility model claimed for protection, but merely represents the selected embodiment of the utility model. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the utility model.
[0025] It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. At the same time, in the description of the utility model, directional terms and order terms are only used to distinguish the description and cannot be understood as indicating or implying relative importance.
[0026] like Figure 1 As shown, a filtering device for a high-voltage power supply includes an active resistance unit 103 and a filtering capacitor unit 104. The active resistance unit 103 is connected in series between the output end of the high-voltage switching power supply 101 and the input end of the piezoelectric driver 102, and the filtering capacitor unit 104 is connected in parallel between the output end of the active resistance unit 103 and the common ground G.
[0027] like Figure 2 The active resistance unit 103 includes a transistor Q1, a resistor R1 and a diode D1, the filter capacitor unit 104 includes a first capacitor C1 and a second capacitor C2, the positive electrode of the high-voltage switching power supply 101 is connected to the collector of the transistor Q1, and the negative electrode of the high-voltage switching power supply 101 is connected to the common ground G; the positive electrode of the diode D1 is connected to the emitter of the transistor Q1, and the negative electrode of the diode D1 is connected to the collector of the transistor Q1; the base of the transistor Q1 is connected to the first end of the resistor R1, the collector of the transistor Q1 is connected to the second end of the resistor R1 and the negative electrode of the diode D1, the emitter of the transistor Q1 is connected to the positive electrode of the first capacitor C1 and the positive electrode of the diode D1, and the negative electrode of the first capacitor C1 is connected to the common ground G; the first end of the second capacitor C2 is connected to the positive electrode of the first capacitor C1, and the second end of the second capacitor C2 is connected to the common ground G; the positive electrode of the piezoelectric driver 102 is connected to the emitter of the transistor Q1, and the negative electrode of the piezoelectric driver 102 is connected to the common ground G.
[0028] The transistor Q1 is an NPN transistor or an NPN Darlington transistor. The first capacitor C1 is an electrolytic capacitor with a capacitance of tens of uF or even higher. The second capacitor C2 is a ceramic capacitor with a capacitance of less than tens of uF. The resistance of the resistor R1 is from one ohm to hundreds of ohms.
[0029] Transistor Q1 and resistor R1 form an active resistor. When the circuit works normally, transistor Q1 is in the on state. The resistance value of resistor R1 is very small, which is used to adjust the conduction degree of transistor Q1 and thus adjust the size of the active resistor.
[0030] The base current of transistor Q1 is determined by the collector current and the current amplification factor hFE. The maximum collector current is only affected by the transistor I CM restrictions.
[0031] The voltage drop caused by the DC component in the switching power supply output flowing through the active resistor is equal to the voltage drop across the resistor R1 plus the forward bias voltage V of the emitter junction of the transistor Q1. BE Since the resistance of resistor R1 and the base current of transistor Q1 are very small, the voltage across resistor R1 can be ignored. Since the DC impedance of the capacitor is infinite, the DC component voltage value obtained at the load input end is:
[0032] V OUT =V IN -V BE
[0033] The first capacitor C1 is an electrolytic capacitor with a relatively large capacity and a relatively small AC impedance. The second capacitor C2 is a ceramic capacitor with a relatively small capacity and a relatively large AC impedance. For the AC component in the switching power supply, according to the voltage division theorem, its high-frequency component will be attenuated after passing through the second capacitor C2, and its low-frequency component will be attenuated after passing through the first capacitor C1.
[0034] The diode D1 is used to protect the transistor Q1 to prevent the transistor Q1 from being damaged due to the collector voltage of the transistor Q1 dropping faster than the emitter voltage of the transistor Q1 after the circuit is powered off.
[0035] In summary, the utility model forms a power filter device based on the active resistor and capacitor of the triode, and uses the high-voltage-resistant triode and filter capacitor. The filter circuit is used in high-voltage and high-current situations; the voltage drop of the filter circuit is very small and is not affected by the load current. The components are easy to select. The circuit structure is simple and the performance is reliable and stable.
[0036] The above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. For those skilled in the art, the utility model may have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model. It should be noted that similar numbers and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.
[0037] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention.
[0038] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.
Claims
1. A filter device for a high voltage power supply, characterized in that: The invention comprises an active resistance unit (103) and a filter capacitor unit (104), wherein the active resistance unit (103) is connected in series between the output end of the high-voltage switching power supply (101) and the input end of the piezoelectric driver (102), and the filter capacitor unit (104) is connected in parallel between the output end of the active resistance unit (103) and a common ground G.
2. The filter device for high voltage power supply according to claim 1, characterized in that: The active resistance unit (103) comprises a transistor (Q1), a resistor (R1) and a diode (D1); the filter capacitor unit (104) comprises a first capacitor (C1) and a second capacitor (C2); the positive electrode of the high-voltage switching power supply (101) is connected to the collector of the transistor (Q1); the negative electrode of the high-voltage switching power supply (101) is connected to the common ground G; the positive electrode of the diode (D1) is connected to the emitter of the transistor (Q1); the negative electrode of the diode (D1) is connected to the collector of the transistor (Q1); the base of the transistor (Q1) is connected to the base of the resistor (R1); The first end, the collector of the transistor (Q1) is connected to the second end of the resistor (R1) and the cathode of the diode (D1), the emitter of the transistor (Q1) is connected to the anode of the first capacitor (C1) and the anode of the diode (D1), and the cathode of the first capacitor (C1) is connected to a common ground G; the first end of the second capacitor (C2) is connected to the anode of the first capacitor (C1), and the second end of the second capacitor (C2) is connected to the common ground G; the anode of the piezoelectric driver (102) is connected to the emitter of the transistor (Q1), and the cathode of the piezoelectric driver (102) is connected to the common ground G.
3. The filter device for high voltage power supply according to claim 2, characterized in that: The transistor (Q1) is an NPN transistor.
4. The filter device for high voltage power supply according to claim 2, characterized in that: The transistor (Q1) is an NPN Darlington transistor.
5. The filter device for high voltage power supply according to claim 2, characterized in that: The first capacitor (C1) is an electrolytic capacitor.
6. The filter device for high voltage power supply according to claim 2, characterized in that: The second capacitor (C2) is a ceramic capacitor.
7. The filter device for high voltage power supply according to claim 2, characterized in that: The resistance of the resistor (R1) is 1 ohm to 900 ohms.