Circuit structure for removing ripples
Through the combination of op amp chip LM358 and transistor, the combination of secondary RC filtering and inductor is used to solve the problem of excessive capacitance and resistance in high-frequency and high-power signal processing in traditional filter circuits, and realize high-efficiency filtering of miniaturized devices The effect reduces cost and volume and improves the filtering ability of high-frequency ripple.
Patent Information
- Application Number
- CN202323615683.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-28
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2033-12-28
AI Technical Summary
When traditional filtering circuits process high-frequency and high-power signals, they require large capacitances and resistors, resulting in increased equipment cost and volume, and limited filtering effect, especially in the case of poor high-frequency characteristics.
The corrugated circuit structure consisting of the op amp chip LM358, resistor, capacitor, inductor, transistor, and field effect transistor are used to adjust the RC gain and drive through the combination of secondary RC filtering, inductor and op amp following, and the current gain characteristics of the transistor are used to adjust the RC gain and drive. Field effect transistors achieve higher power filtering effect and reduce dependence on capacitors.
It achieves the filtering effect of a larger capacitor based on miniaturization capacitors and resistors, reduces cost and volume, and improves the filtering ability of high-frequency ripple.
Smart Images
Figure CN222234827U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of filter circuits, in particular to a circuit structure for removing ripples. Background Art
[0002] Traditional filter circuits mainly include first-order RC filter circuit, second-order RC filter circuit, second-order RC+op amp follower circuit and second-order RC+op amp follower circuit+LDO. Figure 1 As shown in the figure, the traditional first-order RC filter circuit requires the resistance or capacitance of resistor R3 and capacitor C3 to be very large. If the output current of Vout is very large, the capacitor C3 is required to be very large, which may reach the Farad level. This circuit is only suitable for small signals and has limited filtering. Figure 2 As shown in the figure, the traditional second-order RC circuit adds one RC on the original basis. Compared with the first-order RC, the filtering effect is greatly improved and the ripple is reduced, but it also requires large resistance and capacitance, which is also not suitable for use in occasions with large output power; Figure 3 As shown in the figure, the traditional second-order RC+op amp follower circuit is to add an op amp follower on the original basis. The op amp has the characteristics of high gain. At the same time, the bandwidth is greatly improved compared with the second-order RC, and the ripple is reduced. However, it also requires large resistors and capacitors, which is also not suitable for use in occasions with large output power. Figure 4 As shown, the traditional second-order RC+op amp follower circuit+LDO method adds LDO on the original basis to further reduce the ripple combination, but the LDO is a follower. Currently, the LDO is a bipolar or MOS process, and the output current is also limited. The filtering effect on high-frequency ripple is not very obvious, especially the large current and high-frequency characteristics are poor. Summary of the invention
[0003] The utility model aims to solve the above technical problems and provides a circuit structure for removing ripples.
[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is: a circuit structure for removing ripples, including an operational amplifier chip U1A, a resistor R1, a resistor R2, a capacitor C1, a capacitor C2, a capacitor C3, an inductor L1, a transistor Q2 and a field effect transistor Q1, one end of the resistor R1 is respectively connected to the input voltage terminal P1, the collector of the transistor Q2 and the drain of the field effect transistor Q1, the other end of the resistor R1 is connected in series with the inductor L1 and then respectively connected to one end of the resistor R2 and one end of the capacitor C2, the other end of the capacitor C2 is grounded, the other end of the resistor R2 is respectively connected to one end of the capacitor C3 and the positive phase input end of the operational amplifier chip U1A, the inverting input end and the output end of the operational amplifier chip U1A are both connected to the base of the transistor Q2, the emitter of the transistor Q2 is connected to the gate of the field effect transistor Q1, the source of the field effect transistor Q1 is respectively connected to one end of the capacitor C1 and the output VOUT, and the other end of the capacitor C1 is grounded.
[0005] The model of the operational amplifier chip U1A is LM358.
[0006] The advantages and positive effects of the utility model are: a circuit structure for removing ripples, which can achieve higher power filtering for low-frequency ripples and high-frequency ripples by adjusting RC gain and transistor driving field effect tubes, and similarly only requires a small capacitor to achieve the ripple filtering effect of a larger capacitor, and at the same time, resistors, capacitors and inductors can all use miniaturized devices, greatly saving cost and size. BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Figure 1 This is the structure diagram of the traditional first-order RC filter circuit;
[0008] Figure 2 This is the structure diagram of the traditional second-order RC filter circuit;
[0009] Figure 3 This is the traditional second-order RC+ op amp follower circuit structure diagram;
[0010] Figure 4 This is the traditional second-order RC + op amp follower circuit + LDO circuit structure diagram;
[0011] Figure 5 It is a circuit structure diagram for removing ripples;
[0012] Figure 6 This is a structural diagram of a circuit structure embodiment 1 for removing ripples;
[0013] Figure 7 The present invention is a structural diagram of a second embodiment of a circuit structure for removing ripples. DETAILED DESCRIPTION
[0014] The specific embodiments of the present utility model are described in detail below with reference to the accompanying drawings.
[0015] like Figure 5 As shown, in a preferred embodiment of a circuit structure for removing ripples, the circuit structure includes an operational amplifier chip U1A, a resistor R1, a resistor R2, a capacitor C1, a capacitor C2, a capacitor C3, an inductor L1, a transistor Q2 and a field effect transistor Q1, one end of the resistor R1 is respectively connected to the input voltage terminal P1, the collector of the transistor Q2 and the drain of the field effect transistor Q1, the other end of the resistor R1 is connected in series with the inductor L1 and then respectively connected to one end of the resistor R2 and one end of the capacitor C2, the other end of the capacitor C2 is grounded, the other end of the resistor R2 is respectively connected to one end of the capacitor C3 and the positive phase input end of the operational amplifier chip U1A, the inverting input end and the output end of the operational amplifier chip U1A are both connected to the base of the transistor Q2, the emitter of the transistor Q2 is connected to the gate of the field effect transistor Q1, the source of the field effect transistor Q1 is respectively connected to one end of the capacitor C1 and the output VOUT, and the other end of the capacitor C1 is grounded. The model of the operational amplifier chip U1A is LM358.
[0016] The working process of a circuit structure for removing ripples is: secondary RC filtering + inductor + op amp follower. The op amp follows the output end to drive the transistor or power transistor. The transistor is similar to an emitter follower because the output is a transistor. Its function is that the output voltage will follow the base voltage change. Because the base current of the transistor is relatively small, because the transistor has a current gain characteristic, the current flowing through two resistors and an inductor is small. For the transistor collector, the collector is the result of the base current amplification. The ripple passes through the first resistor and reaches the capacitor for the first stage of filtering. This capacitor can be a small capacitor, and then to The inductor has the problem that the current cannot change suddenly. The RLC series resonance is used to filter out the clutter, and the fixed frequency is eliminated and sent to the operational amplifier for further reduction. The output of the operational amplifier drives the base of the transistor. If the current amplification factor of the transistor is 100 times, it is similar to amplifying the two capacitors 100 times. In this way, there is no need for a larger capacitor to filter as traditionally. We can use a small capacitor to amplify through the output transistor to achieve the effect of filtering ripples with a small capacitor and a large capacitor. At the same time, resistors, capacitors, and inductors can all use miniaturized devices, which greatly saves cost and size.
[0017] A circuit structure for removing ripples can achieve higher power filtering for low-frequency and high-frequency ripples by adjusting RC gain and transistor-driven field-effect tubes. Similarly, only a small capacitor is needed to achieve the ripple filtering effect of a larger capacitor. At the same time, resistors, capacitors and inductors can all use miniaturized devices, which greatly saves cost and size. This circuit structure can be used to achieve a larger capacitor filtering effect through small capacitors, resistors and inductors, and can achieve a high-power filtering effect.
[0018] If you only need to use small capacitors, resistors and inductors to achieve a large capacitance filtering effect, and can achieve a large power filtering effect, you can use Figure 6 The circuit structure of the first embodiment shown in the figure has the following working process: the input voltage P6 terminal is connected to a power supply with ripple. From the perspective of this type of structure, it is a secondary RC filter + inductor + op amp follower. The op amp follower output terminal drives the transistor or power transistor. It can be clearly seen from the figure that the added transistor is similar to an emitter follower, because the output is a transistor, and its function is that the output voltage will follow the base voltage change. Because the base current of the transistor is relatively small, and because the transistor has a current gain characteristic, the current flowing through R8, L2, and R9 is small. For Q1 Darlington, the collector is the result of base current amplification. The ripple passes through R8 and reaches C10 as the first stage For filtering, a small capacitor can be selected for the capacitor C10, and then it reaches the inductor L2. The inductor has the condition that the current cannot change suddenly. After passing through R9, it reaches C11, and the clutter is filtered out through the RLC series resonance. The fixed frequency is eliminated and sent to the operational amplifier for further reduction. The output of the operational amplifier drives the base of Q1 Darlington. If the current amplification factor of the transistor is 100 times, it is similar to amplifying the two capacitors C10 and C11 by 100 times. In this way, there is no need for a larger capacitor for filtering as traditionally required. We can use a small capacitor to amplify through the output Q1 Darlington, so that a small capacitor can also achieve the effect of filtering ripples with a large capacitor.
[0019] If you only need to use small capacitors, resistors and inductors to achieve a large capacitor filtering effect, you can use Figure 7The circuit structure of the second embodiment shown in the figure has the following working process: the input voltage terminal P7 is connected to a power supply with ripples. From the perspective of this type of structure, it is a secondary RC filter + inductor + op amp follower. The op amp follower output terminal drives the transistor or power transistor. It can be clearly seen from the figure that the added transistor is similar to an emitter follower, because the output is a transistor, and its function is that the output voltage will follow the base voltage change. Because the base current of the transistor is relatively small, and because the transistor has a current gain characteristic, the current flowing through the resistor R10, the inductor L1, and the resistor R11 is small. For the collector of the transistor Q2, the collector is the result of the base current amplification. The ripple passes through the resistor R10 and reaches the capacitor C12 for the first stage filtering. The capacitor C12 can be A small capacitor can be selected, and then it reaches the inductor L1. The inductor has the condition that the current cannot change suddenly. After passing through the resistor R11, it reaches the capacitor C13. The clutter is filtered out through the RLC series resonance, and the fixed frequency is eliminated and sent to the operational amplifier for further reduction. The output of the operational amplifier drives the base of the transistor Q2. If the current amplification factor of the transistor is 100 times, it is similar to amplifying the two capacitors C12 and C13 by 100 times. In this way, there is no need for a larger capacitor to filter as traditionally. We can use a small capacitor to amplify through the output transistor Q2, so that a small capacitor can also achieve the effect of filtering ripples with a large capacitor. At the same time, resistors, capacitors, and inductors can all use miniaturized devices, which greatly saves cost and size.
[0020] The above embodiments of the utility model are described in detail, but the above contents are only preferred embodiments of the utility model and cannot be considered to limit the scope of implementation of the invention. All equivalent changes and improvements made within the scope of the utility model should still fall within the scope of this patent.
Claims
1. A circuit structure for removing ripples, characterized in that: It includes an operational amplifier chip U1A, a resistor R1, a resistor R2, a capacitor C1, a capacitor C2, a capacitor C3, an inductor L1, a transistor Q2 and a field effect transistor Q1, one end of the resistor R1 is respectively connected to an input voltage terminal P1, a collector of the transistor Q2 and a drain of the field effect transistor Q1, the other end of the resistor R1 is connected in series with the inductor L1 and then respectively connected to one end of the resistor R2 and one end of the capacitor C2, the other end of the capacitor C2 is grounded, the other end of the resistor R2 is respectively connected to one end of the capacitor C3 and a positive phase input end of the operational amplifier chip U1A, the inverting input end and the output end of the operational amplifier chip U1A are both connected to the base of the transistor Q2, the emitter of the transistor Q2 is connected to the gate of the field effect transistor Q1, the source of the field effect transistor Q1 is respectively connected to one end of the capacitor C1 and an output VOUT, and the other end of the capacitor C1 is grounded.
2. The circuit structure for removing ripples according to claim 1, characterized in that: The model of the operational amplifier chip U1A is LM358.