Ripple suppression circuit with voltage reduction and stabilization functions

Abstract

The embodiment of the utility model relates to a ripple suppression circuit with voltage reducing and stabilizing functions, which consists of a signal generator, a current limiting resistor, a capacitor, an adjusting tube, a voltage stabilizing tube, a series feedback resistor, an input side oscilloscope probe and an output side oscilloscope probe, according to the technical scheme provided by the invention, the material cost is reduced and the filtering effect is improved due to mutual coupling of the functions of the elements, and a capacitance amplifier circuit is formed to realize a ripple suppression function. According to the embodiment of the invention, the requirements of voltage regulation, current expansion, response speed adjustment and ripple suppression increase are met, and more performance requirements can be met if corresponding elements are replaced or added.

Description

Technical Field

[0001] This application relates to the field of integrated circuit technology, and in particular to a ripple suppression circuit with buck regulation function. Background Technology

[0002] Commonly used step-down voltage regulator circuits mainly include the buck method and the LDO method. The buck (switching power supply) method uses an inductor as a power switching device, while the LDO (linear regulator) method uses a transistor or MOSFET as a linear control device.

[0003] Common filtering methods (specifically for ripple suppression) include: optimizing the selection of matching inductors and capacitors based on parameters such as the switching frequency, operating voltage, and current of Buck devices, and optimizing PCB layout; using RC, LC, or Π-type filter circuits in the subsequent stages of ripple-sensitive circuits; and connecting large-capacity, low-ESR capacitors in parallel, as well as adding low-ESR capacitors such as MLCCs or tan capacitors.

[0004] However, in practical applications, the Buck scheme is more expensive, the system is more complex, and it is more cumbersome to use. It inevitably introduces switching noise (ripple), the power quality is lower than that of the LDO scheme, and the design requirements are higher. The LDO scheme is less efficient, generates more heat, and generally has lower power. Although it does not actively generate ripple, it has virtually no filtering effect on input ripple.

[0005] Filtering solutions rely on reducing ripple generation at the source. Using filter circuits or parallel capacitor solutions will inevitably introduce voltage drop or reduced dynamic response, increase material costs, increase size, and may also cause power-on current surges and increase EMI burden. Utility Model Content

[0006] The purpose of this application is to provide a ripple suppression circuit with buck regulation function, which solves the problem in the prior art that it is difficult to reduce the voltage of the pre-buck output to the rated voltage of the load and filter it before the rated voltage of the load after pre-buck, and the load device is easily affected by input ripple interference at the rated voltage.

[0007] To achieve the above objectives, this application provides a ripple suppression circuit with buck regulation function. The ripple suppression circuit comprises a signal generator, a current-limiting resistor, a capacitor, a regulating transistor, a Zener transistor, a series feedback resistor, an input-side oscilloscope probe, and an output-side oscilloscope probe. Specifically, it includes:

[0008] The input-side oscilloscope probe is connected in parallel with the signal generator VG1. The negative terminal of the signal generator VG1 is grounded, and the positive terminal of the signal generator VG1 is connected to the current-limiting resistor R1. The other end of the current-limiting resistor R1 is connected to the capacitor C1, and the other end of the capacitor C1 is connected to the negative terminal of the signal generator VG1.

[0009] The current-limiting resistor R1 is also connected to the collector of the regulating tube T1. One end of the current resistor connected to the flashlight C1 is connected to the base of the regulating tube T1. The emitter of the regulating tube T1 is connected to the resistor R2. The other end of the resistor R2 is connected to the resistor R3. The other end of the resistor R3 is connected to the positive terminal of the Zener diode U1. The positive terminal of the Zener diode U1 is also connected to the capacitor C1. Pin 1 of the Zener diode U1 is connected to the base of the regulating tube T1, the capacitor C1, and the resistor R1, respectively.

[0010] One end of resistor R4 is connected to the emitter of the regulating transistor T1, and the other end is connected to capacitor C1, the positive terminal of Zener diode U1, and resistor R3 respectively. At the same time, resistor R4 is connected in parallel with the output side oscilloscope probe.

[0011] Furthermore, the reference voltage terminal of the Zener diode U1 is connected to the middle node of the series feedback resistor, and the resistors R2 and R3 constitute the series feedback resistor.

[0012] Furthermore, the Zener diode U1 is a controllable precision voltage regulator, used to control the output voltage of the regulating diode T1 and adjust the output voltage based on the series feedback resistor.

[0013] Furthermore, when the voltage at the intermediate node of the series feedback resistor is 2.5V, it can be used in conjunction with the Zener diode U1 for voltage regulation.

[0014] Furthermore, the resistor R1 is the current-limiting resistor for the Zener diode U1, and the capacitor C1 and the resistor R1 form an RC filter circuit to provide static current for the regulating transistor T1.

[0015] Furthermore, the base of the regulating transistor T1 is connected to the negative terminal of the Zener transistor U1 to control the output voltage. At the same time, the regulating transistor T1, the Zener transistor U1, and the capacitor C1 constitute a capacitor amplifier.

[0016] Furthermore, the regulating transistor T1 is a 2N5133NPN transistor.

[0017] Furthermore, the Zener diode U1 is a TL431 controllable precision voltage regulator.

[0018] As can be seen from the above, the functional coupling between the components in the technical solution provided by this application reduces material costs while improving the filtering effect, and constitutes a capacitor amplifier circuit to achieve ripple suppression. The embodiments of the present invention meet the needs of voltage regulation, current amplification, response speed adjustment, and increased ripple suppression. If corresponding components are replaced or added, more performance requirements can be met. Attached Figure Description

[0019] Figure 1This is a system schematic diagram of a ripple suppression circuit with buck regulation function in an embodiment of this application;

[0020] Figure 2 This is a diagram illustrating the voltage regulation and filtering effect in a ripple suppression circuit with buck and voltage regulation functions according to an embodiment of this application. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0022] In practical projects, directly using LDO (linear buck) solutions for large voltage drop is often unacceptable. Due to device characteristics, the input and output currents are almost identical, and the voltage difference will be entirely converted into heat dissipation. Excessive voltage drop can lead to device burnout or even fire. Generally, AC-CDC or DC-CDC converters are used for pre-stepping, such as stepping 220VAC down to 24VDC or 12VDC, or 24VDC down to 5VDC. Whenever a switching power supply solution is involved, ripple will be introduced. Excessive ripple can cause active devices such as microcontrollers to crash or become unstable, analog devices to experience excessive interference leading to decreased accuracy, and even electrolytic capacitors to explode.

[0023] To address the problem that when multiple water pump motors within the overall system start alternately or simultaneously, it can cause serious interference to air switches and other equipment.

[0024] This utility model provides a ripple suppression circuit with buck regulation function. Please refer to [link / reference]. Figure 1 The ripple suppression circuit consists of a signal generator, a current-limiting resistor, a capacitor, a regulating transistor, a Zener transistor, a series feedback resistor, an input-side oscilloscope probe, and an output-side oscilloscope probe, specifically including:

[0025] The input-side oscilloscope probe is connected in parallel with the signal generator VG1. The negative terminal of the signal generator VG1 is grounded, and the positive terminal of the signal generator VG1 is connected to the current-limiting resistor R1. The other end of the current-limiting resistor R1 is connected to the capacitor C1, and the other end of the capacitor C1 is connected to the negative terminal of the signal generator VG1.

[0026] The current-limiting resistor R1 is also connected to the collector of the regulating tube T1. One end of the current resistor connected to the flashlight C1 is connected to the base of the regulating tube T1. The emitter of the regulating tube T1 is connected to the resistor R2. The other end of the resistor R2 is connected to the resistor R3. The other end of the resistor R3 is connected to the positive terminal of the Zener diode U1. The positive terminal of the Zener diode U1 is also connected to the capacitor C1. Pin 1 of the Zener diode U1 is connected to the base of the regulating tube T1, the capacitor C1, and the resistor R1, respectively.

[0027] One end of resistor R4 is connected to the emitter of the regulating transistor T1, and the other end is connected to capacitor C1, the positive terminal of Zener diode U1, and resistor R3 respectively. At the same time, resistor R4 is connected in parallel with the output side oscilloscope probe.

[0028] refer to Figure 1 The VG1 voltage output node is connected in parallel with resistor R1 and collector T1. The other node of R1 is connected in parallel with capacitor C1, the negative terminal of TL431 diode, the base of T1, the other end of C1 is grounded, the positive terminal of TL431 is grounded, and the emitter of T1 is connected in parallel with resistors R2 and R3 connected in series and grounded. The middle node of resistors R2 and R3 is connected to the reference voltage terminal of TL431. The emitter of T1 is connected in parallel with load resistor R4. The observation probes VM1 and VM2 are connected in parallel across the VG1 signal generator and resistor R4, respectively.

[0029] Furthermore, the reference voltage terminal of the Zener diode U1 is connected to the middle node of the series feedback resistor, and the resistors R2 and R3 constitute the series feedback resistor.

[0030] Furthermore, the Zener diode U1 is a controllable precision voltage regulator, used to control the output voltage of the regulating diode T1 and adjust the output voltage based on the series feedback resistor.

[0031] Furthermore, when the voltage at the intermediate node of the series feedback resistor is 2.5V, it can be used in conjunction with the Zener diode U1 for voltage regulation.

[0032] At the power input terminal, an RC filter circuit consisting of resistors R1 and C1 is used to stabilize the input voltage signal before regulating the transistor T1. Then, a TL431 is used to regulate the voltage. The output voltage is regulated by the transistor T1 and then passes through R2 and R3 for loop feedback. Finally, the voltage flows through the load R4. R1 also limits the current of the TL431, keeping it in a breakdown regulation state. C1 and T1 together form a capacitor amplifier circuit. The filtering effect is equivalent to connecting an equivalent capacitor with C1 capacitance multiplied by the transistor's amplification factor in parallel with the input power supply. Increasing or decreasing the resistance of R1 can increase the adjustment dynamic response speed.

[0033] It should also be noted that reducing R1 will increase the response speed and quiescent current, and these two parameters need to be balanced during adjustment.

[0034] Furthermore, the resistor R1 is the current-limiting resistor for the Zener diode U1, and the capacitor C1 and the resistor R1 form an RC filter circuit to provide static current for the regulating transistor T1.

[0035] Furthermore, the base of the regulating transistor T1 is connected to the negative terminal of the Zener transistor U1 to control the output voltage. At the same time, the regulating transistor T1, the Zener transistor U1, and the capacitor C1 constitute a capacitor amplifier.

[0036] refer to Figure 1 VG1 is the signal generator (power input), R1 is the current-limiting resistor of TL431, C1 works with the RC filter circuit to provide the quiescent current of T1, C1 and R1 together form an RC filter and T1 together form a capacitor amplifier, the regulating transistor T1 works with TL431 to control the output voltage and C1 together form a capacitor amplifier, U1 is the TL431 Zener diode, which serves as a voltage reference source to control the output voltage of T1 and adjust the output according to the feedback voltage of R2 and R3, R2 and R3 are series feedback resistors, and the series node can be controlled at 2.5V to work with TL431 for voltage regulation.

[0037] R4 is the load resistor, VM1 is the output oscilloscope probe, and VM2 is the input oscilloscope probe.

[0038] Furthermore, the regulating transistor T1 is a 2N5133NPN transistor.

[0039] Furthermore, the Zener diode U1 is a TL431 controllable precision voltage regulator.

[0040] refer to Figure 2 The interconnection of components reduces material costs while improving filtering performance. It features an adjustable voltage mode; the output voltage can be adjusted simply by modifying the values ​​of the feedback resistors R2 and R3. Because it uses a capacitor amplifier circuit, its filtering effect is equivalent to multiple capacitors in parallel, saving material costs and space. With a suitable input voltage, a higher-power transistor can be used to obtain a greater output current capability.

[0041] With an input of 12VDC and a 500kHz±5VAC triangular wave Vpp=10V, the output ripple Vpp is only 10mV. This ripple voltage is sufficient for the needs of most circuits. Comparing the peak-to-peak values ​​of the ripple before and after the input verifies that this circuit has a good suppression effect on input ripple. Furthermore, the voltage is stable at 5.08V within the input range of 7V to 17V, demonstrating that this circuit has a voltage regulation function.

[0042] This utility model embodiment can step down the pre-stepped output voltage to the load's rated voltage and filter it before the load's rated voltage, so that the load device is protected from input ripple interference at the rated voltage. It optimizes the LDO scheme for the problem that it has no effect on suppressing input ripple.

[0043] refer to Figure 2 The voltage regulation and filtering effect diagram shows that the output waveform of the signal generator at the top is a DC 12V superimposed ±5V 500KHz triangular wave, as shown in the red waveform on the right oscilloscope.

[0044] The red waveform at the top of the oscilloscope is the input DC waveform, with each division representing a voltage of 5V. The green waveform at the bottom of the oscilloscope is the output AC waveform, with each division representing a voltage of 5mV. The 5.08V at the top left is the output voltage.

[0045] The foregoing description of various embodiments of this application is provided to those skilled in the art for illustrative purposes. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, various alternatives and variations of this application will be apparent to those skilled in the art to which the foregoing pertains. Therefore, while some alternative embodiments have been specifically discussed, other embodiments will be obvious or readily apparent to those skilled in the art. This application is intended to include all alternatives, modifications, and variations of the invention already discussed herein, as well as other embodiments falling within the spirit and scope of the foregoing application.

Claims

1. A ripple suppression circuit with buck regulation function, characterized in that, The ripple suppression circuit consists of a signal generator, a current-limiting resistor, a capacitor, a regulating transistor, a Zener transistor, a series feedback resistor, an input-side oscilloscope probe, and an output-side oscilloscope probe. Specifically, it includes: The input-side oscilloscope probe is connected in parallel with the signal generator VG1. The negative terminal of the signal generator VG1 is grounded, and the positive terminal of the signal generator VG1 is connected to the current-limiting resistor R1. The other end of the current-limiting resistor R1 is connected to the capacitor C1, and the other end of the capacitor C1 is connected to the negative terminal of the signal generator VG1. The current-limiting resistor R1 is also connected to the collector of the regulating tube T1. One end of the current resistor connected to the flashlight C1 is connected to the base of the regulating tube T1. The emitter of the regulating tube T1 is connected to the resistor R2. The other end of the resistor R2 is connected to the resistor R3. The other end of the resistor R3 is connected to the positive terminal of the Zener diode U1. The positive terminal of the Zener diode U1 is also connected to the capacitor C1. Pin 1 of the Zener diode U1 is connected to the base of the regulating tube T1, the capacitor C1, and the resistor R1, respectively. One end of resistor R4 is connected to the emitter of the regulating transistor T1, and the other end is connected to capacitor C1, the positive terminal of Zener diode U1, and resistor R3 respectively. At the same time, resistor R4 is connected in parallel with the output side oscilloscope probe.

2. The ripple suppression circuit according to claim 1, characterized in that, The reference voltage terminal of the Zener diode U1 is connected to the middle node of the series feedback resistor, and the resistors R2 and R3 constitute the series feedback resistor.

3. The ripple suppression circuit according to claim 2, characterized in that, The Zener diode U1 is a controllable precision voltage regulator used to control the output voltage of the regulating diode T1 and adjust the output voltage based on the series feedback resistor.

4. The ripple suppression circuit according to claim 3, characterized in that, When the voltage at the intermediate node of the series feedback resistor is 2.5V, it can be used in conjunction with Zener diode U1 for voltage regulation.

5. The ripple suppression circuit according to claim 1, characterized in that, The resistor R1 is the current-limiting resistor for the Zener diode U1, and the capacitor C1 and the resistor R1 form an RC filter circuit to provide static current for the regulating diode T1.

6. The ripple suppression circuit according to claim 1, characterized in that, The base of the regulating transistor T1 is connected to the negative terminal of the Zener transistor U1 to control the output voltage. At the same time, the regulating transistor T1, the Zener transistor U1, and the capacitor C1 constitute a capacitor amplifier.

7. The ripple suppression circuit according to claim 1, characterized in that, The regulating transistor T1 is a 2N5133NPN transistor.

8. The ripple suppression circuit according to claim 3, characterized in that, The Zener diode U1 is a TL431 controllable precision voltage regulator.

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