Power supply circuit for DC-DC step-down conversion

Abstract

The utility model belongs to the technical field of power supply circuits, and particularly discloses a power supply circuit used for DC-DC step-down conversion, which comprises an XL7015E1 type step-down chip U2, a pin 4 of the step-down chip U2 is connected with a noise reduction unit used for removing high-frequency noise and peak voltage for the step-down chip U4, and a pin 5 of the step-down chip U2 is connected with a pin 6 of the step-down chip U2. One end of the noise reduction unit is connected with a power supply protection unit for protecting the step-down chip U4, one end of the noise reduction unit is connected with a voltage feedback unit, and one pin of the step-down chip U4 is connected with a first filter circuit; according to the utility model, through cooperation of the XL7015E1 type step-down chip U2, the noise reduction unit, the power supply protection unit, the first filter circuit and the second filter circuit, the linear regulation rate and the load regulation rate of the step-down chip U2 are utilized, so that the step-down chip U2 can provide a more stable output voltage under different load conditions and input voltage changes, and the power supply protection circuit has the advantages that the power supply protection circuit is simple in structure and convenient to use. Therefore, the stability of power supply output is effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply circuits, and specifically to a power supply circuit for DC-DC buck conversion. Background Technique

[0002] Power DC-DC conversion is the process of converting one DC voltage into another DC voltage. Common power DC-DC conversions include buck conversion. A buck converter uses a switch (usually a transistor) to regulate the output voltage by controlling the on and off states of the switch. When the switch is on, current passes through the inductor and the load, and the inductor stores energy. When the switch is off, the inductor releases energy to the load through a freewheeling diode.

[0003] For example, the patent document with the application number: 202322965931.2 discloses a buck conversion circuit, which includes a Buck buck circuit, a first triode, and a second diode. Applying the technical solution of this embodiment, during operation, when an external power supply is input to the power input terminal, the MOS tube of the Buck buck circuit controls the on and off of the current, determining the magnitude of the voltage output to the external load. According to the working state of the MOS tube, the Buck buck circuit operates in two modes. State 1: The MOS tube is on, and at this time, the power input terminal V-IN charges the Buck buck circuit. State 2: The MOS tube is off, and at this time, the Buck buck circuit discharges. This utility model realizes the buck conversion of the input voltage through a reasonably designed circuit structure, and can maintain the stability of the output voltage under conditions such as load fluctuations and input voltage fluctuations, ensuring the normal operation of external load devices. This kind of buck conversion circuit is applicable to various types of automotive electronic control units, providing a reliable guarantee for the stable power supply of automotive electronic systems.

[0004] However, since the above-mentioned buck conversion circuit adopts a discrete component design and requires multiple components such as triodes, diodes, and MOS tubes to cooperate to achieve the buck function, although the stability can be improved by precisely selecting components and optimizing the circuit layout, the inherent complexity of the discrete component design may still affect the overall stability. Therefore, we need to propose a power supply circuit for DC-DC buck conversion to solve the above-mentioned existing problems and enable it to effectively improve the stability of the power output. Content of the Utility Model

[0005] The purpose of the utility model is to provide a power supply circuit for DC-DC buck conversion. Through the cooperation of a buck chip U2 of the XL7015E1 model and a power supply protection unit, by utilizing the line regulation rate and load regulation rate of the buck chip U2, the buck chip U2 can provide a more stable output voltage under different load conditions and input voltage changes, so as to solve the problems raised in the background technique.

[0006] To achieve the above object, the present utility model provides the following technical solutions: A power supply circuit for DC-DC buck conversion, including a buck chip U2 of model XL7015E1. The 4th pin of the buck chip U2 is connected to a noise reduction unit for removing high-frequency noise and spike voltage for the buck chip U4. One end of the noise reduction unit is connected to a power supply protection unit for protecting the buck chip U4, and one end of the noise reduction unit is connected to a voltage feedback unit;

[0007] The 1st pin of the buck chip U4 is connected to a first filter circuit. The 3rd, 6th, and 5th pins of the buck chip U4 are all grounded. One end of the first filter circuit is connected to a second filter circuit, and one end of the second filter circuit is connected to a storage battery BAT.

[0008] Preferably, the noise reduction unit includes a capacitor CFF. One end of the capacitor CFF is connected in parallel with a capacitor C7 and a capacitor C8. The ends of the capacitor C7 and the capacitor C8 far from the capacitor CFF are connected to an inductor L1. One end of the inductor L1 is connected to the 2nd pin of the buck chip U2.

[0009] Preferably, the power supply protection unit includes a diode D1. The diode D1 is connected to the connection end between the buck chip U2 and the inductor L1, and one end of the diode D1 is connected to the 5th pin of the buck chip U2.

[0010] Preferably, the voltage feedback unit includes a resistor R9 and a resistor R10. The resistor R10 is connected between the other end of the inductor L1 and the 4th pin of the buck chip U2. The resistor R9 is connected between the 4th pin of the buck chip U2 and the connection end of the capacitor CFF, and one end of the resistor R9 is connected to the end of the diode D1 far from the inductor L1.

[0011] Preferably, the first filter circuit is composed of a capacitor C4 and a capacitor C5 arranged in parallel. One of the connection ends of the capacitor C4 and the capacitor C5 is grounded, and the other connection ends of the capacitor C4 and the capacitor C5 are connected to the 1st pin of the buck chip U4.

[0012] Preferably, the second filter circuit is composed of a capacitor C39, a capacitor C40, a capacitor C41, and a capacitor C42 arranged in parallel. One of the connection ends of the capacitor C39, the capacitor C40, the capacitor C41, and the capacitor C42 is respectively connected to the positive electrode of the storage battery BAT and the non-ground end of the capacitor C4, and the other connection ends of the capacitor C39, the capacitor C40, the capacitor C41, and the capacitor C42 are connected to the negative electrode end of the storage battery BAT.

[0013] Compared with the prior art, the beneficial effects of the present utility model are:

[0014] 1. Through the cooperation of the step-down chip U2 of model XL7015E1, the noise reduction unit, the power protection unit, the first filter circuit and the second filter circuit, the utility model utilizes the line regulation rate and load regulation rate of the step-down chip U2, enabling the step-down chip U2 to provide a more stable output voltage under different load conditions and input voltage variations, thereby effectively improving the stability of the power output.

[0015] 2. Through the cooperation of the voltage feedback unit and the noise reduction protection unit, the utility model can timely feedback the output voltage of the power supply, facilitating precise voltage reduction through the step-down chip U4. Description of the Drawings

[0016] Figure 1 is the system block diagram of the utility model;

[0017] Figure 2 is the circuit diagram of the step-down chip and its peripherals of the utility model;

[0018] Figure 3 is the circuit diagram of the second filter circuit of the utility model. Detailed Embodiments

[0019] Next, the technical solutions in the embodiments of the utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the utility model.

[0020] Please refer to Figures 1-3 , the utility model provides a technical solution: a power supply circuit for DC-DC step-down conversion, including a step-down chip U2 of model XL7015E1. The 4th pin of the step-down chip U2 is connected to a noise reduction unit for removing high-frequency noise and spike voltage for the step-down chip U4. One end of the noise reduction unit is connected to a power protection unit for protecting the step-down chip U4, and one end of the noise reduction unit is connected to a voltage feedback unit;

[0021] The noise reduction unit includes a capacitor CFF. One end of the capacitor CFF is connected in parallel with a capacitor C7 and a capacitor C8. The ends of the capacitor C7 and the capacitor C8 far from the capacitor CFF are connected to an inductor L1. One end of the inductor L1 is connected to the 2nd pin of the step-down chip U2. Through the noise reduction unit, the noise in the output voltage can be effectively reduced, improving the stability and performance of the power supply.

[0022] The power protection unit includes a diode D1. The diode D1 is connected to the connection terminal between the buck chip U2 and the inductor L1, and one end of the diode D1 is connected to the pin 5 of the buck chip U2. The power protection unit not only provides reverse connection protection through the diode D1 to ensure the correct power supply polarity, but also prevents overvoltage from damaging circuit components through the voltage clamping function.

[0023] The voltage feedback unit includes a resistor R9 and a resistor R10. The resistor R10 is connected between the other end of the inductor L1 and the pin 4 of the buck chip U2. The resistor R9 is connected to the connection terminal between the pin 4 of the buck chip U2 and the capacitor CFF, and one end of the resistor R9 is connected to the end of the diode D1 away from the inductor L1. A voltage divider network is formed by the resistor R9 and the resistor R10. The output voltage is sampled through these two resistors. The resistor R10 is connected between the other end of the inductor L1 and the pin 4 (feedback pin) of the buck chip U2, and the sampled voltage signal is fed back to the chip. This feedback voltage is proportional to the output voltage and is used for the comparison and regulation mechanism inside the buck chip U2.

[0024] One pin of the buck chip U4 is connected to a first filter circuit. The pins 3, 6, and 5 of the buck chip U4 are all grounded. One end of the first filter circuit is connected to a second filter circuit, and one end of the second filter circuit is connected to a battery BAT. The buck chip U4, the first filter circuit, the second filter circuit, and the battery BAT together constitute a complete power management module. By filtering the input voltage, performing buck conversion, and further filtering, an efficient and stable power output is achieved, meeting the high requirements of modern electronic devices for power quality.

[0025] The first filter circuit is composed of a capacitor C4 and a capacitor C5 arranged in parallel. One of the connection terminals of the capacitor C4 and the capacitor C5 is grounded, and the other connection terminals of the capacitor C4 and the capacitor C5 are connected to the pin 1 of the buck chip U4. The first filter circuit removes noise and fluctuations in the power supply to provide a stable DC voltage.

[0026] The second filter circuit is composed of a capacitor C39, a capacitor C40, a capacitor C41 and a capacitor C42 which are arranged in parallel. One connection end of the capacitor C39, the capacitor C40, the capacitor C41 and the capacitor C42 is respectively connected to the positive electrode of the battery BAT and the non-ground end of the capacitor C4. The other connection end of the capacitor C39, the capacitor C40, the capacitor C41 and the capacitor C42 is connected to the negative electrode of the battery BAT. When the input voltage enters the second filter circuit, since the impedance of the capacitor to high-frequency signals is low, these high-frequency noises can be effectively introduced into the ground wire, thereby eliminating their influence on the subsequent circuit. At the same time, since the impedance of the capacitor to direct current is high, the direct current component is retained, thereby ensuring the stability of the output voltage;

[0027] The buck chip U2 automatically adjusts the duty cycle of on and off (i.e., the ratio of the conduction time to the cut-off time) according to the load condition and the change of the input voltage, so as to keep the output voltage stable. In this process, the noise reduction unit, the power protection unit and the voltage feedback unit all play important roles. The noise reduction unit can effectively remove high-frequency noise and spike voltage to ensure the stability of the power supply circuit; the power protection unit can cut off the power supply in time when an abnormal situation occurs in the circuit to protect the whole circuit from damage; the voltage feedback unit can feed back the information of the output voltage to the buck chip U2 so that it can adjust the output voltage more precisely.

[0028] Therefore, the buck chip U2 can provide a more stable output voltage under different load conditions and input voltage changes, mainly relying on the combined action of its internal switched-capacitor technology and the external noise reduction unit, power protection unit and voltage feedback unit.

[0029] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A power supply circuit for DC-DC step-down conversion, characterized in that: It includes a buck chip U2 of the XL7015E1 model, wherein the 4 pins of the buck chip U2 are connected to a noise reduction unit for removing high-frequency noise and peak voltage from the buck chip U4, one end of the noise reduction unit is connected to a power protection unit for protecting the buck chip U4, and one end of the noise reduction unit is connected to a voltage feedback unit; One pin of the buck chip U4 is connected to a first filter circuit, pins 3, 6 and 5 of the buck chip U4 are grounded, one end of the first filter circuit is connected to a second filter circuit, and one end of the second filter circuit is connected to a battery BAT.

2. A power supply circuit for DC-DC step-down conversion according to claim 1, characterized in that: The noise reduction unit includes a capacitor CFF, one end of which is connected in parallel to capacitors C7 and C8, one end of which is away from the capacitor CFF and is connected to an inductor L1, and one end of the inductor L1 is connected to pin 2 of the buck chip U2.

3. A power supply circuit for DC-DC step-down conversion according to claim 2, characterized in that: The power protection unit includes a diode D1 , which is connected to the connection end between the buck chip U2 and the inductor L1 , and one end of the diode D1 is connected to pin 5 of the buck chip U2 .

4. A power supply circuit for DC-DC step-down conversion according to claim 3, characterized in that: The voltage feedback unit includes a resistor R9 and a resistor R10, wherein the resistor R10 is connected between the other end of the inductor L1 and the 4th pin of the buck chip U2, the resistor R9 is connected to the connection end between the 4th pin of the buck chip U2 and the capacitor CFF, and one end of the resistor R9 is connected to the end of the diode D1 away from the inductor L1.

5. A power supply circuit for DC-DC step-down conversion according to claim 4, characterized in that: The first filter circuit is composed of a capacitor C4 and a capacitor C5 which are arranged in parallel. One of the connection ends of the capacitor C4 and the capacitor C5 is grounded, and the other connection ends of the capacitor C4 and the capacitor C5 are connected to pin 1 of the buck chip U4.

6. A power supply circuit for DC-DC step-down conversion according to claim 5, characterized in that: The second filter circuit is composed of a capacitor C39, a capacitor C40, a capacitor C41 and a capacitor C42 which are arranged in parallel, one of the connection ends of the capacitor C39, the capacitor C40, the capacitor C41 and the capacitor C42 is respectively connected to the positive electrode of the battery BAT and the non-grounded end of the capacitor C4, and the other connection ends of the capacitor C39, the capacitor C40, the capacitor C41 and the capacitor C42 is connected to the negative terminal of the battery BAT.

Images