CN210669891U

CN210669891U - Buck converter and electronic device

Info

Publication number: CN210669891U
Application number: CN201921774371.XU
Authority: CN
Inventors: 李健; 张春杰
Original assignee: Beijing Xiaomi Mobile Software Co Ltd
Current assignee: Beijing Xiaomi Mobile Software Co Ltd
Priority date: 2019-10-21
Filing date: 2019-10-21
Publication date: 2020-06-02
Anticipated expiration: 2029-10-21

Abstract

The disclosure relates to a buck converter and an electronic device, and belongs to the technical field of voltage regulation. The buck converter includes: the circuit board to and setting up switch control assembly, inductance and output end electric capacity on the circuit board. The switch control assembly is connected with one end of the inductor and provides pulse voltage for the inductor. The other end of the inductor is connected with the output end capacitor. The output end capacitor is a piezoelectric material capacitor and comprises a first capacitor and a second capacitor which are respectively arranged on two opposite sides of the circuit board, and the first capacitor and the second capacitor are connected in parallel.

Description

Buck converter and electronic device

Technical Field

The present disclosure relates to the field of capacitive noise cancellation technology, and in particular, to a buck converter and an electronic device.

Background

Buck converters are an important component in electronic devices. The input voltage is reduced by the buck converter so that the output voltage is adapted to the load. However, in the related art, noise is accompanied during the use of the buck converter, which affects the user experience.

SUMMERY OF THE UTILITY MODEL

The present disclosure provides a buck converter and an electronic device to solve the drawbacks of the related art.

A buck converter according to a first aspect is provided, the buck converter comprising: the circuit board is provided with a switch control assembly, an inductor and an output end capacitor;

the output end of the switch control assembly is connected with one end of the inductor to provide pulse voltage for the inductor;

the other end of the inductor is connected with the output end capacitor;

the output end capacitor is a piezoelectric material capacitor and comprises a first capacitor and a second capacitor which are respectively arranged on two opposite sides of the circuit board, and the first capacitor is connected with the second capacitor in parallel.

In one embodiment, the first capacitor and the second capacitor are correspondingly arranged on two sides of the circuit board.

In one embodiment, a projection of the first capacitance on the circuit board completely overlaps a projection of the second capacitance on the circuit board.

In one embodiment, a projection of the first capacitance onto the circuit board includes a first portion and a second portion,

the first portion overlaps with a projection of the second capacitance onto the circuit board,

the second portion does not overlap with a projection of the second capacitor on the circuit board.

In one embodiment, the direction of the electric field of the first capacitor is the same as the direction of the electric field of the second capacitor.

In one embodiment, the first and second capacitors have the same specification parameters, which include at least: size and capacitance.

In one embodiment, a via hole is arranged on the circuit board, and the positive electrode of the first capacitor and the positive electrode of the second capacitor are connected to the inductor in parallel through the via hole; and the negative electrode of the first capacitor and the negative electrode of the second capacitor are grounded through the via hole.

In one embodiment, the output terminal capacitor is a piezoelectric ceramic capacitor.

In one embodiment, the switch control assembly comprises: the switch tube is connected with the controller; the controller controls the switching tube to be conducted or blocked according to a preset frequency so as to provide pulse voltage with a preset duty ratio for the inductor.

According to a second aspect, there is provided an electronic device comprising the buck converter provided in the first aspect.

The buck converter and the electronic equipment provided by the present disclosure have at least the following beneficial effects:

the first capacitor and the second capacitor arranged on the two opposite sides of the circuit board weaken the vibration of the circuit board, weaken and even eliminate the noise of the buck converter in the using process, and optimize the user experience.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure.

FIG. 1 is a schematic diagram of a buck converter shown in accordance with an exemplary embodiment;

FIG. 2 is a circuit schematic of a buck converter shown in accordance with an exemplary embodiment;

FIG. 3 is a schematic diagram illustrating a partial structure of a buck converter in accordance with an exemplary embodiment;

FIG. 4 is a schematic diagram illustrating the structure of the output capacitor and circuit board of the buck converter, according to an exemplary embodiment;

fig. 5 is a schematic diagram of an output capacitor and a circuit board of a buck converter according to another exemplary embodiment.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The use of the terms "a" or "an" and the like in the description and in the claims of this disclosure do not denote a limitation of quantity, but rather denote the presence of at least one. Unless otherwise indicated, the word "comprise" or "comprises", and the like, means that the element or item listed before "comprises" or "comprising" covers the element or item listed after "comprises" or "comprising" and its equivalents, and does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

As used in this disclosure and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

The output capacitance is an important component in a buck converter. In the related art, a capacitor made of a piezoelectric material (e.g., a piezoelectric ceramic capacitor) is used in the step-down converter. In this way, the capacitor is always in the periodically varying electric field during use of the buck converter. Under the condition, the capacitor can generate periodic deformation due to the piezoelectric effect of the capacitor, and then the circuit board is driven to vibrate to generate noise.

In one embodiment, a metal substrate is disposed within the capacitor. The stability of the capacitor is improved through the metal substrate, so that the capacitor is difficult to deform, and noise is reduced or even eliminated. However, the metal substrate increases the volume of the capacitor, and is difficult to adapt to a narrow installation space in the electronic device.

In one embodiment, an electrolyte capacitor is adopted to replace a piezoelectric ceramic capacitor so as to avoid the defect that the circuit board vibrates to generate noise. However, the electrolyte capacitor still has the defect of large volume, is easy to leak during use and has short service life.

Based on the above situation, the embodiments of the present disclosure provide a buck converter and an electronic device, which take the installation performance of the buck converter into consideration on the premise of solving the problem of noise generated by the buck converter. Fig. 1-5 are schematic diagrams of structures of buck converters provided in accordance with various exemplary embodiments.

As shown in fig. 1, the buck converter 100 includes a circuit board 110. A switch control component 120, an inductor 130, and an output capacitor 140 are disposed on the circuit board 110. The circuit board 110 includes a first surface 111 and a second surface 112 disposed opposite to each other.

The switch control component 120 and the inductor 130 are disposed on the first side 111. The switch control module 120 has a receiving terminal for receiving the dc input voltage and an output terminal connected to one terminal of the inductor 130. In the buck converter 100, the switch control component 120 is configured to convert the dc input voltage into a rectangular pulse voltage, so as to regulate the current of the inductor 130, such that the inductor 130 is in a dynamic equilibrium state where the current increases and decreases periodically. In this case, the output voltage of the buck converter 100 is regulated based on the volt-second balance principle of the inductor 130 and the duty ratio of the pulse voltage within one cycle is regulated by the switching control component 120.

As an example, as shown in fig. 2, the switch control assembly 120 includes a controller 121 and a switch tube 122 connected to the controller 121. The controller 121 controls the switching tube 122 to be turned on or off according to a preset frequency, so as to convert the dc output voltage into a rectangular pulse voltage.

Optionally, the switch tube 122 includes a P-channel Field Effect Transistor (PFET) 1221 and an N-channel Field Effect Transistor (NFET) 1222. Wherein the input terminal of the P-channel field effect transistor 1221 receives a dc input voltage. The gate G of the P-channel field effect transistor 1221 and the gate G of the N-channel field effect transistor 1222 are both connected to the controller 121, and the drain D of the P-channel field effect transistor 1221 and the drain D of the N-channel field effect transistor 1222 are connected to one end of the inductor 130.

Optionally, the controller 121 is a Pulse Width Modulation (PWM) chip. The controller 121 controls the voltages of the gates G of the P-channel fet 1221 and the N-channel fet according to the preset frequency and the duty ratio, so that the two fets are in a continuous switching state.

In this manner, the switching control module 120 converts the dc input voltage into a pulse voltage having the same amplitude. Further, the current of the inductor 130 is periodically increased and decreased by the pulse voltage, and a dynamic equilibrium state is further achieved.

With continued reference to fig. 1, the other end of the inductor 130 is connected to the output capacitor 140. The output capacitor 140 plays a role of filtering, and ensures that the buck converter 100 stably outputs the dc voltage. When the inductor 130 current rises, the output end capacitor 140 is in a charging state; when the inductor 130 current decreases, the output capacitor 140 is in a discharge state to the load. Thus, the output capacitor 140 is in a continuous charging and discharging process during the operation of the buck converter 100. This corresponds to the capacitor 140 being in a periodically varying electric field at the output.

Further, the output capacitor 140 is a piezoelectric material capacitor, and includes a first capacitor 141 and a second capacitor 142 respectively disposed on two opposite sides of the circuit board 110, and the first capacitor 141 and the second capacitor 142 are disposed in parallel.

As shown in fig. 1, the circuit board 110 includes a first surface 111 and a second surface 112 disposed opposite to each other. The switch control component 120, the inductor 130, and the first capacitor 141 are disposed on the first surface 111 of the circuit board 110. The second capacitor 142 is disposed on the second side 112 of the circuit board 110.

Optionally, as shown in fig. 3, a via 113 is provided on the circuit board 110. The via hole 113 is a metalized hole penetrating through the first surface 111 and the second surface 112, and can electrically connect a circuit or a component on the first surface 111 and the second surface 112. In the embodiment of the present disclosure, the anodes of the first capacitor 141 and the second capacitor 142 are connected in parallel to one end of the inductor 130 through the via 113, and the cathodes of the first capacitor 141 and the second capacitor 142 are connected to the ground through the via 113.

Since the first capacitor 141 and the second capacitor 142 are disposed in parallel, voltages of the first capacitor 141 and the second capacitor 142 change synchronously, and thus electric fields of the first capacitor 141 and the second capacitor 142 change synchronously. Therefore, the deformation of the first capacitor 141 due to the piezoelectric effect is opposite to the deformation of the second capacitor 142 due to the piezoelectric effect. At this time, the deformation of the circuit board 110 caused by the first capacitor 141 can weaken or even cancel the deformation of the circuit board 110 caused by the second capacitor 142, so that the circuit board 110 is in a relatively stable rotation.

For example, the first surface 111 of the circuit board 110 faces upward, and the second surface 112 faces downward. The first capacitor 141 drives the circuit board 110 to be concave downward when deformed by the piezoelectric effect, and the second capacitor 142 drives the circuit board 110 to be convex upward when deformed by the piezoelectric effect.

According to the buck converter 100 provided by the embodiment of the disclosure, the first capacitor 141 and the second capacitor 142 respectively arranged on the two opposite sides of the circuit board 110 weaken the vibration of the circuit board 110 caused by the piezoelectric effect of the output end capacitor 140, further weaken or even avoid the vibration of the circuit board 110 to generate noise, prolong the service life of the circuit board 110 in the buck converter, and optimize the use experience of the buck converter 100.

In addition, in the case where the output end capacitors 140 have the same capacitance, the first capacitor 141 and the second capacitor 142, which are arranged in parallel, can be used to reduce the volume of each capacitor. Thus, the component installation space on the first surface 111 and the second surface 112 is increased. Moreover, the first capacitor 141 and the second capacitor 142 are respectively disposed on two opposite sides of the circuit board 110, so that the structural integration of the circuit board 110 is spatially improved, and the circuit board stacking method is particularly suitable for circuit board stacking design schemes popular in current electronic devices.

In one embodiment, the first capacitor 141 and the second capacitor 142 are disposed on two sides of the circuit board 110. In this way, the effect of offsetting the deformation of the first capacitor 141 and the second capacitor 142 is further improved, and the stability of the circuit board 110 is ensured.

The first capacitor 141 and the second capacitor 142 are correspondingly arranged, that is, a projection of the first capacitor 141 on the first surface 111 and a projection of the second capacitor 142 on the second surface 112 have an overlapping portion.

As an example, as shown in fig. 4, the projection of the first capacitor 141 on the first surface 111 of the circuit board 110 includes a first portion 141a and a second portion 141 b. The first portion 141a overlaps with a projection of the second capacitor 142 on the second surface 112, and the second portion 141b does not overlap with a projection of the second capacitor 142 on the second surface 112.

As another example, as shown in fig. 5, the projection of the first capacitor 141 on the first side 111 of the circuit board 110 completely overlaps the projection of the second capacitor 142 on the second side 112 of the circuit board 110. In this way, the first capacitor 141 and the second capacitor 142 act on opposite sides of the same portion of the circuit board 110, thereby eliminating vibration of the circuit board 110, and further eliminating noise during use of the buck converter 100, further optimizing user experience.

In one embodiment, the direction of the electric field of the first capacitor 141 is the same as the direction of the electric field of the second capacitor 142. Specifically, the two external electrodes of the first capacitor 141 are disposed in the same direction as the two external electrodes of the second capacitor 142.

In this way, the first capacitor 141 and the second capacitor 142 are ensured to be in the same state under the action of the external electric field as much as possible, and then the deformation tendencies of the first capacitor 141 and the second capacitor 142 are opposite, so as to ensure the stability of the circuit board 110.

In one embodiment, the first capacitor 141 and the second capacitor 142 have the same specification parameters. The specification parameters at least include: size and capacitance.

The size refers to the size of the outer space of the first capacitor 141 and the second capacitor 142, and includes: height, width, and length. The first capacitor 141 and the second capacitor 142 with the same size and capacitance are used to make the deformation degree of the circuit board 110 similar. In this way, the deformation of the circuit board 110 driven by the first capacitor 141 and the deformation of the circuit board 110 driven by the second capacitor 142 can be balanced, so as to prevent the circuit board 110 from generating sound by vibration.

In a second aspect, embodiments of the present disclosure provide an electronic device, including but not limited to: a mobile phone, a tablet, a wearable device (e.g., a smart watch, a bracelet, glasses, etc.), an image acquisition device (e.g., a camera, a video camera, etc.) an in-vehicle device, a medical device, etc. The electronic device comprises the buck converter provided by the first aspect. The buck converter is disposed in a power supply module of the electronic device. When the electronic device is in use, the buck converter no longer emits noise, optimizing the user experience.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims

1. A buck converter, the buck converter comprising: the circuit board is provided with a switch control assembly, an inductor and an output end capacitor;

the switch control assembly is connected with one end of the inductor and provides pulse voltage for the inductor;

the other end of the inductor is connected with the output end capacitor;

2. The buck converter according to claim 1, wherein the first capacitor and the second capacitor are disposed on opposite sides of the circuit board.

3. The buck converter according to claim 2, wherein a projection of the first capacitance onto the circuit board completely overlaps a projection of the second capacitance onto the circuit board.

4. The buck converter according to claim 2, wherein a projection of the first capacitance onto the circuit board includes a first portion and a second portion,

5. The buck converter according to claim 1, wherein the electric field direction of the first capacitor is the same as the electric field direction of the second capacitor.

6. The buck converter according to claim 1, wherein the first and second capacitors have the same specification parameters, the specification parameters including at least: size and capacitance.

7. The buck converter according to claim 1, wherein a plurality of vias are provided on the circuit board;

the positive electrode of the first capacitor and the positive electrode of the second capacitor are connected to the inductor in parallel through the via hole; and the negative electrode of the first capacitor and the negative electrode of the second capacitor are grounded through the via hole.

8. The buck converter according to any one of claims 1 to 7, wherein the output capacitance is a piezoelectric ceramic capacitance.

9. The buck converter according to claim 1, wherein the switch control assembly comprises: the switch tube is connected with the controller; the controller controls the switching tube to be conducted or blocked according to a preset frequency so as to provide pulse voltage with a preset duty ratio for the inductor.

10. An electronic device, characterized in that the electronic device comprises a buck converter according to any one of claims 1 to 9.