CN210579111U

CN210579111U - Audio output circuit and bluetooth headset

Info

Publication number: CN210579111U
Application number: CN201921222193.XU
Authority: CN
Inventors: 李金斗; 王丽
Original assignee: Shenzhen Horn Audio Co Ltd
Current assignee: Shenzhen Horn Audio Co Ltd
Priority date: 2019-07-29
Filing date: 2019-07-29
Publication date: 2020-05-19
Anticipated expiration: 2029-07-29

Abstract

This application is applicable to electron technical field, provides an audio output circuit and bluetooth headset, and wherein audio output circuit includes: a speaker; the Bluetooth chip is connected to the loudspeaker through a first output line and a second output line respectively, the first output line and the second output line are connected with resistors with set resistance values related to gain values of the Bluetooth chip, noise signal attenuation is guaranteed, normal transmission of sound is not affected, and earphone quality is improved.

Description

Audio output circuit and bluetooth headset

Technical Field

The application belongs to the technical field of electronics, especially relates to an audio output circuit and bluetooth headset.

Background

With the rapid development of terminals such as mobile phones and tablets, the terminals have already entered the lives of people widely, and bring great convenience to various aspects of people's lives, and earphones used in combination with the terminals also become indispensable electronic devices.

Aiming at the earphones popular in the market at present, the design trend is lighter and lighter, so that higher requirements on the design aspect of products are met.

Most of components of a printed circuit board of a general earphone are designed in a packaging mode, and when the structural design is not reasonable, the output of a loudspeaker is often caused to have noise and low signal-to-noise ratio, so that the quality of the earphone is affected.

SUMMERY OF THE UTILITY MODEL

In view of this, the embodiment of the present application provides an audio output circuit and a bluetooth headset, so as to solve the problems of noise reduction and low signal-to-noise ratio in the output of a speaker in the headset structure in the prior art.

A first aspect of an embodiment of the present application provides an audio output circuit, including:

a speaker;

the Bluetooth chip is connected to the loudspeaker through a first output line and a second output line respectively, and resistors with set resistance values related to the gain value of the Bluetooth chip are connected to the first output line and the second output line respectively.

A second aspect of embodiments of the present application provides a bluetooth headset including an audio output circuit as described above.

It can be seen from above that, the scheme in this application can reduce the end and make an uproar, increases the SNR, makes the end make an uproar reach the unable level of hearing of people's ear for when guaranteeing noise signal decay, not influence the normal transmission of sound, promote the earphone quality.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a block diagram of an audio output circuit according to an embodiment of the present disclosure.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification of the present application 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.

As used in this specification and the appended claims, the term "if" may be interpreted contextually as "when", "upon" or "in response to a determination" or "in response to a detection". Similarly, the phrase "if it is determined" or "if a [ described condition or event ] is detected" may be interpreted contextually to mean "upon determining" or "in response to determining" or "upon detecting [ described condition or event ]" or "in response to detecting [ described condition or event ]".

In order to explain the technical solution described in the present application, the following description will be given by way of specific examples.

Referring to fig. 1, fig. 1 is a structural diagram of an audio output circuit according to an embodiment of the present disclosure. As shown in fig. 1, an audio output circuit includes:

a loudspeaker A;

the Bluetooth chip is connected to the loudspeaker A through a first output line and a second output line respectively, and the first output line and the second output line are both connected with a resistor L which is associated with a gain value of the Bluetooth chip and is set to be a resistance value.

Specifically, the gain value of the bluetooth chip is positively correlated with the set resistance value of the resistor.

The first output circuit and the second output circuit are respectively connected to the positive and negative connecting ends of the loudspeaker A.

The design of a hardware circuit considers that a proper resistor is respectively connected in series on output lines between a Bluetooth chip and a loudspeaker, after resistors are added on a first output line and a second output line, the purpose of attenuating noise signals is firstly achieved, meanwhile, the internal gain of the Bluetooth chip needs to be adjusted to compensate the attenuation of output power caused by adding the resistors, specifically, the gain value is increased, the adjustment of the gain value is associated with the set resistance value of the added resistors, so that the bottom noise can be reduced, the signal-to-noise ratio is increased, the bottom noise reaches the level which cannot be heard by human ears, and the normal transmission of sound is not influenced while the attenuation of the noise signals is ensured.

Further, optionally, the audio output circuit further includes: and the gain adjuster is connected with the Bluetooth chip and used for adjusting the gain value of the Bluetooth chip.

After the gain regulator is connected with the Bluetooth chip, the preset gain initial value in the Bluetooth chip is regulated, so that the regulated gain value can be adapted to the newly increased resistance value.

The adjustment process may be a change made in software, changing the initial value of the gain in the program. The gain adjuster includes but is not limited to a dial switch, a computing device capable of outputting a gain value adjustment instruction, such as a computer; or a gain controller used for gain adjustment in general, to realize adjustment control of the gain value.

Further, optionally, the bluetooth chip includes: a class D audio power amplifier; the gain adjuster is connected with the D-class audio power amplifier.

In the process, the gain adjuster is connected with the D-class audio power amplifier, and the gain value of the Bluetooth chip can be adjusted directly by adjusting the gain of the D-class audio power amplifier.

And because the Bluetooth chip uses the D-type audio power amplifier, the working current is unchanged after the gain adjustment is carried out, the operation of other parts of the system cannot be influenced, and the actual use requirement is met.

Further, as an alternative embodiment, the impedance of the loudspeaker is 15-17 Ω, optionally 16 Ω. Correspondingly, the resistance value of the resistor is 5-5.2 omega, and can be selected as 5.1 omega; the gain adjuster adjusts the gain of 2.5-3.5DB, optionally 3 DB.

In a specific implementation, the designed horn impedance is 16 Ω, and a resistance of 5.1 Ω is added to each of the two output lines. Thus the noise floor is reduced by-3 dB while the sound pressure level SPL of the horn output is reduced by-3 dB and then increased by +3dB by modifying the gain. Thus modified, the horn output SPL is unchanged while the noise floor is reduced. The signal-to-noise ratio required by a client can be achieved, and other parameters are not influenced.

Furthermore, a first capacitor and a second capacitor which are connected in series are connected between the first output line and the second output line, and a grounding end is arranged between the first capacitor and the second capacitor.

The capacitance values of the first capacitor and the second capacitor are selected to be equal, and are between 14 and 16pF, and are selected to be 15 pF. And the optimization effects of filtering, noise reduction and the like on the audio output current are realized.

The embodiment of the application also discloses a Bluetooth headset, which comprises the audio output circuit. The noise floor can be reduced, the signal to noise ratio is increased, the noise floor reaches the level which can not be heard by human ears, the normal transmission of sound is not influenced while the attenuation of noise signals is ensured, and the quality of the earphone is improved.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims

1. An audio output circuit, comprising:

a speaker;

2. The audio output circuit of claim 1, further comprising: and the gain adjuster is connected with the Bluetooth chip and used for adjusting the gain value of the Bluetooth chip.

3. The audio output circuit according to claim 2, wherein the bluetooth chip comprises: a class D audio power amplifier; the gain adjuster is connected with the D-class audio power amplifier.

4. The audio output circuit of claim 1, wherein the impedance of the speaker is 15-17 Ω.

5. The audio output circuit according to claim 4, wherein the resistance of the resistor is 5-5.2 Ω.

6. The audio output circuit of claim 2, wherein the gain adjuster adjusts the gain of the audio signal to be 2.5-3.5 DB.

7. The audio output circuit of claim 1,

a first capacitor and a second capacitor which are connected in series are connected between the first output line and the second output line, and a grounding end is arranged between the first capacitor and the second capacitor.

8. The audio output circuit of claim 7,

the capacitance values of the first capacitor and the second capacitor are 14-16 pF.

9. A bluetooth headset, characterized in that it comprises an audio output circuit according to any of claims 1 to 8.