To evaluate the grade of speakers, the auditory experience is an important part, which is also commonly known as the experience of sound quality. There are many ways to improve the sound quality, such as increasing the output power of the audio power amplifier from the electronic circuit, reducing the distortion; adjusting the frequency response to compensate for the lack of certain frequency points of the speaker or the cavity, and so on. Frequency division is a very effective way to improve sound quality. As for low-frequency, mid-frequency, and perhaps high-frequency speakers with relatively narrow frequency bands, it is very good to do, and the effect is also very good. However, it is more difficult to make a speaker with a full frequency band of 20Hz～20kHz audio, and it may require high-cost materials to make a full-range speaker with better effect. Choosing a 2.1-channel combination belongs to the field of electronic crossover and is a consistent way to improve the sound quality of speakers. The same is true for portable bluetooth speakers. Making mobile 2.1-channel speakers is also a good way to improve sound quality. Especially the shocking low-sound listening experience is difficult to compare with dual-channel or single-speaker.

Based on the CS8611E single-chip mobile 2.1-channel bluetooth speaker solution plan, a dual-cell lithium battery is connected in series with 8.4V as the power supply, and a boost chip CS5036E is boosted to 12V to power the CS8611E to complete 20W+2×10W output; and CS5090EUSB5V is used for charging It is very convenient to input two lithium batteries in series with an 8.4V charging management chip. Provides an auditory experience comparable to traditional 2.1 speakers when the lithium battery is the power source.

The overall function block diagram is as follows:

one. The plan clarifies:

This plan is a 20W+2×10W mobile 2.1 audio amplifier boost charging management combination. Refer to the plan. The power supply is two 18650 batteries connected in series, divided into three main levels:

1. Choose the CS5090 boosted dual-cell lithium battery charging IC, save the traditional external adapter, and use a USB cable to complete the two-cell lithium battery charge;

CS5090E is a USB_5V input used to connect two lithium batteries in series with an 8.4V charging management chip. Built-in intact trickle, constant current, and constant voltage charging process. The biggest feature is the input adaptive function, any USB interface with large or small current can be charged normally, and the maximum charging current is 1.5A. In addition, it has a variety of safe and reliable maintenance measures and charging status indication, and also brings NTC temperature control function.

CS5090E pin map and pin description

2. Two lithium batteries are connected in series with 8.4V as the power supply, which is boosted to 12V by the boost chip CS5036E to supply power to the power amplifier IC; CS5036E is a built-in 12A, MOS high-efficiency DC-DC boost conversion chip. The periphery is extremely concise, the input voltage scale is wide from 3V to 12V, and the efficiency is as high as 93% or more. The current limit value is adjustable on the periphery, which is convenient to match the battery. The EQA16 package is selected, which has functions such as over-temperature maintenance and over-voltage maintenance.

CS5036E pin map and pin description

3. The audio power amplifier chip selects CS8611E, which supplies 20W+2×10W power output at 12V; CS8611E is a 2×15W+30W dedicated 2.1-channel class D audio power amplifier. Advanced EMI suppression technology enables the use of inexpensive magnetic bead filters at the output port to meet EMC requirements. Coupled with the spread-spectrum operation, the FM radio also has an ideal closing effect. In addition, the efficiency of more than 90% makes it unnecessary to use an additional radiator when playing music.

CS8611E pin map and pin description

2. CS5090E+CS5036E+CS8611E+AC6951C overall board schematic diagram

3. CS8611E_2.1 channel audio power amplifier part of the schematic diagram

Four. CS5090E+CS5036E+CS8611E+AC6951C whole board PCB top plan drawing

five. CS5090E+CS5036E+CS8611E+AC6951C whole board PCB bottom plan

six. CS5090E+CS5036E+CS8611E+AC6951C whole board patch map