ACM8625/ACM8628/ACM8622 I2S input built-in DSP digital power amplifier IC series promotes the upgrade and iteration of audio products

introduction

With the continuous development and progress of science and technology, people have higher pursuit of sound quality and listening experience. Music can make life full of passion and relax tense mood. It plays a great role in life and is the continuation of culture. Whether listening to music or watching TV, speakers play a very important role. Speakers are a kind of equipment that converts audio signals into amplified sounds. The speakers have their own power amplifiers. After amplifying the audio signals, the speakers themselves emit sound to amplify the sound. The quality of the sound will directly affect the quality of the music.

In recent years, more and more audio manufacturers have chosen to upgrade from analog input amplifiers to I2S digital amplifiers, such as high-performance soundbar products, large-screen TVs, car audio, Bluetooth speakers, etc. Engineers are increasingly inclined to use digital amplifiers. I2S input digital amplifier chips have the following advantages:

(1) Ultra-low noise floor. Since the digital amplifier chip is not interfered with during the audio signal transmission process, the noise floor is much smaller than that of the analog amplifier itself.

(2) Simple routing and fewer peripherals. Most of the problems such as high background noise and noise are caused by PCB routing or device interference. Many boards cannot avoid interference well due to area and structure limitations. Digital amplifiers are not easily affected by peripheral interference, so there is no need to worry about improper grounding and PCB routing. The gain of the digital amplifier chip is controlled by I2C, and no peripheral resistors are required, resulting in fewer peripheral components.

(3) Built-in DSP sound effect adjustment and DRC. The analog input amplifier chip is generally tuned through the pre-amplifier circuit. Many digital amplifiers have built-in DSP, which greatly simplifies the tuning process. Many low-end Bluetooth master controllers do not have DRC function. With digital amplifier chips, while ensuring high-quality audio output, the overall circuit BOM is cost-effective.

(4) Bluetooth signals are directly connected to the amplifier, which is efficient and fidelity-preserving. The internal signals of the Bluetooth chip are all digital signals, but considering that it may be connected to an analog amplifier externally, an additional DAC conversion chip will be added. However, due to cost constraints, the accuracy is generally not high, which affects the sound quality. Using a digital amplifier can allow digital signals to be directly connected, reducing conversion losses.

Shenzhen Yongfukang Technology Co., Ltd. has been focusing on the audio market. Now it vigorously promotes the I2S input built-in DSP digital amplifier chip series-ACM86XX of Suzhou Zhisheng Semiconductor to promote the upgrade and iteration of audio products. The full series of ACM86XX chips adopts a new PWM pulse width modulation architecture, dynamically adjusts the pulse width according to the signal size, reduces static power consumption and improves efficiency while ensuring audio performance, and prevents the generation of POP sound. A variety of sound effect algorithms are highly integrated. The internal modules can be controlled independently, and the left and right channels can also be controlled independently. The internal integrated digital and analog gain adjustment, signal mixing module, 15 EQ and 5 post EQ, 3-band DRC plus 1-band Lookahead DRC and other independent modules can achieve a variety of sound effects. For example, small signal bass enhancement, high and low bass compensation and other functions can be achieved through these modules. The I2S input digital amplifier chip is incomparable to the traditional analog input amplifier in terms of the warmth and coldness of the sound quality, resolution, background tranquility, and low-frequency shock.

Product selection and parameters are as follows:

Note 1: ACM8622/8625/8628/8685 pins are compatible;

Description 2: Two-channel power amplifier chip series, supports PBTL mode to drive single channel;

Explanation 3: The smaller the Rdson, the stronger the driving capability and the higher the efficiency;

Note 3: The entire series features CLASS H dynamic voltage adjustment and patented audio envelope tracking technology (the battery system playback time is extended by 50%), which improves heat dissipation performance.

Application Notes

1.ACM8622/ACM8625M/P/ACM8628 DSP digital power amplifier DEMO board schematic diagram

2. Schematic diagram of ACM8622/ACM8625M/P/ACM8628 digital amplifier

3. ACM8622/ACM8625M/P/ACM8628 DEMO board top-level design

4. ACM8622/ACM8625M/P/ACM8628 DEMO board bottom design diagram

5. ACM8622/ACM8625M/P/ACM8628 DEMO board patch diagram

6. ACM8622/ACM8625M/P/ACM8628 overall demo board bill of materials

7. ACM8622/ACM8625M/P/ACM8628 overall demonstration board physical picture