ANC is the current top priority

In October 2019, with the release of AirPods Pro, ANC (active noise reduction) replaced "delay" and became a new focus of the TWS headset industry. JL has already been involved.

As previously reported by the semiconductor industry, JL began to conduct active noise reduction research very early. Between AC691N and AC693N, they once introduced a chip with active noise reduction function, which is also JL's first-generation ANC technology. This laid a solid foundation for them to study a new generation of chips with active noise reduction.

Zhang Qiming, deputy general manager of JL Technology, pointed out in an exchange with the author a few days ago that the company’s latest AC897N series chips adopt the second-generation ANC technology. The previous generation ANC chip has increased by 20db.

As we all know, the current mainstream ANC noise reduction methods have three modes: feedforward, feedback and hybrid feed, and JL Technology supports them. However, Zhang Qiming pointed out that these solutions have a natural "defect"-the system's noise reduction adjustment has been set at the factory, which means that the noise reduction method is the same for different usage scenarios. In other words, these methods may not maximize the noise reduction effect.

In view of this, JL Technology is exploring to support high-performance in-use training based on the hybrid feed mode, allowing consumers to adjust the depth of noise reduction according to the different on-site environments when using noise-reducing headphones. The key is the powerful adaptive algorithm provided by JL.

Zhang Qiming told reporters that thanks to this algorithm, JL’s solution breaks the limitation that ANC products can only be adjusted for noise reduction when they leave the factory, allowing related products to automatically learn noise reduction during consumer use to achieve better Effect. This is what they call hybrid feed real-time adaptation.

Of course, hardware strength is the foundation for Jerry to achieve the above functions. Take AC897N as an example, they integrated a 32-bit floating-point DSP dedicated for audio on this chip. Because it has a main frequency of up to 200MHz, it can easily support multiple audio formats including SBC, AAC and LDAC, and it can also support multi-MIC ENC noise reduction technology and complex audio processing algorithms.

Power consumption and size are always the pursuit

In previous reports, we have talked about the rapid development of TWS Bluetooth headsets in the past two years and its high penetration rate, which has a lot to do with its breakthrough in power consumption. It is relatively simple to reduce the power consumption from 30mA to 10mA, but it is a difficult test to reduce the power consumption below 10mA. However, JL Technology rose to the challenge, and the entire chip software and hardware team worked together, and the power consumption of the new AC897N was only 3~4mA. This level of power consumption means that JL has not fallen behind when compared with top-tier manufacturers such as Qualcomm and Apple. To achieve this, the company's task splitting in the chip design process is very important.

First of all, JL uses a 40nm process on the brand-new AC897N, which has a power consumption advantage compared with the current mainstream 55nm process. "According to our understanding of the 40nm process, we have not yet exhausted the power consumption bonus of 40nm. We believe that in the next generation of products, we will provide more impressive power consumption performance," said Zhang Qiming.

Secondly, in the design process of this chip, in addition to using previous experience, JL also regarded power consumption as a hard indicator and introduced it into the chip design considerations. This is a practice that the company has never done before in related chips, Jerry Aspect emphasized.

In addition to power consumption, shrinking size is also a goal pursued by chip design manufacturers, especially in wearable devices. Smaller size means flexibility in product design, while also integrating larger capacity batteries. JL’s AC897N packs memory and other peripherals into the chip through advanced SiP packaging. Its package size and die have always been the smallest in the industry. This technology also makes quality and stocking more controllable, design costs and production The cost is further reduced, and there are advantages such as strong confidentiality, high production efficiency, conducive to product miniaturization, resolution of interference, and improvement of memory performance.

What to focus on in the future?

When asked about his views on the future development of the TWS Bluetooth headset chip, Zhang Qiming told reporters that the future TWS Bluetooth headset will be divided into two product lines: one is the basic functional type, and the other is the extended type.

The so-called basic functional headsets only need to meet the needs of listening to music and talking. The extended type refers to the addition of functions such as AI, hearing aid and pulse detection to the TWS Bluetooth headset. For these applications, JL will not only continue to improve the performance of the chip, but also increase the interface to enhance its expansion capabilities, so that it has enough resources to deal with future needs.

"In the future, we will maintain the development of the two product lines in parallel," said Zhang Qiming. In terms of technology, JL will maintain its focus on new technologies such as Bluetooth 5.2 and LE Audio.