On September 3, 2021, the leading distributor of semiconductor components committed to the Asia Pacific market, general United holdings, announced that its Youshang launched a TWS bone conduction Bluetooth headset scheme based on actions ats3019 and vesper va1200.

  

Figure 1 – display board of TWS bone conduction Bluetooth headset scheme based on actions and vesper products

With the development of Bluetooth headset, bone conduction technology has become a hot topic. The principle of bone conduction is to transmit sound to the auditory nerve through the skull, so as to obtain sound. In recent years, well-known manufacturers such as apple, Huawei and rambler have successively launched bone conduction call noise reduction headphones. These headphones collect the sound emitted by users through bone transmission, which can effectively avoid external sound interference and make the call effect clearer.

The TWS bone conduction Bluetooth headset scheme launched by the United Nations General Assembly Youshang based on acts ats3019 and vesper va120 can separate human voice and environmental noise in real time and bring users a better use experience. The scheme transmits the user’s voice signal through bone vibration, combined with AI human voice extraction, and intelligently recognizes the speaking state. No matter what environment you are in, it ensures the sound transmission effect and greatly improves the clarity and privacy of the call.

  

Figure 2 – scenario application diagram of TWS bone conduction Bluetooth headset scheme based on actions and vesper products

Actions is a low-power system level chip design manufacturer. Its main business is the R & D, design and sales of intelligent audio SOC chips and low-power wireless MCU. The company focuses on providing professional chips and complete solutions for wireless audio, intelligent wear, intelligent multimedia, voice interaction and intelligent Internet of things. Atc3019 is a new generation of Bluetooth headset chip launched by actions. It has Bluetooth 5.0 dual-mode configuration, with transmission power up to 10dBm and reception sensitivity of – 95dbm, which effectively improves the stability of audio connection. In the case of conventional audio playback, the no-load power consumption can be as low as 5.xma. At the same time, it supports low delay mode, and the delay of Bluetooth audio signal is as low as 40ms.

  

Figure 3 – block diagram of TWS bone conduction Bluetooth headset scheme based on actions and vesper products

Va1200 is a piezoelectric MEMS speech accelerometer under vesper. It has an ultra-small package of 2.9 mm x 2.76 mm x 0.9 mm, is compatible with reflow soldering, has no sensitivity degradation, has dust-proof and moisture-proof functions, and can operate stably even in harsh environments. Using va1200 speech accelerometer with standard microphone can effectively reduce background sound and wind noise and achieve excellent audio effect. Vesper is an acoustic sensor developer, which focuses on the research of piezoelectric MEMS technology. Its products are widely used in mobile devices and audible devices.

Core technology advantages:

Advantages of ats3019 chip:

  • The scheme is developed through the configuration tool without writing code (the customized function can modify the code by itself);
  • Support Bluetooth 5.0 protocol stack, HFP V1.7, A2DP v1.3, AVRCP v1.6, hid v1.0 and other profiles;
  • Ble broadcasting and its related functions, dual mobile phone connection and TWS team formation, Bluetooth non master-slave design, TWS binaural song broadcasting (SBC), TWS binaural call (CVSD), hid camera control and other application scenarios;
  • Broadcast incoming call number and ringing tone, three-party call, last call back, call mute, Siri and other functions, as well as call PLC, AEC, AGC, ans, CNG and other algorithm adjustment;
  • It supports sound effect adjustment in scenarios such as power reporting, volume synchronization, song playing and call, 14 segment PEQ, amplitude limiting and pre attenuation;

Advantages of va1200 chip:

  • Provide excellent background sound and wind noise suppression;
  • Small size – 2.9 mm x 2.76 mm x 0.9 mm;
  • Single ended analog output;
  • High frequency bandwidth for user voice pickup;
  • Good compatibility for TWS headphones: very suitable size, power, performance and cost.

Advantages of the overall scheme:

  • The main control platform with good cost performance and bone voiceprint call noise reduction technology make the overall scheme have good cost performance, and the call quality is better than most earphone schemes in the market.

Scheme specification:

Ats3019 chip specification:

  • Qfn32 package: 4 x 4 x 0.75 mm, pitch 0.4 mm;
  • 32 bit RISC, main frequency 200MHz;
  • Support V5.0, compatible with Bluetooth v4.2 / v4.0 Le / V3.0 / v2.1 + EDR systems;
  • Built in ROM, 8mbits SPI flash and 216k bytes ram;
  • Communication interface: spi * 2, UART * 2, I2C * 2;
  • Audio output: 16bit dual channel stereo, 18 MW PA, optional differential or single ended output, I2S TX; Audio input: support dual mic and aux;
  • Pin resources: 9-channel GPIO, 5-channel PWM, 4-channel lradc; Integrated power management, support lithium battery and DC5V power supply, 10 Ma ~ 300 Ma charging current is optional.

Va1200 chip specification:

  • Dimensions: 2.90 mm x 2.75 mm x 0.9 mm;
  • Current consumption: 150ua;
  • Bandwidth: 2.4 kHz;
  • Resonance frequency: 3 kHz;
  • The mechanical stability of all shafts is 10kgee.

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