Audio/Voice User Interface (VUI) is an important emerging trend in human-computer interaction in the future, and will be increasingly used in IoT verticals such as smart home control, building automation, smart retail, connected cars, and healthcare. It involves voice triggering, recognition, processing technology, and designers are also faced with the challenge of how to improve energy efficiency. For local and cloud, ON semiconductor has corresponding VUI solutions, providing advanced functions such as voice triggering, recognition, processing, control, etc., with excellent computing power and energy efficiency, ensuring an excellent user experience.

Audio/Voice User Interface (VUI) is an important emerging trend in human-computer interaction in the future, and will be increasingly used in IoT verticals such as smart home control, building automation, smart retail, connected cars, and healthcare. It involves voice triggering, recognition, processing technology, and designers are also faced with the challenge of how to improve energy efficiency. For local and cloud, ON Semiconductor has corresponding VUI solutions, providing advanced functions such as voice triggering, recognition, processing, control, etc., with excellent computing power and energy efficiency, ensuring an excellent user experience.

VUI Architecture and Classification

Figure 1 is an advanced voice interface architecture based on a microphone array. Local processing requires speaker tracking and voice enhancement, which involves beamforming, wake word detection, sound source localization, noise reduction, voice detection and other technologies. The cloud solution involves natural language. deal with. After that, the instruction needs to be played out through the audio playback function, and at the same time, echo cancellation needs to be performed.

ON Semiconductor’s Audio Solution Enables Ultra-Low-Power, Cost-Effective Voice Interaction Applications

Figure 1: High-level voice interface architecture based on microphone arrays

The local VUI uses pre-stored words or sentences as the recognition unit, and the speaker can be a specific user or a non-specific user, while the cloud VUI performs semantic understanding and speech synthesis based on artificial intelligence, and the speaker is a non-specific user. The local VUI is connected to the network via Bluetooth, while the cloud VUI is usually connected via WiFi. The power consumption of local VUI and the risk of information leakage are relatively lower, and cloud VUI has higher recognition rate and scalability. Relatively speaking, local VUIs consume less power than cloud VUIs. Designers can decide whether to use a local VUI solution or a cloud VUI solution according to specific application requirements.

Native VUI solution

According to the characteristics of the local VUI solution, it must be able to carry out two-way voice communication, be able to recognize non-specific user voices, support sufficient commands and multiple languages, and be flexibly expandable. It is best to integrate technologies such as beamforming and noise reduction on a single chip to reduce costs and footprint. For example, ON Semiconductor’s single-chip solution LC823450 includes dual Cortex-M3 cores, integrated digital signal processing (DSP) for voice front-end processing, SRAM provides 1656k bytes of memory, no auxiliary memory chip is required, and two digital microphone I/ F interface, two digital-to-analog converters, including advanced functions such as echo cancellation and noise reduction, have extremely high scalability, small footprint, and ultra-low power consumption. If combined with the voice control technology of ecosystem partners, such as Sensory’s TrulyHandsfree, Supports customization of wake words and voice commands for voice interaction in home automation and music playback.

Figure 2 shows an example application block diagram and evaluation board for a native VUI solution. It adopts ON Semiconductor’s ultra-low power audio processing single chip LC82345X, microphone pre-amplifier FAN3852, low dropout regulator (LDO) NCP170, synchronous PWM switching buck regulator NCP3170, and mono audio power amplifier NCP2823. With its experience and expertise in power management, ON Semiconductor enables this solution to achieve ultra-low power consumption, which is an advantage over other competitor solutions. Although the existing solution does not integrate WiFi and Bluetooth dual-mode modules, ON Semiconductor has acquired WiFi leader Quantenna and has relevant technologies. In the future, it will consider integrating WiFi modules.

ON Semiconductor’s Audio Solution Enables Ultra-Low-Power, Cost-Effective Voice Interaction ApplicationsON Semiconductor’s Audio Solution Enables Ultra-Low-Power, Cost-Effective Voice Interaction Applications

Figure 2: Voice Control Application Block Diagram and Evaluation Board

Cloud VUI Solution

From the perspective of application scenarios, in addition to semantic understanding and speech synthesis, cloud VUI can also push various services. For example, intelligent voice assistants can play music and tell stories, and also support smart retail, such as taxis and takeaways. One of the pain points of the current cloud VUI is the high frequency of operation, the need for external memory and flash memory, high power consumption, and high bill of materials (BoM) costs. ON Semiconductor’s audio DSP system-on-chip (SoC) LC823455 solution solves these pain points well. It integrates 4M RAM and does not require external storage. In addition to the CPU core, it also includes beamforming, noise reduction, and echo cancellation functions. Integrated pre-implementation Audio hardware (analog-to-digital converter, digital-to-analog converter and power amplifier), reduce the cost of BoM, provide power-optimized MCU due to lower clock frequency, ultra-low power consumption, provide stable connection and extremely high scalability, wide The package lineup supports a variety of audio products such as music players, recorders, smart appliances, WiFi/Bluetooth speakers, and more.

Figure 3 shows the block diagram of the smart speaker reference design. This reference design is based on LC823455. There are 4 ONA101V and 1 ONA40 power amplifier. It includes USB-C PD source/sink interface and supports Strata platform. Designers only need to plug this evaluation board into A computer with Strata installed can automatically identify and start downloading all relevant documents and supporting materials, including schematics, layouts, test reports, user guides, etc., and a graphical user interface (GUI) will appear at the same time, showing all relevant parameters and options For engineers to start evaluating, helping speed and simplify development. This reference design currently supports Amazon’s Alexa voice service, and ON Semiconductor is also in contact with some domestic voice service providers in China, and will support domestic voice assistants in the future. One of the most significant advantages of this solution is also ultra-low power consumption. After testing it with the power consumption of the competitor’s solution, the power consumption of ON Semiconductor’s solution is about half of the power consumption of the competitor’s solution.

ON Semiconductor’s Audio Solution Enables Ultra-Low-Power, Cost-Effective Voice Interaction Applications

Figure 3: Smart Speaker Reference Design Block Diagram

ON Semiconductor’s Mobile and Smart Speaker Audio Technology/IP

ON Semiconductor has rich intellectual property rights to support the design and development of mobile and smart speakers, including audio processing systems, class D power amplifiers, microphone pre-amplifiers, and high-performance audio switches, providing competitive advantages to help designers design products with competitive advantages .

Competitive advantages in audio processing systems include small PCB footprint, highly integrated SoC (CPU+DSP+audio), integrated ARM Cortex-M3 dual-core, proprietary 32-bit DSP.

For Class D amplifiers, it supports less than 10W, 10W to 30W, and only provides samples for applications greater than 30W. Among them, the power amplifier of less than 10W is small in size and adopts analog input, and the power amplifier of 10W to 30W supports digital interface, providing the best dynamic range and gain error drift.

For microphone pre-amplification, ON Semiconductor’s solution uses the smallest standard-pitch WLCSP package to convert analog audio to digital audio, supporting different sensor interfaces.

For audio switches, ON Semiconductor provides depletion switches with the smallest impedance/area.

Peripheral technology: USB Type-C and Class D amplifier

USB Type-C enables every port to be a power, data, video or audio port, which greatly facilitates users and will be increasingly used for various Electronic applications such as voice interaction. ON Semiconductor provides a complete lineup of USB Type-C solutions to support the development of audio applications, including power supply, multiplexing audio signals, signal switches, interface protection, etc., with the smallest footprint, ultra-low static power consumption, and integrated rich protection functions .

Emerging audio applications such as smart speakers have higher and higher requirements for power amplifiers. ON Semiconductor has developed a series of Class D power amplifier product lines with a power level of more than 10 W. Combined with ceramic packaging technology, CMOS circuit technology and different Apply custom power MOSFET technology to provide low thermal resistance, high frequency interconnect, high power density, low noise (summary

Voice interaction is becoming more and more popular. Voice recognition and natural language processing technology are the foundation of VUI. ON Semiconductor provides local VUI solutions and cloud VUI solutions, integrating advanced voice processing technologies such as beamforming, echo cancellation, and noise reduction, and ultra-low power consumption. Power management and peripheral devices such as USB Type-C and Class D power amplifiers, together with ecological chain partners, greatly reduce the cost of BoM, and at the same time have excellent computing power and ultra-low power consumption, providing an excellent user experience.

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