NFMI-based MiGLO streams audio at less than 4mW

Article By : Graham Prophet

NXH2280 operates from a 1V supply and consumes 1.5mW when audio is streamed in a truly wireless earbud application, according to NXP.

NXP Semiconductors' MiGLO platform targets small, wireless earbuds that will offer long battery life, high audio quality and reliable operation.

In 2016, NXP showed use of Near Field Magnetic Induction (NFMI) technology in a completely wireless earbud, supporting wireless audio streaming from ear to ear, using its NxH2280 NFMI-based radio transceiver. There is an obvious attraction of eliminating wires from in-hear transducers for both medical (hearing-aid) and entertainment products. As NXP pointed out, “truly wireless earbuds would provide substantially increased user comfort for sport activities, but in general in all situations where wires are undesired and annoying to users.” In September, NXP and Chinese company Cannice announced a production-ready reference design for wireless earbuds.

Sending a stereo audio stream towards two distinct earbuds is not possible with existing 2.4GHz technology, NXP asserted. A standard Bluetooth A2DP profile, which supports only point-to-point connections, does not support this use case. Forwarding a high quality audio stream from one ear to the other using reasonable power levels is difficult using 2.4GHz technology because most of the signal is absorbed by the human body tissue. To address this problem, NXP applied NFMI, which features ultra-low power consumption and the ability to create a very reliable network in and around the human body. High-quality audio and data streaming can be supported over small distances (<1m). An additional integration advantage is also that it requires few external components. NFMI is a short range technology and as such also creates a private network, making it is less susceptible to interference than 2.4GHz transceivers.

NXH2280 is NXP's second generation fully integrated single-chip NFMI radio transceiver. Operating from a 1V supply, it consumes 1.5mW when audio is streamed in a truly wireless earbud application. The chip supports a maximum bitrate of 596kbps, and can be configured to operate either stand-alone or in conjunction with an MCU. An embedded ultra-low power CoolFluxT DSP provides flexibility for the implementation of audio processing algorithms. A flexible network stack supports up to 15 devices, low latency communication (<5msec) and multiple simultaneous audio and data streams in receive and transmit mode.

Now, NXP has assembled the technology into its first MiGLO solutions, and supplies the silicon in Wafer Level Chip Scale Package (WLCSP), requiring a minimum of external components and occupying a footprint smaller than 11mm². An earbud battery can be significantly smaller for the same battery life, and unlike other wireless solutions, NFMI will be able to work accurately even if earbuds get smaller in future, according to NXP. NFMI based MiGLO solutions are capable of streaming high quality audio ear-to-ear at less than 4mW. NXP aims to enable uninterrupted audio listening for a full day from a small battery without recharging.

MiGLO extends the technique to high quality wearable audio applications, promising a perfect wireless connection (to avoid drop-outs), low latency audio transport (to maintain lip sync) and tightly controlled left and right (L/R) audio synchronisation (to maintain the stereo image).

NXP has secured a number of endorsements from manufacturers already in the market, such as Alpha Audiotronics with its "Skybuds"; Bragi with "The Dash" and "The Headphone"; Doppler Labs with its "Here One," and Nuheara.

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