First speech synthesis chip for EV warnings
Lapis Technology has developed the industry’s first speech synthesis chip to deliver warnings from electric vehicles (EVs)
The ML22120xx series (ML22120TB, ML22120GP) from Lapis, part of Rohm, is designed for Acoustic Vehicle Alerting System (AVAS) in all kinds of EVs.
AVAS regulations are increasingly being enacted that require a warning sound to alert pedestrians of their approach. However, when generating a warning sound using a microcontroller, the pitch and volume must be smoothly controlled and characteristics adjusted to match the vehicle geometry. This increases MCU software development load requiring verification with other software processes inside the MCU.
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The Lapis chips help to speed up AVAS development by producing high-fidelity sound using a novel hardware-based configuration from speech synthesis. They can also be used for external vehicle alert sounds (sliding door open/close, charging completion), etc.
The ML22120TB and the ML22120GP integrate hardware functions that include a warning sound generator, fader, and equalizer. Unlike MCU-based designs, the hardware configuration eliminates the need for software validation – significantly reducing development time. At the same time, dedicated GUI software makes it easy to comply with regulations for volume and frequency characteristics required for AVAS.
The speech synthesis chips can be controlled by simple commands, allowing warning sound to be started in less than one-tenth the time of conventional MCU-generated systems. An included fault detection function detects both erroneous communication with the main controller and erroneous oscillation caused by external components – contributing to vehicle reliability.
An evaluation board along with a Sound Device Control Kit [SDCK3] that includes dedicated GUI software are available, enabling easy evaluation of everything from sound generation to correction and trial listening of alert sounds.
The EV speech synthesis chips and evaluation board are available through Digi-Key, Mouser and Farnell and will be offered at other online distributors as they become available.