Automotive-grade speech-synthesis LSI IC for EVs

Mouser now supplies the ML22120 automotive-grade speech synthesis LSI IC from ROHM Semiconductor. The LSI IC is designed for vehicle approach alert systems in EVs.

The device is the industry's first speech synthesis LSI designed specifically for AVAS sounds for EVs. New AVAS regulations require warning sounds to alert pedestrians of EV approach, and this automotive-grade speech synthesis LSI hardware incorporates a warning sound generator, a fader, and an equaliser for creating and adjusting playback sounds (like vehicle proximity alert sounds) while simplifying sound adjustment after installation in the vehicle. At the same time, dedicated GUI software makes it straightforward to comply with regulations for volume and frequency characteristics needed for AVAS.

The LSI is controlled by simple voice commands, letting warning sounds be initiated in less than one-tenth the time of conventional MCU-generated systems. Unlike MCU-based designs, the series hardware configuration eradicates the necessity for software validation, greatly reducing AVAS development time by using speech synthesis ICs to program high-fidelity sound. The device features a 16-bit D/A converter and low-pass filter, producing high-quality sound with a five-band equaliser for sound-quality effect processing.

The LSI also includes a failure detection function developed to detect abnormalities in communication with the main microcontroller or external oscillator, improving vehicle safety and reliability. The LSI supports a maximum external serial flash memory of 128Mbits, with a serial flash memory interface for sound data and the sound data playback function (sound generator).

The LSI IC is supported by the RB-D22120TB32 reference board and the SDCK3 sound device control kit 3, which is also available from Mouser. Dedicated GUI software allows easy evaluation of everything from sound generation to correction and trial listening of alert sounds.