ROHM Group company LAPIS Technology have introduced the industry’s first speech synthesis ICs — the ML22120xx series (ML22120TB, ML22120GP) — designed for acoustic vehicle alerting systems (AVAS) in electric vehicles (EVs).
To achieve a carbon-neutral (decarbonized) society, the number of hybrid and EVs that silently operate on motor power continues to increase, prompting AVAS regulations to be enacted requiring a warning sound to be emitted to alert pedestrians of their approach.
However, when generating a warning sound using an MCU, 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.
In response, LAPIS has released new products that contribute to reducing the burden of AVAS development by leveraging experience and technology with speech synthesis ICs. The aim is to achieve a high-fidelity sound using a novel hardware-based configuration.
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 system of new ICs 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.
Application examples include:
- Acoustic Vehicle Alerting System (AVAS)
- External vehicle alert sounds (sliding door open/close, charging completion)
Evaluation board and the GUI software
An evaluation board and 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.
Filed Under: Technology News