- Provides voice output for warning and voice guidance
- Offers circuit protection and rugged under high-temperature conditions
In recent years, the technological innovations in the automotive field such as autonomous driving and ADAS require a variety of warning sounds when departing from a particular lane or for surrounding obstacles. As a result, audio output systems utilize speaker amps to generate sound with an MCU, instead of relays and electronic buzzers that produce blinker warning sounds.
Until now it was difficult to ensure safe, stable sound output at loud volumes. However, the new BD783xxEFJ-M series of Class AB monaural speaker amplifiers (BD78306EFJ-M, BD78310EFJ-M and BD78326EFJ-M) by ROHM is ideal for use in vehicles equipped with autonomous driving and ADAS. It produces sound outputs at high volume, including warning sounds, turn signals, welcome tones and voice guidance.
Also, a new type of overcurrent protection (OCP) circuit protects against output shorts (damage due to accidental terminal contact) to deliver high 2.8W output that was difficult to achieve in the past. Additionally, built-in thermal shutdown and under-voltage lockout (UVLO) ensures high-reliability protection against abnormal heat damage.
Furthermore, the ICs meet the AEC-Q100 automotive reliability standard and can withstand high-temperature operation up to 105 degrees Celsius, thus enabling stable voice output even under severe conditions.
1. High 2.8W output with built-in overcurrent protection
With conventional overcurrent protection circuits, the maximum output is limited, since the operating threshold of the protection circuit must be set to a value smaller than the maximum current the speaker amp can provide.
In contrast, ROHM’s new over current protection circuit eliminates that by preventing waveform distortion even at high output. This allows the BD783xxEFJ-M series to provide overcurrent protection from output shorts which was difficult to achieve in the past in combination with high output (2.8W max. at 4Ω load and 10 per cent distortion).
2. Reliability in high temperature
Besides fulfilling reliability standard AEC-Q100 and having a maximum operating temperature of 105 degrees Celsius, the BD783xxEFJ-M series reduces heat generation even at high volumes and unexpected popping/cracking noise during battery interruptions, resulting in stable audio output without compromising functionality.
ROHM offers products featuring output gains of +6dB (BD78306EFJ-M), +10dB (BD78310EFJ-M), and +26dB (BD78626EFJ-M) that are available now.