High-power speaker amp ICs optimized for advanced instrument clusters

ROHM recently announced the AEC-Q100 qualified 2.8W output Class AB monaural speaker amplifiers the BD783xxEFJ-M series (BD78306EFJ-M, BD78310EFJ-M and BD78326EFJ-M) ideal for instrument clusters – used in vehicles equipped with autonomous driving and ADAS.

ROHM developed the BD783xxEFJ-M series for vehicle clusters — requiring various sound outputs at high volume, including warning sounds, turn signals, welcome tones, and voice guidance. Also, adopting a new type of overcurrent protection (OCP) circuit provides protection against output shorts (damage due to accidental terminal contact) to deliver high 2.8W output that was difficult to achieve in the past, making it possible to deliver high 2.8W output. In addition to over current protection, built-in thermal shutdown and under-voltage lockout (UVLO) ensures high-reliability protection against abnormal conditions.

Furthermore, satisfying the automotive reliability standard AEC-Q100 and having the capability of withstanding high-temperature operation up to 105℃, enable stable voice output without compromising functionality even under severe conditions.

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 the need to limit the output 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% distortion).

The BD783xxEFJ-M series is qualified to withstand automotive reliability standard AEC-Q100 and supports a maximum operating temperature of 105℃. At the same time, adopting a power package reduces heat generation even at high volumes, resulting in stable audio output without compromising functionality – even under severe conditions. In addition to over current protection, thermal shutdown and under voltage lock out are built in – preventing damage caused by abnormal heat generation and unexpected popping(/cracking) noise during battery interruptions.

ROHM’s BD783xxEFJ-M series speaker operational amps are mounted on Cypress Semiconductor’s TraveoTM Cluster MCU Family S6J3360 Series Evaluation Board for automotive applications, allowing for easy evaluation under conditions similar to real cases.