ROHM with new 2.8W High Power Speaker Amp ICs for Advanced Instrument Clusters

Optimizing voice output for autonomous driving systems and ADAS

Willich-Münchheide, Germany, April 21, 2020 – 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. (Fig. 1) In recent years, technological innovations in the automotive field - such as autonomous driving and ADAS - require a greater variety of sounds, such as warning sound when departuring from the lane or for surrounding obstacles. As a result, even audio output systems in the instrument cluster are utilizing speaker amps to generate sound with an MCU, instead of relays that produce blinker sounds and electronic buzzers that emit warning sounds. However, until now it was difficult to ensure safe, stable sound output at loud volumes. 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 over current 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 lock out (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°C, enable stable voice output without compromising functionality even under severe conditions. ROHM is committed in contributing to higher safety and greater comfort by developing high quality high reliable products for the automotive field where sound diversification is increasing. (Fig. 2+3) Key Features 1. High 2.8W output with built-in over current protection With conventional over current 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. (Fig. 4) 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 over current 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). 2. Ensuring high reliability in vehicle applications The BD783xxEFJ-M series is qualified to withstand automotive reliability standard AEC-Q100 and supports a maximum operating temperature of 105°C. 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. (Fig. 5) Installed on Cypress Semiconductor’s Reference Board ROHM’s BD783xxEFJ-M series speaker operational amps are mounted on Cypress Semiconductor’s Traveo™ Cluster MCU Family S6J3360 Series Evaluation Board for automotive applications, allowing for easy evaluation under conditions similar to real cases. (Fig. 6) Click on the URL below for more information on the S6J3360 Series. https://www.cypress.com/products/traveo-s6j3360s6j3370-simple-graphics-arm-cortex-r5-mcu Application Note: Traveo https://www.cypress.com/documentation/application-notes/an218589-external-circuit-pcmpwm-sound-system-traveotm-mcus Product Lineup ROHM offers products featuring output gains of +6dB (BD78306EFJ-M), +10dB (BD78310EFJ-M), and +26dB (BD78626EFJ-M). The lineup will be expanded to include a total of 11 models ranging from +6dB to +26dB in 2dB steps. (Table) Availability: Now Application Examples: Automotive instrument clusters Vehicle emergency call systems ADAS-related applications requiring voice functionality And other applications requiring notification, warning and voice guidance output in vehicle environments.

About ROHM Semiconductor ROHM Semiconductor is a global company of 398,989 million yen (3,652 billion US$) revenue per March 31th, 2019 with 22,899 employees. ROHM Semiconductor develops and manufactures a very large product range from the Ultra Low Power Microcontroller, Power Management, Standard ICs, SiC Diodes, MOSFETs and Modules, Power Transistors and Diodes, LEDs to passives components such as Resistors, Tantalum Capacitors and LED display units, thermal Printheads in state-of-the-art manufacturing plants in Japan, Korea, Malaysia, Thailand, the Philippines, China and Europe. LAPIS Semiconductor (former OKI Semiconductor), SiCrystal GmbH, Kionix are companies of ROHM Semiconductor Group. ROHM Semiconductor Europe has its head office near Dusseldorf serving the EMEA region (Europe, Middle East and Africa). For further information, please contact www.rohm.com/eu