Drivers of electric and hybrid vehicles need no longer worry about pedestrians stepping out in front of their cars because they can’t hear them coming. Toshiba has developed a single chip audio power amplifier that adds the sound of a conventional internal combustion engine to electric and hybrid electric vehicles to ensure a minimum level of sound.
To protect other road users, several vehicles are equipped with an acoustic vehicle alerting system (AVAS). It is anticipated that such systems will become more prevalent as legislators seek to establish a minimum level and type of sound for low-speed, all-electric operation. Due to road users’ familiarity with traditional vehicles, a preferred sound is that of a normal vehicle engine.
The TB2909FNG power IC, now available at distributor Rutronik, is a single-channel, Class-AB, single-ended push-pull (SEPP) amplifier specifically developed to amplify the simulated sound of a conventional engine. The device operates from a supply of between 6 and 16V and can deliver a maximum output power of 5W. Total harmonic distortion (THD) is rated at 0.08% for an output power of 0.125W and output noise voltage is 50µV. Guaranteed operation between -40° and +110°C supports use in EV warning sound systems where stable performance and extended temperature is required.
Despite the IC’s small size of only 4.4mm x 5.0mm x 1.0mm, the device provides high levels of integrated functionality including a variety of mute capabilities and a built-in standby switch. Abnormality detection and protection for thermal overload, over-voltage, short circuits to GND or Vcc, and speaker-open conditions are provided as standard, ensuring functional safety. Besides, the TB2909FNG supports other external audible output including reversing alarms and “answerback” confirmation for keyless remote entry security.
The deviceswas developed using the BiCD-0.13 process, which allows the integration of bipolar transistors, CMOS FETs and high-voltage DMOS elements on the same die.