Designed to add the sound of a conventional combustion engine to EVs and HEVs, the TB2909FNG is a single-chip amplifier from Toshiba Electronics Europe. The device also supports other external audible output including reversing alarms and ‘answerback’ confirmation for keyless remote entry security.
Pedestrians, cyclists and other road users may be less aware of Evs and HEVs due to their all-electric mode being quieter than vehicles driven by internal combustion engines. Due to this, manufacturers are equipping their vehicles with an acoustic vehicle alerting system (AVAS), something which is expected to become more prevelant 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 engine1.
Toshiba's device is a single-channel, Class-AB, SEPP amplifier specifically developed to amplify the simulated sound of a conventional engine. Operating between 6V and 16V, the device can deliver a maximum output power of 5W (Vcc = 16V, RL = 8Ω). THD is rated at 0.08% (for an output power of 0.125W) and output noise voltage is just 50μV. Guaranteed operation between -40° and 110°C supports use in EV warning sound systems where stable performance at extended temperatures is required.
The device is available in a TSSOP16 package with dimensions of 4.4 x 5.0 x 1.0mm. The IC 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, supporting functional safety. The device was developed using the comany's BiCD-0.13 process. This process allows the integration of bipolar transistors, CMOS FETs and high-voltage DMOS elements on the same die.