Integrated automotive audio amplifier combines high-definition sound with class-G efficiency

STMicroelectronics has announced the TDA7901, an automotive amplifier that integrates a buck controller for class-G power switching and supports high-definition audio, said to be a unique combination for great listening and high efficiency.

In class-G operation, the TDA7901 buck controller automatically optimises the voltage supplied to the bridge-tied load (BTL) power stage depending on the audio-signal level. The resulting analogue sound comes with near-class-D efficiency at normal listening levels.

Because the power dissipation is much lower compared with a conventional class-A/B amplifier, the heatsink requirement is optimised. Integrating the buck controller in the IC contributes to reducing system size and weight and it also cuts the bill of materials, simplifies circuit design, and saves developing firmware to control the voltage rail.

The TDA7901 is suited to use in many in-vehicle information (IVI) systems, such as head units, smart cockpit systems, and external amplifiers. The amplifier signals full in-play diagnostics including real-time load-current monitoring through I2S or I2C interfaces, enabling ASIL-A certification of safety-related applications like warning-tone generators and acoustic vehicle alerting systems (AVAS).

A digital impedance meter is also provided, ensuring systems containing the TDA7901 can meet the most demanding requirements of automotive OEMs.

With its I2S digital input and intelligent quad-BTL output, the TDA7901 delivers 4x 43W of audio power (at 4Ω load, saturated output at 14.4V). The amplifier has 80kHz bandwidth to handle high-definition audio. Its wide supply-voltage range, spanning 4.5V-18.5V, prevents disruption by start-stop engine operation and general automotive electrical transients.