Some manufacturers estimate that start/stop and other technologies such as high-efficiency engine management programs could be a big contributor to reducing energy usage, cutting fuel consumption by as much as 20% in certain models over the coming years. The system shuts down the engine when the vehicle is stopped, for example at traffic lights, and restarts as the driver prepares to move off. According to market analyst Strategy Analytics, annual demand for vehicles featuring start/stop is expected to reach almost 20 million units by 2015, initially led by customer demand in Europe.
In cars fitted with start/stop, the supply voltage for on-board electrical equipment can fall to as low as 6V when the engine is turned off and restarted and only the battery is supplying electrical power. In addition, switching between battery power and alternator power can generate ‘pop and click’ noise. Left unaddressed, these effects can cause noticeable distortion in the audio system’s output. Hybrid-electric vehicles present similar challenges to electronic equipment designers.
Discrete components external to the audio power amplifier can be used to build circuitry to regulate the supply voltage and suppress pop and click noises. However, these circuits complicate design and add significantly to bill-of-materials costs. ST’s TDA7850LV audio power amplifier makes the use of all these components unnecessary and therefore simplifies design, reduces cost, and saves pc-board space.
ST is building a complete family of start/stop audio power amplifiers that will include entry-level class-AB amplifiers, complex digital devices with diagnostic features, and an automotive class-D family offering outstanding power efficiency.
“This emerging family of devices, beginning with the TDA7850LV, combines advanced start/stop capability with the hi-fi audio quality and outstanding ruggedness that have always distinguished ST’s audio power ICs and ensured our strong market leadership,” said Fabio Marchio, Automotive Product Group Vice-President and General Manager of ST’s Automotive Infotainment Division. “We call this new wave of products ‘green power,’ meaning that we are totally committed to design ICs that can help our customers implement environment-friendly systems. We now aim to build on our leadership as demands for start/stop and hybrid technologies continue to ramp up.”
In addition to its start/stop compatibility and high audio performance, the TDA7850LV delivers the advantages of ST’s Flexiwatt power package, now the de-facto standard for car audio ICs. A variety of configurations are available, including vertically or horizontally mounted packages. In addition, a unique new surface-mount variant now allows car-audio makers to take advantage of high-speed fully automated assembly enabling increased throughput and production quality.