Date: 23/09/2010

Noise-free power amps from ST for vehicles with auto engine start/stop

Car makers have introduced features such as engine start/stop as a measure to enhance fuel efficiency. For cars fitted with start/stop engines STMicroelectronics has introduced a new line of chips that can eliminate the interuptions caused in in-car entertainment equipments during engine turn-off and turn-on. The first chip in production from this new line is TDA7850LV, a 4x50W audio power amplifier.

In vehicles fitted with the start/stop facility the supply voltage for the on-board electrical equipment can drop to as low as 6V when the engine is turned off with only the battery supplying electrical power. While switching between battery power and alternator power a 'pop and click' noise can be generated causing disturbances in the audio output of the systems. ST's TDA7850LV audio power amplifier are used to regulate the supply voltage and suppress such pop and click noises to enable uninhibited audio expierience

ST plans to build a complete family of start/stop audio power amplifiers that include class-AB amplifiers, complex digital devices with diagnostic features, and an automotive class-D family.

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.

"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."

The TDA7850LV also delivers advantages of ST's Flexiwatt power package for car audio ICs. A variety of configurations are available, including vertically or horizontally mounted packages. In addition, a new surface-mount variant now allows car-audio makers to take advantage of high-speed fully automated assembly enabling increased throughput and production quality.

The key features of TDA7850LV include:
--4x50W MOSFET output stage
--2 ohms output driver compatible with diverse speaker types
--Hi-fi class distortion and low output noise
--Integrated 0.35A high-side driver supporting functions such as antenna control
--Protection against common vehicle electrical hazards:
Short circuits to ground and battery
Open-circuited speakers
Highly inductive loads
Load-dump
Over-temperature
ESD

Price: US$5.30 for 1K pieces

Availability: Now