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Old 03-07-2009, 09:59 AM   #18 (permalink)
Master EcoModder
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Why couldn't they use TI's hybrid digital technology to improve efficiency? I have done it for home audio:
Amanda Harris: the Prius of home audio - EcoRenovator
At this time, NO in-dash car head unit has a DC-DC power supply providing rail voltage to its amplifier IC. (some units, such as a discontinued Panasonic model and some specific Alpine and Kenwood units could be fitted with an outboard switching DC-DC unit to double rail voltage)

What this means is, for all practical purposes 100% of all in-dash car head units you can buy are working with 0-12 (or 14.4 under ideal conditions) volts and the vast majority use BTL configured output transitors with a 0.5/1 bias.
Except in hybrid and electric cars that have high voltage electrical systems. No chip amplifier will handle 200+v (discretes can be designed for it - much to the joy of those who build loud car stereos!) so a DC/DC converter will be used to reduce it. Then the design is more like that of a home audio system. In fact, most universal input power supplies for home electronics will run from the high voltage system in a hybrid or electric car without any modifications.

I remember a friend of mine in high school who turned up the (aftermarket) stereo so loud that the lights were dimming... and then complained that gas is too expensive!
If America manages to eliminate obesity, we would save as much fuel as if every American were to stop driving for three days every year. To be slender like Tiffany Yep is to be a real hypermiler...

Allie Moore and I have a combined carbon footprint much smaller than that of one average American...
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