From: Jim Thompson
Subject: Re: Thermal runaway: please settle this dispute!
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Date: Sat, 04 Jan 2003 22:31:22 GMT
NNTP-Posting-Date: Sat, 04 Jan 2003 17:31:22 EST
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On Sat, 04 Jan 2003 22:30:27 GMT,
"Lukas Louw" ,
In Newsgroup: sci.electronics.design,
Entitled: "Re: Thermal runaway: please settle this dispute!",
Wrote the following:
|Most audio power amps use a voltage source, such as the much maligned Vbe
|multiplier to establish output devices base voltage for bias....... Yea,
|that results in base, hence collector current, but the bias source is still
|Gazillions of them out there.......
|> Now the ONLY question left to answer is, "How many transistor designs
|> use a voltage source to bias the B-E junction?"
|> The overwhelming majority of circuits I look at use CURRENT sources for
|> B-E junction bias currents. In that case, reduced "barrier height
|> play a very small part in thermal runaway problems.
There is no such thing as a *general* discussion of thermal runaway.
It's totally dependent on the bias method used.
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| Jim-T@analog_innovations.com Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
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