Re: message repost

From: Anders Knudsen <Anders_Knudsen_at_btc.adaptec.com>
Date: Thu Sep 04 1997 - 19:13:54 EDT

At 03:55 PM 9/4/97 PDT, Zonn wrote:
<snip>
>The difference between this design and the one I was using is that this
>design places the full current load on the regulators.

No it does not. In my case, if you look at the schematic, and see how the
regulated supply is "wired" in, you will see that the *only* thing the
regulators do is drive the base of the power transistors -- i.e., in a bjt
follower configuration, where the collector of the power transistor is
connected directly to the unregulated supply voltage. Thus the only devices
to see the high currents are the power transistors, and none of the parts
on my LV PCB.

So the regulators on my LV PCB only drive the base current to the power
transistors, and drop about 8V...i.e., low power through the regulators.

The WG equiped Star Wars, that is continuously on, has my LV PCB installed,
has been running since January, and when you touch the regulators...they
are cold.

-Anders.

 -----------------------------------------
| Anders Knudsen
| ASIC Design Engineer
| Adaptec, Inc., Boulder Technology Center
| anders_knudsen@btc.adaptec.com
| http://www.adaptec.com
 =========================================
Received on Thu Sep 4 16:15:13 1997

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