VECTORLIST - The Mailing List For The Technical Discussion of Vector-Based Arcade Games

September_1997
Re: message repost


From: Zonn ( )
Date: Thu Sep 04 1997 - 19:23:00 CDT


At 05:13 PM 9/4/97 -0600, you wrote:
>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.

Have you placed you regulators in the same position as the Zener diode and
pre-drivers were? Are the outputs of the pass transistor part of the
regulation circuit or is only the base regulated?

-Zonn


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