Path: utzoo!attcan!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!osu-cis!att!ihnp4!ihlpf!straka
From: straka@ihlpf.ATT.COM (Straka)
Newsgroups: sci.electronics
Subject: Re: 7805 regulator
Message-ID: <5061@ihlpf.ATT.COM>
Date: 17 Jun 88 13:04:49 GMT
References: <592@picuxa.UUCP> <5030002@hpvcla.HP.COM> <22117@amdcad.AMD.COM>
Reply-To: straka@ihlpf.UUCP (55223-Straka,R.J.)
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 19

In article <22117@amdcad.AMD.COM| phil@amdcad.UUCP (Phil Ngai) writes:
|In article <5030002@hpvcla.HP.COM| johne@hpvcla.HP.COM (John Eaton) writes:
||< I have a question about the MC7805 5V 1A regulator. Can you parallel
||< two of these devices together to derive a higher current?
||In a word, NO. Unless they are extremely well matched then one will wind up
||with most of the load and the other will have very little. The best way is
|What is the problem with one taking most of the load? They are over
|current and temperature protected anyway.

I thought that the problem was that if the output voltage of the multiple
regulators were not identical, you end up with the regulator with the highest
voltage supplying most/all of the current.  If the load is sufficient to go
past 1.5A, the one regulator may be in (protected) overload condition all of
the time. Although these devices are pretty bulletproof, I wouldn't want to
run them like this as a matter of course.
-- 
Rich Straka     ihnp4!ihlpf!straka

Avoid BrainDamage: MSDOS - just say no!