The problem with the low cost SMPS controllers is the
quiescent current. This was true 5 years ago and is less
true now. MC34063 is a quite an old product anyway. 

The problem with those nice SMPS controllers from
Intersil/Maxim/AD/Linear/TI is the relative high cost.
OnSemi/Fairchild/National/IR may produce some cheaper
product. There are some new players from Asia whose
product are less know to the public though.

Xiaofan

-----Original Message-----
From: Russell McMahon [mailto:apptech@paradise.net.nz]
Sent: Monday, May 30, 2005 3:07 PM
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Design challenge - boost converter

> I believe the MC33063/MC34063 can do what you want, and is much
> lower-cost at ~US$0.28/1000.

I tried it. Alas, it has a poor quiescent current drain - about 3 mA at
no load in a typical configuration.  Usually this would not be a major
issue but as my load current is in that range it badly hurts the
total current draw. Also, its switch is an internal Darlington and
unless you can get very creative the voltage drop is an appreciable
part of the 4v minimum supply and further hurts efficiency. One way to
get creative is to use it to drive an external FET switch (which is
what I did in the inverter I did for Jinx a few months ago) BUT that
adds to parts count and cost which are at a premium here.
...
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist