Tim Williams wrote:

Somewhere I believe LCD was mentioned. Typically TFTs have a little silicon
chip cemented to the glass, providing interface (parallel, serial,
whatever), control (for at least a buffer, if not some rudimentary fill
routines), memory, and most importantly, the massive fanout (hundreds of
rows and columns) required to drive the array itself (which is mainly crummy
amorphous transistors driving pads which finally drive the liquid crystal).
Last one I busted open had a shiny strip maybe 2 x 15 mm, a hi-def panel
would have a lot more. Probably progress has been made since then and only
a 1mm strip is required.

Putting inductors anywhere near one of those will be an interesting
challenge, because the few components that come with are soldered to the
flex cable. This includes bypass caps, which you may know from experience
do not handle strain very well...

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

"josephkk" wrote in message
...
On Sat, 11 Feb 2012 11:22:38 -0700, Jim Thompson
wrote:

In the past I have designed boost converters in burst mode, with peak
current control, but never with a PWM-controlled loop.

Outputs: +5 @ 25mA, -5V @ 20mA

Can someone point me to a tutorial?

Thanks!

[Don't point me to an off-the-shelf part. This has to go into a
_custom_ chip... just a little thing... 1mm x 25mm :-]

...Jim Thompson

OK it is not in my proper range of expertise, but there has to be a reason
that the device is not 2.5 mm by 10 mm (or even more square). Can you
enlighten us?


I suspect it's a 1 mm sliver of a larger IC. Dicing yield would be a
problem with something 40 thou wide and an inch long, not to mention the
tendency of the chips to fall over.

Cheers

Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net