Breaking News
Comments
Newest First | Oldest First | Threaded View
Page 1 / 2   >   >>
Etmax
User Rank
Rookie
re: Green LED replaces LDO regulator
Etmax   9/26/2011 1:49:27 AM
NO RATINGS
Given that it light up in ise, that may be difficuly :-)

Etmax
User Rank
Rookie
re: Green LED replaces LDO regulator
Etmax   9/26/2011 1:47:29 AM
NO RATINGS
Hmm I get 3 diodes at a cost of 4-5 cents. Compare that to 15 cents for an LED. What are you paying for LED's??

numberone2
User Rank
Rookie
re: Green LED replaces LDO regulator
numberone2   9/28/2010 6:03:48 AM
NO RATINGS
I disagree that the LED replaces 3 components compared with using an LDO. In this case the LDO would share bypassing with the other IC so this solution really only saves a few cents and marginal board space, ie an 0402 LED vs an SOT323 LDO. I would personally take the peace of mind and go with the LDO.

GREAT-Terry
User Rank
CEO
re: Green LED replaces LDO regulator
GREAT-Terry   9/16/2010 6:23:41 PM
NO RATINGS
This is a trick that students usually come up with. I may say this is a simple trick but not always be useful. It may only work well if the load is really light and the tempco. (in other words, the output voltage accuracy) is not an issue. To nowadays demanding digital stuff, it surely is not a good idea. However, for many low voltage consumer stuff, it is still a viable solution but need to be used with great care.

NATRON
User Rank
Rookie
re: Green LED replaces LDO regulator
NATRON   9/15/2010 6:51:32 PM
NO RATINGS
You might consider leaving the led in the dark...they tend to generate a voltage when exposed to strong light...

loggie
User Rank
Rookie
re: Green LED replaces LDO regulator
loggie   9/15/2010 4:03:07 PM
NO RATINGS
I would be concerned about the variation in forward voltage drop across the LED over temperature range (0 to 80 C for a typical consumer device). Typically, core logic operating at 1.8V requires a +/-10% regulated supply voltage. Given that the 3.6V supply has its own tempco and adding this to the LED tempco, it is possible that the 1.8V supply could have a variation over temperature exceeding 10%.

Jack Bauer
User Rank
Rookie
re: Green LED replaces LDO regulator
Jack Bauer   9/15/2010 1:12:00 PM
NO RATINGS
This assumes the VCC current is relatively fixed to generate a nearly constant forward voltage in the green LED. It also assumes the larger supply is exactly a diode drop greater than the logic supply needs to be. That almost never happens. Interesting trick, but not exactly a universal solution.

BicycleBill
User Rank
Rookie
re: Green LED replaces LDO regulator
BicycleBill   9/13/2010 2:55:57 AM
NO RATINGS
t.alex: I'll pass your query to the author. Of course, the circuit is so simple you could try it with and without the resitor, and see for for yourself! What have you got to lose, except an inexpensive LED?

t.alex
User Rank
Rookie
re: Green LED replaces LDO regulator
t.alex   9/10/2010 12:25:35 AM
NO RATINGS
Ah nice trick! The only factor is we need to select good-grade led as it is always ON. Do we need to have a current-limiting resistor?

Avatar Engineer
User Rank
Rookie
re: Green LED replaces LDO regulator
Avatar Engineer   9/9/2010 2:16:00 AM
NO RATINGS
Why not? it's cheaper than 3 diodes in series!

Page 1 / 2   >   >>


Flash Poll
Top Comments of the Week
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Max Maxfield

Saddleback Sale – It's Happy Dance Time
Max Maxfield
Post a comment
It's no secret that I'm a huge fan of the products from Saddleback Leather. As I sit here at my desk, I'm wearing one of their 1¾" wide Tow Belts, upon which rests one of their Belt ...

Engineering Investigations

Air Conditioner Falls From Window, Still Works
Engineering Investigations
1 Comment
It's autumn in New England. The leaves are turning to red, orange, and gold, my roses are in their second bloom, and it's time to remove the air conditioner from the window. On September ...

David Blaza

The Other Tesla
David Blaza
5 comments
I find myself going to Kickstarter and Indiegogo on a regular basis these days because they have become real innovation marketplaces. As far as I'm concerned, this is where a lot of cool ...

Larry Desjardin

Engineers Should Study Finance: 5 Reasons Why
Larry Desjardin
47 comments
I'm a big proponent of engineers learning financial basics. Why? Because engineers are making decisions all the time, in multiple ways. Having a good financial understanding guides these ...