lkml.org 
[lkml]   [2011]   [Dec]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] leds: driver for ab5500 high voltage leds
On Wed, 07 Dec 2011 20:01:46 +0200
Denis Kuzmenko <linux@solonet.org.ua> wrote:

> > The three channels are indeed high-voltage LEDs, they supply
> > up to 20V from a supply voltage of some standard mobile handset
> > battery at say 3.8 V or so. But there is no register to control the
> > voltage or anything like that.
> >
> > My naive understanding is that you set the current limit and then
> > the HV transformer (I guess this is a buck converter of some kind)
> > will raise the voltage level until it either (A) cannot raise it any more
> > at c:a 20V or (b) the current limit is reached.
> >
> > I suspect this is because for LEDs of this type you get a
> > specified current but the voltage just has to be "high enough"
> > to break through some diode barrier threshold or so. After
> > that intensity is controlled by limiting the current.
> >
> > Does this suffice as explanation...?
> >
> > Yours,
> > Linus Walleij
>
> Yeah, It does, thank you.
> Does it worth to make additional comment in code to avoid further questions?

Yes, I think that the fact that a reviewer asked a question such as
this is a reliable sign that subsequent readers will be wondering the
same thing, so it is an "oops it needs a comment" signal.

I won't do anything with this patch yet - I'm waiting to see if Mark
stops being surprised ;)



\
 
 \ /
  Last update: 2011-12-08 01:03    [W:0.069 / U:0.436 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site