From: Neil <picdude3@narwani.org>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Tue, 4 Aug 2020 07:14:19 -0700
Subject: Re: [EE] "Sunlight" brand LEDs
Thread-Topic: [EE] "Sunlight" brand LEDs
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The failures I had with the counterfeits were random segments failing=20
within weeks, months or more, and replacing a 12-pin through-hole=20
display on a very tight PCB was a very difficult task, so the boards had=20
to be replaced.

I recently got some gauges back for upgrades after 12 years (with the=20
original Lite-On LEDs)... still working beautifully!

I have some samples of these Sunlight LEDs, and testing them with an=20
actual multitplexing circuit as they would be used (rather then=20
continuous on).  But extensive testing will get arduous quickly... For=20
example 3 years of testing at a few hours per day can only be crammed=20
down to 136 days.  And if I set an "acceptable" failure threshold of 1%,=20
do I need to test 100 of these?  And these will be used in cars, so=20
continuous bench testing won't be anywhere near a representative test as=20
on/off with lots of thermal cycling.

Cheers,
-Neil.



On 8/3/2020 8:00 PM, RussellMc wrote:
> On Tue, 4 Aug 2020 at 11:41, Neil <picdude3@narwani.org> wrote:
>
>> Anyone have any mid-to-long-term experience with "Sunlight" brand
>> 7-segment LED displays?
>> Looking at these for a long product as the Lite-On LEDs I've used to
>> date are in short supply, being discontinued.  And the ones I found from
>> a broker were counterfeits, which have cost me considerably.
>> Hence, looking for any reviews anyone can provide.
>>
>> I have NO experience of them.
> Chinese LEDs seem to generally be of substantially higher longevity in mo=
st
> cases than when I used them in largish volume around 10 years ago.
> However, if Lite-On fakes are problematic then other names also may be.
> Depending on what the issues are and what time you have available you may
> be able to carry out longevity testing yourself.
> At 168 hours/week, ~ 700 hrs/month you may start to get
> lifetime indications in a useful time period when operated at top end
> currents.
>
> Output often rises initially.
>
> I placed LED strings in series with a constant current source (say 10 LED=
s)
> plus a switchable reference in series - usually shorted out.
> Occasional output checks using a lashup "integrating cone" and light mete=
r
> and multiple strings allowed early degradation to easily be seen.
>
>
>         Russell
>
> _SNS _LED

--=20
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