N00b help for 555 type timer circuit to drive IR LED's

D

DrVette

Jan 1, 1970
0
I have a qty of HP IR LED's, they're hi-power if" driven at a 20% duty cycle etc..

My background is electrical generation, misc electrical repair, auto component repair etc,
I'm pretty versed in basic PCB component replacement, though I don't have a IC tester or tools for one.
Anyhow, I know nothing about designing a PCB and the components, so be forewarned. :)i

I've have the .pdf .
http://www.alldatasheet.com/datasheet-pdf/pdf/64717/HP/HSDL-4230.html

As I read the datasheet, the basic [max] specs;

375mw
1000 ma f/current @ 10 us Pulse
2.5v forward voltage
5 v min reverse voltage @ 100 ua
1.6 - 100us <-high end spec

232323232%7Ffp83232%3Euqcshlukaxroqdfv99%3A%3C%3Dot%3E3%3A38%3D35%3A%3D725%3DXROQDF%3E2825%3B56686258ot1lsi



s_se=FDR


s_se=FDR


s_se=FDR


TIA for any thoughts and suggestions.
DrVette

 
D

DrVette

Jan 1, 1970
0
Don't see the "edit" button,
forgot to mention;

I will use just ONE LED.
The ps will be one 14500 LiOn 3.7v battery.

I posted 3 other jpg's of the datasheet, they didn't show up, guess I have too few postings for them to post.

 

audioguru2

Apr 6, 2004
12,026
Joined
Apr 6, 2004
Messages
12,026
1A is way too much current. It is its absolute maximum NON-RECURRING (occasionally) pulse just before it blows up. Even 500mA is way too high but might be used for the very short duration pulses in a TV remote control.
You forgot to say what you need such high power IR for.

Like all LEDs the forward voltage is a range because each one is different. Its range at 100mA is from 1.40V to 1.85V. The datasheet does not give the voltage range at higher currents so you must test yours yourself which is difficult without burning it out.

A "3.7V" Lithium rechargeable battery cell is 3.2V when it should be disconnected and recharged and it is 4.20V when fully changed.
An ordinary 555 has a minimum supply voltage of 4.5V so it should not be used. An LMC555 or TLC555 has a minimum supply voltage of 2.0V so it can be used but it has low output current. The Cmos 555 can drive TWO transistors that drives the IR LED.

The 2mA output high from the Cmos 555 drives the 1st (NPN) transistor and its 20mA output drives the 2nd (PNP) transistor and its 200mA output drives the LED through a series current-limiting resistor.

 
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