Effecting frequency range for IR LED

[vinoth]

Hi,
I designed IR circuit using 555 timer of frequency 36kHZ. I used 10% duty cycle and 10k Preset for adjusting. I want the signal to reach a maximum range. How can I achieve that.

 

[blueroomelectronics]

Your IR detector probably has an AGC and won't work properly with a continuous stream of IR pulses.
Also the IR emitter LED can usually be pulsed with a fair amount of current, possibly 100ma or so, also more emitter LEDs will help.

 

[vinoth]

So I need to boost up the current rating. So which parameter plays an important role either Current or frequency to achieve long distance.

 

[audioguru]

Translating services in conference rooms use high power (many IR LEDs) blasting high power at listeners.
The remote for your TV blasts high power through maybe 3 IR LEDs.

High power is a high current.
A low duty-cycle is used to avoid over-temperture of the IR LEDs.

 

[Boncuk]

There are high power IR-LEDs on the market with 100mW/sr. The average IR-LED has a value of 10 to 15mW/sr.

The LD274-3 has a value of 80mW/sr.

Also increasing the duty cycle will have effect on the range. IR-receivers like to receive bursts, not a steady signal. Produce bursts using a second astable.

Boncuk

P.S. I just checked out Vishay. The TSAL6100 has 130mW/sr, at 100us it has 1000mW/sr.

 

[RadioRon]

There are high power IR-LEDs on the market with 100mW/sr. The average IR-LED has a value of 10 to 15mW/sr.

The LD274-3 has a value of 80mW/sr.

Also increasing the duty cycle will have effect on the range. IR-receivers like to receive bursts, not a steady signal. Produce bursts using a second astable.

Boncuk

P.S. I just checked out Vishay. The TSAL6100 has 130mW/sr, at 100us it has 1000mW/sr.

Thanks for the tip. I need a high power ir-led for an upcoming project.

 

[Boncuk]

Thanks for the tip. I need a high power ir-led for an upcoming project.

If you use two TSLA6100 in series at 2.6V forward voltage (for a single LED, total 5.2V (5.0V)and a forward current of 250 to 300mA and a duty cycle of 150µs the power output will be 980mW/sr (very close to the maximum) still being in the safe operating range the maximum distance should easily be 15m to 20.

For a total forward voltage of 5.0V you might omit any current limiting resistor. Check the timing accurately for long time safe operation.

The recovery and cooling phase (when deactivated) should suffice for a long lasting LED lifetime.

Boncuk