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Posts: 15
Registered: ‎02-13-2014

LED current of si1143 ?

Hello

 

i have si1143-MFB sensor and its bottom side has a LED.

 

That LED's max current is 100mili Amper in the datasheed.

 

But in source code 359mA is given. What just happened here?

 

s16 current[3]= {0x0f, 0x00, 0x00};    // 359 mA, 0 mA, 0 mA

 

 

 

 

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Posts: 298
Registered: ‎09-22-2009

Re: LED current of si1143 ?

Please keep in mind that the Si1143 only pulses the LEDs for a default pulse of 25.6 us per sample. When evaluating the IR LED's datasheet, you must pay attention to the rating for constant current versus pulse (surge) current as well as pulse duration. You may end up just having to calculate the amount of power your system is currently configured for (your LED drive current and sample rate compose this) and compare it to the maximum power dissipation rating in the datasheet of the LED.