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I'm having trouble understanding why this application note for this proximity sensor suggests reducing the current for the IRED depending on the on time pulse duration. What is the relationship between current and pulse duration, and what will happen if I don't reduce the current?
(Application Note) https://www.vishay.com/docs/84327/designingvcnl4200.pdf
When IRED is used for proximity sensor system, it's often needed to drive using pules. You need to maintain the total energy delivered to the IRED.
The total energy is propotional to the current and the duration of the pulse. The maximum absolute current rating doesn't mean you can drive IRED at that current with steady current. Same principal restrictions are often in the power transistors or MOSFETs.
Basically, any electronic components should not exceed:
As there are heat conducting inertia, as frequency is getting lower, max peak power consumption also drops.
