The Wiki for LED Configuration, under Overheat Protection talks about using a struct to setup values for the LED etc… It says
the PWM ratio (the fraction of time that the FET is ON for each 800Hz cycle) is adjusted downwards to try to protect the LED.
Does this mean it would not be the same if using a data pad for PWM since it’s not an LED 1-6 FET?
Specifically, this is regarding a switch button LED, not a high power main blade LED.
PWM is PWM, so if you have PWM on a different pad, it can still do overheat protection. However there are several caveats around this:
- overheat protection is based on the battery voltage, this assumes that the LED positive side is hooked up to the battery. If it’s hooked up to the 3.3v pad or some other power source, then the overheat protection will not work as intended.
- Please note that the overheat ptotection has not been extensively tested, so it’s not entirely clear how good it is at making sure that the LED doesn’t actually overheat. In particular, it’s not clear how far over the LEDs limits it is safe to use the overheat protection instead of a resistor.
- Small LEDs, such as those in buttons overheat and die very fast. That means that the overheat protection might not work well for small LEDs. (Again, more testing would be required to actually know.)
My personal policy is to only use the overheat protection when the LED is probably fine with the extra voltage anyways.