Hi Spec,
What type/model of LEDs can you suggest with those parameters... I have been experimenting with some warm white 5050 types, they have three LEDs per chip, approx 10mA for each LED, high brightness (19 lumens per LED)
https://www.superbrightleds.com/moreinfo/surface-mount-smd/warm-white-5050-smd-led-120-degree-viewing-angle-6000-mcd/317/#/tab/Specifications
Hy Andy,
Here is a list of high brightness LEDSs (none are white though) which are specified at 2mA and some have a forward voltage (VF) of around 2.5V:
That is a good point but, without a regulator, the change in LED current would be less than +- 30% and, as the human eye's response is logarithmic, the brightness would not be too noticeable.The reason that I want the regulator is to keep the supply to the LEDs constant... if I forget the regulator and simply go with series resistors to limit current, then the current (and LED brightness) with change significantly as the li-ion battery voltage drops over its range from 4.2V to ~3.4V.
A bipolar transistor could be configured as a switch to drop less than 100mV but a MOSFET would drop 0V in practical terms.Also, I need to be able to switch the LED on and off... using a transistor to do this will lose 0.6V, but the RT8059 would only lose 0.2V (and the RT8059 has a handy enable pin to switch the device on and off).
I think you are aiming at a constant voltage source through a resistor, but a LED is best driven by a constant current to define the brightness.Essentially what I'm trying to do here, is drive a LED(s) from a consistent source that is powered by a li-ion battery (whose voltage isn't consistent).
Hmm, interesting: have to investigate ceramic inductors.I hadn't heard of a ceramic inductor before either! But here they are... (this is just an example, not where I bought them)
https://www.coilcraft.com/0603cs.cfm
spec
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