Power 2.6V-3V LED with 3V battery through a MCU

Thread Starter

Goxeman

Joined Feb 28, 2017
171
Hello,

I have this case:
- Im working with a low power MCU which is going to be powered with a 3V battery through a silicon diode, we have to count that in worse case the MCU will be powered with 2.3V
- Through the MCU I want to turn on two white LEDs in pararallel (2.6V-3V and 5mA to work)

Which would be the best way to turn on the LEDs? An NPN transistor?

I attach a schematic of what I have rounding my head
Thanks for reading
 

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Thread Starter

Goxeman

Joined Feb 28, 2017
171
Yes that would work, don't see the point of the diode D1, is there a reason for it?
The reason of D1 is because of the rest of the circuit, the diode is not directly on the power net of the MCU but the main power net of the whole design, the battery net is connected to different switches that power different parts of the circuit through diodes

What base resistor of the NPN transistor would you choose? I would be choosing a BC547 which hfe is 110
 
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