Which wiring is best suited for energy efficiency ??

Other Hardware LEDs and Multiplexing
1

I'm designing a circuit and i was wondering if the option would be much suited
in saving energy.

this is a simple status indicator that will be mixing colors to display the status of the device..
the rgb led are the smd types incapsulated in a 1.3mm chip.
Of course, i will be adding resistors to limit the current at the Gates on the first option
and some pull-ups but which is best that is likely to save me energy: Option 1 or 2 ??

Also, I will be wiring up option 1 tomorrow to test it out.
this circuit will work right ??

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2

I can’t see why you would use FETs, they are just a waste of FETs they are not needed unless the current rating of your output is poor.

As to energy consumption they are just the same.

3

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What MCU will you be using? What voltage will it run at?

Do you need the indicator to show white? If so, you need a higher value resistor for the red led.

Why are you concerned about saving energy? Why do you think option 1 or 2 would be more efficient than the other?

4

In option #1, move the LED and its resistor into the Drain leg.

5

Grumpy_Mike,
You're right,
with the FETs the overall circuit was consuming 12mA more. each gate is driven with a 4mA
Not worth it considering that it is indeed a wast of FETs and resistors + drives up cost.
There overall performance between the two options were the same.

larryd,
I can't since the anodes of the LEDs are connected together.
It would be possible with an N-channel FET.

PaulRB,
ATmega328PB

Option 2 for the win then. the LEDs are very bright at 13mA each

6

“ It would be possible with an N-channel FET.”

An application for the N channel MOSFET then :wink:

7

with the FETs the overall circuit was consuming 12mA more. each gate is driven with a 4mA

That is odd as a FET does not take any drive current it is purely a voltage driven device. There is a charging and discharging of the FET’s input gate capacitor as you switch them on and off. Maybe your test was rapidly blinking the LEDs?

You can get LEDs with common cathodes if you want to top switch them but again there is no point.

8

Of course, i will be adding resistors to limit the current at the Gates on the first option
and some pull-ups

Perhaps the pull-ups are the source of current you are measuring. What value resistor? This current is not flowing into the FET gate, it is flowing from Vcc through the pull-up resistor, into the Arduino pin and then to ground.