Hi,
I'm moderately new to electronics and i have a question about my current project.
I have an arduino micro powered by a 6 AA battery pack to VIN. I use the arduino to drive a bluetooth shield (chinese €6 board) and an M5450 current sink through the 5V regulated output. I as use those 5v to drive up to 35 leds (3v, 20mA) using the m5450 as a driver/sink.
My prototype did not connect more that 20 leds now, that worked.
My question is: can I continue to drive all leds from the arduino regulator or do i need to add an external regulator to power the leds? I have an lm7805 here somewhere...
Thank you for your time to help me out!
Use the rule of thumb:
Put your thumb on the Arduino regulator. If it's hot, use an external regulator.
The regulator is only rated for 800mA.
35mA * 20 = 700mA, plus some current for the Arduino. How much does the bluetooth need?
Here's a m5450 datasheet I found.
Maybe regulator is not even needed for the LEDs, just run from 6V and change the current limit resistor for the brightness desired.
M5450 STM LED driver.pdf (145 KB)
CrossRoads:
Maybe regulator is not even needed for the LEDs, just run from 6V and change the current limit resistor for the brightness desired.
Thanks, i'll take that road!
CrossRoads:
Maybe regulator is not even needed for the LEDs, just run from 6V and change the current limit resistor for the brightness desired.
Success! I've finished the board without the extra regulator and powered the leds directly from the battery. Thanks