Electrical – Avoid neopixel power on USB

arduinomosfetpower supplyusb

I am designing a lamp based on neopixel leds and arduino. I'm designing the badge on Eagle and I've noticed a problem. I have noticed that with the consumption of the LEDs (5A) when the user tries to program the lamp ​Will try to turn on the leds of the usb and can be damaged. How can I make the lamp only turn on when the Power supply is connected and if the USB is not alone?

I have thought of a system based on MOSFET

Best Answer

You could just use a schottky diode, a large (1Mohm recommended) resistor to drain diode leakage to GND, and an N-channel FET to detect power supply power, and cut off all the LEDs any time the power supply isn't providing voltage.

Something like this:


simulate this circuit – Schematic created using CircuitLab

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