Do you think that it is safe to directly drive SMD LEDs with 5mA operating current from output pins of CC3200? It should handle up to 6mA.
I am asking because heartbeat LED on WiPy is driven through MOSFET.
Direct driving of SMD LEDs
- pythoncoder
- Posts: 5956
- Joined: Fri Jul 18, 2014 8:01 am
- Location: UK
- Contact:
Re: Direct driving of SMD LEDs
In general it's only safe to drive an LED via a limiting resistor. If the WiPy output is rated at 5mA/3.3V, a red LED will drop about 1.7V. So the resistor you need is (3.3 -1.7)/0.005 = 330 ohms (nearest preferred value).
Note I haven't checked the WiPy specs and LED voltage drops depend on colour but this should give a pointer as to how to calculate the value. A MOSFET would enable you to put more current through the LED.
Note I haven't checked the WiPy specs and LED voltage drops depend on colour but this should give a pointer as to how to calculate the value. A MOSFET would enable you to put more current through the LED.
Peter Hinch
Index to my micropython libraries.
Index to my micropython libraries.