Re: 300 mA from a microcontroller pin


CBFalconer <cbfalconer@xxxxxxxxx> writes:
Ignoring total dissipation, a single tri-state driver will do:

+5
|
R1
|
tri state here >---|X|-----+
LED |
R2
|
GND

with R1 approximately equal to R2. The ratio controls brightness.

If you replace R1/R2 with the 1/2 Vcc op-amp circuit I posted earlier,
you can use a single resistor in series with the LED and reduce the
"off" leakage current.
.

Relevant Pages

  • Re: 300 mA from a microcontroller pin
    ... The ratio controls brightness. ... If you replace R1/R2 with the 1/2 Vcc op-amp circuit I posted ... Yes, but I wouldn't trust the op-amp output impedence, especially ...
    (comp.arch.embedded)
  • Re: 300 mA from a microcontroller pin
    ... The ratio controls brightness. ... If you replace R1/R2 with the 1/2 Vcc op-amp circuit I posted earlier, ... Neither circuit will work particularly well if the Vf of the LEDs is ...
    (comp.arch.embedded)