I found that IRemote don´t work as expected if I attach a bjt to other PWM pin (IRremote attached to pin11). I know about the relation between IRemote and internal timers but I am sure that isn´t the problem because the IRremote problem is produced by a NPN attached to pin 6 in PWM mode, the transistor is BC547 (max 100mA) and it is used to power (with GND) a 5v@200mA fan, and also was added a transients protection diode between GND (from the bjt output) and +5V .
If change the bjt, resistor, fan and the diode, and if I connect a led with the mandatory resistor, all work as expected. All is powered from the laptop USB.
If I use the fan configuration with PWM, sometimes IR receive remote control data, and sometimes do not receive.
@DrDiettrich Yes if I remove only the fan also is working ok. I am agree, the fan consumes the double of current that the transistor can achieve (I have this spare components and I tryed the pwm with this, despiste the classic led dimming. But, why this transistor current comsumption can influence MCUs other PWM pins? I dont understand, It is a 1k resistor in the transistor base to limit mcu I/O current