I’m trying to design a IR remote controller. I tried to design IR LED driver. I designed this circuit for IR driver.
I used ESP8266 for first test for IR LED. I used though-hole version of MMBT2222A (2N2222A). I tried to design Ic current for one LED approximately 100 mA. And also I chose hfe=40 for Ib calculation and I calculated approximately 1 kΩ for base resistor. When I tried to measure with multimeter, I observed one of IR LEDs current flows about 50 mA and base current is approximately 3 mA. And LEDs voltage approximately 0.7 V. I thought BJT is not properly works on for my circuit. I tested of this circuit with 2 LED. It works about 13 meter distance (sends NEC code properly) but the voltage and current values did not come out as I calculated and also I couldn't use 5 LEDs at the same time (with 5 LEDs I used base resistors and without base resistor result is very closer).
Therefore I changed BJT to MOSFET for driving LED with voltage. And I tested this circuit IRLZ44N logic MOSFET. I tried to drive this circuit with directly 3.3 V high output. That time current flows over LED about 100 mA but when I tried with continuously NEC output signal. MOSFET not fully opened. I looked voltage with multimeter I saw 0.3 V at ESP8266 output signal. Thats the reason my guess I couldn't open MOSFET with this NEC Code. I'm open to your suggestions, thanks.