Hi, I am trying to add a current limiter to my little circuit at about 80mA.
Theres 5V comming in, then I drop it down to 3.3V with a LDO (NCP1117) regulator.
The 3.3V regulator needs to be 1.2V above 3.3V, so then I have (5V - 3.3V - 1.2V =) 0.5V spare to make a current limiter with. Those few milli volts are precious!
I have designed a standard two PNP transistor current limiter, but the transistor along with the series resistor drops too much voltage.
:idea:I was wondering why does no-one seem to use MOSFETs in their current limiters? Are they too slow?
I feel I could save a few tenths of a volt with MOSFETS, but I am sure I am not smart enough to realise why people dont do this.
I am open to suggestions, however I prefer to use standard off the shelve components because its hard for me to source anything other than a 1K resistor or 100nF cap.
Thank you for any advice/help!