I am looking for a design for a low quiescent CCS using only discrete transistors (no op amps) suitable for driving a magnetic relay coil at a frequency of several tens of Hertz. Input is a 4V sinewave direct from a PIC micro. Yes, it is not a squarewave in this case.
This seems to suggest a darlington pair, with perhaps an FET being the first stage.
Can anyone advise what are the design considerations that will result in an absolute minimum quiescent current as would be suitable to a 9V battery powered device? And, if possible, provide an example circuit.
Thank you for your suggestions.
James Karmen