Input: To turn on circuit I would like ideally to be as low as about 1.2V, but 1.8V is acceptable but anything higher and its no good.
Output: Again, ideally able to switch up to 12/24V but only need to switch up to 5V
Current: Output current 500mA required, 1A desired
So what I would normally use for this is a BJT such as a 2N3415 which turns on at 0.6 to 1.3V on the base and can switch 25V / 500mA. By the way this is just turning on/off LEDs most of the time, from low voltage low current trigger sources.
However the downside here is mainly the amount of current needed at the base is 3mA for 500mA output, needing a 600 ohm resistor on the gate, which is quite high, and a little volts drop over CE of 0.2V.
I know FETs use practically zero current at the gate as they are voltage controlled, however I would require an inverting circuit of some form to swap the n-channel to activating when the input is high not low, and also the Vgs difference will always be based on the input, so the worse case of say a 20V output from a 1.2V input would be difficult to achieve maybe?
I am presuming there is maybe an IC already out there for switching higher voltage loads from CMOS level inputs with little or no current? If not, what are your suggestions for a circuit to do this? I don't mind making a circuit board for this involving several ICs and passives if needed, I'm just after input firstly in case there already exists such a device that I am just not aware of at the moment?