I have been trying to build a simple PWM power supply to use a 3.7v battery to drive a small heating element with a DC resistance of about 1 ohm. I have built a slightly modified version of the following LT3759 based circuit:
I modified the circuit for an output voltage of 5.0V.
I have no problem getting the expected behavior from the circuit on my scope with a large load, in the kOhm range. When I try to drive the heating element I want, the voltage drops to about 400mV.
I suspected this might be some sort of impedance issue, so I put a simple voltage follower with a mosfet at the output, but this failed to resolve my issue.
Does anyone have any insight as to why this is happening? I am guessing it is something trivial that I am missing due to my lack of background in this area.