I am trying to get a boost converter working. This is the schematic:
The clock signal is 12V and 100KHz, the output capacitor is 330uF and I got it from the output of a PC power supply so is better than a common electrolytic capacitor. The load is a 7W resistor and the coil is a toroidal inductor I got also from a PC power supply but I don't know how much Henri's it is and I don't have an inductometer to measure it. The inductor is something like this:
I can't get this to boost the 12V input voltage and the MOSFET heat up a lot even with a large heat sink on it. I am having from 2A to 3A of current being drawn from the power supply. Here is the the waveform at the output of the boost (diode cathode):
As you can see I am getting a 24.8V peak (the zero voltage line is two divisions below the center horizontal line) but just a peak, I can't get a constant boosted voltage. In the MOSFET gate the signal is a perfect square wave of 12V so problem should not be there.
Can the MOSFET heat up problem being caused because I need a diode in anti-parallel with the MOSFET?