I have constructed the following 12v in - 3.3v out buck converter circuit using a TL5001 PWM controller based on this document. After etching PCBs and soldering surface mount components the board unfortunately does not do what I expect it to. The output voltage is measured to be about 11.6v rather than 3.3v.
Measuring the output of the TL5001, i would expect a PWM signal however there is just a constant 12v (same as the input voltage). It appears that there is no switching happening in the circuit hence no change in the output voltage. I have double checked all component values and checked for shorts. Fairly certain that the circuit I have built is exactly the same as the one I designed. Have also replaced the MOSFET driver IC, TL5001 and the MOSFET itself to no avail.
This is the first time I have done any PCB layout. I don't think my board layout was very good - the filtering capacitors for the ICs are too spaced out for example. I'm not sure if this might be the problem?
Any ideas what might be wrong?
