I am working on a switch mode psu in step down configuration with the key components being: LM2592 (adj) http://www.ti.com/lit/ds/symlink/lm2592hv.pdf 530-PC-24-1000 http://www.mouser.com/ds/2/643/PC-594199.pdf GSIB-25 http://www.vishay.com/docs/88646/gsib25xx.pdf Using a slightly modified version of the example circuit where: R2 = 23.82 KOhm L1 = 100 mH The diode on the left is not included but CFF is included as vin does not exceed 40vdc. I am using /HALF/ of the transformer and ending up with 20vdc at the output of the rectifier. (reading into this, it appears higher loads and adjustments of the filter capacitor should drop this down closer to 12vdc.) initially with both windings of the transformer attached, the rectifier was outputting a stunning ~40 vdc. ^this is not my issue however... (at least i dont think) At the moment the power supply is outputting ~18.6 vdc... (to a 5watt load of LEDs) With Vin reading 19.5 vdc and feedback to ground reading 0.75 vdc. I am not sure why i am getting practically no step-down? Adjusting R2 seems to have minimal affect on the output voltage. It's also important to note that the LM2592 produces little to no heat... slightly disturbing.. Does anyone have a clue of some methods to troubleshoot this issue?