I don't know if this will help, but I had something like this on a clock I was prototyping. The error I had was that the MOSFET was sometimes being left in the ON state for longer than I expected sometimes.
Once the inductor has "saturated", you effectively have a short from VIN to GND, and of course the MOSFET gets hot when that happens, and the consumption goes right up. This can happen if the frequency of the drive is too low, or the duty cycle is wrong (too much "on" time). Have you investigated the frequency and duty cycle of the output of the TL494? >From the schematic, it looks like the frequency is fixed (at around 18kHz), and the voltage output is controlled by the duty cycle. I have no idea what the time constant of the inductor circuit will be, but after 5 of them, you are in dead short. Just a thought... -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/3ced45ee-c647-43c3-82d2-fa73d4f67362%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
