Sounds great! I have some 18v supplies as well. Bill
On Sat, Sep 21, 2019, 7:13 PM Kevin A. <ka...@scarletmail.rutgers.edu> wrote: > And to be clear, it does run at 12 volts as well. However, the controller > will turn the HV off at around 110-130 milliamps as the inductor duty cycle > approaches 100%. > > On Saturday, September 21, 2019 at 10:07:07 PM UTC-4, Kevin A. wrote: >> >> Update: >> >> A quick test shows that the 40 watt version works! It turns out, however, >> that 12 volts in is a bit too low for this design at this power level. By >> upping the input voltage to 24 volts (which is reasonable - there are >> plenty of cheap 24 volt wall warts as well), the design functioned as >> intended (all components within rated spec at 24 volts as well). Output >> across a fixed 876 ohm load settled at 179 volt ~201 milliamps for a 24 >> volt 1.65 amp input, which translates to 91% efficiency. There really isn't >> any practical benefit to running at 12 volts with double the input current. >> Efficiency would drop and heat would increase throughout the circuit to >> attain the same power. >> >> If any clocks or systems out there need a lower operating voltage and you >> want to run off of one power input, I can add 24 volt breakouts for your >> own DC-DC converter. A second option would be to build in a second switcher >> to step the input 24 volts down to an adjustable voltage between 1.2V-24V. >> This is fairly straightforward using a controller like the LM2576T-ADJ. It >> will, however, increase size and cost (current size is 3.3 inches x 2.1 >> inches). >> >> I want to perform some thermal testing when I have access to my infrared >> camera this week as well. I did some poking around to see what was warm >> after the supply was turned off. As expected, the transistor and diode did >> produce some heat, but they were only warm to touch. My 100 watt load >> resistor, however, was getting pretty warm! >> > -- > You received this message because you are subscribed to a topic in the > Google Groups "neonixie-l" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/neonixie-l/uqpK9r37Frw/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > neonixie-l+unsubscr...@googlegroups.com. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/05033a3c-4ab9-4837-9dac-62c5bc9de3ab%40googlegroups.com > <https://groups.google.com/d/msgid/neonixie-l/05033a3c-4ab9-4837-9dac-62c5bc9de3ab%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- 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 neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/CADToqn1MOR%2BEo8A0a7wB2M-35bnhyuxoGkjv%3DwFJQ9LR%3DGw%2BMg%40mail.gmail.com.
