I got my prototype boards for my DC-1248 (12Volts to 48Volts DC-DC Converter). Quickly built a prototype, and nervously turning on the power, there was no smoke, fyring bacon sound, or anything getting hot. Yey! So far so good… Measured the output voltage and it was 48.2 Volts. Nice.
I began loading the DC-DC converter and looking at it’s ripple waveform on my scope. Happy to say that performance improved significantly just by moving it from a breadboard into a properly designed PCB! The board is a tiny 1″x1″ square, with (4) Millmax pins so you can easily plug-it in to our FAB1215 Power Supply Board.
On the experimental breadboard, the maximum load current I can achieve was 30mA. Anything beyond that, and the converter’s voltage would fall below 48Volts, or would not start.
Now, the same circuit running on the PCB… get this.. it can now do 60mA @ 47.7 Volts! Ripple is 266mV, or just 0.55% of output voltage. But we don’t need that much when we’re just powering a few condenser mics…. most modern ones draw an average of just 5mA. The ripple frequency is a high 166Khz, way beyond the audio range. The inductor is very quiet, and everything is running cool even at 70mA output.
Efficiency increases as the PSU load also increases. But at very light loading, the efficiency is just a little over 55%.
I made some final touches to the board, adding additional bypass caps, and an SMD option for the Schottky diode, and fixing some silkscreen fonts. Rev2 prototype board should be in before the end of this month… I’ll do another round of testing, and then these little DC-DC converters can go on sale at a very reasonable price.
If you’re building a battery powered mic preamp, and you don’t know where/how to obtain your 48Volts for your phantom power, this is the solution! Just feed it 12VDC, and out comes 48Volts DC, ready for your phantom power use.
Until I can get my shopping cart running, just email me if you’re interested in buying a 48V converter board.