DEVMO 8-32V to 45-390V DC-DC High Voltage Boost Converter ZVS Step-up Booster Module

I'm not sure if this is standard but my board has an extra capacitor and output for a negative rail! I measured a maximum 815VDC between them!That's a lot of voltage from such a tiny package :)

Though this power supply says it is 45-390 Volts, it actually delivers two equal outputs: +45 to +390VDC and -45 to -390VDC at the same time, a max differential of 780 volts. The two outputs track, more or less. A precision 25-turn pot sets the output voltage. Output is not floated, but is tied to the common input ground. The two 10-uF aluminum electrolytic caps on the two outputs are rated 400V, so it is probably best to operate this thing at 300V or less. If you are using only the positive (+) output, it might be a good idea to lightly load the minus (-) output to keep it from floating up too high and popping the cap on the negative rail - may be unnecessary - just good HV practice. The unit does have bleeder resistors on the output, so that when you turn it off, the output voltages drain off within 10 seconds or so to safe levels. This is a regulated switching power supply. Output voltage does not track input voltage, but rather is independent of input voltage so long as supply voltage is sufficient. One reviewer stated that he wanted high voltage and 700 mA for plating; assuming 300 VDC or so, that would be 210 watts, well above the rated and fairly respectable 40W. Another (3-star) stated that it took him a while to figure out that output voltage is adjusted by a tiny screw. Please, people. This product is for folks who have a basic familiarity with electronics or aren't afraid to do a little googling to figure out what they may not know. Yes, documentation could be a little better, but then they'd have to charge more. The trimpot on this unit is a look-alike of the 25-turn Bourns unit; just the trimpot here in the US runs $14.66. Go figure. I recommend this unit, plan to use it to supply +200V to power an old 6E5 fluorescent "tuning eye," bought on eBay, if you remember those from old AM radios. I think it will do just fine. Just don't lick the output when it's set to 300V to test if it's on. Ouch! Use a voltmeter instead. If you don't have a voltmeter, buy a voltmeter first. If you aren't sure what a volt is, maybe you should start with lower voltages. 1.5 volts, for instance. Buy a AA battery and measure that. Electricity and electronics isn't that hard. But learn a little before you start fiddling with hundreds of volts. Learn, live long and prosper. In that order.

I've toasted several 2, 3, and 5W resistors with this thing and it keeps going.Does well at maintaining the set voltage from no load to about 10W ( the max I have).Only negative is with no load the output voltage cycles up and down by 3-5V (at 170V) every 0.5 to 1 second... slow enough I can see it on a 500V analog meter, and I confirmed 2 different DVMs.Nice bonus: They have a 12V output to drive a constant voltage fan except it's always on even when the "enable" / shorting jumper is removed and the output voltage goes to zero.I replaced the 10-turn trimming pot with a outboard full size 50K 10-turn POT and it does well, just not linear. Slow change at the lower voltage, quick change at 150V and above.

A week ago I wrote a review that 3 units that I received would not get above 185 volts. Thinking that as you increased the input voltage the output volts would increase. Wrong! I purchased 2 new units thinking that all of these units cannot be bad. When I tried the new units I got the same results. Looking at the units more carefully I finally notice the very small screw on a component next to the inputs terminals. Turning this screw clockwise many turns I started to get the voltage to increase. I stopped at 250 volts which is what I wanted. Changing the input voltage did not change the output voltage. It appears that when you go from 0 to the voltage you had set (the 250 volts) it acted as a switch. No variable input control, just off to the full output setting. All this is because I did not understand DC to DC converters. It would be great if there were some directions how use the converters.Bob Wilson

This module worked just fine. The documentation is poor, but an average person should be able to figure it out. The labels on the input and the output are very small, but they are there, near the terminals. A single screw, not labeled, adjusts the output voltage. We were able to generate about 225 Volts, which is what we needed for our application. Came quickly, bubble wrapped. Reasonable price. Overall, happy customer.