I am interested in this as well- I have several decent quality 12v supplies, and I was thinking of buying a bench top power supply for my projects/tinkering. I'd rather just use the 12v supplies and buck converters, but I am not sure of the downside to that.
Anyone have any thoughts on this sort of thing? Is it better to just go out and buy a decent variable output supply? I am mostly just learning electronics at this point, and doing some arduino projects.
Yeah, it is of course better to "go buy a decent variable output supply" but far less fun. If you just want something that works, go buy one that works. As a hobbyist, one of the thing I found educational is to improvise. To improvise means I have to learn what something needs, and learns how to supply that something adequately. The other issue is $. One is always making a trade off about quality vs $. Less I spend on item A, more I have for item B, C, and D. You can spend a million dollar on a power supply but someone can spend two million and make a better one. So the issue really is "is it good enough for what you use it for."
I used a boost+buck cc cv board as power supply for a while now. Attached is a photo of the one I use.
Not the one that started this thread, but your question seem to be about typical cc/cv type boards as power supply instead of a specific cc/cv board, so that is what I am addressing.
When I purchased them > 1 year ago, they were in the range of $11-12 USD in single quanty. (I have three of this kind). Now they can be had for under $6. Note that like many of those cheap boards, their quality varies.
I have found it adequate for over a year, but now looking to something better, read on.
The downsides are:
1. ripple/noise (+-100mV typical and worst around +-150mV, depending on supply source as well. Noise level is slightly lower with 12V SLA battery as power source). Typically, it is an up-to-100mV saw-tooth wave riding on DC.
2. wear out trimpot (if wiper loose contact, voltage is uncontrolled and may hit max!)
3. cc value drifts after set but settles, cv is much firmer (+-2% spec looks accurate).
4. This particular one is very low power I would not use it for over 5W, but some higher power ones are out there
The upsides are:
1. it is boost+buck, which means you can pretty much choose any power brick (or battery) with adequate power.
2. Voltage regulation is very stable (within the ripple/noise) unless load varies significantly.
Plus or minus, you choose:
You can pretty much tame lot of the noise with a huge capacitor, but it defeats the CC say if you shorted something, your huge capacitor will continue to supply component-killing power. So, when needed, I add a 1000uF or even 4800uF to trim the noise down.
Yes, you can "digitally control" them. I had fun doing it. I had removed the trimpots and use an Arduino to control them successfully: 0.1 ohm low-side shunt, ADS1115 as ADC for voltage and current sense, analogy circuits driven by digital produced comparative voltages (12 bit dac for CV and arduino's pwm as dac for CC) so once set it response with analog electronic speed instead of a slow program loop. But difficult in packaging it well and cost make it not worth while to convert for day-to-day use. The ADS1115 Adafruit breakout board alone is more expensive then the power supply discussed in this thread. Even with digital conversion, it would still be the same board with all the draw-backs but one: CC could be programmed to actually push the load to CC verses trimpot setup which really is a current-limit with CV.
I found this cc/cv cheap board to be adequate for a year now using mainly for poking around and build a few projects using this to power the initial prototypes for the projects. But the noise issue bother me a lot. I am never sure in my test circuits if my oscillation (or noise) started because of my power supply or my circuit. I am trying to experiment things now that I would like something with cleaner power.
By the way, I also have a couple of 5A ones for heavy duty. Their noise could be up to 300-500mV's. Not sure if it is the different chip or just the nature of bigger load, bigger swing. Percentage
seem to be about the same if I plot noise vs power but never actually did calculate it as a percentage.
Hope this helps answer your question.
Rick
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