EEVblog #221 - Lab Power Supply Design - Part 1

What people said

Recommends venzen · 2017-01 · Electrical Engineering Stack Exchange · on “Making LM317 output voltage adjustable down to 0 V”

@Virgil Litan, a useful explanation and demonstration of an LM317 implementation that can output 0V: [this video]

Recommends Bimpelrekkie · 2017-06 · Electrical Engineering Stack Exchange · on “How does a benchtop power supply measure and control current?”

Basically the output current is measured (through a shunt resistor) and compared to a reference value (which you set with the knob). The result of this measurement influences the voltage regulation circuit such that it decreases the output voltage to not exceed the current you chose. You should watch this EEVblog video: [this video] where it is all explained.

Recommends Phil C · 2018-04 · Electrical Engineering Stack Exchange · on “Arduino-controlled bench power supply”

If you're interested in a start to end video tutorial on basically this exact project, EEVBlog Power Supply Design #1-8 [this video] might be a good resource if you run into any "traps for young players."

Recommends Bimpelrekkie · 2021-04 · Electrical Engineering Stack Exchange · on “Need design best practice: microcontroller controlled, variable, DC voltage source”

Have you watched the series of videos that Dave from the EEVBlog made: [this video] ? That should introduce you to (lab) power supply design. *I don't really design power supplies.* and *Can anyone point me to how get started quickly?* if you want to do this "quickly" then you might want to **simplify things**, a rushed/ quick design is rarely a good design. Especially your *I plan to commercialize a product* means you have to get it right. Or are you aiming to dissapointed your customers?

Cites Paul · 2012-03 · Electrical Engineering Stack Exchange · on “Understanding a transistor configuration”

I started watching this video series [this video] on a DIY lab power supply by Dave @ EEVBlog. On his video he's analyzing mostly simple constant current circuit. However, at the top of the circuit there's two transistors in the op-amp feedback. He explains fairly well how the circuit works, but I'm unsure (I have my suspicions) why there are two transistors as opposed to one.

Cites helloworld922 · 2012-10 · Electrical Engineering Stack Exchange · on “Bench Power Supply Design”

I've been thinking about designing and building my own bench-top power supply for general use. I envision the primary use to be with prototyping low-power analog/digital circuits with the occasional small DC motor and other electro-mechanical devices. The primary reason I'm doing this is to become more familiar with power supply design, and having a useful bench-top supply is an added bonus. Target specs and device goals so far, recommendations/suggestions are welcome: Powered from mains electricity (I live in the US, so I'm targeting ~ 120VAC@60Hz ). Mains isolated. Variable voltage and current output, at least 1A max output current and 12V max output voltage. Preferably I'd like a 15V or 2

Cites Matthew Sainsbury · 2014-04 · Electrical Engineering Stack Exchange · on “What's wrong with an opamp as a voltage regulator?”

I was watching a video [this video] about power supply design and it was mentioned that an opamp being used as a regulator like this: simulate this circuit [LINK] – Schematic created using CircuitLab [LINK] in practice, isn't an inherently stable configuration - "it's very tricky to get it stable over a range of output loads and capacitances" Why is this? What happens in this circuit to make it unstable?

Cites Dado87 · 2015-06 · Electrical Engineering Stack Exchange · on “Arduino Controlled adjustable current 0-1A,18V”

Hello Masters of Electronics, I'm civil ingeneer, electronics are big unknown to me, but it wakes up my interest. I would like to control proportional pressure with electronic proportional pressure regulator. If I got right I need to control it with current from 0-1A at constant voltage of 18V. I would like to control it from Arduino. In last weeks I was looking for helping material on internet... and I found Youtube series from EEVBlog ( [this video] ...Circuit is shown at time 20:00) about making own Power Supply Unit. I took out "Costant Current" part, bought 18V, 1A Adapter... Here is Shematic pdf to download LINK [LINK] First I would really apreciate if someone can take a look onto Shematic

Cites Anthony · 2016-04 · Electrical Engineering Stack Exchange · on “What's an efficient way to get below the standard 1.25V on buck converters?”

So, I purchased a buck converter which was advertised to be able to range down to 0.8V but, as you can probably guess, it only goes down to 1.25V which I understand is the reference voltage for the chip it uses and quite common. I'd like to know if there's an efficient and easy way that I can step down the output range further so that I can get down to that 0.8V or even 0V, without modifying the module too much. I'll be using 24VDC as the input and the actual chip used in the converter, the XL4016 [LINK] , has a range of 1.25V to 36V. The solution in EEVblog #221 [this video] is to replicate and replace the entire chip. That's just too much for me as I'm fairly new to electronics. Another solutio

Cites esoterik · 2016-07 · Electrical Engineering Stack Exchange · on “Inexpensive circuit architecture for power supply voltage adjustment?”

The tactic that Dave Jones (EEVBlog) took in designing a Lab power supply ( part1 [this video] , part2 [LINK] ) was to use an op-amp to set the control voltages, and the micro-controller's output (PWM??) pins would be used to control the op-amps. I don't recall the exact reasons for his methodology though. As far as I know, a reference circuit generally is an example; i.e. a good starting point for designing and/or learning about the chip. The data sheet containing the reference circuit should have some indication as to what is required to make the chip work and what is there as tune-able parameter. is the voltage-divider required as a feedback mechanism, or is simply to set the control voltage?