EEVblog #222 - Lab Power Supply Design - Part 2

PART 1 is HERE: http://www.youtube.com/watch?v=CIGjActDeoM
Part 2 of Dave's Open Hardware constant current linear regulated lab power supply design. An in-depth look at the LT3080 datasheet, the LM334 current source, and a few more circuit tweaks before it's ready to build in the next episode to see if it works!

Category:

Science & Technology

Tags:

• power
• supply
• linear
• bench
• lab
• laboratory
• switchmode
• lt3080
• voltage
• constant
• current
• regulated
• design
• circuit
• lm317
• lm334
• source
• shunt
• resistor
• capacitor
• feedback
• opamp
• construction
• diy
• project
• inverting
• compensation
• high
• side
• low
• drop
• measurement
• open source hardware
• open hardware
• oshw

[Nadrealis]

What type of package did you use for the LT 3080 in your final design?

[EEVblog]

@Nadrealis TO-220-5

[PetrFM]

This design is becoming more and more complicated.

Simple charge pump like ICL 7660 and you have negative rail for all opamps. This give you the opportunity to use cheap LM317 have real zero voltage output etc.

Noise is not such problem as opapms usually have high supply voltage ripple rejection ratio ...

[EEVblog]

@PetrFM The LM317 neg supply would actually make it more complicated. Not only the 7660, but the output divider will have a varying current based on output voltage, and that throws out your current sensing at low values. The LT3080 and LM334 is simpler IMO.

[CampKohler]

Dave, are you going to enter Agilent's PS contest and try to win that juicy USD11K digital supply?

[EEVblog]

@CampKohler Never heard of it...

[DanFrederiksen]

interesting videos. how about a follow up where you do a 30V 10A switchmode supply. enter the 21st century and such. linear is the dog's breakfast : )

the idea that switchmode can't be smooth is an old wives' tale.

maybe two stage unisolated with IGRP4069 IGBT on the first stage and IRFP4368 super efficient FET for extreme coolness. maybe even do something ugly like only chop the half sine so there is only one voltage drop so it's super efficient and cheap. unless it's against your religion : )

[First2ner]

man I love this long videos

[pcbdev]

I like it that your explanations are not for dummy-beginners who never had to do anything with electronics. This level is perfect :)

[MatrixOfDynamism]

@EEVblog Once we have learnt simple stuff like linear circuit design (RLC), and stuff about transistors and other simle components and OpAmp configurations, how do we move onto being able to use such exotic ICs? ICs with datasheets that have so many words that look so unfamiliar? I really want to know that. There are soo many ICs how do we know which one is best. since our criteria only defines some of the things, and there can be soo many ICs that fit that criteria.

[Marzec309]

What rail to rail op-amp are you planning to use?

[EEVblog]

@spelunkerd Yes, Part 3 will be testing the circuit on the breadboard to see how it performs. The real build will come later, I have an idea in mind, and will do another Part 4 when that is complete (that will take some time).