Hi,
I will try to explane some things, but bear with me, i am a dyslect and English is not my nativ langguage.
And of course... I am from Amsterdam in the Netherlands, that means that I am direct and do not lie , and no bullshit.
And again, the reference section...The powerline at my lab is noisy and has a relativ high Ri.
Its a powerfull noise generator
There are several tricks to keep the line noise out of the LT1021 and the LM334.
First the extra resistors R3 and R5 in combination with C3 and C4 yes low ESR types.
I lifted the TL317 regulator with D6, so the noise of the TL317 would not be amplified 6 or 7 times.
R23 and C20 makes another low pass filter, this has a double function, C19 en C20 makes a time constand, so there are no power on abberations.
The output of the TL317 is also used for the opamps.
The negative power supply for the opamps is just a simple zener regulator, and again C8 makes and R9 makes a slow power on.
Replacements for the LT1021-5V, but why... eat one big Mac less and you can affort a LT1021-5V...
Ore use one of these: AD587, MAX6350, MAX6126, LTC6655, LT1027 and if you have money to spend, buy a VRE3050 *grin*
TimI have explained before, that when I draw this schematic, I could not find the MOSfet in the library of my drawing package.
Power dissipationThere are several ways to limit the power loss, the dissipation limiter shown here is one of them.
But this needs some attention, for the transformer used.
The performance is good enough, but not as high as a switcher.
When using say a buck regulator (how often did I have to hear that ...) the efficiency is better.
Designing a extremely low noise 200-Watt pre-regulator is difficult.
After a number of measurements (test circuits) I decided not to use it. (Most switchers are like a Pulsar sweeping there powerful beam of noise, over sensetive electronics)
A transformer with multiple taps, or as I already mentioned, two transformers of 2x9V works well enough for me and saves enough energy.
Thermal protectionThis is not the latest schematic, thre are some sensors on the power section and the transformer.
Current sourceSorry, i'am talking about the current source that is not in this schematic
There is a current source (about 50mA) at the collector of Q2 or Q4, it alway puls this current out of the power stage.
This makes the dynamic behavior better and also ensures that the output voltage decreases rapidly when it is turned down at low load.
Power sectionThis is the best I could make, I also tested with smaller power transistors, this was a version with 4 compound stages.
I did blow up this version during testing and was worse in terms of Ri than the 2SA1943 / 2SC2911 transistors.
Why these transistors, this is to keep the delay of this stage as low as possible, so it would not at to much to the phase delay to the opamps.
Dynamic performanceTim explane, why i may not show a picture of the performance, at a peak current of 9.5-Ampere?
And do you realy think i'am that stupid, that i measure the performance of this power supply at the dummy load input?
This is one of my tests of the power supply, how it would reacts in a practical situation.
And of course I also test in a different way, with my Jim Williams Dummy Load, which has a very high bandwidth and is then connected to the power supply to be tested without cables.
Search fore AN104 on the LT website, i use te MOSFet version.
For real!!!...Double-wait. Why is the test at 9.5A when the supply is rated for 5A!? Why is it not dropping out during the pulse?Of course i am a liar!
Why is er no dropping of the line in the middle of the picture at 9,5-Ampere...
Because the performance of this power supply is that good !!! There are many measurements and information about this power supply on this page, use google translate is you cant read Dutch.
https://www.circuitsonline.net/forum/view/110029Kind regards
Bram