2
\$\begingroup\$

I'm in the process of designing linear psu based on KORAD3005D. I started by simulating this circuit, but I have trouble doing that - it oscillates horribly. I'm not an expert in analog circuits, but I think it's some sort of problem with spice models.

SIMULATION FILE

ORGINAL SCHEMATIC

EDIT:

Sorry for these 3'rd party symbols, changed them to OP27, which should work the same in this circuit. (it doesn't stop strange behavior)

There is the interesting part of whole supply (glued together and signed): enter image description here In spice, i used only one power transistor, and used voltage sources as references. It looked complicated in pdf, due to a lot of other stuff. And this circuit (at least for me) "looks" correctly. Grounding in this point is used, because all opamps have ground referenced to output positive terminal (see "GNDF").

enter image description here

So this circuit is just redraw to spice. R6 serves as load, V4 and V5 are emulated references from microcontroller (set voltages), input rectifier is replaced by voltage source.

enter image description here

V(N003,N007) is voltage across output resistor - reference is only 1V for voltage and current, which means around 35/5 * 1 output voltage, so around 7V, but the voltage at the output is maximum and oscillates (after zooming). I (R3) is current of load (measured through R3) - it oscillates also hugely (it's higher at startup probably due to output capacitance).

I don't have idea what happens, this is all I know.

New spice file: LINK

EDIT2

KIND OF STABLE VERSION with working cc and cv

EDIT 3

A concerned citizen's last version is I think best, but it as one disadvantage - voltage feedback is took before current shunt, so it lies when current is significant. Unfortunetly - connecting voltage feedback opamp's termianal directly to load leads to horrible oscillation... Changing output capacitance doesn't help

Version 4
SHEET 1 2468 1308
WIRE 160 -96 96 -96
WIRE 336 -96 224 -96
WIRE 1264 -32 592 -32
WIRE 1296 0 784 0
WIRE 1168 48 1072 48
WIRE -288 80 -416 80
WIRE -80 80 -288 80
WIRE 96 80 96 -96
WIRE 96 80 -80 80
WIRE 144 80 96 80
WIRE 336 80 336 -96
WIRE 336 80 240 80
WIRE 448 80 336 80
WIRE 528 80 448 80
WIRE 592 80 592 -32
WIRE 592 80 528 80
WIRE 624 80 592 80
WIRE 784 80 784 0
WIRE 784 80 704 80
WIRE 912 80 784 80
WIRE 1072 80 1072 48
WIRE 1072 80 912 80
WIRE 448 96 448 80
WIRE 1072 96 1072 80
WIRE -416 128 -416 80
WIRE -288 128 -288 80
WIRE 912 192 912 80
WIRE 1072 192 1072 176
WIRE 1152 192 1072 192
WIRE -80 208 -80 80
WIRE 64 208 16 208
WIRE 80 208 64 208
WIRE 192 208 192 144
WIRE 192 208 160 208
WIRE 224 208 192 208
WIRE 336 208 336 80
WIRE 336 208 304 208
WIRE 528 208 528 80
WIRE 784 208 784 80
WIRE 1072 224 1072 192
WIRE -416 320 -416 208
WIRE -288 320 -288 192
WIRE -288 320 -416 320
WIRE 528 320 528 288
WIRE 528 320 -288 320
WIRE 672 320 528 320
WIRE 784 320 784 272
WIRE 784 320 672 320
WIRE 912 320 912 272
WIRE 912 320 784 320
WIRE 1072 320 1072 304
WIRE 1072 320 912 320
WIRE -32 416 -32 272
WIRE 720 416 704 416
WIRE 816 416 784 416
WIRE 96 496 96 416
WIRE 256 496 240 496
WIRE 368 496 320 496
WIRE 704 512 704 416
WIRE 720 512 704 512
WIRE 816 512 816 416
WIRE 816 512 800 512
WIRE -384 544 -384 528
WIRE -272 544 -272 528
WIRE -32 592 -32 496
WIRE 816 608 816 512
WIRE 816 608 784 608
WIRE 944 608 816 608
WIRE 1152 608 1152 192
WIRE 1152 608 1024 608
WIRE 368 624 368 496
WIRE 368 624 336 624
WIRE 560 624 368 624
WIRE 704 624 704 512
WIRE 704 624 640 624
WIRE 720 624 704 624
WIRE 96 640 96 576
WIRE 96 640 32 640
WIRE 128 640 96 640
WIRE 240 640 240 496
WIRE 240 640 192 640
WIRE 272 640 240 640
WIRE 816 640 784 640
WIRE 560 656 336 656
WIRE 1168 656 1168 48
WIRE 1168 656 880 656
WIRE -32 704 -32 688
WIRE 816 704 816 640
WIRE 928 752 896 752
WIRE 1008 752 992 752
WIRE -32 800 -32 784
WIRE 816 800 816 784
WIRE 880 800 880 656
WIRE 880 800 816 800
WIRE 896 832 896 752
WIRE 912 832 896 832
WIRE 1008 832 1008 752
WIRE 1008 832 992 832
WIRE 448 944 336 944
WIRE 96 960 96 640
WIRE 128 960 96 960
WIRE 240 960 192 960
WIRE 272 960 240 960
WIRE 1008 960 1008 832
WIRE 1008 960 992 960
WIRE 1136 960 1008 960
WIRE 1296 960 1296 0
WIRE 1296 960 1216 960
WIRE 368 976 336 976
WIRE 720 976 368 976
WIRE 896 976 896 832
WIRE 896 976 800 976
WIRE 928 976 896 976
WIRE 1024 992 992 992
WIRE 1040 992 1024 992
WIRE 1264 992 1264 -32
WIRE 1264 992 1120 992
WIRE 448 1040 448 944
WIRE 560 1040 560 656
WIRE 240 1104 240 960
WIRE 272 1104 240 1104
WIRE 368 1104 368 976
WIRE 368 1104 336 1104
WIRE 1024 1104 1024 992
WIRE 448 1184 448 1120
WIRE 560 1184 560 1120
FLAG 448 96 0
FLAG -384 544 0
FLAG -272 544 0
FLAG -384 448 +12V
FLAG -272 448 -12V
FLAG 304 992 +12V
FLAG 304 928 -12V
FLAG 304 608 +12V
FLAG 304 672 -12V
FLAG 560 1264 0
FLAG 448 1264 0
FLAG 752 592 +12V
FLAG 752 656 -12V
FLAG 960 944 +12V
FLAG 960 1008 -12V
FLAG 1024 1184 0
FLAG -32 800 +12V
FLAG 96 416 +12V
FLAG 672 320 out
SYMBOL npn 144 144 R270
SYMATTR InstName Q1
SYMATTR Value 2N3055
SYMBOL res 720 64 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 0.1
SYMBOL res 512 192 R0
SYMATTR InstName R2
SYMATTR Value 1k5
SYMBOL res 208 224 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R4
SYMATTR Value 1k
SYMBOL res 64 224 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R5
SYMATTR Value 1
SYMBOL diode 224 -112 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D1
SYMATTR Value ES1D
SYMBOL voltage -416 112 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 124 Left 2
SYMATTR InstName V1
SYMATTR Value 40
SYMBOL cap -304 128 R0
SYMATTR InstName C1
SYMATTR Value 1000µ
SYMATTR SpiceLine Rser=10m
SYMBOL cap 768 208 R0
SYMATTR InstName C2
SYMATTR Value 330µ
SYMATTR SpiceLine Rser=0.001
SYMBOL res 896 176 R0
SYMATTR InstName R6
SYMATTR Value 6
SYMBOL voltage -384 432 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 124 Left 2
SYMATTR SpiceLine Rser=0.01
SYMATTR InstName V2
SYMATTR Value 12
SYMBOL voltage -272 432 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 124 Left 2
SYMATTR SpiceLine Rser=0.01
SYMATTR InstName V3
SYMATTR Value -12
SYMBOL res -48 688 R0
SYMATTR InstName R7
SYMATTR Value 2k
SYMBOL diode 128 656 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D3
SYMATTR Value 1N4148
SYMBOL diode 128 976 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D4
SYMATTR Value 1N4148
SYMBOL cap 320 480 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C3
SYMATTR Value 10n rpar=10meg
SYMATTR SpiceLine Rser=1m
SYMBOL cap 336 1088 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C4
SYMATTR Value 10n rpar=10meg
SYMATTR SpiceLine Rser=1m
SYMBOL res 464 1136 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R9
SYMATTR Value 100
SYMBOL res 576 1136 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R10
SYMATTR Value 100
SYMBOL voltage 448 1168 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 124 Left 2
SYMATTR SpiceLine Rser=0.01
SYMATTR InstName V4
SYMATTR Value 3.3
SYMBOL voltage 560 1168 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 124 Left 2
SYMATTR SpiceLine Rser=0.01
SYMATTR InstName V5
SYMATTR Value PWL(0 0.1 0.2 3.3)
SYMBOL cap 784 432 M270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName C5
SYMATTR Value 100p
SYMATTR SpiceLine Rser=1m
SYMBOL res 656 608 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R11
SYMATTR Value 100
SYMBOL res 816 528 M270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R12
SYMATTR Value 10k
SYMBOL res 1040 592 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R13
SYMATTR Value 10k
SYMBOL res 800 800 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R15
SYMATTR Value 10k
SYMBOL res 1088 192 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R18
SYMATTR Value 4.3k
SYMBOL res 1056 208 R0
SYMATTR InstName R19
SYMATTR Value 30k
SYMBOL res 1008 816 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R21
SYMATTR Value 10k
SYMBOL cap 992 736 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C7
SYMATTR Value 100p
SYMATTR SpiceLine Rser=1m
SYMBOL res 816 960 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R22
SYMATTR Value 100
SYMBOL res 1232 944 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R23
SYMATTR Value 2k
SYMBOL res 1136 976 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R24
SYMATTR Value 2k
SYMBOL res 1040 1200 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R26
SYMATTR Value 10k
SYMBOL res 80 480 R0
SYMATTR InstName R8
SYMATTR Value 10k
SYMBOL npn 32 688 R180
SYMATTR InstName Q3
SYMATTR Value 2N3904
SYMBOL Opamps\\LT1055 960 912 M0
SYMATTR InstName U4
SYMBOL Opamps\\LT1055 752 560 M0
SYMATTR InstName U2
SYMBOL Opamps\\LT1055 304 1024 R180
SYMATTR InstName U1
SYMBOL Opamps\\LT1055 304 576 M0
SYMATTR InstName U3
SYMBOL res -48 400 R0
SYMATTR InstName R16
SYMATTR Value 2k
SYMBOL lib\\sym\\ZZZ\\Darlington\\TIP120 -16 208 R270
SYMATTR InstName U5
TEXT -360 840 Left 2 !.tran 0.4
TEXT -344 896 Left 2 ;.ac dec 101 1 1meg
TEXT 1368 232 Left 2 !.model MYSW SW(Ron=1 Roff=1Meg Vt=.5 Vh=-.4)
\$\endgroup\$
2
  • \$\begingroup\$ 1) Your schematic has 3rd party symbols and libraries, you have to include them since not everybody uses what you do. 2) You posted a SPICE schematic, and a bunch of files describing a complete board, out of which you expect us to deduce what you have cherry-picked and how, and complain it's not working, further expecting us to decipher your doing. 3) There are some strange choices in your schematic, such as grounding after the would-be Darlington, which looks like you've drawn it all wrong. 4) Where are you probing? Saying it oscillates is meaningless without pointing where. \$\endgroup\$
    – a concerned citizen
    Oct 22, 2020 at 8:31
  • 1
    \$\begingroup\$ In short: if you want help, help us help you. \$\endgroup\$
    – a concerned citizen
    Oct 22, 2020 at 8:32

1 Answer 1

Reset to default
1
\$\begingroup\$

This is a re-written answer because the drawings you've shown are not reliable for several reasons: voltage/current sensors with positive feedback, the supply is in series with the series regulator but after it, the schematic is drawn very ugly and causes errors of reading, but also because, despite selecting the answer (which means "la comedia e finita"), you keep updating your question. Even if it happened for good reasons, it still needs addressing.

So I've made another version, see how this fares. It's not made to win a prize, and I haven't tested it -- and never will, because the efficiency is awful. Even a bad switching regulator will be more efficient and "deliver the goods". It's not much different than your schematic, because they're all very similar, but it's drawn in a way that makes more sense. The control voltages now are negative, but they can be made positive with a simple inverting amplifier. It also has a rudimentary current protection in case of shorted output: it limits at about -3 A but the reference is afected by the diode.

V4 controls the output voltage, V5 the current. V4 ramps up , the output follows, until the output current is limited by V5; from then on, despite V4 still increasing the voltage, the output stays flat. At around 0.6 s there's a short-circuit modelled with S1 and its controlling voltage, V6. The output adjusts itself to match the current limit of V5. At 0.8 s, V5 jumps at a tenfold value for the current, which is limited by R11 and D4. Note that this current limit is not enough, since Rcs can be shorted, too, so if you need an over-current protection, you need a different solution -- honestly I don't feel particularly invested in an LDO.

Version 4
SHEET 1 1820 1660
WIRE 992 -32 944 -32
WIRE 1120 -32 1056 -32
WIRE 1168 -32 1120 -32
WIRE 1280 -32 1232 -32
WIRE 1120 96 1120 -32
WIRE 1120 96 1072 96
WIRE 1168 96 1120 96
WIRE 1280 96 1280 -32
WIRE 1280 96 1248 96
WIRE 1296 96 1280 96
WIRE 816 112 688 112
WIRE 944 112 944 -32
WIRE 944 112 880 112
WIRE 1008 112 944 112
WIRE 1120 128 1072 128
WIRE 1120 208 1120 128
WIRE 1168 208 1120 208
WIRE 1280 208 1248 208
WIRE 1328 208 1280 208
WIRE 1440 208 1408 208
WIRE 1280 224 1280 208
WIRE 432 304 432 208
WIRE 544 304 432 304
WIRE 1280 320 1280 288
WIRE 432 352 432 304
WIRE 544 352 544 304
WIRE 1008 384 960 384
WIRE 1136 384 1072 384
WIRE 1184 384 1136 384
WIRE 1296 384 1248 384
WIRE 432 480 432 432
WIRE 1136 512 1136 384
WIRE 1136 512 1088 512
WIRE 1184 512 1136 512
WIRE 1296 512 1296 384
WIRE 1296 512 1264 512
WIRE 1312 512 1296 512
WIRE 544 528 544 432
WIRE 544 528 496 528
WIRE 688 528 688 112
WIRE 688 528 544 528
WIRE 800 528 688 528
WIRE 960 528 960 384
WIRE 960 528 880 528
WIRE 1024 528 960 528
WIRE 1184 544 1088 544
WIRE 1184 576 1184 544
WIRE 432 640 432 576
WIRE 1184 720 1184 656
WIRE 1440 720 1440 208
WIRE 80 880 16 880
WIRE 560 880 80 880
WIRE 736 880 560 880
WIRE 880 880 736 880
WIRE 1104 880 880 880
WIRE 1408 880 1104 880
WIRE 880 896 880 880
WIRE 1104 896 1104 880
WIRE 1408 896 1408 880
WIRE 16 912 16 880
WIRE 432 960 432 720
WIRE 560 960 560 880
WIRE 736 960 736 880
WIRE 80 976 80 880
WIRE 880 992 880 976
WIRE 960 992 880 992
WIRE 1104 992 1104 960
WIRE 1104 992 1040 992
WIRE 1200 992 1104 992
WIRE 1408 992 1408 976
WIRE 1456 992 1408 992
WIRE 208 1024 176 1024
WIRE 336 1024 288 1024
WIRE 384 1024 336 1024
WIRE 880 1024 880 992
WIRE 1408 1024 1408 992
WIRE 336 1056 336 1024
WIRE 1120 1088 928 1088
WIRE 80 1120 80 1056
WIRE 176 1120 176 1024
WIRE 176 1120 80 1120
WIRE 288 1120 176 1120
WIRE 480 1120 480 1024
WIRE 480 1120 384 1120
WIRE 560 1120 560 1040
WIRE 560 1120 480 1120
WIRE 608 1120 560 1120
WIRE 736 1120 736 1024
WIRE 736 1120 688 1120
WIRE 880 1120 880 1104
WIRE 880 1120 736 1120
WIRE 1408 1120 1408 1104
WIRE 1408 1120 880 1120
WIRE 1472 1120 1408 1120
WIRE 1120 1136 1120 1088
WIRE 176 1232 176 1120
WIRE 304 1232 176 1232
WIRE 480 1232 480 1120
WIRE 480 1232 368 1232
FLAG 1472 1120 out
FLAG 112 608 Vcc
FLAG 1056 496 Vcc
FLAG 1056 560 Vee
FLAG 16 608 Vee
FLAG 16 688 0
FLAG 112 688 0
FLAG 1200 992 Isense
FLAG 1184 800 0
FLAG 432 208 0
FLAG 1040 80 Vcc
FLAG 1040 144 Vee
FLAG 1440 800 0
FLAG 1296 96 Isense
FLAG 1456 992 Vsense
FLAG 1312 512 Vsense
FLAG 928 1040 0
FLAG 1280 320 0
FLAG 16 912 0
FLAG 1120 1216 0
SYMBOL voltage 80 960 R0
WINDOW 123 24 118 Left 2
WINDOW 39 24 140 Left 2
SYMATTR Value2 Rser=10m
SYMATTR SpiceLine Cpar=1m
SYMATTR InstName V1
SYMATTR Value 40
SYMBOL npn 384 1056 R90
SYMATTR InstName Q1
SYMATTR Value 2N3055
SYMBOL res 304 1040 M270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R1
SYMATTR Value 1k
SYMBOL diode 304 1216 M90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D1
SYMATTR Value ES1D
SYMBOL res 544 1056 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R2
SYMATTR Value 10k
SYMBOL cap 720 1024 M180
WINDOW 123 24 78 Left 2
SYMATTR Value2 Rser=25m
SYMATTR InstName C1
SYMATTR Value 470u
SYMBOL res 864 992 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName Rcs
SYMATTR Value 0.1
SYMBOL Opamps\\LT1055 1056 464 M0
SYMATTR InstName U1
SYMBOL cap 1072 368 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
WINDOW 123 54 32 VTop 2
SYMATTR InstName C2
SYMATTR Value 100p
SYMATTR Value2 Rpar=1Meg
SYMBOL voltage 112 592 R0
WINDOW 123 24 118 Left 2
WINDOW 39 24 140 Left 2
SYMATTR Value2 Rser=10m
SYMATTR SpiceLine Cpar=1m
SYMATTR InstName V2
SYMATTR Value 12
SYMBOL voltage 16 592 R0
WINDOW 123 24 118 Left 2
WINDOW 39 24 140 Left 2
SYMATTR Value2 Rser=10m
SYMATTR SpiceLine Cpar=1m
SYMATTR InstName V3
SYMATTR Value -12
SYMBOL res 1392 1120 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R3
SYMATTR Value 27k
SYMBOL res 1392 992 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R4
SYMATTR Value 4.7k
SYMBOL res 1280 496 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R5
SYMATTR Value 1k
SYMBOL voltage 1184 704 R0
WINDOW 123 24 118 Left 2
WINDOW 39 24 140 Left 2
SYMATTR InstName V4
SYMATTR Value pwl 0 0 1 -10
SYMBOL res 1168 560 R0
SYMATTR InstName R6
SYMATTR Value 1k
SYMBOL res 416 736 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R7
SYMATTR Value 10k
SYMBOL res 896 512 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R8
SYMATTR Value 10k
SYMBOL res 416 448 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R9
SYMATTR Value 2.7k
SYMBOL res 528 448 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R10
SYMATTR Value 10k
SYMBOL pnp 496 576 R180
SYMATTR InstName Q3
SYMATTR Value 2N2905A
SYMBOL npn 480 960 R90
SYMATTR InstName Q2
SYMATTR Value 2N2219A
SYMBOL Opamps\\LT1055 1040 48 M0
SYMATTR InstName U2
SYMBOL cap 1056 -48 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
WINDOW 123 54 32 VTop 2
SYMATTR InstName C3
SYMATTR Value 100p
SYMATTR Value2 Rpar=1Meg
SYMBOL res 1264 80 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R13
SYMATTR Value 1k
SYMBOL voltage 1440 704 R0
WINDOW 123 24 118 Left 2
WINDOW 39 24 140 Left 2
SYMATTR InstName V5
SYMATTR Value pwl 0.8 -0.2 +1u -1
SYMBOL res 1152 224 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R14
SYMATTR Value 1k
SYMBOL diode 880 128 M270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D3
SYMATTR Value 1N4148
SYMBOL cap 1232 -48 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
WINDOW 123 54 32 VTop 2
SYMATTR InstName C4
SYMATTR Value 10n
SYMBOL cap 1248 368 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
WINDOW 123 54 32 VTop 2
SYMATTR InstName C5
SYMATTR Value 10n
SYMBOL sw 880 1008 M0
SYMATTR InstName S1
SYMATTR Value load
SYMBOL voltage 1120 1120 R0
WINDOW 3 31 92 Left 2
WINDOW 123 24 118 Left 2
WINDOW 39 24 140 Left 2
SYMATTR Value pwl 0.6 0 +1u 1
SYMATTR InstName V6
SYMBOL res 1056 1008 M270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R12
SYMATTR Value 1k
SYMBOL cap 1088 960 M180
WINDOW 0 24 56 Left 2
WINDOW 3 24 8 Left 2
SYMATTR InstName C6
SYMATTR Value 1n
SYMBOL voltage 592 1120 M90
WINDOW 0 46 48 VRight 2
WINDOW 3 -60 122 VRight 2
WINDOW 123 24 118 Left 2
WINDOW 39 24 140 Left 2
SYMATTR InstName Vi
SYMATTR Value ""
SYMBOL schottky 1264 288 M180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D4
SYMATTR Value BAT54
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 1312 192 M90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R11
SYMATTR Value 100
TEXT 8 48 Left 2 !.tran 1
TEXT 8 80 Left 2 !.model load sw ron=1m roff=10 vt=0.5 vh=-0.5
TEXT 528 1200 Left 2 ;plot current through Vi and voltage at V(out)
\$\endgroup\$
14
  • \$\begingroup\$ Thank for Your time, but Your circuit doesn't want to work as expected... It is stable, but not stabilizing correctly. I played quite a lot with it (after Your modification) and it's kind of stable now and it regulates nicely. See edit2 I think I can breadboard it now \$\endgroup\$
    – fifi_22
    Oct 22, 2020 at 13:42
  • \$\begingroup\$ @fifi_22 If you read everything I said, you'll see that I said it's not working properly. Neither is your latest circuit, since varying either V4 or V5 has no visible effect. I also said it's the way the connections are drawn that make me think the schematic is not translated well. I would seriously reconsider breadboarding this. Side note: your modification alters the current sensing (it was a lowpass before). \$\endgroup\$
    – a concerned citizen
    Oct 22, 2020 at 14:59
  • \$\begingroup\$ Ok, I will do that next time (and this one too). BTW this is my server, but i understand the problem. \$\endgroup\$
    – fifi_22
    Oct 22, 2020 at 19:08
  • \$\begingroup\$ I know this circuit needs some tuning, but in the school We use this supplies (original schematic) and they act quite nicely. There are probably errors in the orginal schematics - when corona ends I can go to school and measure values of components inside. \$\endgroup\$
    – fifi_22
    Oct 23, 2020 at 17:18
  • \$\begingroup\$ @fifi_22 It's not only about the values, it's about the whole schematic. What I've re-made is based on the usual approach, while trying to maintain what was drawn, but the most important thing is to have a correct schematic to begin with. Once that is achieved, you can poke around with values, but until then... \$\endgroup\$
    – a concerned citizen
    Oct 23, 2020 at 17:22

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