Version 4 SHEET 1 1620 1136 WIRE 240 -48 128 -48 WIRE 240 0 240 -48 WIRE 128 32 128 -48 WIRE 240 112 240 80 WIRE 128 176 128 112 WIRE 288 176 128 176 WIRE 128 224 128 176 WIRE -160 272 -240 272 WIRE -48 272 -96 272 WIRE 0 272 -48 272 WIRE 80 272 0 272 WIRE -240 352 -240 272 WIRE -48 352 -48 272 WIRE 96 352 96 320 WIRE 672 352 96 352 WIRE 880 352 672 352 WIRE 96 368 96 352 WIRE 880 432 880 352 WIRE -240 464 -240 432 WIRE 96 464 96 448 WIRE -48 544 -48 432 WIRE 32 544 -48 544 WIRE 192 544 112 544 WIRE 272 544 192 544 WIRE 352 544 272 544 WIRE 464 544 352 544 WIRE 656 544 528 544 WIRE 720 544 656 544 WIRE 880 544 880 512 WIRE 880 544 800 544 WIRE 976 544 880 544 WIRE 1088 544 1040 544 WIRE 880 560 880 544 WIRE -48 576 -48 544 WIRE 352 576 352 544 WIRE 432 624 416 624 WIRE 560 624 512 624 WIRE 656 624 656 544 WIRE 656 624 624 624 WIRE -48 672 -48 640 WIRE 880 672 880 640 WIRE 192 704 192 544 WIRE 352 704 352 672 WIRE 432 720 432 624 WIRE 592 784 592 768 WIRE 656 800 656 624 WIRE 656 800 624 800 WIRE 912 800 800 800 WIRE 352 816 352 784 WIRE 432 816 352 816 WIRE 512 816 512 624 WIRE 512 816 432 816 WIRE 560 816 512 816 WIRE 656 832 624 832 WIRE 800 832 800 800 WIRE 592 880 592 848 WIRE 912 896 912 800 WIRE 656 928 656 832 WIRE 704 928 656 928 WIRE 800 928 800 912 WIRE 800 928 704 928 WIRE -80 944 -80 912 WIRE 192 944 192 784 WIRE 800 960 800 928 WIRE -80 1072 -80 1024 WIRE 192 1072 192 1024 WIRE 800 1072 800 1040 WIRE 912 1072 912 976 FLAG 96 464 0 FLAG 240 112 0 FLAG -240 464 0 FLAG -48 672 0 FLAG 192 1072 0 FLAG 592 768 VOP IOPIN 592 768 In FLAG 592 880 0 FLAG 912 1072 0 FLAG 672 352 Sense IOPIN 672 352 Out FLAG -80 1072 0 FLAG -80 912 VOP IOPIN -80 912 Out FLAG 432 720 0 FLAG 880 672 0 FLAG 800 1072 0 FLAG 1088 544 VOP IOPIN 1088 544 In FLAG 288 176 OUT IOPIN 288 176 Out FLAG 0 272 GRID FLAG -240 272 IN IOPIN -240 272 In FLAG 704 928 REF FLAG 432 816 OP FLAG 272 544 CTRL SYMBOL res 112 16 R0 SYMATTR InstName R1 SYMATTR Value 2k SYMBOL res 80 352 R0 SYMATTR InstName R2 SYMATTR Value 20 SYMBOL voltage 240 -16 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 WINDOW 0 -13 58 Left 0 WINDOW 3 -60 2 Left 0 SYMATTR InstName V1 SYMATTR Value 800V SYMBOL voltage -240 336 R0 WINDOW 3 32 92 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR Value 0 SYMATTR InstName V2 SYMBOL cap -96 256 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C1 SYMATTR Value 0.1µ SYMBOL res -64 336 R0 SYMATTR InstName R3 SYMATTR Value 470k SYMBOL cap -32 576 M0 WINDOW 0 -33 10 Left 0 WINDOW 3 -37 58 Left 0 SYMATTR InstName C2 SYMATTR Value 0.1µ SYMBOL res 128 528 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R4 SYMATTR Value 33k SYMBOL res 208 800 R180 WINDOW 0 36 76 Left 0 WINDOW 3 36 40 Left 0 SYMATTR InstName R5 SYMATTR Value 22k SYMBOL cap 528 528 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C3 SYMATTR Value 0.1µ SYMBOL voltage 192 928 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value -90 SYMBOL voltage 912 880 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V4 SYMATTR Value PULSE(1 1.2 100u 100n 100n 1 2) SYMBOL res 816 528 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R7 SYMATTR Value 22k SYMBOL res 368 800 R180 WINDOW 0 36 76 Left 0 WINDOW 3 36 40 Left 0 SYMATTR InstName R6 SYMATTR Value 4.7k SYMBOL voltage -80 928 M0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V5 SYMATTR Value 12.5V SYMBOL res 864 416 R0 SYMATTR InstName R9 SYMATTR Value 10k SYMBOL res 864 544 R0 SYMATTR InstName R10 SYMATTR Value 10k SYMBOL res 784 816 R0 SYMATTR InstName R11 SYMATTR Value 10k SYMBOL res 784 944 R0 SYMATTR InstName R12 SYMATTR Value 10k SYMBOL cap 560 640 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName C4 SYMATTR Value 0.01µ SYMBOL diode 976 560 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName D1 SYMBOL pnp 416 576 M0 SYMATTR InstName Q1 SYMATTR Value 2N5401 SYMBOL Robertugo\\OPAMP5 592 752 M0 SYMATTR InstName U1 SYMATTR SpiceModel LM324/NS SYMBOL Valve\\triode 128 272 R0 WINDOW 38 107 43 Center 0 SYMATTR InstName T1 SYMATTR SpiceModel NH3CX300 TEXT -208 112 Left 0 !.op TEXT -232 8 Left 0 ;.NODESET V(N009)=1.2V TEXT -208 80 Left 0 !.tran 1 TEXT 152 1120 Left 0 ;Test PS ripple supression with 2Vpp SINE TEXT 968 488 Left 0 ;Protection TEXT 848 1112 Left 0 ;Test step response and loop stability TEXT 264 960 Left 0 ;-90V TEXT 256 992 Left 0 ;SINE(-90 1 50) TEXT 376 -32 Left 0 ;DC operating point regulator for a valve audio amplifier\n \nHelmut Sennewald, 03/01/04\n \nSet the post gain defined by R5/R6 as small as possible. This is one of the keys for stability.\n \nI further recommend to use a small signal PNP transistor(e.g. 2N5401) or \na small signal PMOS transistor like a BSS192. Don't use a big power PMOS.\nWhen using a PMOS, the gate has to be connected to ground and the source to R6.\n \nIncrease C1 and C3 if you want a lower corner frequency below 20Hz.\nYou will never use more than 1uF for C1 and C3. TEXT -208 464 Left 0 ;SINE(0 1 20) TEXT -376 520 Left 0 ;Check low frequency corner TEXT 936 840 Left 0 ;Referenz TEXT 968 920 Left 0 ;1.2V