Re: Another design

On 10/05/2024 4:11 am, Edward Rawde wrote:

"Edward Rawde" <invalid@invalid.invalid> wrote in message
news:v1ho21$4ps$1@nnrp.usenet.blueworldhosting.com...

Now with 9V to 15V input range, direct gate drive and 500mA LED current.
>
Startup behaviour is not ideal but maybe that can be fixed if it needs
fixing.
>
What's the cheapest op amp I can use for U2 instead of OP07?
>
Is there a cheaper comparator instead of LT1719 which will work?
Also the fet is bigger than it needs to ne.
>
Is there a better device for D4? Particularly if R4 can be reduced.
>
Will it work at all? Except in simulation.
>

 I think I've answered my own question for the current controller but I don't
think it's feasible to attempt a discrete comparator on cost grounds.
 Version 4
SHEET 1 3044 680
WIRE 2032 -272 64 -272
WIRE 2192 -272 2032 -272
WIRE 2480 -272 2192 -272
WIRE 2192 -224 2192 -272
WIRE 2480 -224 2480 -272
WIRE 2336 -176 2256 -176
WIRE 2416 -176 2336 -176
WIRE 976 -128 160 -128
WIRE 1072 -128 1040 -128
WIRE 2032 -128 2032 -272
WIRE 2192 -80 2192 -128
WIRE 2336 -80 2336 -176
WIRE 2336 -80 2192 -80
WIRE 2480 -64 2480 -128
WIRE 2688 -64 2480 -64
WIRE 16 -48 -16 -48
WIRE 64 -48 64 -272
WIRE 64 -48 16 -48
WIRE 96 -48 64 -48
WIRE 240 -48 96 -48
WIRE 336 -48 240 -48
WIRE 448 -48 336 -48
WIRE 464 -48 448 -48
WIRE 528 -48 464 -48
WIRE 608 -48 528 -48
WIRE 672 -48 608 -48
WIRE 784 -48 768 -48
WIRE 816 -48 784 -48
WIRE 864 -48 816 -48
WIRE 992 -48 944 -48
WIRE 1024 -48 992 -48
WIRE 1072 -48 1072 -128
WIRE 1072 -48 1024 -48
WIRE 1264 -48 1072 -48
WIRE 1360 -48 1264 -48
WIRE 240 -16 240 -48
WIRE 336 -16 336 -48
WIRE 2192 -16 2192 -80
WIRE 2480 -16 2480 -64
WIRE 1264 0 1264 -48
WIRE 1360 0 1360 -48
WIRE -16 32 -16 -48
WIRE 2128 32 1872 32
WIRE 2592 32 2544 32
WIRE 448 64 448 -48
WIRE 464 64 464 -48
WIRE 96 80 96 -48
WIRE 160 80 160 -128
WIRE 240 80 240 64
WIRE 240 80 160 80
WIRE 336 80 336 64
WIRE 384 80 336 80
WIRE 416 80 384 80
WIRE 816 80 816 -48
WIRE 992 80 992 -48
WIRE 336 96 336 80
WIRE 336 96 288 96
WIRE 656 96 480 96
WIRE 688 96 688 0
WIRE 688 96 656 96
WIRE 1264 96 1264 64
WIRE 1312 96 1264 96
WIRE 1936 96 1312 96
WIRE 240 112 240 80
WIRE 384 112 240 112
WIRE 416 112 384 112
WIRE 528 112 528 -48
WIRE 608 112 608 -48
WIRE 240 128 240 112
WIRE 336 128 336 96
WIRE 1360 128 1360 80
WIRE 1424 128 1360 128
WIRE 1872 128 1872 32
WIRE 1872 128 1424 128
WIRE 2192 128 2192 80
WIRE 2352 128 2192 128
WIRE 2480 128 2480 80
WIRE 2480 128 2352 128
WIRE 2032 144 2032 -48
WIRE 2128 144 2032 144
WIRE 1360 160 1360 128
WIRE -16 176 -16 112
WIRE 2032 192 2032 144
WIRE 2352 192 2352 128
WIRE 240 240 240 208
WIRE 336 240 336 208
WIRE 336 240 240 240
WIRE 384 240 336 240
WIRE 432 240 432 128
WIRE 432 240 384 240
WIRE 448 240 448 128
WIRE 448 240 432 240
WIRE 464 240 464 128
WIRE 464 240 448 240
WIRE 528 240 528 176
WIRE 528 240 464 240
WIRE 544 240 528 240
WIRE 608 240 608 176
WIRE 608 240 544 240
WIRE 1360 240 1360 224
WIRE 1424 240 1360 240
WIRE 1536 240 1424 240
WIRE 1696 240 1600 240
WIRE 1872 240 1760 240
WIRE 2128 240 2128 144
WIRE 2128 240 2096 240
WIRE 2288 240 2128 240
WIRE 544 272 544 240
WIRE 1264 272 1264 96
WIRE 1360 272 1360 240
WIRE -16 368 -16 256
WIRE 96 368 96 144
WIRE 96 368 -16 368
WIRE 544 368 544 352
WIRE 544 368 96 368
WIRE 816 368 816 144
WIRE 816 368 544 368
WIRE 992 368 992 144
WIRE 992 368 816 368
WIRE 1264 368 1264 352
WIRE 1264 368 992 368
WIRE 1360 368 1360 336
WIRE 1360 368 1264 368
WIRE 1872 368 1872 240
WIRE 1872 368 1360 368
WIRE 2032 368 2032 288
WIRE 2032 368 1872 368
WIRE 2352 368 2352 288
WIRE 2352 368 2032 368
WIRE -16 384 -16 368
WIRE 1936 400 1936 96
WIRE 2592 400 2592 32
WIRE 2592 400 1936 400
WIRE 288 448 288 96
WIRE 992 448 288 448
WIRE 1328 448 1072 448
WIRE 2688 448 2688 -64
WIRE 2688 448 1328 448
FLAG -16 384 0
FLAG 16 -48 in
FLAG 784 -48 sw
FLAG 1024 -48 out
FLAG 1424 128 isense
FLAG 1312 96 iref
FLAG 1328 448 ifb
FLAG 384 80 cmp-
FLAG 384 112 cmp+
FLAG 656 96 gate
FLAG 384 240 cmpv-
FLAG 1424 240 led
SYMBOL Comparators\LT1719 448 32 R0
WINDOW 0 27 27 Left 2
WINDOW 3 -92 6 Left 2
SYMATTR InstName U1
SYMBOL res 320 112 R0
WINDOW 0 41 34 Left 2
WINDOW 3 35 64 Left 2
SYMATTR InstName R4
SYMATTR Value 10K
SYMATTR SpiceLine tol=1 pwr=0.1
SYMBOL ind 960 -64 R90
WINDOW 0 63 51 VBottom 2
WINDOW 3 -27 53 VTop 2
SYMATTR InstName L1
SYMATTR Value 68µ
SYMATTR SpiceLine Ipk=0.85 Rser=0.21 Rpar=0 Cpar=0 mfg="Sumida"
pn="CDR105B-680"
SYMBOL res 1376 -16 M0
WINDOW 0 -37 34 Left 2
WINDOW 3 -57 63 Left 2
SYMATTR InstName R8
SYMATTR Value 0.68
SYMATTR SpiceLine tol=1 pwr=0.1
SYMBOL res 224 -32 R0
WINDOW 0 -35 19 Left 2
WINDOW 3 -49 48 Left 2
SYMATTR InstName R1
SYMATTR Value 10K
SYMATTR SpiceLine tol=1 pwr=0.1
SYMBOL schottky 832 144 R180
WINDOW 0 -42 30 Left 2
WINDOW 3 -119 -3 Left 2
SYMATTR InstName D2
SYMATTR Value MBRS130L
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL pmos 768 0 M270
WINDOW 0 10 129 VLeft 2
WINDOW 3 -10 67 VLeft 2
SYMATTR InstName M1
SYMATTR Value AO6407
SYMBOL voltage -16 160 R0
WINDOW 0 -75 16 Left 2
WINDOW 3 -71 54 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 -185 81 Left 2
SYMATTR InstName V3
SYMATTR Value 12
SYMBOL res -32 16 R0
WINDOW 0 -39 29 Left 2
WINDOW 3 -63 65 Left 2
SYMATTR InstName R9
SYMATTR Value 0.001
SYMBOL zener 544 176 R180
WINDOW 0 37 29 Left 2
WINDOW 3 68 -5 Right 2
SYMATTR InstName D1
SYMATTR Value UMZ5_1N
SYMBOL res 320 -32 R0
WINDOW 0 40 7 Left 2
WINDOW 3 37 33 Left 2
SYMATTR InstName R3
SYMATTR Value 10K
SYMATTR SpiceLine tol=1 pwr=0.1
SYMBOL res 528 368 M180
WINDOW 0 39 76 Left 2
WINDOW 3 38 42 Left 2
SYMATTR InstName R5
SYMATTR Value 220
SYMATTR SpiceLine tol=1 pwr=0.1
SYMBOL cap 592 176 M180
WINDOW 0 29 52 Left 2
WINDOW 3 30 13 Left 2
SYMATTR InstName C3
SYMATTR Value 0.1µ
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0.0337 Lser=180p
SYMBOL polcap 976 80 R0
WINDOW 3 24 56 Left 2
WINDOW 0 27 9 Left 2
SYMATTR Value 100µ
SYMATTR InstName C1
SYMATTR Description Capacitor
SYMATTR Type cap
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0.9 Lser=0
SYMBOL res 224 112 R0
WINDOW 0 -40 33 Left 2
WINDOW 3 -52 57 Left 2
SYMATTR InstName R2
SYMATTR Value 10K
SYMATTR SpiceLine tol=1 pwr=0.1
SYMBOL polcap 80 80 R0
WINDOW 3 -57 61 Left 2
WINDOW 0 -39 4 Left 2
SYMATTR Value 100µ
SYMATTR InstName C2
SYMATTR Description Capacitor
SYMATTR Type cap
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0.9 Lser=0
SYMBOL LED 1536 256 R270
WINDOW 0 72 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName LED1
SYMATTR Value LXZ1-PB01
SYMBOL res 976 432 M90
WINDOW 0 -2 59 VBottom 2
WINDOW 3 35 64 VTop 2
SYMATTR InstName R6
SYMATTR Value 220K
SYMATTR SpiceLine tol=1 pwr=0.1
SYMBOL cap 976 -144 M90
WINDOW 0 -3 31 VBottom 2
WINDOW 3 36 35 VTop 2
SYMATTR InstName C5
SYMATTR Value 0.01µ
SYMATTR SpiceLine V=16 Irms=291m Rser=0.34258 Lser=0
SYMBOL res 1248 368 M180
WINDOW 0 -40 81 Left 2
WINDOW 3 -51 46 Left 2
SYMATTR InstName R7
SYMATTR Value 470
SYMATTR SpiceLine tol=1 pwr=0.1
SYMBOL schottky 1280 0 M0
WINDOW 0 43 24 Left 2
WINDOW 3 40 -8 Left 2
SYMATTR InstName D3
SYMATTR Value BAT54AHY
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL FerriteBead 1360 192 R0
SYMATTR InstName L2
SYMATTR Value 6µ
SYMATTR SpiceLine Ipk=3 Rser=0.0102 Rpar=1220 Cpar=1.9p
SYMBOL cap 1344 272 R0
SYMATTR InstName C4
SYMATTR Value 0.001µ
SYMATTR SpiceLine V=10 Irms=0 Rser=0.1909 Lser=177p mfg="Würth Elektronik"
pn="885012205006 WCAP-CSGP 0402" type="X7R"
SYMBOL LED 1696 256 R270
WINDOW 0 72 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName LED2
SYMATTR Value LXZ1-PB01
SYMBOL pnp 2256 -128 R180
SYMATTR InstName Q2
SYMATTR Value 2N3906
SYMBOL pnp 2416 -128 M180
SYMATTR InstName Q3
SYMATTR Value 2N3906
SYMBOL npn 2128 -16 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL npn 2544 -16 M0
SYMATTR InstName Q4
SYMATTR Value 2N3904
SYMBOL npn 2288 192 R0
SYMATTR InstName Q5
SYMATTR Value 2N3904
SYMBOL npn 2096 192 M0
SYMATTR InstName Q6
SYMATTR Value 2N3904
SYMBOL res 2016 -144 R0
SYMATTR InstName R10
SYMATTR Value 100K
TEXT 16 392 Left 2 !.tran 0.001 startup
 

The venerable LM311 is still a good value comparator, if you want to penny pinch omit the gate driver buffers and lower the pullup resistor but efficiency will drop a lot from 85% to ca 72%.
Version 4
SHEET 1 996 708
WIRE -544 -112 -704 -112
WIRE -48 -112 -544 -112
WIRE 48 -112 -48 -112
WIRE 192 -112 48 -112
WIRE 336 -112 192 -112
WIRE 48 -96 48 -112
WIRE 192 -48 192 -112
WIRE -544 -16 -544 -112
WIRE 48 0 48 -16
WIRE 128 0 48 0
WIRE 336 64 336 -112
WIRE 192 80 192 48
WIRE 288 80 192 80
WIRE -544 176 -544 64
WIRE -448 176 -544 176
WIRE -240 224 -288 224
WIRE 336 224 336 160
WIRE 336 224 -160 224
WIRE -448 240 -448 176
WIRE 336 272 336 224
WIRE 416 272 336 272
WIRE 592 272 496 272
WIRE -704 320 -704 -112
WIRE 592 320 592 272
WIRE 592 320 416 320
WIRE -160 336 -192 336
WIRE -48 336 -48 -112
WIRE -48 336 -80 336
WIRE -544 352 -544 176
WIRE 592 352 592 320
WIRE 416 368 416 320
WIRE -48 384 -48 336
WIRE 192 384 192 80
WIRE -448 416 -448 320
WIRE -288 416 -288 224
WIRE -288 416 -448 416
WIRE -80 416 -288 416
WIRE 48 432 48 0
WIRE 48 432 0 432
WIRE 128 432 48 432
WIRE -192 448 -192 336
WIRE -80 448 -192 448
WIRE -448 464 -448 416
WIRE 336 464 336 272
WIRE 416 464 416 432
WIRE 592 464 592 416
WIRE 592 464 416 464
WIRE -192 496 -192 448
WIRE 592 496 592 464
WIRE -704 592 -704 400
WIRE -544 592 -544 416
WIRE -544 592 -704 592
WIRE -448 592 -448 544
WIRE -448 592 -544 592
WIRE -64 592 -64 480
WIRE -64 592 -448 592
WIRE -48 592 -48 480
WIRE -48 592 -64 592
WIRE 192 592 192 480
WIRE 192 592 -48 592
WIRE 336 592 336 528
WIRE 336 592 192 592
WIRE 592 592 592 576
WIRE 592 592 336 592
WIRE -704 640 -704 592
WIRE -192 672 -192 576
WIRE 416 672 416 464
WIRE 416 672 -192 672
FLAG -704 640 0
SYMBOL schottky 352 528 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D1
SYMATTR Value 1N5817
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL ind 400 288 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 5 56 VBottom 2
SYMATTR InstName L1
SYMATTR Value 0.22m
SYMATTR SpiceLine Rser=50m
SYMBOL LED 576 352 R0
SYMATTR InstName D2
SYMATTR Value LXK2-PW14
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL voltage -704 304 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL res 576 480 R0
SYMATTR InstName R8
SYMATTR Value 0.15
SYMBOL zener -528 416 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D3
SYMATTR Value 1N750
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res -560 -32 R0
SYMATTR InstName R1
SYMATTR Value 2k
SYMBOL res -464 448 R0
SYMATTR InstName R3
SYMATTR Value 100
SYMBOL res -464 224 R0
SYMATTR InstName R2
SYMATTR Value 4.3k
SYMBOL res 32 -112 R0
SYMATTR InstName R7
SYMATTR Value 10k
SYMBOL cap 400 368 R0
SYMATTR InstName C1
SYMATTR Value 0.1m
SYMBOL res -144 208 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R4
SYMATTR Value 33k
SYMBOL res -176 592 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R5
SYMATTR Value 100
SYMBOL npn 128 -48 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL pnp 128 480 M180
SYMATTR InstName Q2
SYMATTR Value 2N3906
SYMBOL pmos 288 160 M180
SYMATTR InstName M2
SYMATTR Value AO6407
SYMBOL res -64 320 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R6
SYMATTR Value 33k
SYMBOL Comparators\LT1011 -48 432 R0
SYMATTR InstName U2
TEXT -400 664 Left 2 !.tran 1m
TEXT 496 -96 Left 2 ;EPW SED MAY 2024
TEXT 496 -48 Left 2 ;LED BUCK USING LM311
TEXT -152 616 Left 2 ;R6 IS OPT LINE REGULATION FEED FWD CORR
TEXT -312 160 Left 2 ;R4 SETS HYSTERESIS
TEXT 472 616 Left 2 ;C1 OPT EMI/RFI FILT FOR REMOTE LED
TEXT -440 392 Left 2 ;VREF 100mV
piglet