micropower boost circuit idea

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As shown, starts up from ~0.75 volts and can provide several mA into a load, output tracking the full ~15 volts above the input voltage once the input comes above 1 volt. With a logic-level MOSFET for M1 and a germanium transistor for Q1, it would probably start significantly lower. The comparator and regulator don't have to be the expensive LT parts, they're just an example. 1:1 CT ADSL transformers are really cheap, too.

Version 4 SHEET 1 2020 852 WIRE -176 -384 -624 -384 WIRE 1424 -384 -176 -384 WIRE -352 -272 -560 -272 WIRE -352 -224 -352 -272 WIRE -176 -224 -176 -384 WIRE -560 -176 -560 -272 WIRE -496 -176 -560 -176 WIRE -384 -176 -416 -176 WIRE -240 -176 -288 -176 WIRE -624 0 -624 -384 WIRE -496 0 -624 0 WIRE -384 0 -416 0 WIRE -288 0 -336 0 WIRE -176 0 -176 -128 WIRE -176 0 -208 0 WIRE 256 32 -32 32 WIRE 544 32 320 32 WIRE -560 160 -560 -176 WIRE -496 160 -560 160 WIRE -384 160 -336 0 WIRE -384 160 -416 160 WIRE -336 160 -384 0 WIRE -288 160 -336 160 WIRE -160 160 -208 160 WIRE -96 160 -112 160 WIRE -32 160 -32 32 WIRE -32 160 -96 160 WIRE 16 160 -32 160 WIRE 144 160 80 160 WIRE 288 160 144 160 WIRE 432 160 288 160 WIRE 640 160 432 160 WIRE 864 160 640 160 WIRE 1424 176 1424 -384 WIRE 1424 176 1200 176 WIRE 864 208 864 160 WIRE -384 240 -384 160 WIRE 432 240 432 160 WIRE 1424 272 1424 176 WIRE 640 320 640 160 WIRE 736 320 640 320 WIRE 1072 320 992 320 WIRE -336 352 -336 160 WIRE -32 384 -32 160 WIRE 144 384 144 160 WIRE 288 384 288 160 WIRE 432 400 432 304 WIRE 432 400 320 400 WIRE 544 400 544 32 WIRE 544 400 432 400 WIRE 624 400 544 400 WIRE 256 416 224 416 WIRE -384 432 -448 432 WIRE 368 432 320 432 WIRE 1072 480 1072 320 WIRE 544 512 544 400 WIRE 624 512 624 400 WIRE 864 512 864 432 WIRE -448 528 -448 432 WIRE 1424 656 1424 352 WIRE -336 672 -336 448 WIRE -32 672 -32 448 WIRE 144 672 144 448 WIRE 288 672 288 448 WIRE 368 672 368 432 WIRE 544 672 544 576 WIRE 624 672 624 592 WIRE 1072 672 1072 560 WIRE -448 720 -448 608 WIRE 224 720 224 416 WIRE 224 720 -448 720 WIRE 864 736 864 576 WIRE 1200 736 1200 176 WIRE 1200 736 864 736 FLAG 1424 656 0 FLAG -336 672 0 FLAG -32 672 0 FLAG 144 672 0 FLAG -384 240 0 FLAG 288 672 0 FLAG 544 672 0 FLAG 1072 672 0 FLAG 624 672 0 FLAG 368 672 0 SYMBOL voltage 1424 256 R0 WINDOW 123 0 0 Left 2 WINDOW 39 24 124 Left 2 SYMATTR SpiceLine Rser=0.01 SYMATTR InstName V1 SYMATTR Value 0.8 SYMBOL ind2 -512 16 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L1 SYMATTR Value 100µH SYMBOL ind2 -192 -16 R90 WINDOW 0 4 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName L2 SYMATTR Value 100µH SYMBOL ind2 -400 144 R90 WINDOW 0 4 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName L3 SYMATTR Value 100µH SYMBOL ind2 -304 176 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L4 SYMATTR Value 100µH SYMBOL schottky -16 448 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D2 SYMATTR Value 1N5817 SYMATTR Description Diode SYMATTR Type diode SYMBOL nmos -384 352 R0 SYMATTR InstName M1 SYMATTR Value 2N7002 SYMBOL cap 160 448 R180 WINDOW 0 24 56 Left 2 WINDOW 3 24 8 Left 2 SYMATTR InstName C2 SYMATTR Value 4.7µF SYMBOL schottky 16 176 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D1 SYMATTR Value 1N5817 SYMATTR Description Diode SYMATTR Type diode SYMBOL pnp -240 -128 M180 SYMATTR InstName Q1 SYMATTR Value 2N2907 SYMBOL Comparators\\LT1018 288 416 M0 SYMATTR InstName U1 SYMBOL diode 560 576 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 98 Left 2 SYMATTR InstName D3 SYMATTR Value 1N4148 SYMBOL res 1056 464 R0 SYMATTR InstName R3 SYMATTR Value 4.7k SYMBOL res 608 496 R0 SYMATTR InstName R4 SYMATTR Value 4.7k SYMBOL res -464 512 R0 SYMATTR InstName R5 SYMATTR Value 100 SYMBOL PowerProducts\\LT3080 864 320 R0 SYMATTR InstName U3 SYMBOL zener 880 576 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D5 SYMATTR Value BZX84C15L SYMBOL cap 320 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3 SYMATTR Value 470p SYMBOL cap -96 144 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 4.7µF SYMBOL njf -288 -224 R90 SYMATTR InstName J1 SYMATTR Value 2N4338 SYMBOL res -400 -192 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10k SYMBOL zener 448 304 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D4 SYMATTR Value DFLZ33 TEXT -776 712 Left 2 !.tran 0 10 0 10u startup TEXT -768 680 Left 2 !K L1 L2 L3 L4 0.99 TEXT 1032 280 Left 2 ;RLOAD TEXT -432 -56 Left 2 ;ADSL XFRMR

Reply to
bitrex
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On 9/24/2013 5:49 AM, bitrex wrote:

This version gets rid of the linear regulator: simpler and more efficient:

Version 4 SHEET 1 2020 852 WIRE -176 -384 -624 -384 WIRE 816 -384 -176 -384 WIRE -352 -272 -560 -272 WIRE -352 -224 -352 -272 WIRE -176 -224 -176 -384 WIRE -560 -176 -560 -272 WIRE -496 -176 -560 -176 WIRE -384 -176 -416 -176 WIRE -240 -176 -288 -176 WIRE -624 0 -624 -384 WIRE -496 0 -624 0 WIRE -384 0 -416 0 WIRE -288 0 -336 0 WIRE -176 0 -176 -128 WIRE -176 0 -208 0 WIRE 176 32 -32 32 WIRE 464 32 240 32 WIRE -560 160 -560 -176 WIRE -496 160 -560 160 WIRE -384 160 -336 0 WIRE -384 160 -416 160 WIRE -336 160 -384 0 WIRE -288 160 -336 160 WIRE -160 160 -208 160 WIRE -96 160 -112 160 WIRE -32 160 -32 32 WIRE -32 160 -96 160 WIRE 16 160 -32 160 WIRE 144 160 80 160 WIRE 288 160 144 160 WIRE 544 160 288 160 WIRE 640 160 544 160 WIRE 816 176 816 -384 WIRE 816 176 736 176 WIRE -384 240 -384 160 WIRE 544 256 544 160 WIRE 816 288 816 176 WIRE -336 352 -336 160 WIRE -32 384 -32 160 WIRE 144 384 144 160 WIRE 288 384 288 160 WIRE 640 384 640 160 WIRE 464 400 464 32 WIRE 464 400 320 400 WIRE 544 400 544 320 WIRE 544 400 464 400 WIRE 256 416 224 416 WIRE -384 432 -448 432 WIRE 368 432 320 432 WIRE 544 496 544 400 WIRE 464 512 464 400 WIRE -448 528 -448 432 WIRE -336 672 -336 448 WIRE -32 672 -32 448 WIRE 144 672 144 448 WIRE 288 672 288 448 WIRE 368 672 368 432 WIRE 464 672 464 576 WIRE 544 672 544 576 WIRE 640 672 640 464 WIRE 816 672 816 368 WIRE -448 720 -448 608 WIRE 224 720 224 416 WIRE 224 720 -448 720 FLAG 816 672 0 FLAG -336 672 0 FLAG -384 240 0 FLAG 736 176 Vin FLAG -32 672 Vin FLAG 144 672 Vin FLAG 288 672 Vin FLAG 368 672 Vin FLAG 464 672 Vin FLAG 544 672 Vin FLAG 640 672 Vin SYMBOL voltage 816 272 R0 WINDOW 123 0 0 Left 2 WINDOW 39 24 124 Left 2 SYMATTR SpiceLine Rser=0.01 SYMATTR InstName V1 SYMATTR Value 0.8 SYMBOL ind2 -512 16 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L1 SYMATTR Value 100µH SYMBOL ind2 -192 -16 R90 WINDOW 0 4 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName L2 SYMATTR Value 100µH SYMBOL ind2 -400 144 R90 WINDOW 0 4 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName L3 SYMATTR Value 100µH SYMBOL ind2 -304 176 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L4 SYMATTR Value 100µH SYMBOL schottky -16 448 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D2 SYMATTR Value 1N5817 SYMATTR Description Diode SYMATTR Type diode SYMBOL nmos -384 352 R0 SYMATTR InstName M1 SYMATTR Value 2N7002 SYMBOL cap 160 448 R180 WINDOW 0 24 56 Left 2 WINDOW 3 24 8 Left 2 SYMATTR InstName C2 SYMATTR Value 4.7µF SYMBOL schottky 16 176 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D1 SYMATTR Value 1N5817 SYMATTR Description Diode SYMATTR Type diode SYMBOL pnp -240 -128 M180 SYMATTR InstName Q1 SYMATTR Value 2N2907 SYMBOL diode 480 576 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 98 Left 2 SYMATTR InstName D3 SYMATTR Value 1N4148 SYMBOL res -464 512 R0 SYMATTR InstName R5 SYMATTR Value 100 SYMBOL cap 240 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3 SYMATTR Value 470p SYMBOL cap -96 144 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 4.7µF SYMBOL njf -288 -224 R90 SYMATTR InstName J1 SYMATTR Value 2N4338 SYMBOL res -400 -192 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10k SYMBOL Comparators\\LT1018 288 416 M0 SYMATTR InstName U1 SYMBOL res 528 480 R0 SYMATTR InstName R4 SYMATTR Value 4.7k SYMBOL res 624 368 R0 SYMATTR InstName R2 SYMATTR Value 4.7k SYMBOL zener 560 320 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D4 SYMATTR Value BZX84C15L TEXT -776 712 Left 2 !.tran 0 10 0 10u startup uic TEXT -768 680 Left 2 !K L1 L2 L3 L4 0.99 TEXT -432 -48 Left 2 ;ADSL XFRMR

Reply to
bitrex

No, this version is VERY BAD! A big problem. Even so, there should be a way to float the output so the linear regulator isn't needed. I'll work on it more.

Reply to
bitrex

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