5V to 5V regulators

TI used to make a switched cap regulator that was pretty sweet. It was good up to 100 mA or so and regulated the switches like an LDO to maintain a given output voltage. But I don't think they make it anymore.

Rick

Cap multiplier: an emitter follower where the base is supplied by RC-filtered power. Effectively, the capacitance as seen from the emitter is C 1* hFE, which improves HF performance considerably. It also acts as a reversed grounded-base amplifier, so the C-E isolation is large (only Early effect working into the equivalent emitter impedance plus additional bypass).

I recall Phil Hobbs had an application that required two or three stages. Nice part about that is, subsequent stages can be biased from the already-filtered base supply, which means an additional Vbe + Vce(sat) is not incurred, only another Vce(sat).

Tim

-- Deep Friar: a very philos>>

Oh Sorry, the cap multiplier is just a RC and transistor circuit fragment,

George H.

LDOs typically have poor ripple rejection; that's the price for regulator stability. SEPIC needs special good capacitor with low loss and sustaining high current. A transformer flyback is usually better solution.

Vladimir Vassilevsky DSP and Mixed Signal Consultant

Hey, how about this?

The max input is only 4.4, so it would need another diode or something. Too bad.

But a cheap charge-pump doubler and any good regulator would work. You could make your own doubler for about 25 cents worth of parts.

I picked it up from an audio preamp by Walt Jung, iirc--he had an a cute one that included a LED + emitter follower voltage reference. Would have been about 30 years ago, and the design is much older than that.

Cheers

Phil Hobbs

Yup. When I was in junior high school I suggested it to a guy who was doing NMR and had too much hum in his electromagnet. I think it was Vernon Cottles.

I must have picked it up from one of the electronics mags, PopTronics or the other one.

ke to feed into a LDO regulator to clean it up a bit.... but I'm not sure h ow I can do this since I would have to be consistently above 5V in order fo r the LDO to do its thing.... does anyone know a good way to do this?

I've found a part that appears to reccommend a way of doing what I'm trying to do, but I'm confused...

the part is DCP0105

the datasheet is here

on page 16 it starts talking about using an LDO after the 5V to 5V isolator

"It is possible to post regulate the 5VOUT DCP0105 and still guarantee a mi nimum VOUT of 4.75V. This still gives the benefits of isolation in reducing the power supply noise to 5V digital circuitry."

I don't understand what they mean... guarantee Vout of 4.75V? That's terrib le... that's 0.25V away from 5V.... are they talking about something else? I thought adding a post regulator requires a higher votlage than 5V at th e input of the regulator and that the point is to have the 5V LDO provide a nice clean 5V at its output.... will this do that?

thanks!

to feed into a LDO regulator to clean it up a bit.... but I'm not sure how I can do this since I would have to be consistently above 5V in order for the LDO to do its thing.... does anyone know a good way to do this?

do, but I'm confused...

minimum VOUT of 4.75V. This still gives the benefits of isolation in reducing the power supply noise to 5V digital circuitry."

terrible... that's 0.25V away from 5V.... are they talking about something else? I thought adding a post regulator requires a higher votlage than 5V at the input of the regulator and that the point is to have the 5V LDO provide a nice clean 5V at its output.... will this do that?

You could buy a little CUI/Murata SIP dc/dc converter, say 5 to 12 volts, and regulate after that. Or get a 5 to 3.3 dc/dc and stack the output on the input to get 8.3, and linear regulate that. The SIPs are cheap and easy to use.

Or make a charge pump booster, cheap in production and more fun.

like to feed into a LDO regulator to clean it up a bit.... but I'm not sur e how I can do this since I would have to be consistently above 5V in order for the LDO to do its thing.... does anyone know a good way to do this?

ing to do, but I'm confused...

tor

minimum VOUT of 4.75V. This still gives the benefits of isolation in reduc ing the power supply noise to 5V digital circuitry."

rible... that's 0.25V away from 5V.... are they talking about something el se? I thought adding a post regulator requires a higher votlage than 5V at the input of the regulator and that the point is to have the 5V LDO provid e a nice clean 5V at its output.... will this do that?

much thanks for all the replies, this is the solution I'm going with, I'm g oing to end up just boosting up the voltage and then regulating after that

On Wed, 16 Jan 2013 08:17:26 -0800 (PST), panfilero wrote:

to end up just boosting up the voltage and then regulating after that

--- Version 4 SHEET 1 2232 1228 WIRE 1040 -192 688 -192 WIRE 720 -128 416 -128 WIRE 1088 -128 720 -128 WIRE 1280 -128 1088 -128 WIRE 560 -48 512 -48 WIRE 720 -48 720 -128 WIRE 720 -48 640 -48 WIRE 752 -48 720 -48 WIRE 1136 -48 976 -48 WIRE 1280 -32 1280 -128 WIRE 416 0 416 -128 WIRE 512 16 512 -48 WIRE 752 16 512 16 WIRE 1040 16 1040 -192 WIRE 1040 16 976 16 WIRE 512 80 512 16 WIRE 560 80 512 80 WIRE 688 80 688 -192 WIRE 688 80 640 80 WIRE 752 80 688 80 WIRE 1168 80 976 80 WIRE 1280 80 1280 32 WIRE 1280 80 1232 80 WIRE 1328 80 1280 80 WIRE 1440 80 1392 80 WIRE 1504 80 1440 80 WIRE 1552 80 1504 80 WIRE 1872 80 1840 80 WIRE 1936 80 1872 80 WIRE 2064 80 1936 80 WIRE 2064 112 2064 80 WIRE 688 128 688 80 WIRE 1440 128 1440 80 WIRE 1936 128 1936 80 WIRE 1088 144 1088 -128 WIRE 1088 144 976 144 WIRE 1504 176 1504 80 WIRE 1552 176 1504 176 WIRE 1872 176 1872 80 WIRE 1872 176 1840 176 WIRE 416 240 416 80 WIRE 688 240 688 192 WIRE 688 240 416 240 WIRE 1136 240 1136 -48 WIRE 1136 240 688 240 WIRE 1440 240 1440 192 WIRE 1440 240 1136 240 WIRE 1936 240 1936 192 WIRE 2064 240 2064 192 WIRE 416 304 416 240 WIRE 1696 304 1696 240 FLAG 416 304 0 FLAG 2064 240 0 FLAG 1696 304 0 FLAG 1936 240 0 SYMBOL Misc\\NE555 864 48 M0 SYMATTR InstName U2 SYMBOL voltage 416 -16 M0 WINDOW 123 0 0 Left 2 SYMATTR SpiceLine Rser=0 SYMATTR InstName V1 SYMATTR Value 4.5 SYMBOL cap 704 128 M0 SYMATTR InstName C4 SYMATTR Value 1n SYMBOL res 544 -64 M90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 1000 SYMBOL res 544 64 M90 WINDOW 0 65 55 VBottom 2 WINDOW 3 68 58 VTop 2 SYMATTR InstName R5 SYMATTR Value 10k SYMBOL cap 1232 64 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C5 SYMATTR Value 1µ SYMBOL diode 1296 -32 M0 WINDOW 0 -50 -3 Left 2 WINDOW 3 -86 31 Left 2 SYMATTR InstName D3 SYMATTR Value 1N4148 SYMBOL diode 1328 64 M90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D4 SYMATTR Value 1N4148 SYMBOL cap 1456 128 M0 WINDOW 0 53 38 Left 2 WINDOW 3 45 67 Left 2 SYMATTR InstName C6 SYMATTR Value 10µ SYMBOL res 2080 96 M0 SYMATTR InstName R7 SYMATTR Value 220 SYMBOL PowerProducts\\LT3010-5 1696 128 R0 SYMATTR InstName U1 SYMBOL cap 1920 128 R0 SYMATTR InstName C1 SYMATTR Value 1µ TEXT 426 264 Left 2 !.tran .02

-- JF

On Sat, 19 Jan 2013 08:33:05 -0600, John Fields wrote:

going to end up just boosting up the voltage and then regulating after that

--- If you've got a few gates lying around...

Version 4 SHEET 1 1300 680 WIRE -336 -320 -496 -320 WIRE 160 -320 -336 -320 WIRE -336 -304 -336 -320 WIRE 160 -272 160 -320 WIRE -496 -256 -496 -320 WIRE -336 -224 -336 -240 WIRE -288 -224 -336 -224 WIRE -128 -224 -288 -224 WIRE 16 -224 -128 -224 WIRE -336 -208 -336 -224 WIRE -128 -192 -128 -224 WIRE 16 -192 16 -224 WIRE -496 -128 -496 -176 WIRE -336 -128 -336 -144 WIRE -288 -80 -288 -224 WIRE -240 -80 -288 -80 WIRE -128 -80 -128 -112 WIRE -128 -80 -176 -80 WIRE -112 -80 -128 -80 WIRE -80 -80 -112 -80 WIRE 0 -80 -16 -80 WIRE 16 -80 16 -128 WIRE 16 -80 0 -80 WIRE 64 -80 16 -80 WIRE 160 -80 160 -208 WIRE 160 -80 128 -80 WIRE 192 -80 160 -80 WIRE 288 -80 256 -80 WIRE 368 -80 288 -80 WIRE 416 -80 368 -80 WIRE 736 -80 704 -80 WIRE 800 -80 736 -80 WIRE 928 -80 800 -80 WIRE 928 -48 928 -80 WIRE 288 -32 288 -80 WIRE 800 -32 800 -80 WIRE -112 0 -112 -80 WIRE -80 0 -112 0 WIRE 0 0 0 -80 WIRE 0 0 -16 0 WIRE 368 16 368 -80 WIRE 416 16 368 16 WIRE 736 16 736 -80 WIRE 736 16 704 16 WIRE 800 80 800 32 WIRE 928 80 928 32 WIRE 288 128 288 32 WIRE 560 144 560 80 FLAG -496 -128 0 FLAG -336 -128 0 FLAG 288 128 0 FLAG 928 80 0 FLAG 560 144 0 FLAG 800 80 0 SYMBOL res -112 -96 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R1 SYMATTR Value 10k SYMBOL cap 32 -128 R180 WINDOW 0 24 56 Left 2 WINDOW 3 24 8 Left 2 SYMATTR InstName C1 SYMATTR Value 10n SYMBOL voltage -496 -272 R0 WINDOW 3 24 104 Invisible 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 WINDOW 0 10 105 Left 2 SYMATTR Value 4.5 SYMATTR InstName V1 SYMBOL schottky -320 -240 R180 WINDOW 0 45 36 Left 2 WINDOW 3 42 8 Left 2 SYMATTR InstName D1 SYMATTR Value BAT54 SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 128 -96 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 10µ SYMBOL cap 304 32 R180 WINDOW 0 24 56 Left 2 WINDOW 3 24 8 Left 2 SYMATTR InstName C3 SYMATTR Value 100µ SYMBOL Digital\\inv -240 -144 R0 WINDOW 3 8 104 Invisible 2 SYMATTR Value Vhigh 5v trise 10n tfall 120n SYMATTR InstName A3 SYMBOL Digital\\inv -80 -144 R0 WINDOW 3 8 104 Invisible 2 SYMATTR Value Vhigh 5v trise 10n tfall 120n SYMATTR InstName A1 SYMBOL schottky -320 -144 R180 WINDOW 0 45 36 Left 2 WINDOW 3 42 8 Left 2 SYMATTR InstName D2 SYMATTR Value BAT54 SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 144 -272 R0 SYMATTR InstName D3 SYMATTR Value BAT54 SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 192 -64 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D4 SYMATTR Value BAT54 SYMATTR Description Diode SYMATTR Type diode SYMBOL Digital\\inv -80 -64 R0 WINDOW 3 8 104 Invisible 2 SYMATTR Value Vhigh 5v trise 10n tfall 120n SYMATTR InstName A2 SYMBOL res 944 -64 M0 SYMATTR InstName R3 SYMATTR Value 220 SYMBOL PowerProducts\\LT3010-5 560 -32 R0 SYMATTR InstName U1 SYMBOL cap 784 -32 R0 SYMATTR InstName C4 SYMATTR Value 1µ TEXT -480 -104 Left 2 !.tran .1 uic

-- JF

going to end up just boosting up the voltage and then regulating after that

That can be simplified a bit...

If there's a clock available, like a spare uP PWM or something, you could use a single HC4053 and a couple of caps to make a charge pump with no diodes.

going to end up just boosting up the voltage and then regulating after that

going to end up just boosting up the voltage and then regulating after that

It doesn't really need additional capacitance. That circuit will oscillate fine. The frequency doesn't much matter. The resistor will be ballpark 1M maybe.

If it has enough drive, yes.

going to end up just boosting up the voltage and then regulating after that

You should try a 3 phase version of that going into a single DC node point. It gives a nice DC output.

Jamie

going to end up just boosting up the voltage and then regulating after that

Yeah, like a polyphase buck switcher.

(Which I invented. As did lots of other people.)

going to end up just boosting up the voltage and then regulating after that

Where I come from, there is only one inventor and many copy cats.

Of course, if you talk to a lawyer, they may have a different view of things.:) Jamie

going to end up just boosting up the voltage and then regulating after that

use a

What if the cats didn't copy anyone?

There's a statement!