Re: [time-nuts] Power supply for OCXO using "USB power blocks"
At 07:38 PM 3/9/2019, jimlux wrote: Has anyone tried a +5V to +15V DC/DC to run an OCXO, getting the 5V from one of those rechargeable USB power bricks. I was thinking about portable operation. My USB power bricks shut off the 5 V output if there's not enough load. Something to watch for. -- newell N5TNL ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Power supply for OCXO using "USB power blocks"
Let me try it. I have a few of those 5V USB power supply. I have on my desk, DC/DC converter that will take whatever to whatever. Got a dozen from Amazon. I'll set it to 12V. I'm sure it will work in some fashion. I've used unknown power supply (switching type) for various things, and I have yet to see it in any meaningful way in output. But, measure it well enough, I'm sure it is there. I'm also interested in re-using those laptop power supplies. Only problem is, each one is SO different. My result won't apply to you or anyone else. A few months ago, Apple actually did a recall on counterfeit products. I think a person died or house burned down or something of that nature of what was supposed to be a genuine product - except it was not. An amazing response from Apple. But, I'm curious enough now. I'll try apple kind and generic kind. What shall I look for? Load it up to say 100mA and measure voltage and ripple? I wonder if I should put DC de-coupling and put it though an audio frequency FFT? I'd expect NOT to see 60Hz anywhere but probably few 100KHz. I will report back in few days. --- (Mr.) Taka Kamiya I'm stuck in a wormhole Hello, worms! On Sunday, March 10, 2019, 7:00:12 PM EDT, jimlux wrote: On 3/10/19 12:07 PM, Achim Gratz wrote: > jimlux writes: >> How quiet is the output from those USB battery things..I've used one >> to run a RTL-SDR, but that's hardly a ultimate low noise receiver. > > Depends, but I suspect that most of them favor cheap over quiet -- they > do already have a DC-DC in there that gets whatever the accumulator > voltage is to 5V. I also have one of these that is really noisy when it > has no load, but seems to be OK when I start pulling a few mA. > > Plus, chaining DC-DC like you outline really isn't helping efficiency > wise. Unless you already have a bunch of USB power banks you want to > reuse (I'd still think about just using the cells then), perhaps have a > look at some of the stuff that the RC model crowd is using. it was the idea of reuse of the ubiquitous USB 5V sources, whether line powered or battery powered. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Power supply for OCXO using "USB power blocks"
Jim said: The question is really more one of "how much filtering do I need to design into the downstream power supply circuits" The answer of course depends on the source and receiver of the noise. Common USB type systems and accessories are built to maximize cheapness, pass EMC testing well enough to get by, be small, and provide the required power. The normal-mode ripple and noise can be made as good as necessary with enough filtering and active regulation, at one point of use. The bigger problem is the common-mode signals that permeate everything. If you're using a compact, battery-powered SMPS to run your OCXO, then you can take advantage of the situation by "canning it up," as I always say. Don't have a bunch of cords and cables and wallwarts going all over the place - everything will carry some common-mode current and make a mess. If you package up the battery/power supply unit along with the OCXO inside of a metal case that more or less completely encloses it, then it will be very much easier to get control of the C-M currents within the box, and make them nearly invisible outside the box. Picture a metal box with the proper guts inside, and say, the outside sports a BNC 10 MHz out, a power switch, maybe some indicator lights, and a charging port. All the action inside can be well hidden from the outside, and the desired output signal will have one ground reference point. During charging, there will be another C-M current issue due to connection to the port, so the EMC performance will be degraded somewhat. But, that can be improved internally too, because the system is mostly canned up. Ed ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Power supply for OCXO using "USB power blocks"
Hi Part of the problem is radiated / mag coupled spur energy. One of the things that makes the fancier switchers more friendly is that they can contain this better. Bob > On Mar 10, 2019, at 12:10 PM, jimlux wrote: > > On 3/10/19 8:58 AM, Richard (Rick) Karlquist wrote: >> Check out the LT3045-1. > Ive used the LT3042 in a space application, it is basically the same thing > with lower output current. The really great thing is that the rejection > extends up to 10 MHz. > > > > It is an ultra low noise (2nv) linear >> regulator with very high PSRR that has a 1 MHz bandwidth. >> The -1 version can control an external switcher (or linear) >> regulator ahead of it, where the voltage drop across the >> LT3045-1 can be set to, say 1V, and the front end supply >> output voltage automatically is 1V above the LT3045-1 >> output voltage. > > I didn't know about the -1 version.. I'll have to take a look. > > > > It has 120 dB PSRR at 120 Hz. You >> can buy an eval board for it. Multiple LT3045's can be >> paralleled for additional current handling. If the switcher >> is of the isolated type, you have galvanic isolation for >> the ultimate OCXO performance. >> I think the vendor really got this right. > > Yes, indeed > > > So my notional "run noise sensitive electronics from ubiquitous 5V USB" is > "5V to TBD V boost converter (in a module from someone like Cui, most > likely)" followed by a LT304X. > > I will have to look into the "LT3045-1 feeds back a control signal".. > > And as Bob notes - layout is critical (isn't it always) - but I must confess, > the first one's going to be haywired with double stick foam tape for mounting. > > > >> Rick N6RK > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Power supply for OCXO using "USB power blocks"
On 3/10/19 8:58 AM, Richard (Rick) Karlquist wrote: Check out the LT3045-1. Ive used the LT3042 in a space application, it is basically the same thing with lower output current. The really great thing is that the rejection extends up to 10 MHz. It is an ultra low noise (2nv) linear regulator with very high PSRR that has a 1 MHz bandwidth. The -1 version can control an external switcher (or linear) regulator ahead of it, where the voltage drop across the LT3045-1 can be set to, say 1V, and the front end supply output voltage automatically is 1V above the LT3045-1 output voltage. I didn't know about the -1 version.. I'll have to take a look. It has 120 dB PSRR at 120 Hz. You can buy an eval board for it. Multiple LT3045's can be paralleled for additional current handling. If the switcher is of the isolated type, you have galvanic isolation for the ultimate OCXO performance. I think the vendor really got this right. Yes, indeed So my notional "run noise sensitive electronics from ubiquitous 5V USB" is "5V to TBD V boost converter (in a module from someone like Cui, most likely)" followed by a LT304X. I will have to look into the "LT3045-1 feeds back a control signal".. And as Bob notes - layout is critical (isn't it always) - but I must confess, the first one's going to be haywired with double stick foam tape for mounting. Rick N6RK ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Power supply for OCXO using "USB power blocks"
Am 10.03.19 um 15:54 schrieb jimlux: True.. but there are a plethora of the USB 5V power blocks around - in general, there are lots of USB 5V (noisy, I'm sure), e.g. Cars now have 5V USB jacks, so I was thinking about designing with that in mind. The question is really more one of "how much filtering do I need to design into the downstream power supply circuits" It should not be too hard since there are no ground loops involved. < https://www.flickr.com/photos/137684711@N07/39972841815/in/album-72157662535945536/ > The squares on the paper are 5mm. Noise density is better than 1nV / rtHz above 100 Hz. You definitely need a fuse. Ishort is >> 30A. BTW, the next picture to the left is the noise of 2 cells = 8Vdc. 14 dB below 1 nV. The steep rise below 30Hz is the too small coupling capacitor. for all practical purposes any legitimate 18650 sized Li-ion cell is around 3.5 Ah. yes. the really good ones. (who thinks about using a dozen of these for portable EME tests on 432 :-) ) You're going to run your kilowatt amp off 36 cells in series? Why not.. No, 100W from a GaN FET at 48V and <= 10 element antenna is more than enough. The rest is mostly a Dell XPS13 notebook and a Red Pitaya + up/down converter. Lunchbox size. < https://www.redpitaya.com/ > It is easy when your partner station looks like this: < http://dl7apv.darc.de/Neue%20Antennen/Neue%20Antennen.htm > To be more on-topic, two Red Pitayas can be synced and should easily provide the hardware for a Timepod work-alike. That would be 4 125 MSPS 14 Bit ADC channels, two FPGAs and ARMs with Linux and web server. (and with dual use as VNA, Bode plotter, signal generator...) regards, Gerhard ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Power supply for OCXO using "USB power blocks"
Check out the LT3045-1. It is an ultra low noise (2nv) linear regulator with very high PSRR that has a 1 MHz bandwidth. The -1 version can control an external switcher (or linear) regulator ahead of it, where the voltage drop across the LT3045-1 can be set to, say 1V, and the front end supply output voltage automatically is 1V above the LT3045-1 output voltage. It has 120 dB PSRR at 120 Hz. You can buy an eval board for it. Multiple LT3045's can be paralleled for additional current handling. If the switcher is of the isolated type, you have galvanic isolation for the ultimate OCXO performance. I think the vendor really got this right. Rick N6RK ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Power supply for OCXO using "USB power blocks"
Hi If you use the typical eBay units, they have a *lot* of noise. There are devices like the Linear Tech “switchers on a chip” ( = Silent Switcher) modules that can be quieted down pretty well. You needed a good board layout to do it though. They claim to have reduced that problem with the latest versions. Bob From: jimlux Sent: Saturday, March 9, 2019 9:00 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Power supply for OCXO using "USB power blocks" Has anyone tried a +5V to +15V DC/DC to run an OCXO, getting the 5V from one of those rechargeable USB power bricks. I was thinking about portable operation. In my case, the OCXO is something like a Wenzel streamline. I would think that the DC/DC probably has some noise, but maybe DC/DC to a higher voltage, then a good linear regulator to clean it up (or would the radiated noise just leak around). How quiet is the output from those USB battery things..I've used one to run a RTL-SDR, but that's hardly a ultimate low noise receiver. jim ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Power supply for OCXO using "USB power blocks"
On 3/9/19 7:42 PM, Gerhard Hoffmann wrote: Am 10.03.19 um 01:38 schrieb jimlux: Has anyone tried a +5V to +15V DC/DC to run an OCXO, getting the 5V from one of those rechargeable USB power bricks. I was thinking about portable operation. In my case, the OCXO is something like a Wenzel streamline. I would think that the DC/DC probably has some noise, but maybe DC/DC to a higher voltage, then a good linear regulator to clean it up (or would the radiated noise just leak around). How quiet is the output from those USB battery things..I've used one to run a RTL-SDR, but that's hardly a ultimate low noise receiver. That's impossible to predict. These boxes normally contain one Lithium cell and a DC/DC converter to 5V. Its output noise depends on the skill of the designer and the mood of the bean counter. It is probably not a high priority. Also, there my be "effects" from the interaction of their switcher and your's. And the efficiencies multiply. BUT: 3 of these Li cells deliver 12V in ultimate quality: True.. but there are a plethora of the USB 5V power blocks around - in general, there are lots of USB 5V (noisy, I'm sure), e.g. Cars now have 5V USB jacks, so I was thinking about designing with that in mind. The question is really more one of "how much filtering do I need to design into the downstream power supply circuits" < https://www.flickr.com/photos/137684711@N07/39972841815/in/album-72157662535945536/ > The squares on the paper are 5mm. Noise density is better than 1nV / rtHz above 100 Hz. You definitely need a fuse. Ishort is >> 30A. Oh ho.. yes, as long as you stay with cylindrical cells.. if you go to pouch cells, they can catch fire internally with no load needing to be attached. We had a bit of excitement on lab a couple summers ago, luridly captured in this nice headline from the Daily Mail "Nasa reveals shocking video of secretive military 'RoboSimian' EXPLODING as its batteries catch fire" (I *am* disappointed that they didn't work aliens into it somehow) Or from everyone's favorite, RT: "Shocking video shows NASA military robot exploding due to battery failure" https://media.wired.com/photos/5926a837cfe0d93c47430f84/master/w_582,c_limit/robot-explosion.gif This Panasonic type is OK. There are lots of others on the market that claim twice the power capacity but it's a blatant lie. for all practical purposes any legitimate 18650 sized Li-ion cell is around 3.5 Ah. regards, Gerhard (who thinks about using a dozen of these for portable EME tests on 432 :-) ) You're going to run your kilowatt amp off 36 cells in series? Why not.. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Power supply for OCXO using "USB power blocks"
Nortel GPTM operates on 24 or 48V DC. Internally, there is a step down dc/dc converter and 3 terminal regulators. It creates whatever it needs internally. So it can be done. It does have quite a bit of filtering though. I have run Oven oscillators with a regular cheap switcher. Spec says ripple is 150mV p-p. I really didn't have problems using it as a reference clock. If I were to multiply it to GHz range, it would likely not work. According to spec for Wenzel Streamline, it says 15V or 12V 2.2 watts. Warm up is 5 watts at 5 minutes. Seem like one can simply get 12V battery of sufficient capacity and run with that. If I were to consider a portable operation, I would rather have gell cell batteries. It's a simple and proven technology with no catastrophic failures. I would also have it large enough so it can be started ahead of time and keep it running. --- (Mr.) Taka Kamiya I'm stuck in a wormhole Hello, worms! On Saturday, March 9, 2019, 11:03:45 PM EST, Gerhard Hoffmann wrote: Am 10.03.19 um 01:38 schrieb jimlux: > Has anyone tried a +5V to +15V DC/DC to run an OCXO, getting the 5V > from one of those rechargeable USB power bricks. I was thinking about > portable operation. > > In my case, the OCXO is something like a Wenzel streamline. I would > think that the DC/DC probably has some noise, but maybe DC/DC to a > higher voltage, then a good linear regulator to clean it up (or would > the radiated noise just leak around). > > How quiet is the output from those USB battery things..I've used one > to run a RTL-SDR, but that's hardly a ultimate low noise receiver. > That's impossible to predict. These boxes normally contain one Lithium cell and a DC/DC converter to 5V. Its output noise depends on the skill of the designer and the mood of the bean counter. It is probably not a high priority. Also, there my be "effects" from the interaction of their switcher and your's. And the efficiencies multiply. BUT: 3 of these Li cells deliver 12V in ultimate quality: < https://www.flickr.com/photos/137684711@N07/39972841815/in/album-72157662535945536/ > The squares on the paper are 5mm. Noise density is better than 1nV / rtHz above 100 Hz. You definitely need a fuse. Ishort is >> 30A. This Panasonic type is OK. There are lots of others on the market that claim twice the power capacity but it's a blatant lie. regards, Gerhard (who thinks about using a dozen of these for portable EME tests on 432 :-) ) ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Power supply for OCXO using "USB power blocks"
Am 10.03.19 um 01:38 schrieb jimlux: Has anyone tried a +5V to +15V DC/DC to run an OCXO, getting the 5V from one of those rechargeable USB power bricks. I was thinking about portable operation. In my case, the OCXO is something like a Wenzel streamline. I would think that the DC/DC probably has some noise, but maybe DC/DC to a higher voltage, then a good linear regulator to clean it up (or would the radiated noise just leak around). How quiet is the output from those USB battery things..I've used one to run a RTL-SDR, but that's hardly a ultimate low noise receiver. That's impossible to predict. These boxes normally contain one Lithium cell and a DC/DC converter to 5V. Its output noise depends on the skill of the designer and the mood of the bean counter. It is probably not a high priority. Also, there my be "effects" from the interaction of their switcher and your's. And the efficiencies multiply. BUT: 3 of these Li cells deliver 12V in ultimate quality: < https://www.flickr.com/photos/137684711@N07/39972841815/in/album-72157662535945536/ > The squares on the paper are 5mm. Noise density is better than 1nV / rtHz above 100 Hz. You definitely need a fuse. Ishort is >> 30A. This Panasonic type is OK. There are lots of others on the market that claim twice the power capacity but it's a blatant lie. regards, Gerhard (who thinks about using a dozen of these for portable EME tests on 432 :-) ) ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Power supply for OCXO using "USB power blocks"
Usually they are very noisy, with the noise rising rapidly with load current. goughlui.com, lygte-info.dk, and a few others have published some tests. I think bigclive has also done some tests. -- > How quiet is the output from those USB battery things..I've used one to run a RTL-SDR, but that's hardly a ultimate low noise receiver. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Power supply for OCXO using "USB power blocks"
Has anyone tried a +5V to +15V DC/DC to run an OCXO, getting the 5V from one of those rechargeable USB power bricks. I was thinking about portable operation. In my case, the OCXO is something like a Wenzel streamline. I would think that the DC/DC probably has some noise, but maybe DC/DC to a higher voltage, then a good linear regulator to clean it up (or would the radiated noise just leak around). How quiet is the output from those USB battery things..I've used one to run a RTL-SDR, but that's hardly a ultimate low noise receiver. jim ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
