Forums

series input parallel output SMPS

Started by bitrex March 29, 2018
Well I am the head n----r rigger (don't tell Black people I said that, it is like hitting below the belt) and the King of clip leads, so...

Is there a drive optimization network on board you can modify for the new chopper ? If so, great. If it runs directly off the IC or whatever then you have to choose the replacement with much care. If these things are used/surplus there are probably better transistors available now, but don't spend the rent on them. Heat might be a problem, that is why switching is so important. I've seen 100 watt class D amps with  NO heatsinking except the foil on the board. So this is doable. 

That brings up the question of load variation, is it going to drive a motor ? Can the rotor be locked under certain conditions ? I'm sure you can do the modifications to the current limiting, or putit in, but it still has to do its job. 

If the rectifiers won't make it replace them of course. If you deem extra filtering to be necessary just put it on the outside. Much easier and allows you to use a better quality cap. As big as you want. 

Just some recommendations from an old gizmawhatchit builder. My latest project is almost silly. I wanted a remote control tester. I know they have IR cards but fuck all that. So I took and cut the board from the front of an old VCR and a part of a board from a TV with the standby supply. Put them together with solder and silicone goop, put in a regulator and a buffer for a light bulb, and have an output for a scope or use as a remote extender.

I know I know, I have too much time on my hands. Wanna gimme a job ? 

Anyway, there is another advantage to modding them, you get twice as many as you would running them in pairs, even if that got figured out. 

Have fun. I would.
On Thu, 29 Mar 2018 09:20:28 -0400, bitrex
<bitrex@de.lete.earthlink.net> wrote:

>I have a bunch of small 12 volt input ATX SMPS power modules each rated >for 120 watts. about 14 bux each, surplus. Fanless 200 watt modules are >harder to come by and significantly more expensive. > >I'd like to slave two together to get ~200 watts out, with the inputs in >series. 24 volt 8 amp power bricks are pretty common. > >I found this whitepaper on voltage balancing SMPS inputs in series but >it seems more applicable to from-scratch designs. > ><http://www.deltartp.com/dpel/dpelconferencepapers/apec11_yj.pdf> > >Got any suggestions?
Doing it right will cost you less than the cost of the lab clean-up after the fire ;-) ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Understanding is a fountain of life to one who has it, But the instruction of fools is folly. Proverbs 16:22
On Sat, 31 Mar 2018 10:55:44 -0700 (PDT), tabbypurr@gmail.com wrote:

>On Saturday, 31 March 2018 15:41:27 UTC+1, k...@notreal.com wrote: >> On Sat, 31 Mar 2018 11:38:07 +0300, Tauno Voipio >> <tauno.voipio@notused.fi.invalid> wrote: >> >On 30.3.18 23:13, Jon Elson wrote: >> >> George Herold wrote: >> >>> On Thursday, March 29, 2018 at 3:04:18 PM UTC-4, Jon Elson wrote: >> >>>> bitrex wrote: >> >>>> >> >>>>> I have a bunch of small 12 volt input ATX SMPS power modules each rated >> >>>>> for 120 watts. about 14 bux each, surplus. Fanless 200 watt modules are >> >>>>> harder to come by and significantly more expensive. >> >>>>> >> >>>>> I'd like to slave two together to get ~200 watts out, with the inputs >> >>>>> in series. 24 volt 8 amp power bricks are pretty common. >> >>>>> >> >>>>> I found this whitepaper on voltage balancing SMPS inputs in series but >> >>>>> it seems more applicable to from-scratch designs. >> >>>>> >> >>>> Nope, won't work. Paralleled outputs will likely not current share, one >> >>>> will put out limit current, the other will pick up the remaining current >> >>>> demand. So, with delivered power not being shared equally, the voltage >> >>>> drop across the supplies will be different, but in series the input >> >>>> current MUST >> >>>> be the same. So, the one carrying less output current will have less >> >>>> voltage drop, and it will increase until the other unit is starved for >> >>>> voltage. It will be totally unstable, and the supplies will be pulsing >> >>>> on and off. >> >>>> >> >>>> Jon >> >>> >> >>> I've done it with bench power supplies. (individual adjustments >> >>> for voltage and current.) I never thought much about it but it's >> >>> worked fine the few times I've needed more current. I see bitrex >> >>> is asking about DC-DC converters, which may behave differently. >> >>> >> >> >> >> Sure, paralleling the OUTPUTS of well-behaved supplies should work fine. >> >> Paralleling the inputs to DC-DC supplies should also work. The OP wants to >> >> parallel the outputs and SERIES the inputs! As far as I can see, that can >> >> NEVER work in the real world. >> >> >> >> Jon >> > >> > >> > >> >A good switcher behaves as a negative resistance load to the input. >> >Putting two of them in series will create interesting effects, for sure. >> >It will not work, even with isolated supplies. >> >> There is no problem as long as you have adequate (input) capacitance >> between them. We do it all the time (by the millions). Galvanic >> isolation has nothing to do with it. > >I sure am curious what mass market appliance contains switchers in series
Sorry, I was confusing this thread (didn't notice the subject jump) for the one where JL and I were discussing heterodyning SMPSs. "Nevermind!"
On 03/31/2018 08:18 PM, jurb6006@gmail.com wrote:
> Well I am the head n----r rigger (don't tell Black people I said that, it is like hitting below the belt) and the King of clip leads, so... > > Is there a drive optimization network on board you can modify for the new chopper ? If so, great. If it runs directly off the IC or whatever then you have to choose the replacement with much care. If these things are used/surplus there are probably better transistors available now, but don't spend the rent on them. Heat might be a problem, that is why switching is so important. I've seen 100 watt class D amps with NO heatsinking except the foil on the board. So this is doable. > > That brings up the question of load variation, is it going to drive a motor ? Can the rotor be locked under certain conditions ? I'm sure you can do the modifications to the current limiting, or putit in, but it still has to do its job.
No moving parts, just need to run a 95 watt max dissipation processor in a very tight enclosure. Disk drive will be solid state. But 120 limit doesn't leave much headroom for the rest of the hardware when it's running flat out, I'll likely need another 30-40 overhead for the small GPU in the expansion slot and a few tens more for the mobo and drive etc. You basically just need all that power to dump it right back out into space via a hefty heatsinking system but that's the way it is...
> If the rectifiers won't make it replace them of course. If you deem extra filtering to be necessary just put it on the outside. Much easier and allows you to use a better quality cap. As big as you want. > > Just some recommendations from an old gizmawhatchit builder. My latest project is almost silly. I wanted a remote control tester. I know they have IR cards but fuck all that. So I took and cut the board from the front of an old VCR and a part of a board from a TV with the standby supply. Put them together with solder and silicone goop, put in a regulator and a buffer for a light bulb, and have an output for a scope or use as a remote extender. > > I know I know, I have too much time on my hands. Wanna gimme a job ?
You interested in relocating to Massachusetts? Not sure it'd be a good, ah, "cultural fit."
> Anyway, there is another advantage to modding them, you get twice as many as you would running them in pairs, even if that got figured out. > > Have fun. I would. >
On 03/31/2018 08:38 PM, Jim Thompson wrote:
> On Thu, 29 Mar 2018 09:20:28 -0400, bitrex > <bitrex@de.lete.earthlink.net> wrote: > >> I have a bunch of small 12 volt input ATX SMPS power modules each rated >> for 120 watts. about 14 bux each, surplus. Fanless 200 watt modules are >> harder to come by and significantly more expensive. >> >> I'd like to slave two together to get ~200 watts out, with the inputs in >> series. 24 volt 8 amp power bricks are pretty common. >> >> I found this whitepaper on voltage balancing SMPS inputs in series but >> it seems more applicable to from-scratch designs. >> >> <http://www.deltartp.com/dpel/dpelconferencepapers/apec11_yj.pdf> >> >> Got any suggestions? > > Doing it right will cost you less than the cost of the lab clean-up > after the fire ;-) > > ...Jim Thompson >
Doing a calculated inductor/MOSFET/cap swap on the high current rails seems like a plausible mod, I have to wait a while for the proper unit to arrive anyway. The synchronous buck controllers for +3.3 and +12 aren't being worked particularly hard and all the power-handling components except the MOSFETs are through-hole. It won't be that big a fire, anyway.
>"You interested in relocating to Massachusetts? Not sure it'd be a good, ah, "cultural fit." "
Romneyville ? The state that had a balanced budget by raising every tax and fee possible except personal income tax ? The state where if you hold a CCW anywhere they dismantle your car if they catch you driving on their roads ? Cultural fit ? The Kennedys ? (get in the caa nigaa) I would last about five minutes and I'm White.
On 03/31/2018 11:08 PM, jurb6006@gmail.com wrote:
>> "You interested in relocating to Massachusetts? Not sure it'd be a good, ah, "cultural fit."" > > Romneyville ? The state that had a balanced budget by raising every tax and fee possible except personal income tax ? The state where if you hold a CCW anywhere they dismantle your car if they catch you driving on their roads ? > > Cultural fit ? The Kennedys ? (get in the caa nigaa) > > I would last about five minutes and I'm White. >
Yeah they tax you twice as hard but you can often get paid significantly more for the same job as compared to e.g. lots of places in the South so for many people including myself it ends up a net win. Sales tax is pretty easy to knock down by buying most essentials on Amazon and putting other expenses that you can't like gas on credit cards which dump reward points to your Amazon account. There are always companies looking for even part-time skilled electronics tech/assembly work around here though, I'm looking at about 60 open positions within 50 miles of me at BAE, Siemens, etc.
I really have no wish to work for a corporation. I do well as a big fish in a small pond. I had one job that was corporate and it felt corporate, I quit in 8 months. I has another corporate job that didn't feel corporate. I got tired of the unprofessionalism there but it wasn't so bad. 

I had a 1973 Electra 225 without a catalytic, I used to fill my tank with half premium and half unleaded on the company card and it ran like a raped ape. At the end of the day we also got beer on the company card. the boss, err manager brought in some good weed and once in a while some coke. It wasn't all that much money but I could take whatever I want and I had respect, to some extent. 

They were a rental chain, rent to own, you know. they had mainly two types of TVs the rented/sold so I not only set up jigs specifically for those, I went into their boneyard and found enough parts to put together chassis' for each. The road Man no longer had to pull the chassis and wait for it to get fixed and then take it back, I equipped him with chassis' ready to roll and he changed them and brought the bad ones in. In the next day or so I would have them fixed. Usually the same day unless they were dogs or needed parts ordered. I was worth my salt and as usual I was only out of work for a month and that was by choice. I had enough money and partied my ass off. But the money ran low and again I had a job as of the first interview. No more free gas and partying materials but the money was actually better so OK, I could live with that. At the old place I made the maximum that the budget allowed so I didn't work full time. I could work 4 days or leave early, whatever. I could also work on anything I want at their facility, including my car. It was worth it to make a bit less money there but all good things come to an end. 

I didn't mean to write an autobiography but I guess I'll let it stand. What's the worst that can happen, I get a TLDR ?
On Sun, 1 Apr 2018 01:37:13 -0400, bitrex
<bitrex@de.lete.earthlink.net> wrote:

>On 03/31/2018 11:08 PM, jurb6006@gmail.com wrote: >>> "You interested in relocating to Massachusetts? Not sure it'd be a good, ah, "cultural fit."" >> >> Romneyville ? The state that had a balanced budget by raising every tax and fee possible except personal income tax ? The state where if you hold a CCW anywhere they dismantle your car if they catch you driving on their roads ? >> >> Cultural fit ? The Kennedys ? (get in the caa nigaa) >> >> I would last about five minutes and I'm White. >> > >Yeah they tax you twice as hard but you can often get paid significantly >more for the same job as compared to e.g. lots of places in the South so >for many people including myself it ends up a net win. Sales tax is >pretty easy to knock down by buying most essentials on Amazon and >putting other expenses that you can't like gas on credit cards which >dump reward points to your Amazon account.
No, it's not a win. I've been on both sides of that fence. It's not even close. The pay in blue states is somewhat higher than red but the cost of living is fantastically higher in the blue. It's not just taxes, either, though that's huge.
> >There are always companies looking for even part-time skilled >electronics tech/assembly work around here though, I'm looking at about >60 open positions within 50 miles of me at BAE, Siemens, etc.
There are at _least_ that many around here. There are a third of that number in the little city (pop 35,000) I work in. I think my employer has at least five (maybe more, haven't checked) open reqs for engineers. No part-time, that I know of. I get emails from Glassdoor about open position in the area constantly (half dozen a day).
On 04/01/2018 09:26 AM, krw@notreal.com wrote:
> On Sun, 1 Apr 2018 01:37:13 -0400, bitrex > <bitrex@de.lete.earthlink.net> wrote: > >> On 03/31/2018 11:08 PM, jurb6006@gmail.com wrote: >>>> "You interested in relocating to Massachusetts? Not sure it'd be a good, ah, "cultural fit."" >>> >>> Romneyville ? The state that had a balanced budget by raising every tax and fee possible except personal income tax ? The state where if you hold a CCW anywhere they dismantle your car if they catch you driving on their roads ? >>> >>> Cultural fit ? The Kennedys ? (get in the caa nigaa) >>> >>> I would last about five minutes and I'm White. >>> >> >> Yeah they tax you twice as hard but you can often get paid significantly >> more for the same job as compared to e.g. lots of places in the South so >> for many people including myself it ends up a net win. Sales tax is >> pretty easy to knock down by buying most essentials on Amazon and >> putting other expenses that you can't like gas on credit cards which >> dump reward points to your Amazon account. > > No, it's not a win. I've been on both sides of that fence. It's not > even close. The pay in blue states is somewhat higher than red but > the cost of living is fantastically higher in the blue. It's not just > taxes, either, though that's huge.
It's fantastically expensive to own even a medium-sized home in the suburbs here and pay Boston-area real estate costs and property taxes and all that stuff. So don't do that, duh! Ain't no law says you have to.
>> >> There are always companies looking for even part-time skilled >> electronics tech/assembly work around here though, I'm looking at about >> 60 open positions within 50 miles of me at BAE, Siemens, etc. > > There are at _least_ that many around here. There are a third of that > number in the little city (pop 35,000) I work in. I think my employer > has at least five (maybe more, haven't checked) open reqs for > engineers. No part-time, that I know of. I get emails from Glassdoor > about open position in the area constantly (half dozen a day). >