Resources for Switching Power supplies

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naljta
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Resources for Switching Power supplies

Post by naljta » Mon Apr 21, 2003 4:04 pm

I want to build a switching power supply for the learning experience. Can anyone suggested a good website or book? The more detailed the better. <p>Thanks,
Nevin

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Edd
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Re: Resources for Switching Power supplies

Post by Edd » Mon Apr 21, 2003 8:33 pm

Nevin:
Here are some “freebies” on the Net that provide a wealth of worthwhile info.
And probably if you were to get a “freebie” used computer power supply,you could learn a lot from its components and construction.
Specific links are:
http://www.epanorama.net/links/psu.html
http://www.epanorama.net/links/psu_switching.html
http://www.hills2.u-net.com/electron/offline <p>73's de Edd
[email protected] ............(Interstellar~~~~~Warp~~Speed)
[email protected]........(Firewalled-Spam*Cookies*Crumbs)<p> ;)

skrallman
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Re: Resources for Switching Power supplies

Post by skrallman » Mon Apr 21, 2003 9:00 pm

Radio Shack has a book for about $8 called Building Power Supplies. I think it has three switching supply projects. It has a little background theory, but mostly it just gives you the equations for sizing the components. I found it very helpful, but I'm a hobbiest, not an EE.
Scott

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Re: Resources for Switching Power supplies

Post by bodgy » Mon Apr 21, 2003 10:54 pm

Toddle over to Linear Technologies website. They have a nifty program to help work out component values - mainly for their IC's of course, but they have some good info.<p>As do Natsemi and if I can find the link again Philips on their website on how to design equipment with their power Mosfets.<p>If you can find a kind soul who receives Elektor magazine (the English version), a series of discrete switcher schematics and if you're into nifty and experimentation Roman Black at http://www.romanblack.com/smps.htm has some really intersting 2 transistor designs.<p>Colin
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rshayes
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Re: Resources for Switching Power supplies

Post by rshayes » Tue Apr 22, 2003 12:01 am

Unitrode used to be a major figure in the switching power supply business. It was recently sold to Texas Instruments. I would try looking for application notes on the TI web site. They may have continued the old Unitrode application books, which were a good introduction to the subject.

rshayes
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Re: Resources for Switching Power supplies

Post by rshayes » Tue Apr 22, 2003 1:45 am

Try searching for "unitrode seminar" on the Texas Instruments web site (www.ti.com). This should direct you to about a dozen of the Unitrode seminars (sem100, etc). The earlier ones give the basic principles. The complete versions are about a 10 megabyte download each. Individual topics can also be downloaded, and I would recommend this if you are using a dial-up connection.

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Joseph
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Re: Resources for Switching Power supplies

Post by Joseph » Tue Apr 22, 2003 5:38 am

Have you seen the design which I have come up with at http://groups.yahoo.com/group/switchmode/
yet? It is the basis of all of my switching power supply projects. It is the culmination of years of R & D. If you study this design and experiment with it, you can become proficient in SMPS design theory.

Bernius1
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Re: Resources for Switching Power supplies

Post by Bernius1 » Tue Apr 22, 2003 5:55 am

Something I haven't seen mentioned on power supply posts: Can they be set-up as PWM's for variable output voltage? And, like a class-c amp, will an LC tank restore sine & dampen RF noise & voltage spikes ????
Can't we end all posts with a comical quip?

russlk
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Re: Resources for Switching Power supplies

Post by russlk » Tue Apr 22, 2003 2:19 pm

If yu want sine waves from a switching supply, check out Don Lancasters's "magic sinewaves". Don't remember the URL, but Google should find it. I built a simple one using a Basic Stamp.

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Joseph
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Re: Resources for Switching Power supplies

Post by Joseph » Wed Apr 23, 2003 7:12 am

As far as reproducing sine waves, I have done some preliminary experimenting with using one of the Universal SMPS circuits I made as an audio amplifier driving an 8 ohm load and a pull down resistor. I think the pull-down resistor could be replaced with another SMPS. Then both halves of a waveform could be reproduced symmetrically. Since the circuit uses discrete components, it has the flexibility to work in a wide range of applications because there are no finicky "black box" ICs to try to finagle or placate.<p>One important consideration I have learned to always think about in driving power MOSFETS in high voltage circuits like line operated SMPSs is MOSFET gate drive. If the gate is not damped, usually by a gate series resistor, the oxide layer can be destroyed by excessive voltage swings due to oscillations caused by an internal parasitic LC tank circuit built into the MOSFET.<p>In the Universal SMPS circuit, the gate damping is accomplished not only by a series resistor, but also by the buffer MOSFET pair driving each gate. Since these buffers are configured as source-followers, they lose gain as they approach the limits of their voltage swing. This effect may be superior to even the gate series resistor in providing gate damping. But I have not done much comparison study to determine the amount of the actual benefit.<p>On the question of the LC tank circuit smoothing out the output and filtering spikes--the answer is yes. In fact, choosing the right output filter inductor can increase the efficiency of the power supply. This happens because the current drawn by the load lags the voltage transitions of the power MOSFETs, lowering switching losses. This effect can be maximized in DC output applications. Such applications should include using one SMPS to produce a positive waveform and another to produce a negative waveform.

nedtron
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Re: Resources for Switching Power supplies

Post by nedtron » Thu Apr 24, 2003 7:42 am

Sine Waves: The Exar 2206 monolithic function generator IC simultaneously produces sine, triangle, square and bipolar square waves over a frequency range of 0.1Hz to 100KHz using minimal external components (7 capacitors, 8 resistors & 4 trim potentiometers).
The Exar 2206 (XR2206), 16 pin DIP, is available from Jameco (www.jameco.com) as part # 34972CP for $3.59.
The "signal level" output of the XR2206 may be amplified to any desired level.
A function generator kit is also available from Jameco that includes the XR2206, a printed circuit board, resistors, capacitors and the trim potentiometrs.
The function generator kit is available as part # 20685CP for $24.95.
I have used the XR2206 countless times in designs during the last 20 years.
By using precision, high Q, low loss capacitors and appropriate circuit board layout, the XR2206 may operate up to 1MHz.
The XR2206 has been used in conjunction with amplifiers to produce 10 KW power supplies with near perfect sine waves.<p>Ned

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Re: Resources for Switching Power supplies

Post by dyarker » Tue Jul 20, 2004 4:52 am

Don Lancaster's site is: www.tinaja.com
Dale Y

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