Power supply topology question ...

• posted

Could some electronics guru please shed some light on the following. The standard topology for a linear regulated power supply is basically as follows: isolation step-down transformer | v rectifier(bridge or 2 - diode) | v capacitor ripple filter bank | v voltage regulator | v capacitor ripple filter bank | V Let us suppose that the transformer is a step-down 9 - 0 - 9 1 Amp output device.

Now suppose I want to get two 1 Amp outputs by having a 9 - 0 -9 2 Amp transformer and splitting its output equally with resistors as : isolation step-down transformer | | v v resistor resistor | | V V rectifier etc., rectifier etc., Is this a valid topology ? Or should there be two 9 - 0 - 9 1 Amp isolation transformers connected to the common Ac wall input, and then parallel topology as above, without the resistors. Any thoughts, suggestions would be appreciated. Thanks in advance.

• posted

a 9-0-9 2A transformer is probably sufficienctly oversized

use one transofrmer, one rectifier, and one input capacitor bank. double up the regulators and everything downstream.

```--
For a good time: install ntp

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---```
• posted

Draw the circuit with the ground/return(s). That, coupled with a clear definition/specification of your objective should give you the answer.

• posted

```--
No.

Neglecting the transformer's regulation, whether the transformer is ```
• posted

On Mon, 04 Nov 2013 05:55:27 -0600, John Fields wrote:

Version 4 SHEET 1 880 920 WIRE -2000 -16 -2144 -16 WIRE -1632 -16 -1808 -16 WIRE -1440 -16 -1632 -16 WIRE -1632 16 -1632 -16 WIRE -1440 16 -1440 -16 WIRE -2000 112 -2000 -16 WIRE -1808 112 -1808 -16 WIRE -2144 128 -2144 -16 WIRE -1632 128 -1632 80 WIRE -1568 128 -1632 128 WIRE -1440 128 -1440 80 WIRE -1440 128 -1488 128 WIRE -1632 176 -1632 128 WIRE -1632 176 -1680 176 WIRE -1440 176 -1440 128 WIRE -1392 176 -1440 176 WIRE -1680 208 -1680 176 WIRE -1632 224 -1632 176 WIRE -1568 224 -1632 224 WIRE -1440 224 -1440 176 WIRE -1440 224 -1504 224 WIRE -1632 272 -1632 224 WIRE -1440 272 -1440 224 WIRE -2144 368 -2144 208 WIRE -2000 368 -2000 192 WIRE -2000 368 -2144 368 WIRE -1936 368 -2000 368 WIRE -1808 368 -1808 192 WIRE -1808 368 -1856 368 WIRE -1632 368 -1632 336 WIRE -1632 368 -1808 368 WIRE -1440 368 -1440 336 WIRE -1440 368 -1632 368 WIRE -1632 480 -1808 480 WIRE -1440 480 -1632 480 WIRE -1632 512 -1632 480 WIRE -1440 512 -1440 480 WIRE -1808 608 -1808 480 WIRE -1632 624 -1632 576 WIRE -1568 624 -1632 624 WIRE -1440 624 -1440 576 WIRE -1440 624 -1488 624 WIRE -1632 672 -1632 624 WIRE -1632 672 -1680 672 WIRE -1440 672 -1440 624 WIRE -1392 672 -1440 672 WIRE -1680 704 -1680 672 WIRE -1632 720 -1632 672 WIRE -1568 720 -1632 720 WIRE -1440 720 -1440 672 WIRE -1440 720 -1504 720 WIRE -1632 768 -1632 720 WIRE -1440 768 -1440 720 WIRE -2000 864 -2000 368 WIRE -1936 864 -2000 864 WIRE -1808 864 -1808 688 WIRE -1808 864 -1856 864 WIRE -1632 864 -1632 832 WIRE -1632 864 -1808 864 WIRE -1440 864 -1440 832 WIRE -1440 864 -1632 864 FLAG -1680 208 0 FLAG -1680 704 0 FLAG -1392 176 OUT1 FLAG -1392 672 OUT2 SYMBOL ind2 -2016 96 R0 WINDOW 0 45 47 Left 2 WINDOW 3 45 79 Left 2 SYMATTR InstName L1 SYMATTR Value 50 SYMATTR Type ind SYMATTR SpiceLine Rser=,1 SYMBOL voltage -2144 112 R0 WINDOW 3 24 104 Invisible 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR Value SINE(0 170 60) SYMATTR InstName V2 SYMBOL ind2 -1792 208 R180 WINDOW 0 42 73 Left 2 WINDOW 3 48 42 Left 2 SYMATTR InstName L2 SYMATTR Value .5 SYMATTR Type ind SYMBOL res -1472 112 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName RL1 SYMATTR Value 16 SYMBOL diode -1456 16 R0 WINDOW 0 -38 34 Left 2 WINDOW 3 -98 -1 Left 2 SYMATTR InstName D3 SYMATTR Value MURS320 SYMBOL diode -1648 272 R0 WINDOW 0 -38 34 Left 2 WINDOW 3 -96 72 Left 2 SYMATTR InstName D2 SYMATTR Value MURS320 SYMBOL diode -1616 80 R180 WINDOW 0 42 34 Left 2 WINDOW 3 24 69 Left 2 SYMATTR InstName D1 SYMATTR Value MURS320 SYMBOL diode -1424 336 R180 WINDOW 0 42 32 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D4 SYMATTR Value MURS320 SYMBOL ind2 -1792 704 R180 WINDOW 0 40 67 Left 2 WINDOW 3 45 40 Left 2 SYMATTR InstName L3 SYMATTR Value .5 SYMATTR Type ind SYMBOL res -1472 608 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName RL2 SYMATTR Value 16 SYMBOL diode -1456 512 R0 WINDOW 0 -38 34 Left 2 WINDOW 3 -98 -1 Left 2 SYMATTR InstName D7 SYMATTR Value MURS320 SYMBOL diode -1648 768 R0 WINDOW 0 -38 34 Left 2 WINDOW 3 -96 72 Left 2 SYMATTR InstName D6 SYMATTR Value MURS320 SYMBOL diode -1616 576 R180 WINDOW 0 42 34 Left 2 WINDOW 3 24 69 Left 2 SYMATTR InstName D5 SYMATTR Value MURS320 SYMBOL diode -1424 832 R180 WINDOW 0 42 32 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D8 SYMATTR Value MURS320 SYMBOL res -1840 352 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 1G SYMBOL res -1840 848 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 1G SYMBOL polcap -1504 208 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 10000µ SYMBOL polcap -1504 704 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 10000µ TEXT -2136 400 Left 2 !.tran 1 TEXT -1984 80 Left 2 !K1 L1 L2 L3 1 TEXT -2160 432 Left 2 ;JOHN FIELDS TEXT -2160 464 Left 2 ;04 OCT 2013

• posted

The resistors are unnecessary.

If you don't need it to be isolated, just make a 2A supply and hook the loads up in parallel.

I think you fail to understand the distinction between the current _rating_ on a supply and the current drawn by a load at a particular voltage, but I'm not sure.

```--
Tim Wescott
Control system and signal processing consulting ```
• posted

Thanks for the LTSpice file, but I use Ngspice, which like HSpice, uses text file input.

• posted

Thanks. I am aware of the power rating, versus the actual current drawn by the load. Thanks to each of you for your feedback.

• posted

```--
Sorry to have disturbed your turpor.```
• posted

[snip]

Suggestions:

(1) Lose google and the added white-space (2) Get LTspice, it's free (3) If you must use NGspice, export the netlist from LTspice into NGspice. ...Jim Thompson

```--
| James E.Thompson                                 |    mens     |
• posted

Who are you and what have you done with John?

• posted

Could you please explain your question a bit ? I personally do not know who John Fields is, so I have no clue why he states that he has disturbed my torpor. Ngspice is freely-downloadable, compiles and can be installed very easily on any platform, especially Linux. I find it very convenient to use it especially when importing the sub-micron MOS files BSIM3, BSIM4 etc., that I often use in my work - for example I recently used it to analyze a 32 64-bit shift register structure with 15 nanometer MOSFET gate length. I am sure it would have taken me a lot longer, and would have made lot more mistakes, if I had set it up with a GUI based version of SPICE. taken me

• posted

I gotta ask... If you can do this, how come you need to ask such a simple power supply question? Something seems horribly disconnected here.

• posted

```--
A ray of sunshine on an otherwise bleak day.  Thanks! :-)```
• posted

```--
Strange, since you replied to my posts related to alleviating your
misconceptions and power supply problems.```
• posted

May the rest of the day be better.

Best regards, Spehro Pefhany

```--
"it's the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com ```
• posted

Here is the answer Sir. I was just bouncing off ideas. May I point out that the first power supply, the one with 9 - 0 - 9

2 A rated output transformer has already built and works fine. I was just thinking of alternatives.
• posted

```--
Did you have to add the current-limiting resistors?```
• posted

+3

?-)

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.