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Power supply design question.


JGale
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I need 15v 2amp regulated DC.

I am having of a problem when I try to Goggle low voltage DC power supplies. Too much stuff and insufficient EE knowledge to discern the difference.

So, here is my solution question.

https://www.antekinc.com/an-0120-10va-20v-transformer is a 20V output stepdown transformer.

https://www.antekinc.com/dr-12b-12v-2a-regulator-module/ is a 2A 12V rectifier/regulator. It would be better if it was 15V. The questions arising out of all this is:

When the regulator specifies no more than 15V over, are they referring to the secondary output of the Transformer? 15V out of the rectifier would be good for a maximum transformer voltage of 15 +15= 30V? Going over is a thermal load on the rectifier it can not handle?

Anyone know where I can get either an all-in-one solution or a 15V version of the regulator above?

TIA 

It's to power this amp https://londonpower.com/electronics/micro-cigar-box-amp/

12.6V may be the best I can do. This is nice all-in-one solution: https://glass-ware.stores.yahoo.net/trps1.html

Trying to avoid switching power supplies (SMPS).

Edited by JGale
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Not enough info. You need the spec of the regulator IC on the module.  The transformer needs to provide more than the desired DC output voltage, within limits.

The regulator IC will specify a max input voltage or max voltage drop. I forget the formula, but the 20 VAC from the transformer gets rectified by diodes on the regulator module, think that will be more than 20 volts.

The seller of the module should supply that detail or suggest a transformer. I find it easier and cleaner to buy a power supply complete.

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1 hour ago, JGale said:

I need 15v 2amp regulated DC.

I am having of a problem when I try to Goggle low voltage DC power supplies. Too much stuff and insufficient EE knowledge to discern the difference.

So, here is my solution question.

https://www.antekinc.com/an-0120-10va-20v-transformer is a 20V output stepdown transformer.

https://www.antekinc.com/dr-12b-12v-2a-regulator-module/ is a 2A 12V rectifier/regulator. It would be better if it was 15V. The questions arising out of all this is:

When the regulator specifies no more than 15V over, are they referring to the secondary output of the Transformer? 15V out of the rectifier would be good for a maximum transformer voltage of 15 +15= 30V? Going over is a thermal load on the rectifier it can not handle?

Anyone know where I can get either an all-in-one solution or a 15V version of the regulator above?

TIA 

It's to power this amp https://londonpower.com/electronics/micro-cigar-box-amp/

12.6V may be the best I can do. This is nice all-in-one solution: https://glass-ware.stores.yahoo.net/trps1.html

Trying to avoid switching power supplies (SMPS).

Not much info from them but in the pictures I'm seeing 9v. and Gnd. solder points.

This would imply that a single ended 9 volt power supply is needed.

 

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I always use the LM317 ic, but only delivers 1,5 amp, so in this case I would use a LT1083, which can deliver up to 7 amp. Another option is the LM338, but it needs 3V from output to input instead of the 1 V needed by the LT1073.

Which brings me to the transformer: after the rectification you will have 1,41 times the AC voltage (square root of 2), so if you use the LT1083 you can use a 12V AC transformer (~17V DC after rectification) instead of a 15V AC one (~21V DC). The greater the output-input voltage, the more dissipation (and heat) there will be.

 

Note: damn, now that I reread your question I'm realizing that you asked for a module. I don't know if you are handy with a soldering iron and a veroboard (or PCB), but I think this is not going to be a complicated circuit and may be a good gateway drug to other electronics.

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