Author Topic: Adj Power Supply PCB suggestions  (Read 1007 times)

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Offline IamSynthetiCTopic starter

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Adj Power Supply PCB suggestions
« on: June 08, 2020, 10:51:57 pm »
Greetings,

I have a need for a  small adjustable power supply to power my circuits that are not on the bench (where the lab power supply sits), or simply require a second rail. And since power supplies fascinate me, i though of designing and building my own. Unfortunately, i have no expirience designing, nor building power supplies, hence i've come to the experts ;D

I wanted this supply to have
  • High  Efficiency
  • Low Noise
  • Small Footprint
  • Powerd by 12V wall adapter or an 18V drill battery

i have selected some parts that seem to fit my needs, and i followed their datasheets as best as i could. I will attach my design bellow.
This design is definetly not final as it lacks safety features, and its dimensions will probably change to fit into an enclosure

So, have i done something wrong? is there something that can be improved ? is there something i should note ?

Thanks for your time and have a good day

*Edit : i attach the design as an image aswell :
1001348-0

1001352-1
« Last Edit: June 09, 2020, 12:40:59 am by IamSynthetiC »
 

Offline PlasmaArcEng

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Re: Adj Power Supply PCB suggestions
« Reply #1 on: June 11, 2020, 03:01:26 am »
Without looking too deeply into it, the MIC29303 pin 1 is a FLAG, a sinking (active low) output for an error condition, so the led attached has to be reversed and attached to the +ve rail. I am sure the resistors you have for the LEDs are place holders as 100K wont give you any appreciable output.
I try not to let my age dictate how old I act
 
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Offline IamSynthetiCTopic starter

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Re: Adj Power Supply PCB suggestions
« Reply #2 on: June 12, 2020, 08:55:10 am »
Wow, nice catch. I must have missed this about 20 times so far  |O. Thanks.

other than that, i think i'll order the parts and pcb and make one or two.
 

Offline bin_liu

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Re: Adj Power Supply PCB suggestions
« Reply #3 on: June 13, 2020, 03:48:51 am »
The noise of the switching power supply is not small. ;D
 

Offline IamSynthetiCTopic starter

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Re: Adj Power Supply PCB suggestions
« Reply #4 on: June 13, 2020, 09:56:48 pm »
 |O |O |O |O |O |O

I put this together very hastefully, but still. I though in the datasheet i had seen the words "low noise" but no. Doesnt even provide a noise graph.
Thank you kind sir, for saving me some troubles, aswell as from my own stupidity and self.

Do you have any switching supplies suggestions ? Any you have worked with ?
I'll probably select one with a higher frequency for now.

Thanks again.
 

Offline Vovk_Z

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Re: Adj Power Supply PCB suggestions
« Reply #5 on: June 14, 2020, 06:57:23 am »
Properly designed dc-dc won't make much noise (until you need really ultra low noise power supply).
It is an interesting task to make it quiet.
 

Offline ocset

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Re: Adj Power Supply PCB suggestions
« Reply #6 on: June 14, 2020, 01:11:56 pm »
Here is an adjustable smps in the free ltspice simulator.

The idea is you use an external error amp and then adjust its reference depending on what vout you want.
 


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