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Topic: Using LM2596 DC/DC (buck) converter to power ATMEGA328 (Read 2548 times) previous topic - next topic

MasterSquid

Hi all,

I'm designing a board with a standalone ATMEGA328p-au. The entire board will draw roughly 1.1A (worst case) so that the usually recommended 7805 Voltage Regulator won't do. Instead I've decided to use a LM2596 DC/DC converter to power the board and the chip, and was wondering if my schematic seems all right.

Many thanks,
T


raschemmel

#1
Jan 12, 2015, 04:41 pm Last Edit: Jan 12, 2015, 04:44 pm by raschemmel
Maybe I haven't had enough coffee but it looks incredibly screwed up. Maybe if you label the 5V lines so I
can see where they are I can tell but it looks like your outputs are shorted. Like I say, it could be me but
without the 5V lines labeled I have to say it's no good. Maybe someone else can sort it  out. I just don't see how you can have Vcc connected to the LM2596 ground.  Maybe I need some more coffee. You need to separate the component blocks with a block diagram and draw the connecting lines to inputs and outputs.
As it stands it looks like your atmega is connected to the converter ground.
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

Paulcet

I had my coffee this morning... 

Looks like "To Vcc" and "To GND" labels are swapped.

raschemmel

#3
Jan 12, 2015, 09:20 pm Last Edit: Jan 13, 2015, 01:10 am by raschemmel
Aside from that, I would add that the schematic doesn't conform to the standard convention of ground at the bottom and power at the top. After swapping the labels it still looks weird even if it is electrically correct.

Redraw the schematic with the ground at the bottom and the power at the top. See attached photo for example.
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

MasterSquid

Hi raschemmel,

You were right, its the first time I've made a big schematic like that. Many tutorials later I finally redid the schematic using proper conventions. Thanks for your time anyways, sorry to have posted such poor schematics...


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