Current consumption

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Plons
Posts: 1
Joined: Sat Jul 18, 2015 2:23 pm

Current consumption

Post by Plons »

At the end of PowerUpTest1, the red LED didn't light up at all. The 20MHz crystal caused this (it didn't oscillate, checked with an oscilloscope :geek: ) and I replaced it with one from my stock. Now it works. :)

What worries me a bit is the current consumption:
@ 4V on J6, the battery connector, it uses 176 mA.
Direct suppying of 5V on the 5V testpin shows 126 mA.

What are acceptable values for the current consumption ?

FYI: I sticked strictly to the Assembly Guide. So no LCD, no switches, no encoder.
I don't want to proceed with the next steps until I feel confident on the current consumption.

No components are running warm and of course I checked and re-checked my soldering.

My compliments on the kit design, the components and the documentation. Three feathers on your hat !

Nard

Edit1: with 4V battery power and JP4 open, the current consumption is less than 1mA, with 4.92V on the 5V testpoint. So the boostconverter BOB4 is doing fine.

Edit2: Some figures of power consumption, just for indication:
Mega64: 37 mA @5V and @20MHz
Mega48PA: 9 mA
TLC5510: 18 mA
LM6172: 5 mA
TL082: 2mA
That makes 71mA typical @ 5V
BOB5 makes the -5V. 55 mA is a fair value.

I guess it's OK. But I will leave this post here for reference.

Edit3: :oops: The current consumption is specified in the User Manual: 300 mA. Should have read the User Manual at an earlier stage.

Edit4: All done :) Works like a charme. Posted my findings on AVRfreaks.net http://www.avrfreaks.net/comment/161401 ... nt-1614011

And for the next software revision: may I suggest to make the Slope-button bahave simular to the Hold-button. In other words: give it the a toggle functionality. Thanks.
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: Current consumption

Post by jye1 »

Sorry for the crystal issue and thank you for the posting and suggestion. We can do the mod in next firmware change.
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