Blower output voltage jumping


 
N

NickH82

New member
Hi,
I have an issue with the blower output. When I put it in manual mode the voltage is not constant but jumps up and down.
Any ideas what I can check?
Thx!
 
Is this a v4.2 board with the output mode set to "Voltage"? If so, check the three points here on the feedback circuit for stable voltages proportional to your output.
 
Thx Brian. It is a 4.2.4 board on voltage mode indeed, I guess my blower (BFB0512VHD) does not support this as it was blowing randomly. Pulse mode seems to work however (aldough the blower seems to produce a lot more wind than I expected...).

When I put the board in voltage mode, the voltage at your indicated points is also not stable... Would something be wrong? Also I would expect a stable voltage at the BLOW output?
 
Yeah there should be a stable voltage give or take some amount of ripple. The output is pulsed at 62000 times a second and the feedback measures the resulting voltage and tries to reach the target voltage by varying the duty cycle so if the feedback isn't working properly the output will jump all over.

Especially at the rightmost circled pin at the ATmega, that should be pretty noise-free.

How fast is it changing voltages? Once a second, many times a second, once every few seconds? I'm not sure what else to check unless there's some sort of bridged connection or something causing the feedback to be all loopy, or the output to not behave properly.
 
Ok I did some resoldering in a few places and the issue is fixed now. Stable voltage at the BLOW output.
Thx for your help Bryan.
 
BAM! Good to hear, Nick. Glad it wasn't your crazy electrical outlets over there having a bad interaction with the design :-D
 
You must log in or register to reply here.

 

Back
Top