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Old 09-11-2014, 04:17 PM
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mushy409 mushy409 is offline
Join Date: Sep 2014
Location: Sheffield
Posts: 15

Another update!

Parts arrived this morning via Fedex. I've already installed the MOSFETs and driver.
Seems there may be more damaged components on this card

Plugged into PC and tested each phase output with a pocket oscilloscope...

Top phase (one with parts replaced) now outputs a nice clean voltage (1.05v) and I can see what appears to be the MOSFETs switching on and off (shown by rising and falling square wave)
The next 3 phases down show quite a rough looking 0.988v and there doesn't appear to be any input back to the CHL8510 from the high-side MOSFETs (there should be a similar looking wave but measuring 12v)

Further testing shows the top phase, and bottom 3 phases are working fine, the middle 3 are not.

Can anyone offer any advice on this? From what I can tell the other 3 CHL8510 are not working correctly and are not switching the high/lowside FETs as they should. The datasheet on the CHL8228 indicates that if any faults are found in the phase circuit (OVP, OCP, UVP etc) it simply shuts down the phase.

Any suggestions on my next move?

My thoughts are to replace the suspected faulty CHL8510 drivers. The MOSFETs attached to these drivers appear fine (no shorts between source & gate)
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