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power problem ADATA SU900
http://forum.hddguru.com/viewtopic.php?f=10&t=37194		 Page 2 of 2
Author:  fzabkar [ August 5th, 2018, 18:29 ]
Post subject:  Re: power problem ADATA SU900
One thing you might like to try is to disable U6 by shorting its enable pin to ground.

Quote:
Enable

When input voltage is greater than the undervoltage lockout threshold (UVLO), typically 2.3V, MP2162 can be enabled by pulling EN pin to higher than 1.2V. Leaving EN pin float or pull down to ground will disable MP2162.

Then see if the other voltages are stable.

Attachments:
MP2162_AZ_app_cct.gif
MP2162_AZ_app_cct.gif [ 18.83 KiB | Viewed 6067 times ]
MP2162_AZ_pinout.gif
MP2162_AZ_pinout.gif [ 14.75 KiB | Viewed 6067 times ]
MP2162_AZ_pin_definitions.gif
MP2162_AZ_pin_definitions.gif [ 35.16 KiB | Viewed 6067 times ]
Reg_1V5.jpg
Reg_1V5.jpg [ 110.26 KiB | Viewed 6067 times ]
Reg_1V5_resistors.jpg
Reg_1V5_resistors.jpg [ 57.05 KiB | Viewed 6067 times ]
Author:  lasek [ August 6th, 2018, 11:20 ]
Post subject:  Re: power problem ADATA SU900
After disabled MP2162 current is still not stable and still changing in every points. I marked capacitors connected to 1.5V point.

Attachments:
capa.jpg
capa.jpg [ 1.38 MiB | Viewed 6028 times ]
Author:  fzabkar [ August 6th, 2018, 17:24 ]
Post subject:  Re: power problem ADATA SU900
When you grounded the enable pin of U6, did its output remain at 0V? If not, then it must be faulty.

Otherwise I'm out of ideas.
Author:  lasek [ August 7th, 2018, 2:30 ]
Post subject:  Re: power problem ADATA SU900
No, after grounded enable pin still showing changing current between 0,1 to about 2,2V but not 0V.
Author:  fzabkar [ August 7th, 2018, 2:47 ]
Post subject:  Re: power problem ADATA SU900
Either U6 is faulty, or there is an open feedback resistor. See R1 and R2 in the application circuit.
Author:  lasek [ August 7th, 2018, 3:09 ]
Post subject:  Re: power problem ADATA SU900
sorry where is resistor R1 and R2 ?
Author:  fzabkar [ August 7th, 2018, 3:28 ]
Post subject:  Re: power problem ADATA SU900
See attachment.

Attachments:
Reg_1V5_resistors_feedback.jpg
Reg_1V5_resistors_feedback.jpg [ 62.99 KiB | Viewed 5981 times ]
Author:  lasek [ August 9th, 2018, 10:23 ]
Post subject:  Re: power problem ADATA SU900
Thank you fzabkar for your help. Unfortunately I don't resolved this case.
Author:  arvika [ August 10th, 2018, 14:14 ]
Post subject:  Re: power problem ADATA SU900
This case probably can be solved, so hope you redirect client to another lab.
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