SAMV71 Power converter issue

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I am using SAMV71 Ultra Xplained evaluation Board , when i power the board with a USB cable from the PC , i am able to measure 5V on the board where as i am not able to measure 3.3V .

 

I have also measured the voltage across the IC LM26480 which is the power converter used, and could not find any voltage across the IC. 

 

Is there any other reason other than the LM26480 IC getting damaged?

 

Aishwarya

Last Edited: Thu. May 17, 2018 - 06:56 AM
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What do you mean "not find any voltage across the IC"? That device has TWO buck switchers and TWO LDOs. So, all together, there are 4 possible outputs. I would expect to measure from an output to ground, not "across" an IC.

 

This is purported to  be the schematic: http://ds.arm.com/media/resource...

 

The second and third sheets appear to show you everything you need to trace voltages. Note that there are several "voltage multiplexers" and power switches. One of those MAY be in a state that you don't expect.

 

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

Last Edited: Thu. May 17, 2018 - 05:52 AM
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Thanks Jim.

 

I have already probed and confirmed that there is no voltage measured at Buck1 where it should be 3V, at Buck2  3.3V,  at LDO1   1.8V, at LDO2  1.2V.

 

Haven't identified voltage at any of them . 

 

 

Aishwarya

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In SAMV71 ultra Xplained board ,  have tried powering it in two ways that is by external supply as well as USB power supply , in both the ways when the power switch (SW101) is pressed, the power LED is glowing continuously and  also  4 output voltages (i.e, 2V, 3.3V,1.8V,1.2V)of the power converter IC were present.

 

If the switch is released then these voltages are not present at the outputs and the power LED is also not glowing.

 

What may be the reason for this and how to resolve it? 

Aishwarya

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Regarding the above issue, the problem got solved by adding the jumper for the header J102.

 

 

Now, we are able to measure all the output voltages of the power converter IC. 

 

 

Aishwarya