Problem with DPDM lines voltages

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PrRe_3492461
Level 4
Level 4
First like received 50 sign-ins 50 replies posted

Hello community,

I'm using ccg3pa DVK for my product development, I'm using only main board for my development.

My requirement is :

1. Providing 3.3v on Dp and Dm lines.

Issue:

When I tried sourcing 3.3v by writing to the register " bch_det_0_ctrl /* 0x400a0700 */ ", It is giving me only ~3.1v output which is unexpected, it shall be 3.3v.

Please find respective captures below:

1. Setup being used for testing:

PrRe_3492461_2-1651223156088.png

 

 

Scope captures:

1. with 3v3 on Dp,DM lines

PrRe_3492461_1-1651223058657.png

2. with 0.6v on Dp,Dm lines:

PrRe_3492461_3-1651223206276.png

 

Code being used:

PrRe_3492461_4-1651223226093.png

 

In the above code snippet I'm using case 0 and case 1 for sourcing 3v3 on Dp,Dm lines which is not giving me the output voltage in expected range ie., supposed to be 3v3 but I'm seeing only 3.1v.

Is this voltage range expected? Anyway to source exact 3.3v on Dp,Dm lines ?

@Pranava_YN ,  This is in extension to Thread. In which you said that you're able to observe Dp voltage more than 3v, can you say me exact Dp voltage observeed ? Also please provide me your setup details ? like Is the power board is also connected or you're using only main board ?

 

Thanks in advance .

 

Best regards,

Pranay.

0 Likes
1 Solution
Pranava_YN
Moderator
Moderator
Moderator
100 likes received 500 replies posted 250 solutions authored

Hi Pranay,

 

As you have specified, the DP DM outputs are around 3.1V (irrespective of the setup). This value is well within the QC specification and there should be no issue in applying these terminations. I will do some more tests at my end and get back to you in some time.

Best regards,
Pranava

View solution in original post

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1 Reply
Pranava_YN
Moderator
Moderator
Moderator
100 likes received 500 replies posted 250 solutions authored

Hi Pranay,

 

As you have specified, the DP DM outputs are around 3.1V (irrespective of the setup). This value is well within the QC specification and there should be no issue in applying these terminations. I will do some more tests at my end and get back to you in some time.

Best regards,
Pranava
0 Likes