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USB EZ-PD Type-C

OlEr_1999891
Contributor

Hi!

We have had some problem to support 20V/5A in our solution due to the challenge of practically implementing an exact current-protection at 5A. On one hand we need to support up to 5A so that certain laptops don't complain that there is not enough power, on the other hand for our CE-certification, Intertek compains that we should absolutely not provide more than 5A before over-current protection happends.

Is there any guidance in regards to which margins are available here? Or the hardware and software implementation needs to ensure that we hit 5.00A as max current?

Cheers

Olof

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YiZ_31
Moderator
Moderator

Hi Olof,

Unfortunatedly there are not spcified value for the margin. Typically, Cypress use 120%*current for OCP threshold. You need to adjust it by yourself if this value cannot meet your requirement.


Regards,
Eddie

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YiZ_31
Moderator
Moderator

Hi Olof,

May I know which product you're using for your design?  Usually we have a OCP threshold value in the config table. You can set it as 0 so the maximum current won't exceed 5A.

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OlEr_1999891
Contributor

Hi!

We are using CCG4 with SC8815 DC/DC over I2C, so we can't use that function you describe above ( I guess?). We use the current-protection that is built into SC8815 right now.

If we add 20% margin, meaning 6A, I believe Intertek might not approve the product due to safety regulation. But regardless if we use 0 or 20%, it is technically impossible to exactly hit 5A. So our question is if there is any best-practices or guidelines what margin to use to both pass regulation and support laptops that requires 5A.

Cheers

Olof

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YiZ_31
Moderator
Moderator

Hi Olof,

For SC8815, you can change its current limit register via I2C.

Regards,
Eddie

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OlEr_1999891
Contributor

Hi Eddie!

Yes, that is what we have done. But when fine-tune the system, it is impossible to hit exactly 5A load, so the question was if there is a best-practice for which margin (typically upwards) that you know are approved by safety regulations. Because if we put the margin below 5A, certain laptops are complaining.

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YiZ_31
Moderator
Moderator

Hi Olof,

Unfortunatedly there are not spcified value for the margin. Typically, Cypress use 120%*current for OCP threshold. You need to adjust it by yourself if this value cannot meet your requirement.


Regards,
Eddie

View solution in original post

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