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USB EZ-PD Type-C

TeMa_2997106
Contributor II

How is the current limit calculated?

In KBA229013, Rsense recommends 5m-ohm. Why is this value?

OCP Threshold can only be set as a percentage in the Configuration Utility.

What should I do if I set the current value?

Thanks,

Tetsuo

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1 Solution
PranavaYN
Moderator
Moderator

Hi,

How is the current limit calculated?

>> Current limit value is calculated as percentage of maximum current negotiated. i.e. max_current + (max_current * percentage/100)

5m-ohm resistor is recommended because internal amplifier used for current sense operates optimally for the voltage drop range of this resistor throughout allowed current range(upto 5A). Higher value of this resistance would increase voltage drop thereby reducing load voltage. power dissipation would also increase.

OCP Threshold can only be set as a percentage in the Configuration Utility.

What should I do if I set the current value?

>> OCP Threshold can be set as percentage of maximum current negotiated. It is done so to accommodate application of threshold value to wide range of negotiated current values. The only way to set it is in terms of percentage.

May i know why you not want to set it in terms of percentage?

Best regards,
Pranava

View solution in original post

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2 Replies
PranavaYN
Moderator
Moderator

Hi,

How is the current limit calculated?

>> Current limit value is calculated as percentage of maximum current negotiated. i.e. max_current + (max_current * percentage/100)

5m-ohm resistor is recommended because internal amplifier used for current sense operates optimally for the voltage drop range of this resistor throughout allowed current range(upto 5A). Higher value of this resistance would increase voltage drop thereby reducing load voltage. power dissipation would also increase.

OCP Threshold can only be set as a percentage in the Configuration Utility.

What should I do if I set the current value?

>> OCP Threshold can be set as percentage of maximum current negotiated. It is done so to accommodate application of threshold value to wide range of negotiated current values. The only way to set it is in terms of percentage.

May i know why you not want to set it in terms of percentage?

Best regards,
Pranava

View solution in original post

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TeMa_2997106
Contributor II

Pranava-san,

Thank you for your reply.

Sorry I was a mislead question.

I don't want to set it as a percentage.

I asked because I don't know how to set it.

I understand the reason for the percentage setting.

I also understand that there is no sense in setting the current value.

Thanks,

Tetsuo

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