CYPD3177 Max/Min Current Request

[AdBi_4635021]

When I set the voltage dividers for Isnk COarse/Fine, am I setting the maximum current allowed through the power path or is this the minimum?  I have a CYPD4533 evaluation kit and I have modified the Isnk dividers with 5k/2.4k Ohm resistors to give 2A Coarse and 500mA Fine, yet I am able to pull currents both above and below this level depending on my load.  Am I misunderstanding what is being set with these dividers, I thought this set the maximum current load through the power path?

[YiZ_31 · Accepted solution]

Hi,

This is the requested current value used in CC communication. You can check this if you have a CC sniffer like CY4500. BCR do not have OCP feature, so it cannot cut off the VBUS path when current is higher.

Regards,
Eddie

[AdBi_4635021]

Hi Eddie,

So this is requesting a certain amount, but I could get more or less than this based on what my downstream load is sinking?  The resistor divider then, and the BCR, do not actually restrict the current at all then?  If my adapter cannot source the requested current, I will still be able to charge, just at the lower level the adapter can provide?

[YiZ_31]

Hi,

Actually your adapter side can detect the OCP event. BCR schematic actually do not have a resistor devidor. VBUS_IN pin is used for voltage monitoring. If your adapter can not source the requested current, then it will advertise this information in its PDO. BCR'll request this PDO with the maximum operating current it can get.