Current drawn by USB C connector for the charger IC

Hi all,

I am designing product which has battery charger to charge the battery. Powering the board with adaptor and board is having USB C connector in it. But USB C is having only power and ground lines, No data lines in it. is that USB C provide complete 2-3A to the board?, is there any standard protocol for the USB C to provide current of 2-3A?

Kindly let us know

Hi gururaja,
Thank you for using the MPS technical forum.

To better help ya with the question, can you kindly let us know which MPS component are you using?

Regards,
Nouman

HI Nouman,

Thank you for your reply.

Find the MPS part number: MP2615B.

Thanks
Guru

Hi Guru,
USB-C power cables current ratings are within 3-5A. Therefore, in your application, 2-3A can be supported.

Although USB-C cable is rated for higher amperage, please note that the Icc (constant charge current) max rating is only 2.2A. To set this programmable charge current to 2A, select Rs1= 50m-ohms.

Regards,
Nouman

image

Hi Nouman,

selected the Rs1 = 50 ohms and your saying even I can use USB C connector to deliver the 2A without D+/D- lines with MCU? but USB cable should support of 2A current rating?

Thanks and regards,
Guru

Hi Guru,

To better understand the application, what are you highlighting in the diagram you sent?
Can you also please verify the type of cable connection you are using? Which version is it?
→ Is it USB-C end to end or USB A to USB-C?

Yes, the USB-C cable will support up to 2A. Some USB types have lower current rating. If you are only using it for a charging application. I was mentioning to not go above Icc = 2.2A because that is the max current rating for constant charge current. I will need further clarification on how you are utilizing the the data lines D+ and D- with your MCU.

From the datasheet -


image

Thanks,
Nouman

Hi,
I suggest you to read the USB type-C and power delivery specifications.
image

USB C source uses a pull up resistor (Rp) and the sink uses a pull down (Rd) resistor on CC pins of USB C connector.
Rd value is usually 5,1K and Rp could be 56K, 22K or 10K.
56K: default USB power
22K: 1.5A
10K: 3A
For USB-PD is a bit more complicated.

Best regards,
Pablo

1 Like

Hi Nouman,

To better understand the application, what are you highlighting in the diagram you sent? - Shared because in our design, we are using RS1 = 50 Ohms.
USB cable is USB C- to USB-A_->5V adaptor.

we are using the USB C connector in our board without D+/D- lines connecting to MCU, will this USB C connector will provide 2A current to whole circuit?

Thanks and regards,
Guru

Hi Guru,

Thank you for clarifying the type of cable you are using. For USB-A, its typically used for peripheral interfacing (example: mouse or keyboard) and the current delivery is lower. They are much lower than 2A.
Therefore, no, it will not be able to support your application and provide 2A.

USB-A to USB-C are used for phone charging application for instance, and in those cases current delivery ratings are between 0.5A or 0.7A.

Regards,
Nouman

HI Nouman sir,

Thank you for your information.

Could you provide the cable details, which delivers the 2A using USB C cable on one o side and other side?

and could you suggest us which USB combination will deliver the 2A?

Thanks,
Guru

Hi Guru,
I suggest USB-PD for power delivery.

Majority of USB-C to USB-C end to end cables should work, and be able to deliver 2A.

Regards,
Nouman

HI Nouman sir,

USB C connector on PCB with USB-C to USB-C cable work for 2A PD?

Thanks and regards,
Guru