Single cell Li+ charger, 15W USB-C or next highest level of power

Erik Anderson41

Other Parts Discussed in Thread: BQ25895, TPS25750, TPS25810

Hi,

I posted in the power management forum and got some ideas. Basically we have a USB 2.0 pass through board that has some power management on it (charger, power path control to a touch controller downstream, and bluetooth module that communicates with touchcontroller). We'd like to be able to charge at 15W using USB-C, but also be able to fall back to the next highest charge rates if USB-C is not detected (e.g. USB-3.0 dedicated charge port 7.5W). Our block diagram currently looks like this:

The thinking was to use pull-up resistors to negotiate USB-C power (3A if possible) and have the BLE module read the voltages at CC1/2 to ensure the BQ25895 matches its charging current appropriately. But I'm wondering if this is too simple a solution and maybe you have a USB-C controller that is more appropriate? Like the TPS25750? Thanks for any advice you have.

Erik

over 3 years ago

0 Tommy Lin over 3 years ago

TI__Mastermind 32280 points

Hi,

Thank you for reaching out. I will get back to you as soon as possible.

Regards.

0 Tommy Lin over 3 years ago

TI__Mastermind 32280 points

Hi,

The device I would recommend for your application is TPS25810 since you are only charging at a max of 15W and TPS25810 have STD/1.5-A/3-A Capability Advertisement on the CC lines.

Regards.

0 Erik Anderson41 over 3 years ago in reply to Tommy Lin

Intellectual 925 points

Hi Tommy,

We are actually an upstream facing port (sorry I mentioned downstream in original post because we are sending some power down to another device). But essentially we want to pull 15W to charge our battery. Do you have an upstream port solution that will handle the CC lines?

0 Hari Patel1 over 3 years ago in reply to Erik Anderson41

TI__Genius 12700 points

Hi Erik,

Could you share additional details on your requirements then on the system level to Tommy? Or is the only requirement needed is to just sink 15W of power to charge battery?

Thank you,

Hari

0 Erik Anderson41 over 3 years ago in reply to Hari Patel1

Intellectual 925 points

Yes, only requirement is to sink 15W if USB-C is connected. If however USB-C is not connected (CC pins not connected), then we would like to charge at the next highest level of power possible (probably 7.5W USB-3.0, but maybe as low as 2.5W for USB2.0).

The BQ25895 charge controller can handle everything except USB-C. So, I'm wondering if I can take care of the CC pins with my host processor measuring the voltage divider, or do I need a special USB-C chip to negotiate the power? Do you have a USB-C upstream facing port IC that simply negotiates power levels on the CC pins?

0 Tommy Lin over 3 years ago in reply to Erik Anderson41

TI__Mastermind 32280 points

Hi,

Based on your requirements, handle CC pin detection to determine whether the Type-C of the Type-A connector is connected, sink capability at 15W max, UFP, I don't think our group have a solution for this.

That being said, you might want to look the TUSB32x family. They have the capability of handling CC logic, can be configured as UFP, and support Up to 3 A of Current Advertisement.

Hopefully this help answer your questions.

Regards

0 Erik Anderson41 over 3 years ago in reply to Tommy Lin

Intellectual 925 points

Seems like TUSB32x is what I want, thanks.

0 Tommy Lin over 3 years ago in reply to Erik Anderson41

TI__Mastermind 32280 points

Hi,

Glad you found the device you are look for, closing this thread based on the feedback.

Regards.

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Single cell Li+ charger, 15W USB-C or next highest level of power