BQ25758: Can BQ25758 be controlled by TPS25751's I2C?

Hello Hiroaki,

Thanks for being patient with this. I'm the apps engineer for the BQ25758. Let me loop in the experts for the TPS25751 and they'll get back to you.

Best Regards,
Ethan Galloway

Hi Yamazaki-san, 

TPS25751 currently does not have integrated support for BQ25758, can you provide further details on what kind of end application are you designing and what PD capabilities are you looking for (i.e. power role, data role, source and sink PDOs, voltage and current ratings, etc.)?

Thanks and Regards,

Raymond Lin

Hi Ethan and Raymond, thank you both for your responses.

The end application is measuring instrument.

I am looking for a combination of a PD controller and a DC-DC converter that can meet the following requirements:

• USB-PD can be used as a sub power source for devices that can be equipped with a DC barrel jack.
• In SINK mode, it should support receiving power at 15V/3A (45W) via USB-PD.
• In SOURCE mode, it should boost or buck the power from the DC barrel jack using a DC-DC converter and output 15V/3A.
• Battery charging is not required.

Best regards.

TPS55289 is work?

Hi Yamazaki-san, 

When TPS25751 is in sink mode, where is the 15V/3A (45W) being drawn to? Is the plan to pass-through the power from PD->DCDC->system? 

Do you have a block diagram of what this setup would look like? Since you mentioned  a DC barrel jack, I'm a little confused on how this would work when TPS25751 is in sink mode. 

Thanks and Regards,

Raymond Lin

Hi Raymond,

In sink mode, it would be great if the 45W PD power could be pass-through to the system power supply.

The goal is to distribute power from one DC power source to two devices.
I am wondering if it is possible to feed power from the source mode to the sink mode (they have the same circuit) with a PD as shown in the figure.

Hi Yamazaki-san, 

Is the intention for TPS25751 to control TPS55289? Or is there a MCU that will handle the I2C configuration for TPS55289 based on the negotiated PDO?

At this time TPS25751 does not have the integrated support for TPS55289, the only integrated I2C control embedded in TPS25751 are the BQ battery charger listed on the datasheet and the GUI. 
Thanks and Regards,

Raymond Lin

It is unfortunate that I cannot control the BQ25758 or TPS55289 from the TPS25751 using I2C.

In fact, I don't need a complete PPS. I just need to switch between 5V3A and 15V3A. Is it possible to prepare these two power supplies, input them to the PPHV and PP5V of the TPS25751, and switch the voltage by turning the internal FETs of the TPS25751 on and off?