TPS26750: Source only, 240W PPS AVS

Richard Axelsson

Part Number: TPS26750
Other Parts Discussed in Thread: BQ25756

Tool/software:

Building a 240W source and wondering if there are any "plug and play" buck converters that can be used, or do I need a MCU, DAC and buck converter?

What I want is to build a source with full PPS/AVS capability. Input will likely be 48V/5A, TPS26750 as PD controller, then I will need to switch the output voltage to what the sink request, so I2C->DAC/switch regulator

I have not seen any chip that does this, only charging.

I understand I can use the GPIOs to trigger fixed voltages, but can I do it easily for PPS/AVS, or do I need an MCU as a translator?

3 months ago

0 Chris Sterzik 3 months ago

TI__Guru 64131 points

Hello,

Richard Axelsson said:
I have not seen any chip that does this, only charging.

This device is intended for sink only and dual role power but not source only. Specifically, charging with the BQ25756.

Richard Axelsson said:
Building a 240W source and wondering if there are any "plug and play" buck converters that can be used, or do I need a MCU, DAC and buck converter?

You would need to work through the implications of being Dual role, but yes you would need an MCU to manage the voltages which are negotiated and sourced on VBUS (PD would negotiate a specific contract and then MCU would need to read the contract negotiated and set the voltage before the power path is opened.)

Richard Axelsson said:
I understand I can use the GPIOs to trigger fixed voltages, but can I do it easily for PPS/AVS, or do I need an MCU as a translator?

The GPIOs can be configured as outputs triggered from the negotiated PDO.

https://dev.ti.com/gallery/view/USBPD/USBCPD_Application_Customization_Tool/ver/1.1.0/