STUSB4500 PD controller hardware constraints for battery charging

[SG.2]

Dear Team,

We are designing a project where the supply is battery driven. We would like to go with USB Power Delivery(PD) for fast charging and high power management. Basically we are using 3S Lithium 18650 battery(3 batteries in series = 11.1 V), when Type C PD supported USB connector is connected we would like to charge the battery.

I need some clarification on following queries,

1. I am following the STEVAL-ISC005V1 as a reference for drafting my schematics. Which is the output pin that delivers me an output of 5V/ 9V/ 12V or 20V? I hope single pin can output these voltages. As I could see 3 connectors VSNK, PDO2 and PDO3 present in the eval board. I would like to confirm on these so that I could finalize and connect that pin to my battery charger IC input.
2. We have a CM3+ processor SOM on board, hope the processor can be used to program the NVM of STUSB4500 through I2C interface. However the power would still be through the Type C USB connector or may be our battery power on board for programming the NVM for the first time.
3. For the address pins I could see we have a pull up and pull down config and pull down is enabled in hardware, is this sufficient or do we need to connect the address pins(ADDR0 and ADDR1) to any of the I/Os of the processor?
4. Lastly for setting the output to different voltages, I hope we could control to I2C and nothing else is required to be taken care in hardware. If there is any special instructions, please do let me know what has to be taken care in hardware aspects?

Let me know if you need any further information from my end. Any response in this aspect would be much appreciated. Thanks in advance.

Regards,

Sandeep G

[Benoit FORET · Accepted solution]

​Hi Sandeep,

1. the main output is VSNK: output voltage is the result of power negotiation. My advice is to follow EVAL-SCS001V1 ref design: this is the minimal implementation, suitable to most uses cases, Gerber and Altium libraries available for quick design. PDO2 and PDO3 outputs from the board could be useful to separate power paths with different voltage levels, but VSNK output is the recommended one by default.

2. For initial NVM programming, power can be VDD but also VSYS if needed. no problem

3. usually, I2C address is fixed. This mechanism is provided in case multiple devices are used in a same application or in case of I2C  address conflict for different ICs.

4. Only I2C is enough. No specific hardware settings

Best regards,

Benoit

[SG.2]

Hi Benoit FORET,

Thank you so much for the reply. I would follow the EVAL-SCS001V1 reference design to draw an output of max 20v/5A. One final connection I would like to confirm is on the POWER_OKx pins can they be left floating as in image? So that it will not affect the output.

Thanks again for your support.

Regards,

Sandeep G

[Benoit FORET]

​Hi Sandeep,

yes, these 4 pins are open drain outputs and can be left open if unused.

Regards,

Benoit

[SG.2]

Hi Benoit FORET,

Got it. Thank you for your support!

Regards,

Sandeep G

[SG.2]

Hi Benoit FORET,

Thank you for all your support. I just want to confirm that VSNK pin can source all the voltages 5V/ 9V/ 12V or 20V as per the NVM programming? I just want to confirm and finalize before we release our design.

Thanks again.

Regards,

Sandeep G

[Benoit FORET]

​Hi Sandeep,

yes, VSINK will get the voltage value negotiated by the controller.

It can be any value between 5V and 20V according to the standard, and it depends on the matching between the Source profile and the NVM settings from the IC.

Rgds,

Benoit