TPS65988: DRP Power Path Configuration

Bahar,

TPS65988 can do this. Few questions though:

• Are you planning for USB-IF certification? 
• Do you plan to have DisplayPort/USB4 or other PD-specific alternate modes supported? 
• Will you have some kind of EC/MCU controlling the TPS65988?

Thanks,

Chris

Hello Chris,

Thanks for the quick reply.Without the need of an external path, right?

Answering your questions:

• No, we are not planning for USB-IF, but I need to double check that with my team.
• Yes, we are planning to support DisplayPort.
• Yes, we will have MCu controlling the TPS65988.

Thanks!

Bahar

Bahar,

Yes this can be done. What I recommend is for the Dual-Power port A have the PP Switch configured as 'PPx configured for Sink (input) and Source (output), but will wait for SYS_RDY command (SRDY) before closing the switch.' 

This way the MCu will control when to turn on/off the power-path. There is a potential system design issue with this though:

Bahar Bülbül said:

Use Case 1:   The device is powered from VBUS only, port A sinks, port B sources

For Use Case 1, if the MCu is powered from PP_HV1 <-> Port A, but the TPS65988 will NOT turn on the sink switch because MCu needs to send the 'SRDY' command. This will lock up your system when booting from dead-battery. To avoid this, there are 2 options:

1. it may be good to see if the MCu can boot from the LDO_3V3 output of the PD controller but be careful not to exceed the current rating for LDO_3V3. 

2. Configure the ADCIN to be in one of the highlighted configurations to enable the sink path at boot regardless of the SRDY command in dead-battery mode. This could be problematic since Port B could also turn on and become the sink path but once configuration is loaded, it will default to Source and reboot continually. 

Hi Chris,

Thanks for the information. This is already very helpful.

Can I send you my schematic with private message for a review?

Thanks!

Bahar