Does the STUSB4500 support charging from a non-PD source?

[Hua]

When connecting to a charging port with a USB-C to USB-A cable, the device repeatedly switches between charging and not charging.

If the STUSB4500 is supposed to support non-PD sources, how should I configure it to ensure stable charging in this scenario?

Thanks!

[Didier HERROUIN]

Yes, STUSB4500 is compliant to USB PD, so it supports both USB-PD and USB-C only sources.
If you use a USB-C to USB-A cable, logically the power profile will be 5V (@500mA or 900mA).

Do you use an STUSB4500 eval kit or your own board ? Is there a load connected on Sink side ?

[Hua]

Thanks for reply.

 Not the eval kit, Use my own board, I just use in default, don't control the chip through I2C. 

 Currently， use c to c cable , it identified as 5V , 1.5A

                    use c to a cable, he device repeatedly switches between charging and not charging
I can control the chip through I2C, is there any register need to set?

[Didier HERROUIN]

The STUSB4500 is a standalone solution, you do not need to write the I2C registers if you use it in a standard way (which is your case).

Please send your schematics or if you want to keep confidentiality, I recommend to open a case (and attach your schematics) at : https://www.st.com/content/st_com/en/support/support-home.html#

You could also monitor the VBus_EN_SNK signal to check if the charging/not charging states are due to STUSB4500 opening/closing the switch.

[Hua]

This is the PD schematics, and I try to set the PDO1 5V 1.5A, PDO2 9V 1.5A, PDO3 12V 1.5A, and send soft reset
Are these the correct configuration steps? 

Thanks!

[Didier HERROUIN]

Looking at your schematics, I see that you did not implement the discharge circuit as in our schematics (see below).

This circuit is recommended, especially if you are expecting high current surge, because:

• While stsub4500 is in explicit contract, if there is a current surge system, the drop induced by surge will be absorbed by the RC circuit in order to avoid stusb4500 to disconnect due to UVLO (VBUS monitoring is done through VBUS_VS_Disch pin).
• During VBUS voltage ramp up, it has is no impact 

 

Please add this circuit and let me know.

[Hua]

use the STREF-SCS001V1 schematic above,  Is this difference the cause of the problem?

If I want to configure the PDO, 

1. set the PDO1, PDO2, PDO3 register through I2C

2. do softreset.

Are these the correct configuration steps? 

Thanks

[Didier HERROUIN]

If you have some spurious on VBUS, it could be detected as "VBUS under-voltage" by the STUSB4500 : these schematics filter these unexpected drops.

For changing the PDOs, you have to change the PDO values through I2C, but then you must apply a HW reset (through reset pin) so that the new values are considered (it will also generate a disconnection of the Source, which will renegotiate a new power profile with the Sink at next connection).

[Hua]

Thanks for reply,

   Need some time to modify the hardware circuit.

   And I monitor the VBUS_EN_SNK signal when use c to a cable,  charging/not charging states are due to STUSB4500 opening/closing the switch. 

How should this situation be handled?

Thanks