stwlc38 VOUT pin input voltage dependent op mode switching issue

[lighthouse0625]

Hi I am currently working on a project using stwlc38.
I am using it in conjunction with a power management IC, MAX17330.
The circuit is simple, VOUT and system power is connected and normally I use it to discharge the battery which is connected to MAX17330 ic, but when the stwlc38 chip detects the wireless charging and sends the output to VOUT, MAX17330 ic receives the output and charges the battery.

There is a problem in this part When the system voltage connected to the VOUT pin is 3.05V or less, it recognizes that it is charging well.
When the voltage is higher than 3.05V, it does not recognize that it is connected to TX (op mode is fixed to 1).

Do you know of any settings or workarounds related to this?

[willzhou · Accepted solution]

Hi 

This is because when wlc38 vout is high than 3.05V, RX chip is working and default it is in SA mode.

I think you need to add some hardware between RX VOUT and MAX17330, for example diode.

This will make RX voltage only forward to MAX17330, can not reverse voltage from MAX17330

[willzhou]

Also you can refer to this

Solved: Using a STWLC38 with an optional USB-C charging - STMicroelectronics Community

[lighthouse0625]

thanks.

[lighthouse0625]

I was confused because the datasheet says that it operates in SA mode when 5V is applied to the VOUT pin. Thank you.