Hi Team,
My customer is using TPS65265 and has some concerns about the enable function.
1. TPS65265 can start up normally with EN pin open or external 5V signal.
2. TPS65265 cannot start up by customer's external transistor control circuit (green square), which aims to enable the TPS65265 after the -5V supply's start up. Using this external circuit, the EN pin voltage is around 0.7V.
I notice that in datasheet [Page 16: The EN pin has an internal pullup current source, allowing the user to float the EN pin for enabling the device. If an application requires controlling the EN pin, use open drain or open collector output logic to interface with the pin.]
The question is, what else circuit inside the Enable function block to let this transistor control circuit fail? or we say, why this cannot work?
Please help, or have you met some similar applications?
Thanks a lot.
Yang
