Hello,
I'm running into an issue where the LDOs are turning on before a power on request is sent out to the TPS659037. Based off the datasheet, the three following items trigger a power on request for the PMIC:
- PWRON is briefly pulled low, then back high
- RPWRON is pulled low, then back high
- GPIO7/POWERHOLD is pulled high to LDO_VRTC, or any other supply that meets datasheet specs, which allows the PMIC to automatically turn on.
My situation is that I need one of the LDOs to be delayed in order to meet the processors power sequence recommendation. With that being said, I used pulled up resistors to VCC on PWRON and RPWRON. With the pull up resistors on these two lines and no way to pull them low, I shouldn't expect a turn on sequence. I also pulled GPIO 7/POWERHOLD to an external 1.8V supply. I should expect my 1.8V supply to turn on first, followed by the PMICs LDOs and SMPS lines turning on. However, I am seeing the PMICs LDOs and SMPS lines turning on before POWERHOLD is pulled high. Is there anything that I am missing that is causing the PMIC to turn on the LDOs and SMPS lines before the POWERHOLD line is pulled up high?
Thanks.
