TPS65917-Q1: TPS65917-Q1 is shutting down after several seconds

Hi Andrew,

Please take a scope shot of PWRON, VCCA, and POWERHOLD during the startup and shutdown of the TPS65917-Q1. Additionally, please see section 5.3.5 of the datasheet on Power on acknowledgements that can be required. https://www.ti.com/lit/gpn/tps65917-q1

Thanks,

Daniel W

Daniel,

Startup (yel=PWRON, cyan=VCCA, pink = POWERHOLD):

Shutdown (yel=PWRON, cyan=VCCA, pink = POWERHOLD):

It is apparent that POWERHOLD is not being asserted. The rail for this signal requires enabling by REGEN1, which is also not being asserted. At this point, the device is behaving according to Figure 5-5 in the datasheet you linked, but shutting down after the 8 seconds elapse since POWERHOLD is not present. Additionally, RESET_OUT is not being asserted per Figure 5-5.

-Andrew

Daniel,

One point of confusion: in the OFF2ACT sequence, REGEN2 (GPIO_4) is referenced to the VIO rail, but in user guide SLVUAS4E page 3:

In the user guide, the TPS22965-Q1 is enabled by REGEN1 (GPIO_3) of the TPS65917-Q1, but according to the OFF2ACT timing diagram on page 15, REGEN1 is not asserted until after REGEN2. However, REGEN2 is referenced to VIO and VIO is enabled by REGEN1.

-Andrew

Hi Andrew,

Yes it seems that if you use this case REGEN2 will not really enable until REGEN1 does. Where is POWERHOLD being supplied from? Additionally are you seeing RESET_OUT go high when the pmic turns on?

Thanks,

Daniel W

Daniel,

POWERHOLD is supplied from another 3.3V regulator that requires REGEN1 to enable. RESET_OUT does not go high when the PMIC turns on. However, I changed the VIO supply to share the same supply as the TPS65917-Q1 input and now see REGEN2 and RESET_OUT go high, but REGEN1 is still not asserting. REGEN1 is pulled up to VRTC, which is at 1.8 V.

-Andrew