MP2760 power on without battery

DC-DC Power Converters
1

Hi,
I have a questions regarding the startup behavior of the MP2760 and need to ensure that the device can perform up to the requirements.

Requirement

System implements multiple behaviors that transition between power states.
In one particular state

  • System must be completely powered off
  • USB C reconnect is the only wakeup event to exit that state

Strategy

  1. Disconnect battery by disabling BATFET (forced turn off by setting BGATE_ CTRL in the configuration register REG10h to1).
    If V IN is absent, the MP2760 is no longer able to generate its VCC and is completely powered off ==> system is dead.
  2. On USB C reconnect, MP2760 can generate VCC from VIN and boots and generates VSYS which then causes the other system components to boot ==> system is alive.

Question

  1. When BATFET was forced off via I²C, will the MP2760 reset the BGATE_ CTRL flag to 0 after a reset to reconnect the battery or will it sense a missing battery and fail to restart as BGATE_ CTRL is persisted across resets? (I expect all registers to be set to default after a power cycle reset)

  2. Regarding the “Missing battery detection” feature: will the MP2670 halt or continue to operate and feed SYS with VIN when battery is not present?
    From the datasheet:

    Battery Missing Detection
    The MP2760 counts how often charging
    terminates every 10s. If charging terminates
    more than three times in 10s, the MP2760
    reports that the battery is missing in the status
    register and initiates an INT signal.

    Based on my interpretation that means that the MP2760 infinitely loops through 10s cycles trying to detect the battery where within each cycle the battery presence is asserted >3 times. And in addition, after every 10s cycle the INT signal is issued. Then cycling stops once the battery was detected.

    However, whether VSYS is populated during the absence of a battery is not clear.
    Also whether MP2760 continuous charging after connecting a battery is not clear. There are sources that state that similar MP devices don’t tolerate a battery connect event after startup.
    Furthermore, will disabling BATFET (and therefore disconnect the battery) also trigger the “missing battery” detection? I assume the MP2760 senses the BATT pin, which should have a valid VBATT independent from the state of BATFET?
    Will connecting a battery also raise INT?

This is the only uncertainity I have and that I like to sort out before ordering the part for further evaluation.
Thanks for your time!