Hello,
For my application, I need fully automatic operation where the MP2639B (or A) seamlessly switches between VBUS and battery power without any external intervention (no use of the PB pin or dynamic control of MODE).
If I permanently tie the MODE pin to GND (MODE = LOW) and leave the PB pin unconnected, can you please confirm that:
- The IC will charge the battery when VBUS is present.
- The IC will automatically switch to powering VSYS from the battery when VBUS is no longer available.
Are there any limitations or edge cases in this configuration — for example, if the device has previously been put into MODE = HIGH, does that prevent future automatic operation with MODE = LOW?
Thank you in advance for your clarification!
Hello Nicusor.cojocaru,
Could you specify if you are asking if the MP2639B will stay on from battery power when VBUS is disconnected, or are you asking if the IC will supply an output voltage at the IN pin? In your case what functionality from the MP2639B are you hoping to maintain?
Hello again,
I would like to use the MP2639B as a UPS. My question is: when VBUS is disconnected, will the MP2639B seamlessly switch (automatic) to battery power and continue supplying output voltage without interruption, so the load remains powered without reset?
Hello nicusor.cojocaru,
The section titled “internal power supply” on page 18 leads me to believe that IC would power seamlessly. However, I still do not understand the functionality you are looking for from this statement.
Are you looking for power path functionality from MP2639B? Meaning that Vbus provides power to other devices while also charging battery. I do not think this part has that functionality. Please provide a drawing showing where the “output voltage” you are looking for would be.
An example of a part that has the described functionality is shown below. The MP2760 describes this on page 27 of the datasheet
