I have a question
if Vin power off but VOUT power is supplied by ups power block(VOUT= 4.2) (UPS OUT=4.2~3.6)
when then mp24943 ok? and how much consum a Quiescent current in mp24943 IC?
Hi LSWAIN82,
The quiescent current for the MP24943 is listed on Pg. 3 of the datasheet:
I will get back to you on if the MP24943 would be fine in this situation.
thank you i am awaiting feedback !~
Hi LSWAIN82,
The 4.2V output will power the device through the body diode of the high-side switch. Even though the Vout is biased high, the device will keep switching and can actually boost to the input which obviously is not a good thing. I would advise against this unless you add a diode, or better yet a switch, at the output to block the reverse bias if possible. I would also recommend using a newer, synchronous device like the MP4570 along with the diode/switch on the output.
Thank you solution
I will change the power IC from mp24943 to mp4570.
We plan to use LC filters instead of diodes and switches to prevent output noise.
Except for the output noise when the power is off, is there a problem with the durability of the part?
** Power off situation means floating or ground or low voltage.
(In unexpected circumstances, Vin and EN pins are separated by power supply)
Hi LSWAIN82,
I think there’s a misunderstanding. You will need a switch or diode on the output of the converter (MP24943 or MP4570) that will disconnect it from the 4.2V of your UPS when the converter is not regulating. The converter and your whole system will not function properly if the converter’s output is pulled high when it is not regulating or receiving an input.