Hello. we have design MP2760 to 1 cell batttery with 12V dc input. When systme operating current rappid raising from 2A to 3.5A in ms, there will 0.3~0.5V votlage drop with dead or no battery. It cause sytem shut down unexpectly. IIN_LIM and fsw already set to 4.836A and1000Khz.
Could you help on this issue?
Would you shorlty explain the root cause, and how to aviod this issue, when we select an charging ic?
Hello Hilary,
I wanted to see if we could get some more information of your issue such that we may find the root cause to your problem.
Are you able to provide a schematic of your MP2760 design? However just by initially reading this, I can see that since the load rapidly increases from 2A to 3.5A which causes a voltage drop (and no battery to buffer this change) the input capacitance may not be enough to stabilize the voltage at the input. Possibly adding some low-ESR input caps could help smoothen out the input and prevent spikes.
Another issue could be your IIN_LIM setting. increasing this limit will make the MP2760 pull more current during load transients, which would reduce the risk of voltage drops. Be sure you are setting this limit below 6A.
Hope to hear back from you and hope this helps.
Best,
Krishan
Thanks for your reply. I update schematics here.
I find the the voltge drop was happened on link LTE function.
the current is decrease to 0.3A~0.5A, but 0.3~0.5V votage drop still there. I also tried adding 100uF ,IIN_LIM setting is 4.836A , but they are not works
Hello again Hilary,
There doesn’t appear to be anything alarming about the way you have set up your schematic as it aligns well enough with the datasheet. Perhaps there may be a layout issue with your board? Ensure that you have adhered to the following as specified in the MP2760 datasheet:
If your issue is not addressed from this, then perhaps there is some initialization or register setup issue that is limiting your current in which case I would encourage more in depth support with the engineers at MPS Now Technical Support.
Best,
Krishan
Hi Krishan
Thanks for you sharing.
Could you help review my layout as below?
The shap is similar with datasheet, but gnd vias number and location are a liitle different. could you figure any doubts that cause the issue?
Hello Hilary, it is a bit hard to review this screenshot of your layout. Please defer to the following guidelines as previously posted. If you require more in depth and prompt support for a lower-level analysis, please submit a ticket to MPS Now Tech Support as also previously posted.
When you do submit a ticket, it may also be useful to provide not just your layout, but any updates to the schematic and perhaps a register file as well to see how all bits in this part are set. A 0.3-0.5V voltage drop from a current increase from 2A to 3.5A may also be caused by a software issue since there are no apparent issues with the schematic.
Best,
Krishan