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Does the MCP73831 have a way to set a protection to shut down the main output if the supply voltage is too low?

I would like to implement (without coding) a protection which disconnects the cell if its voltage is below 3 V.

For example, in the TPS61200 (from TI,) this feature can be implemented by a special resistance divider. I don't see this feature in the MCP7381's datasheet, but I see UVLO and I wonder how to use it to set a 3V threshold.

MCP73831 datasheet

Karlsson
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    The charger is a charger - not a battery management IC. As the battery IS the output the IC cannot disconnect the load regardless of its functionality. Your question is phrased in terms of "how do I make this solution fit my need". A preferable approach is to fully specify your requirement and ask for solutions. By all means also then suggest possible solutions and tell us what you have attempted and thought of. You need to supply all available information - web links if available - battery capacity and model, target charge rates, input supply characteristics, more ... . – Russell McMahon Jan 18 '21 at 00:07
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    It may be that low cost off the shelf TP4056 modules with separate battery and Vout ports do what you want. Until we know what you actually want this cannot be guaranteed. – Russell McMahon Jan 18 '21 at 00:07
  • @bodzio_stawiski This site does not follow the forum format, take the tour (which teaches you how to use the site). You posted an answer to the question that wasn't an answer. Help->Tour – Voltage Spike Jan 20 '21 at 16:16
  • I just answered to the Russell's post, because he wanted me to precise some information. I – Karlsson Jan 20 '21 at 22:32

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The charger is a charger - not a battery management IC. As the battery IS the output the IC cannot disconnect the load regardless of its functionality.

The UVLO action is detailed on section 4.1 of the datasheet.
UVLO is asserted if Vin is less than about 3.4 V (see datasheet page 3). You COULD use this feature in conjunction with an output switch and battery voltage sensing and possibly voltage offsetting BUT this would be a very complex approach given that there are existing devices that do what you want.

Your question is phrased in terms of "how do I make this solution fit my need". A preferable approach is to fully specify your requirement and ask for solutions. By all means also then suggest possible solutions and tell us what you have attempted and thought of.

You need to supply all available information - web links if available - battery capacity and model, target charge rates, input supply characteristics, more ... .

It may be that low cost off the shelf TP4056 modules with separate battery and Vout ports do what you want. Until we know what you actually want this cannot be guaranteed.

TP4056 battery cutoff voltage alteration.

Summary: Lower the "battery" voltage seen by DW01 so that higher low-battery threshold is achieved.

The circuit diagram of a typical TP4056 modules with included low battery isolation is given below.

You'd need to look at the DW01 data sheet (which is available) to be sure but 'at a glance' it appears that by putting a resistive divider on pin 5 of the DW01 to lower the voltage that it 'sees' that you may be able to raise the low battery cutoff voltage.
Failing that, adding a comparator on pin 5 that switches when target Vbat_low is reached would allow any desired low battery value above the original one to be set.

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Russell McMahon
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  • Thank you for the reply:) How much "complex" would it be? On the other hand, it would be better for me to use MCP73831 as a charger and protection IC in the same time. Another, typical protection ICs like DW-01 have too small voltage threshold (about 2.5 V). MCP73831's ~3.4 is ok for me :) – Karlsson Jan 19 '21 at 10:24
  • I plan to use 14500 cell and I expect to use in normal discharge <1A. – Karlsson Jan 19 '21 at 10:48
  • @bodzio_stawski See addition to my answer re possibility of raising DW01 low battery threshhold. It would be "easy enough" to replace the DW01 with a comparator to drive the FS8205A back to back FETs. Note that a divider in the DW01 front end will draw battery current at all times. How high resistor values can be used depend on the DW01 spec. – Russell McMahon Jan 19 '21 at 12:39
  • Ok, now i understand how to adjust too low voltage threshold. But the MCP73831 by itself won't do it, if I understand correctly. (from page 13 of MCP73831 datasheet) The UVLO circuit is always active. Whenever the input supply is below the UVLO threshold or within +50 mV of the voltage at the VBAT pin, the MCP73831/2 are placed in Shutdown mode. – Karlsson Jan 19 '21 at 22:29
  • This is the only reference to what UVLO is used for in this arrangement. From this I also conclude that the MCP73831 is not applicable to cut-off the 3.4 V cell voltage on its own. Of course, page 3 shows that value, but for me, it looks as if this value determines whether the system turns on the charging or not, instead of cutting off the cell itself. It would be enough for me if I had a system that would cut the cell from the receiving circuit powered by this cell at e.g. 3.4 V. – Karlsson Jan 19 '21 at 22:29