Hello,

We are planing to use a MP2636 to charge a Li-Ion Battery at low temperatures. Therefore the battery needs a lower charging current (0.2C @ 0-10°C) instead of (0.5C @ higher Temperatures).

Now the 0.2C would be approx. 120mA.

The qestion we can get above ist what the minimum Current is, the chip can deliver.

Due to the fact the datasheet says trickle min is 200mA or 10% of Icc

If i would take this date i would end @ a min ICC of 2A? could this be?

Is it in the end not just Ichg=2400/(Riset x RS1) ?

If yes, where are the limitations of Riset and RS1 regarding values?

Hi gmu,

Thanks for posting on the MPSNow Forum.

The minimum trickle charge current when Ichg = 2.0A is 200mA as stated the EV table on page 6 , (when RS1 = 20mohm, RISET >=60Kohm)

The trickle charge current is dependent on Ichg.

For example, when Ichg = 3A, ITC = 3A(0.1) = 300mA.

RISET and RS1 set the charge current for the charger. I’d recommend using the values stated on page 36 of the table:

Thanks,

Cindy

Hi Cindy

Thank you for your answer. This point about the formulas we got.

But still not sure, does Minimum Trickle Charge Current just state it at the given values, or does it state the minimum the chip can, indipendently of the External values.

The second thing is, as i stated, we would need 120mA Charge current (and therefore 12mA Trickle Charge) if its possible to do whit this chip? If yes, what are the formulas to calculate the relations for RS1 and Riset.

Example: The 2400 / RS1 x Riset could be solved like

120mA=2400/ (20mOhm x 1MOhm) if the 20mOhm is a limit

or

120mA=2400/ (166.66mOhm x 120kOhm) if the 120kOhm is a limit

I assume for RS1 the only Limit is the Efficiency and Power loss over it. Therefore it should be as low as possible. But how high can Riset be choosen?

Thank you in advance for advice.

Hello,

Can you please give me some advice regarding the minimal charging current für the 2636?

Best regards,