MPS EV2637A-R-00A, Manual, Page: 6 / 8

EV2637A-R-00A –2.5A SINGLE-CELL SWITCH MODE BATTERY CHARGER
EV2637A-R-00A Rev. 1.0 www.MonolithicPower.com
6
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6. Charge Timer
The MP2637A has a charge timer as an extra precaution against charging damaged batteries. The
total charge time can be set as:
6
TMR
TOTAL _ TMR
CHG
3.4 10 1.6(V) C ( F)
(s)
1.25 I (A) RS1(m ) 2( A)
   
 
    
(5)
So if the charge current is 2.5A, a C
TMR
of
0.1μF provides a t
TOTAL_TMR
of 2.4 hours.
Boost Mode
1. System Output Voltage
The MODE pin can enable or disable the EV2637A when in boost mode. The resistor divider
–R1
and R2
–can adjust the output voltage as per the following equation:
2
2 1
15 . 1 ) (
_
R
R R
V V V
REG SYS

 
(6)
Select R1 and R2 as 31.6kΩ and 10kΩ, respectively, for a system voltage of 4.8V.
2. System-Output-Current Limit
Set the system-output-current limit in boost mode for the EV2637A to operate like a standard
adapter. Set the output current limit as per the following equation:
OLIM
OLIM
2400
I (A)
R (k ) RS1(m )

  
(7)
For the other detailed description on the operation of the MP2637A, please refer to the
datasheet.