EV2637A-R-00A –2.5A SINGLE-CELL SWITCH MODE BATTERY CHARGER
EV2637A-R-00A Rev. 1.0
www.MonolithicPower.com
5
10/11/2019
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QUICK START GUIDE
This board is designed for the MP2637A, a stand-alone switch-mode battery charge management and
system power path management device with integrated reverse directional boost from BATT to SYS.
The board’ layout accommodates most commonly-used capacitors. The default function of this board is
preset at charge mode, and the charge full voltage is preset to 4.2V for a 1-cell Li-Ion battery.
Charge Mode Setting
1. Input-Over-Voltage-Limit
The MP2637A has a PWIN pin to monitor the input voltage. Once the voltage input voltage at PWIN
pin exceeds 1.15V, the input to system path is cut off to protect the device from being damaged.
The maximum input is 6V, and the external resistor divider must meet the following equation:
PWIN
IN
V
1.15
RL
V
6
RH RL
(1)
Assume that RL=5.1k
Ω, then RH is 21.5kΩ.
2. REG Voltage
When the input power source is not sufficient to support both the charge current and system load
current, the charge current is reduced to allow priority of system power and maintain the input
voltage avoid dropping further. The REG pin is the input-voltage regulation feedback. The input
voltage can be regulated by a resistor divider from VIN pin to REG pin to AGND
)
(
4
4
R3
15
.
1
V
R
R
V
V
REG
(2)
If V
REG
=4.75V, given R4=5.1k
Ω, then R3=15.8kΩ.
3. Input Current Limit
An input current limit can be set slightly below the
input source’s maximum current rating. When the
input current hits this limit, the charge current will decrease to keep the input current constant at the
limit value to initially power the system. R
ILIM
—the resistor connected to the ILIM pin—programs this
limit. To set the input current limit at 2.7A, use an R
ILIM
of 16.5k
Ω.
ILIM
ILIM
45(kV)
I
(A)
R
(k
Ω)
(3)
4. Charge-Full Voltage
To set the charge-full voltage, either leave the VB pin floating, or connect it to high logic for 4.055V
and to connect to GND for 4.2V.
5. Charge Current
The charge current can be programmed via both RS1 and R
ISET
. With given RS1=20m
Ω, determine
the charge current using the following formula:
CHG
ISET
2400
I
(A)
R
(k ) RS1(mA)
(4)
For example, for a charge current of 2.5A, use a 47.5k
Ω R
ISET
.