MP2625B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH CONTROL

MP2625B Rev. 1.01

www.MonolithicPower.com

20

1/15/2018

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

Input re-startup



Refresh EN

_____

/ISET signal



Auto-Recharge

NTC Thermistor

The NTC pin allows MP2625B to sense the

battery temperature using the Negative Thermal

Coefficient (NTC) thermistor usually available in

the battery pack to ensure safe operating

environment of the battery. A resistor with

appropriate value should be connected from VCC

to NTC and the NTC resistor is from NTC pin to

AGND. The voltage on NTC pin is determined by

the resistor divider whose divide ratio as the

different resistance of the NTC thermistor

depends on the ambient temperature of the

battery.

The MP2625B has an internal NTC voltage

comparator to set the upper and lower limit of the

divide ratio. If NTC pin voltage falls out of this

range it means the temperature is outside the

safe operating range,

As a result, The MP2625B will stop charging and

report it on indication pins. Charging will

automatically resume after the temperature falls

back into the safe range.

Thermal Protection

The MP2625B implements thermal protection to

prevent the thermal damage to the IC or

surrounding components. An internal thermal

sense and feedback loop will automatically

decrease the charge current when the die-

referred as charge current thermal fold-back.

This

feature

protects

the

MP2625B

from

excessive temperature due to high power

operation or high ambient thermal conditions.

Another benefit of this feature is charge current

can be set according to the requirement rather

than worst-case conditions for a given application

with the assurance of safe operation. The

MP2625B will stop charging if the junction

thermal shutdown protection.

Battery Discharge Protection

When the input power is removed or invalid, the

system load will draw power from the battery via

the battery switch. Under this condition, the

battery switch is fully on to minimize the power

loss. The MP2625B integrates battery discharge

protection. If the battery discharge current is

larger than the discharge current limit threshold

preset limited value. And if the current increases

further, the SYS voltage starts to decrease.

condition, the discharge current is limited at

230mA. In the event of a short from system to

GND the discharge current from the battery to

the system is also limited to 230mA.

Furthermore, battery voltage UVLO is always

monitored. If the battery voltage is lower than the

battery UVLO threshold, the battery switch is

turned off immediately. This feature makes sure

the battery from over-discharged.

Dynamic Power Path Management (DPPM)

In the presence of a valid input source, the PWM

converter will supply the current to both the

system and the battery charger.

3.4V, to ensure the system can still be powered

regulated at constant 3.6V.

When the input source is overloaded, either the

current exceeds the input current limit or the

voltage falls below the input voltage limit, the

MP2625B then reduces the charge current until

the input current falls below the input current limit

and the input voltage rises above the input

voltage limit. If the system current increases

beyond the power allowed by the input source,

additional power will be drawn from the battery

via an on-chip 40mΩ MOSFET working as an

ideal diode.

Additionally, if the input source is removed, the

MP2625B will turn on the 40mΩ MOSFET

allowing the battery to power the system load to

keep the operation of the portable device.

Operation Flow Chart

Figure 5 shows the operation flow chart of the

MP2625B.

Figure 6 shows the operation process.