MP2617A, MP2617B

– SINGLE CELL SWITCHING CHARGER WITH POWER PATH

MP2617A, MP2617B Rev. 1.23

www.MonolithicPower.com

21

1/15/2018

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© 2018 MPS. All Rights Reserved.

of the following events happens, the timer is

refreshed and the MP2617A and MP2617B re-

starts the charge cycle.



Input re-startup



Refresh EN

_____

/ISET signal



Auto-Recharge

NTC Thermistor

The NTC pin allows MP2617A and MP2617B 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 MP2617A and MP2617B 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 MP2617A and MP2617B 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

MP2617A

and

MP2617B

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-temperature rises to about 120

function is referred as charge current thermal

fold-back. This feature protects the MP2617A

and MP2617B 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 MP2617A and MP2617B will stop

charging if the junction temperature rises above

150

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 MP2617A and MP2617B integrates

battery

discharge

protection.

If

the

battery

discharge current is larger than the discharge

regulated at the preset limited value. And if the

current increases further, the SYS voltage starts

Under this 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

MP2617A and MP2617B 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

MP2617A and MP2617B will turn on the 40m

Ω