MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER

MP2612 Rev. 1.0

www.MonolithicPower.com

13

9/7/2011

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0.1uF

C

30mins

T

TMR

TICKLE_TMR





The total charge time is:

0.1uF

C

3hours

T

TMR

TOTAL_TMR





Negative

Thermal

Coefficient

(NTC)

Thermistor

The MP2612 has a built-in NTC resistance

window comparator, which allows MP2612 to

sense the battery temperature via the thermistor

packed internally in the battery pack to ensure a

safe operating environment of the battery. A

resistor with appropriate value should be

connected from VREF33 to NTC pin and the

thermistor is connected from NTC pin to GND.

The voltage on NTC pin is determined by the

resistor divider whose divide ratio depends on

the battery temperature. When the voltage of pin

NTC falls out of NTC window range, MP2612 will

stop the charging. The charger will restart if the

temperature goes back into NTC window range.

Power Path Management

Using MP8110 together with MP2612 can

implement a switching charger circuit with power

path management function, which realizes the

current sharing of the charger and system load

(Figure 2). In another word, MP8110 senses the

system current and feeds back to MP2612 and

MP2612 reduces charge current according to the

increase of the system current.

However, after the charge current decrease to 0,

the system current can only be limited by the

adapter.

The system current is satisfied first and always. It

chooses the adapter as its power source when

the adapter plugs in, and the battery is the

backup power source when the adapter is

removed.

Figure 4 to 8 shows the charge profile, operation

waveform and flow chart, respectively.