MP2617 – SINGLE CELL SWITCHING CHARGER WITH POWER PATH CONTROL

MP2617 Rev. 1.03

www.MonolithicPower.com

17

8/23/2013

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When both M0 and M1 are float, they are pulled

to the logic high, under this condition, the input

current is limited to a default value of 2A.

Table 1―Input Current Limit Setting

M0

M1

Mode

Low

Low

USB2.0 Mode

Low

High

USB3.0 Mode

High

Low

Programmable Mode

High/Float High/Float Default Mode

Input Voltage Limit Setting

The input voltage can be limited at a value set by

a resistor divider from IN pin to VLIM pin to

AGND according to the following expression

(Typical Application Circuit):

IN_LIM

R1+R2

V

=1.52

(V)

R2

×

When the voltage on VLIM pin drops and hits the

reference voltage 1.52V, the input voltage will be

clamped to the setting value.

Battery Charger

The MP2617 completes charge operation consist

of trickle charge, automatic charge termination,

charge status indication, timer control, NTC

indication, automatic recharge, and thermal

limiting.

When the PWM converter is out of soft start, the

battery charge cycle begins, the MP2617 first

determines if the battery is deeply discharged. If

the battery voltage is lower than the trick charge

threshold (typical 3.0V), the battery charger starts

in “trickle charge mode”. The trickle charge

current is limited to 10% of the programmed

charge current until the battery voltage reaches

3.0V. If the charge stays in the “trickle charging

mode” for longer than 45 minutes, the “timer out”

condition is triggered, the charge is terminated

and CHGOK

_____________

will start blinking to indicate that the

battery is unresponsive. When the battery

voltage is above 3.0V, the charger is operating at

“constant current mode.” The current delivered to

the

battery

will

try

to

reach

the

value

programmed by the ISET pin. Depending on the

available input power and system load conditions,

the battery charger may or may not be able to

charge at the full programmed rate. The system

load is always satisfied first over the battery

charge current. If the system load requirement is

low, the battery can be charged at full constant

current.

When the battery voltage reaches the battery full

threshold, the charger enters the “constant

voltage mode” operation.

End of Charge (EOC) and Indication

In constant voltage charge mode, the battery

voltage is regulated at 4.2V (when SYSFB is float

or SYS is programmed higher than battery full

threshold) and the charge current decreases

naturally. Once the charge current hits the

charge current), the battery is fully charged and

charge cycle is terminated.

any limit condition, the MP2617 will come out of

CV mode, and the charge full detection is invalid.

A safe timer starts at the beginning of each new

charge cycle and it monitors if the whole charge

period is within the programmed time limit. After

each charge cycle, when the battery is indicated

as full, the timer counter will be reset. If the time

is expired while the charging is still on going, the

timer will force the MP2617 to terminate charging

CHGOK

_____________

is blinking to indicate the fault condition.

If system voltage is programmed lower than 4.2V

by the resistor divider at the SYSFB pin, the

During charging, the PWM converter continues to

power the system at the same time, if the system

load increases over the input current limit, the

battery charger will change to “ideal diode mode”.

is triggered, the ideal diode mode is enabled,

the ideal diode mode is disabled as shown in

Figure 3.