MP2607 – LI-ION CHARGER WITH POWER PATH MANAGEMENT

MP2607 Rev. 1.03

www.MonolithicPower.com

12

5/18/2015

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Charging

current

USB port

current

SYS load

current

BATT voltage

SYS voltage

Battery

supplements load

Figure 3—Power Path Management for USB

Mode

Power path management allows use of lower

current limited sources while still provides

continuous system supply and optimal battery

charging at the same time.

USB Mode Input Switch Current Limit

When IN is connected to an USB port, the

switch between IN and SYS has a built-in

current limit that is set by an internal resistor

with typical value of 450mA. Post-package

trimming keeps the variation within +-5%.

Charging Current Thermal Fold-back

MP2607 has internal monitoring circuit that will

reduce the charging current if the chip junction

temperature reaches 120°C. This prevents

overheat of the chip and avoids unnecessary

thermal shutdown.

Floating Charging Voltage

The floating voltage for the constant voltage

regulation phase is 4.2V. It has ±0.75%

accuracy over the ambient temperature range

of -10°C to +70°C.

Auto Recharge

MP2607 automatically recharge the battery if

BATT pin voltage falls below a predetermined

threshold VRECHG. This allows the battery to

always stay at full or near full condition,

increasing the battery life.

Status Indication output

STAT1 and STAT1 are two open-drain NMOS

outputs which should be connected to pull-up

resistors to SYS output or desired supply rail.

Their output logic level combinations are used

to indicate 4 status of the charger:

Regardless of the charger status, however, the

charger does not turn off as long as a valid

input power source is attached.

Charger Status

STAT1

STAT2

Charging

Low

Low

End of Charge

Low

High

Charge Suspended (due

to Battery supplement

mode or NTC out of

range)

High

Low

Fault/Disable

(due

to

time-out,

internal

thermal

shutdown),

EN>2V, or no VIN

High

High

NTC Temperature Sensor

The NTC pin allows MP2607 to sense the

ambient

temperature

using

the

Negative

Thermal Coefficient (NTC) thermistor usually

available in the battery pack to ensure a safe

operating environment of the battery. A resistor

with appropriate value should be connected

from VIN to NTC and the NTC resistor parallel

connected a regular resistor is connected form

NTC pin to ground. The voltage on NTC pin is

determined by the resistor divider whose divide

ratio depends on the ambient temperature.

MP2607 internally sets a pre-determined upper

and lower bound of the divide ratio. If NTC pin

voltage falls out of this range which means the

temperature is outside the safe operating range,

MP2607 will stop charging and report it on

status pins. Charging will automatically resume

after the temperature falls back into the safe

range.

Enable

Enable of MP2607 is controlled by pulling

CEB

pin below 0.3V. Pulling

CEB pin above 2V will

put MP2607 in sleep mode, which disables

power path management and battery charger.

In sleep mode, the N-channel switch between

BATT and SYS is fully on to maintain system

supply. Battery under-voltage and current limit

are kept alive to provide safeguard.