MP26028 Datasheet, PDF (9/11 Pages) Monolithic Power Systems – 1A Linear Li-Ion Battery Charger with Trickle Charge

MP26028 – 1A LINEAR LI-ION BATTERY CHARGER WITH TRICKLE CHARGE
Charge Status Indicator (CHG)
The MP26028 has an integrated charge status
pin that remains low while the battery is
charging. Once the charge current has reduced
to the battery full charge current threshold (I_BF),
the CHG pin will become high impedance.
The ACOK and CHG can be used to drive
LEDs ( Figure 1) or to interface with the system.
When interfacing with the system, glitches may
occur on the power supply input (IN) when the
AC-power adapter is plugged in and out. It is
desirable to blank the glitches so that the
system can properly operate with AC power
adaptor. A simple Solution is to add the RC
filter (C5 and C6)on the pin ACOK / CHG as
shown in Figure 5. The size of C5 and C6
depends on the width of the glitch and the rise
time of the interface.
Thermal Protection
The MP26028 has proprietary thermal
protection to prevent the IC from overheating.
When in thermal protection mode, the charge
current becomes a saw-tooth waveform instead
of a DC current. The average current of the
saw-tooth waveform will be lower than the
programmed DC charge current to prevent the
IC from overheating. The frequency and
amplitude of the saw-tooth current waveform
can be altered by changing the capacitance
value connected to the SS pin. Operating in
thermal protection mode will slow down the
charging process. Lowering the input voltage
and enhancing thermal dissipation to the
environment can effectively prevent the IC from
going into thermal protection mode.
Figure 5—Filtered Charge Status & Input Power Good Interface
MP26028 Rev.1.01
www.MonolithicPower.com
9
10/28/2011
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