Rainbow Electronics MAX1507 User Manual
Page 7
MAX1507
Linear Li+Battery Charger with Integrated Pass FET
and Thermal Regulation in 3mm x 3mm Thin DFN
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maintain the battery at full charge. If, at any point while
charging the battery, the die temperature approaches
the user-selected temperature setting (TEMP pin), the
MAX1507 reduces the charging current so the die tem-
perature does not exceed the temperature-regulation
set point.
The thermal-regulation loop limits the MAX1507 die
temperature to the value selected by the TEMP input by
reducing the charge current as necessary (see the
Thermal-Regulation Selection section). This feature not
only protects the MAX1507 from overheating, but also
allows higher charge current without risking damage to
the system.
EN
Charger Enable Input
EN is a logic input (active low) to enable the charger.
Drive EN low, leave floating, or connect to GND to
enable the charger control circuitry. Drive EN high to
disable the charger control circuitry. EN has a 200k
Ω
internal pulldown resistance.
VL Internal Voltage Regulator
The MAX1507 linear charger contains an internal linear
regulator available on the VL output pin. VL requires a
0.47µF ceramic bypass capacitor to GND. VL is regulat-
ed to 3.3V whenever the input voltage is above 3.5V.
SHUTDOWN
CHARGER = OFF
LED = OFF
PRECHARGE
100% CHARGE CURRENT
LED = ON
FAST CHARGE
100% CHARGER CURRENT
LED = ON
FULL BATT CONTINUES
TO REGULATE BATT
UP TO 4.2V
I
CHARGE
< 10%
OF ISET
V
BATT
> 2.5V
V
BATT
< 2.4V
V
BATT
< 2.5V
V
IN
< 7V AND
V
IN
> V
BA
TT
AND
EN = LOW
V
IN
> 7V +
V
BATT
> V
IN
+
EN = HIGH
ASYNCHRONOUS FROM
ANYWHERE
V
IN
> 7V +
V
BATT
> VIN +
EN = HIGH
I
CHARGE
> 20%
OF ISET
FULL BATT
LED = OFF
Figure 2. Charge State Diagram