Func�on Descrip�on

Precharge Current

The FC9056 is a linear charger circuit specially designed for

single cell lithium-ion ba�eries. When the FC9056 is

powered with a ba�ery connected, the IC first detects if the

cell voltage is ready for full charge current. If the cell voltage

is less than the prequal level (3V typ), the ba�ery is

precharged with a 55mA current un�l the cell reaches the

proper level. The full charging current, as set by PROG pin, is

then applied

Soft-Start

The FC9056 includes a soft-start function to control the rise rate

of the charging current rising from zero to the fast-charging

current level in constant current mode. During charger soft-start,

the FC9056 ramps up the voltage on PROG pin with constant

well-controlled slew rate. The charging current is proportional to

the PROG voltage. The soft-start time is 20us (typical), which is

independent of the fast-charging current level.

Charging Current Se�ng

The charge current is programmed by using a resistor from

the PROG pin to the ground. The ba�ery charge current is

1000 �mes the current out of the PROG pin. The ba�ery

charge current is calculated by the following equa�on:

charging current set factor and the PROG regula�on voltage

are shown in the Electrical Characteris�cs. The PROG

regula�on voltage is reduced by thermal regula�on func�on.

Battery Full Indication

the FC9056 stopped current mode charging, it keeps operating in

voltage mode without turning off the charger. When the PROG

pin's voltage down to 100mv over 2ms, the charger will stop

operating and the Vcc current down to 55uA.

Charge Status Outputs

The open-drain CHRG and STDBY outputs can be used to drive

LED indicate four charger operations are shown in Table 1.

Charge state

Red LED

（

CHRG）

Greed

LED(STDBY)

charging

bright

extinguish

Charge Termination

extinguish

bright

Vin too low;

Temperature of

battery too low or

too high; no battery

extinguish

extinguish

BAT PIN Connect

10u Capacitance;

No battery

Extinguish

(T=1-4s)

Table1

External Thermistor Monitor (TEMP)

The FC9056 con�nuously detects the ba�ery temperature

by measuring the TEMP pin voltage. A NTC or PTC thermistor

can parallel with R2 to deviate the TEMP pin voltage.

Internal of FC9056, Vlow is preset to 45%*Vcc, Vhigh is

preset to 80%*Vcc, The normal temperature voltage is,

above Vlow and below Vhigh. The TEMP Pin voltage must be

within normal temperature voltage range, and then FC9056

can start working normally. If the TEMP pin voltage above

Vhigh or below Vlow, it means the temperature of the

ba�ery is too high or too low, the charger will be turn off.

The R1 and R2 can be derived from following equa�ons:

For NTC Thermistors:

2

1

th

tl

1

2

th

tl

k

*

K

*

)

R

R

(

)

K

K

(

*

R

*

R

1

R

−

−

=

)

k

*

k

K

(

R

)

K

*

K

K

(

*

R

)

K

K

(

*

R

*

R

2

R

2

1

2

th

2

1

1

tl

1

2

th

tl

−

−

−

−

=

For PTC Thermistors:

2

1

tl

th

1

2

th

tl

k

*

K

*

)

R

R

(

)

K

K

(

*

R

*

R

1

R

−

−

=

2018. 05. 15

6/9

Revision No : 0

FC9056

1A Stand alone Linear Li-Ion Battery Charger with Thermal Regulation