AIC1790 Datasheet, PDF (11/19 Pages) Analog Intergrations Corporation – 1 Cell Linear Lithium-Ion Battery Charger

AIC1790
 ^{PIN DESCRIPTIONS}
IN Pin:
Charge input voltage. (For MSOP10
package, this input must be tied to
the VCC pin.)
VCC Pin: VCC supply input. (For MSOP10
package)
STAT1 Pin: Charge status output 1 (open-drain).
STAT2 Pin: Charge status output 2 (open-drain).
(For MSOP10 package)
 ^{APPLICATION INFORMATIONS}
The AIC1790 is a Li-ion and Li-Pol linear charge de-
vice. It supports a precision Li-Ion, Li-Pol charging sys-
tem suitable for single-cells. The function flow chart
and the typical charging profile are shown in figure 13
and figure 14, respectively.
Battery Precharge Current
During a charge cycle, the AIC1790 provides a
precharge current to revive the deeply discharged bat-
tery if the battery voltage is lower than the V_(LOWV). The
precharge current can be determined by the resistor
connected between the ISET pin and VSS pin, R_SET.
I_{OPRECHG}

V_{PRECHG}  K _{SET}
R_SET
The V_(PRECHG) and K_(SET) parameters are specified in
the specifications table. During the precharge period,
the safety timer, t(_PRECHG), can be activated. If the bat-
tery voltage cannot reach the V_(LOWV) within the timer
period, the AIC1790 can terminate the precharge ac-
tion and indicates FAULT on the STAT1 and STAT2
pins.
Battery Charge Current
The AIC1790 provides a constant charge current to
charge the battery when the battery voltage is between
the V_(LOWV) and V_O(REG). The charge current can be de-
VSS Pin:
ISET Pin:
PG Pin:
TS Pin:
BAT Pin:
OUT Pin:
Ground input.
Charge current set point.
Power good status output.
Temperature sense input.
Battery voltage sense input.
Charge current output.
termined by the resistor connected between the ISET
pin and VSS pin, R_SET.
I_{OOUT }

V_{CHG}  K _{SET}
R_SET
The V_(CHG) and K_(SET) parameters are specified in the
specifications table.
Battery Voltage Regulation
The AIC1790 monitors the battery-pack voltage
through the BAT pin. When the battery voltage rises to
V_O(REG), the AIC1790 will enter voltage regulation mode
and the charge current will begin to decrease.
During the charge period, the safety timer, t(_CHG), can
be activated. If the taper threshold, I_O(TAPER), is not de-
tected within the timer period, the AIC1790 can termi-
nate the charge action and indicates FAULT on the
STAT1 and STAT2 pins.
Charge Taper Detection and Termination
Once the taper threshold is detected during the voltage
regulation period, the AIC1790 initiates the taper timer,
t_(TAPER). The AIC1790 can terminate the charge action
after the timer expires. The taper detection level can
be determined by the resistor connected between the
ISET pin and VSS pin, R_SET.
11