LTC4006 Datasheet, PDF (6/16 Pages) Linear Technology – 4A, High Efficiency, Standalone Li-Ion Battery Charger

LTC4006
BLOCK DIAGRA
V_IN
DCIN
1
0.01µF
INFET
5.8V
Q3
16
ACP/SHDN 3
CLN
I_CL
1.105V
708mV
TIMER/CONTROLLER
RESTART
LOBAT
35mV
25µA
CHG ^100k
2
OSCILLATOR
4 ^RT
R_RT
T_BAD
THERMISTOR
NTC ^32.4k
6
0.47µF
C/10
397mV
GND
5
1.19V
5.1k
R_CL 15nF
CLP
11
CLN
12
–
100mV
CL1
+
g_m = 1.5m^Ω
+
EA
–
g_m = 1m^Ω
20µF
DCIN
OSCILLATOR
WATCH DOG
DETECT t_OFF
OV
1.28V
11.67µA
CA1
3k
BAT
10
R_SENSE
CSP
9
3k
g_m = 1m^Ω
CA2
9k
1.19V
BUFFERED I_TH
÷5
I_TH
7
6.04k
0.12µF
V_LOGIC
10k
NTC
20µF
TGATE
Q1
13
BGATE
Q2
15
PGND
14
L1
S
Q
R
PWM CHARGE
LOGIC
I_REV
–+
I_CMP
17mV
R_IMON1
26.44k
I_MON
8
4.7nF
R_IMON2
52.87k
4006 BD
U
OPERATIO
Overview
The LTC4006 is a synchronous current mode PWM step-
down (buck) switcher battery charger controller. The charge
current is programmed by the sense resistor (R_SENSE)
between the CSP and BAT pins. The final float voltage is
internally programmed to 8.4V (LTC4006-6), 12.6V
6
(LTC4006-2) or 16.8V (LTC4006-4) with better than ±0.8%
accuracy. Charging begins when the potential at the DCIN
pin rises above the voltage at CLN (and the UVLO voltage)
and the ACP/SHDN pin is allowed to go high; the CHG pin
is set low. At the beginning of the charge cycle, if the cell
voltage is below 2.5V, the charger will trickle charge the
battery with 10% of the maximum programmed current.
sn4006 4006is