User's Manual

14
3.4 Battery charger
Battery charger
Min
Typ
Max
Unit
VDD_CHG
4.5
-
6.5
V
Charging mode (VDD_BAT rising to 4.2 V)
Supply current
(a)
-
4.5
6
mA
Battery trickle charge
current
(b) (c)
Maximum setting
-
14
-
mA
Minimum setting
-
4
-
mA
Maximum battery fast
charge current
(d) (c)
Headroom > 0.7 V
(e)
-
140
-
mA
Headroom = 0.3 V
-
120
-
mA
Minimum battery fast
charge current
(d) (c)
Headroom > 0.7 V
-
40
-
mA
Headroom = 0.3 V
-
35
-
mA
Trickle charge voltage threshold
-
2.9
-
V
Float voltage (with correct trim value set),
V
FLOAT
(f)
4.17
4.2
4.23
V
Float voltage trim step size
(f)
-
50
-
mV
Battery charge termination current, as a
percentage of the fast charge current
5
10
20
%
Standby Mode (BAT_P falling from 4.2V)
Supply current
(a)
-
1.5
2
mA
Battery current
-
-5
-
μA
Battery recharge hysteresis
(g)
100
-
200
mV
Shutdown Mode (VDD_CHG too low or disabled by firmware)
VDD_CHG under-
voltage
threshold
VDD_CHG rising
-
3.9
-
V
VDD_CHG falling
-
3.7
-
V
VDD_CHG - BAT_P
lockout
threshold
VDD_CHG rising
-
0.22
-
V
VDD_CHG falling
-
0.17
-
V
Supply current
-
1.5
2
mA
Battery current
-1
-
0
μA
(a)
Current into VDD_CHG - does not include current delivered to battery (I VDD_CHG - I BAT_P)
(b)
BAT_P < Float voltage
(c)
Charge current can be set in 16 equally spaced steps
(d)
Trickle charge threshold < BAT_P < Float voltage
(e)
Where headroom = VDD_CHG - BAT_P
(f)
Float voltage can be adjusted in 15 steps. Trim setting is determined in production test and must be loaded into the battery
charger by firmware during boot-up sequence
(g)
Hysteresis of (VFLOAT - BAT_P) for charging to restart
Table 4: Battery charger characteristics