User's Manual

7
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
Ta ble 4 : Batt ery charger charact erist ics