BC3770 Datasheet, PDF (20/45 Pages) Freescale Semiconductor, Inc – 2.0 A Switch-Mode Charger

5.3.10.1 Charger Enable Control
The CHGEN bit in the control register and CHGENB pin are used to enable or disable the charging process.
CH GENB
300 k _{I2C bit,}
CHGEN=1
Charger
Enabled
Figure 8. Charger Enable
If the CHGENB pin is not used in the application, leave the pin float since CHGENB has an internal 300 k pull-down resistance to ground.
5.3.10.2 Battery Presence Detection
The BC3770 monitors battery presence via the NOBAT pin in any condition. This function utilizes the pull-down resistor on VF in the
battery pack. If no battery is detected, the charging is suspended immediately and the corresponding interrupt event is reported to the
processor via the INTB pin. If the NOBAT pin needs to be connected to an ADC input on the main processor, a resistor-divided
configuration in fig should be done to lower the voltage rating to 1.8 V.
around 1.6V
if no battery
attached _{ADC Input}
S^BM^C5³4⁷⁷18⁰
NO BA T
10⁰0 k^k?^
1₁₀00_0kk_?
+
VF/ID
1-Cell
L i-Io n
Battery
-
Figure 9. Resister Divided Network
If NOBAT is not used as a battery presence indicator, the following configuration is also possible.
S^BM^C35⁷4⁷1⁰8
NO BA T
IO_1 V8
110000kk?
o_or _r
O_ot_th_he_er_r
V_va_alu_lue_e
ADC Input
+
VF/ID
1-Cell
L i-Io n
Battery
-
Figure 10. Resister Divided Network Option
Analog Integrated Circuit Device Data
Freescale Semiconductor
BC3770
20