BQ24140_14 Datasheet, PDF (21/39 Pages) Texas Instruments – Integrated Dual-Input Switch-Mode One-Cell Li-Ion Charger with Full USB Compliance and USB-OTG Support

bq24140
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SLUSAO5 – OCTOBER 2011
BAD ADAPTOR DETECTION
At POR of VBUS or VIN, the IC performs the bad adaptor detection by applying a current sink of 30mA to the
valid power pin. If the power pin is higher than VIN(MIN) for 30ms, the adaptor is good and the charge process
begins. Otherwise, if the power pin drops below VIN(MIN), a bad adaptor is detected. Once a bad adaptor is
detected, the IC disables the current sink, sends a send fault pulse in FAULT pin and sets the bad adaptor flag
(B2-B0=011 for Register 0x00). After a delay of T_INT, the IC repeats the adaptor detection process, as shown in
the flowchart below:
VIN or VBUS POR
Delay 1ms
Enable Adaptor Detection
Start 30ms timer
No
Enable 30mA current source
VIN or VBUS
>
Yes
V_{IN MIN}?
30ms Timer
expired?
No
Bad Adaptor Detected
Pulse STAT pin
Set Bad Adaptor Flag
Good Adaptor Detected
Disable Adaptor Detection
Start Charge
Enable V_{IN DPM}
Delay TINT
2s
Figure 20. Bad Adaptor Detection
BATTERY DETECTION
Battery detection during charging
During normal charging process with host control, once the voltage at the VBAT pin is above the battery
recharge threshold, V_OREG–V_RCH, and the termination charge current is detected, the IC turns off the PWM
charge and enables a discharge current, I_DETECT, for a period of t_DETECT, then checks the battery voltage. If the
battery voltage is still above recharge threshold, the IC concludes that the battery is present and charge is
completed. On the other hand, if the battery voltage is below battery recharge threshold, the IC concludes that
the battery was removed. Under this condition, the charge parameters (such as input current limit) are reset to
the default values and charge resumes after a delay of t_INT. This function ensures that the charge parameters are
reset whenever the battery is replaced.
Copyright © 2011, Texas Instruments Incorporated
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