BQ24150A Datasheet, PDF (17/41 Pages) Texas Instruments – Fully Integrated Switch-Mode One-Cell Li-Ion Charger With Full USB Compliance and USB-OTG Support

bq24150A
bq24151A
www.ti.com ..................................................................................................................................................................................................... SLUS931 – APRIL 2009
Charge Start
Start T32min
Timer
Reset Charge
Parameters
Yes
Start T32sec
Stop T32min
No
Yes
T32min Active?
Yes
Any I²C Write-
No
Action?
T32min
Expired?
T32sec Expired?
No
Charge
No
Host Should Reset
T32sec Timer
Yes
Timer Fault
(a)
Charge Start
(From Host Control)
T32sec Expired?
Yes
Timer Fault
Stop Charge
No
Charge
Host Should Reset
T32sec Timer
(b)
Figure 25. Timer Flow Chart for (a) bq24150A and (b) bq24151A in Charge Mode
USB Friendly Boot-Up Sequence
At power on reset (POR) of VBUS, if the battery voltage is above the weak battery threshold, V_(LOWV), bq24150A
operates in a mode dictated by the I²C control registers. If the battery voltage is below V_(LOWV) and the host
control through I²C interface is lost (32 minute mode), the bq24150A resets all I²C registers with default values
and enable the charger with an input current limit dictated by the OTG pin voltage level until the host programs
the I²C registers. During this period, the input current limit is 100 mA when the voltage level of OTG pin is low;
while the input current limit is 500 mA when the voltage level of OTG pin is high. This feature can revive the
deeply discharged cell. The charge process continues even the battery is charged to the regulation voltage
(default at 3.54 V) since termination is disabled by default. In another case, if the battery voltage is below
V_(LOWV), but the host control using I²C interface is available (32 second mode), the bq24150A operates in a mode
dictated by control registers. However, at POR of VBUS, bq24151A goes to high impedance mode even the
battery voltage is below V_(LOWV) and no host control through I²C interface is available. That is the major
difference between bq24150A and bq24151A.
Copyright © 2009, Texas Instruments Incorporated
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