BQ24072T_1 Datasheet, PDF (21/34 Pages) Texas Instruments – 1.5A USB-Friendly Li-Ion Battery Charger and Power-Path Management IC

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bq24072T
bq24075T, bq24079T
SLUS937A – DECEMBER 2009 – REVISED APRIL 2010
CHARGE CURRENT TRANSLATOR
When the charger is enabled, internal circuits generate a current proportional to the charge current at the ISET
input. The current out of ISET is 1/400 (±10%) of the charge current. This current, when applied to the external
charge current programming resistor, R_ISET, generates an analog voltage that can be monitored by an external
host to calculate the current sourced from BAT.
V_ISET = I_CHARGE / 400 × R_ISET
Begin Charging
Yes
Battery short detecte?d
No
Start Precharge
/CHG= Low
No
VBAT > VLOWV
Yes
Start Fastcharge
ICHARGE set by ISET
IBAT < ITERM
No
Yes
Charge Done
/CHG= Hi-Z
No
tPRECHARGE
Elapsed?
End Charge
Flash/CHG
No
tFASTCHARGE
Elapsed?
End Charge
Flash/CHG
TD= Low
(’72, ’73 Only)
No
(’74, ’75= YES)
Yes
Termination Reached
BATTFET Off
Wait for VBAT < VRCH
No
VBAT < VRCH
Yes
Run Battery Detection
No
Battery Detecte?d
Yes
Figure 33. Battery Charging Flow Diagram
Copyright © 2009–2010, Texas Instruments Incorporated
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