bq24030, bq24031, bq24032,
bq24032A, bq24035, bq24038, bq24039
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SLUS618C–AUGUST 2004–REVISED JUNE 2005
5.4 V; channel 2 (CH2) V(USB) = 5 V; channel 3 (CH3) VOUT; output current, IOUT = 0.25 A; channel 4 (CH4) VBAT
= 3.5 V; and I(PGM-CHG) = 1 A. The USB source is removed (2nd div) and the output drops to the battery voltage
(declares USB bad, 4th div) and switches to AC (in USB mode) and recovers similar to the figure that is switching
to USB power. This power transfer occurred with PSEL low, which means that the AC input is regulated as if it
were a USB.
AC is Applied (USB Mode)
V
AC
AC Hits USB (ISET2) limit
DPPM Mode
V
OUT
V
V
USB
BAT
USB Declared not Present
Figure 10. Remove USB – PWR XFER From USB to AC
Figure 11 illustrates when the battery is absent, power transfers to USB; PSEL = H; channel 1 (CH1) VAC = 5.4
V; channel 2 (CH2) V(USB) = 5 V; channel 3 (CH3) VOUT; output current, IOUT = 0.25 A; channel 4 (CH4) VBAT
I(PGM-CHG) = 1 A. Note the saw-tooth waveform due to cycling between charge done and refresh (new charge).
;
V
AC
V
USB
OUT
V
V
BAT
BAT PIN Capacitance Discharging to Refresh Threshold
Charging (Step) Followed by Charge Done
Figure 11. Battery Absent – PWR XFER to USB
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