BQ24030_07 Datasheet, PDF (19/38 Pages) Texas Instruments – SINGLE-CHIP CHARGE AND SYSTEM POWER-PATH MANAGEMENT IC (bqTINY)

bq24030, bq24031, bq24032A
bq24035, bq24038
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SLUS618F – AUGUST 2004 – REVISED NOVEMBER 2006
Figure 10 illustrates when USB is removed, power transfers from USB to AC; PSEL = L; channel 1 (CH1) VAC =
5.4 V; channel 2 (CH2) V_(USB) = 5 V; channel 3 (CH3) V_OUT; output current, I_OUT = 0.25 A; channel 4 (CH4) V_BAT
= 3.5 V; and I_(PGM-CHG) = 1 A. The USB source is removed (2^nd div) and the output drops to the battery voltage
(declares USB bad, 4^th 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)
AC Hits USB (ISET2) limit
DPPM Mode
USB Declared not Present
V_AC
V_OUT
V_USB
V_BAT
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) V_OUT; output current, I_OUT = 0.25 A; channel 4 (CH4) V_BAT;
I_(PGM-CHG) = 1 A. Note the saw-tooth waveform due to cycling between charge done and refresh (new charge).
V_AC
V_USB
V_OUT
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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