Datasheet

V
AC
V
USB
V
OUT
V
BAT
Break Before Make
System Capacitance
Powering System
USB is Charging System Capacitance
DPPM Mode
Hi
Low
PSEL
V
BAT
V
OUT
bq24070
bq24071
www.ti.com SLUS694F –MARCH 2006–REVISED DECEMBER 2009
Figure 7. Toggle Mode Low
Figure 8 illustrates when a battery is inserted for power up; channel 1 (CH1) VAC = 0 V; channel 2 (CH2) V
USB
=
0 V; channel 3 (CH3) V
OUT
; output current, I
OUT
= 0.25 A for V
OUT
> 2 V; channel 4 (CH4) V
BAT
= 3.5 V; C
(DPPM)
=
0 pF. When there are no power sources and the battery is inserted, the output tracks the battery voltage if there
is no load (<10 mA of load) on the output, as shown. If a load is present that keeps the output more than 200 mV
below the battery, a short-circuit condition is declared. At this time, the load has to be removed to recover. A
capacitor can be placed on the DPPM pin to delay implementing the short-circuit mode and get unrestricted (not
limited) current.
Figure 8. Insert Battery – Power-Up Output via BAT
Figure 9 illustrates USB boot up and power-up via USB; channel 1 (CH1) V
(USH)
= 0 to 5 V; channel 2 (CH2) USB
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