BQ24030_07 Datasheet, PDF (26/38 Pages) Texas Instruments – SINGLE-CHIP CHARGE AND SYSTEM POWER-PATH MANAGEMENT IC (bqTINY)

bq24030, bq24031, bq24032A
bq24035, bq24038
SLUS618F – AUGUST 2004 – REVISED NOVEMBER 2006
www.ti.com
If the short is removed, and the minimum system load is still too large [R<(VBat –200 mV / 2mA)], the
short-circuit protection can be temporarily defeated. The battery short-circuit protection can be disabled
(recommended only for a short time) if the voltage on the DPPM pin is less than 1 V. Pulsing this pin below 1 V,
for a few microseconds, should be enough to recover.
This short-circuit disable feature was implemented mainly for power up when inserting a battery. Because the
BAT input voltage rises much faster than the OUT voltage (Vout<Vbat-200 mV), with most any capacitive load
on the output, the part can get stuck in short-circuit mode. Placing a capacitor between the DPPM pin and
ground slows the V_DPPM rise time, during power up, and delays the short-circuit protection. Too large a
capacitance on this pin (too much of a delay) could allow too-high currents if the output was shorted to ground.
The recommended capacitance is 1 nF to 10 nF. The V_DPPM rise time is a function of the 100-µA DPPM current
source, the DPPM resistor, and the capacitor added.
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