BQ24161B_15 Datasheet, PDF (36/52 Pages) Texas Instruments – bq2416xx 2.5A, Dual-Input, Single-Cell Switched-Mode Li-Ion Battery Charger with Power Path Management and I2C Interface

bq24160, bq24160A, bq24161
bq24161B, bq24163, bq24168
SLUSAO0F – NOVEMBER 2011 – REVISED JULY 2014
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The inductor selected must have a saturation current rating greater than or equal to the calculated I_PEAK. Due to
the high currents possible with the bq2416xx, a thermal analysis must also be done for the inductor. Many
inductors have a 40°C temperature-rise rating. The DC component of the current can cause a 40°C temperature
rise above the ambient temperature in the inductor. For this analysis, the typical load current may be used
adjusted for the duty cycle of the load transients. For example, if the application requires a 1.5A DC load with
peaks at 2.5A 20% of the time, a Δ40°C temperature rise current must be greater than 1.7A:
( ) ( ) I_TEMPRISE = I_LOAD + D ´ I_PEAK - I_LOAD = 1.5A + 0.2 × 2.5A - 1 .5A = 1.7A
(6)
The bq2416xx provides internal loop compensation. Using this scheme, the bq2416xx is stable with 10µF to
200µF of local capacitance on the SYS output. The capacitance on the SYS rail can be higher if distributed
amongst the rail. To reduce the output voltage ripple, a ceramic capacitor with the capacitance between 10µF
and 47µF is recommended for local bypass to SYS. A 47µF bypass capacitor is recommended for optimal
transient response.
10.2.3 Application Curves
USB500
925mA Charge Setting
Figure 23. USB Plug-In with Battery Connected
1500mA ILIM
1300mA Charge Setting
Figure 24. IN Plug-in with Battery Connected
Figure 25. Adapter Detection USB
Termination Enabled
Figure 26. Battery Insert During Battery Detection
36
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