BQ25050 Datasheet, PDF (13/28 Pages) Texas Instruments – 1A, Single-Input, Single Cell Li-Ion Battery Charger with 50-mA LDO, External Power Path

bq25050
www.ti.com
SLUSA33 – MARCH 2010
Enable/ Disable External Power Path Control
When power is first applied to the bq25050, either at the IN or BAT input, the bq25050 checks the BGATE
output. The device sources a small current out of BGATE for 32ms and monitors the voltage. If VBGATE is
connected to ground and the voltage does not rise above logic High, the External Power Path Control feature is
disabled and VLOWV is set to 2.5V. If the BGATE voltage rises above logic High, the External Power Path
Control feature is enabled and V_LOWV is set to 2.9V. The bq25050 only does this check when power is initially
applied. Power must removed from IN and BAT and then reapplied to initiate another check. Figure 21 illustrates
the startup check procedure.
No Input Source or
Battery Connected
Input source OR
NO
Battery connected?
YES
Source Current to
BGATE
BGATE =
VSS?
NO
YES
External
Power Path
Control
Disabled
VLOWV = 2.5V
External
Power Path
Control
Enabled
VLOWV = 2.9V
Figure 21. BGATE Monitor Sequence
Charging Operation
The bq25050 charges a battery in 3 stages while maintaining a minimum system output. When the bq25050 is
enabled by CTRL, the battery voltage is monitored to verify which stage of charging must be used. The bq25050
charges in precharge mode, minimum output regulation mode, or normal CC/CV mode based on the battery
voltage.
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
Submit Documentation Feedback
13