BQ24040 Datasheet, PDF (22/31 Pages) Texas Instruments – 800mA Single-Input Single Cell Li-Ion Battery Charger With Auto Start

bq24040
bq24041
SLUS941A – SEPTEMBER 2009 – REVISED SEPTEMBER 2009.................................................................................................................................... www.ti.com
Battery Detect Routine
The battery detect routine should check for a missing battery while keeping the OUT pin at a useable voltage.
Whenever the battery is missing the CHG pin should be high impedance.
The battery detect routine is run when entering and exiting TTDM to verify if battery is present, or run all the time
if battery is missing and not in TTDM. On power-up, if battery voltage is greater than V_RCH thereshold, a battery
detect routine is run to determine if a battery is present.
The battery detect routine is disabled while the IC is in TTDM, or has a TS fault. See Figure 28for the Battery
Detect Flow Diagram.
Refresh Threshold
After termination, if the OUT pin voltage drops to V_RCH (100mV below regulation) then a new charge is initiated,
but the CHG pin remains at a high impedance (off).
Starting a Charge on a Full Battery
The termination threshold is raised by 14%, for the first minute of a charge cycle so if a full battery is removed
and reinserted or a new charge cycle is initiated, that the new charge terminates (less than 1 minute). Batteries
that have relaxed many hours may take several minutes to taper to the termination threshold and terminate
charge.
22
Submit Documentation Feedback
Product Folder Link(s): bq24040 bq24041
Copyright © 2009, Texas Instruments Incorporated