bq24039

· Small 3,5 mm × 4,5 mm QFN Package
· Designed for Single-Cell Li-Ion- or Li-Polymer-Based Portable Applications
· Integrated Dynamic Power-Path Management (DPPM) Feature Allowing the AC Adapter or the USB Port to Simultaneously Power the System and Charge the Battery
· Power Supplement Mode Allows Battery to Supplement the USB or AC Input Current
· Autonomous Power Source Selection (AC Adapter or USB)
· Integrated USB Charge Control With Selectable 100-mA and 500-mA Maximum Input Current Regulation Limits
· USB High Current Regulation Limit, 1 A Max (bq24039 Only)
· Dynamic Total Current Management  for USB
· Supports Up to 2-A Total Current
· 3.3-V Integrated LDO Output
· Thermal Regulation for Charge Control
· Charge Status Outputs for LED or System Interface Indicates Charge and Fault Conditions
· Reverse Current, Short-Circuit, and Thermal Protection
· Power Good (AC Adapter and USB Port Present) Status Outputs
· Charge Voltage Options: 4.2 V or 4.36 V

· Smart Phones and PDA
· MP3 Players
· Digital Cameras Handheld Devices
· Internet Appliances

(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. All voltage values are with respect to the network ground terminal unless otherwise noted.
(2) Negative current is defined as current flowing into the BAT pin.

The bqTINY™-III series of devices are highly inte-grated Li-ion linear chargers and system power-path management devices targeted at space-limited portable applications. The bqTINY-III series offer integrated USB-port and DC supply (AC adapter),power-path management  with autonomous power-source selection, power FETs and current sensors, high accuracy current and voltage regu-lation, charge status, and charge termination, in a single monolithic device.

The bqTINY-III powers the system while independently charging the battery. This feature reduces the charge and discharge cycles on the battery, allows for proper charge termination and allows the system to run with an absent or defective battery pack. The bq24039  feature also allows for the system to instantaneously turn on from an external power source in the case of  a deeply discharged battery pack. The IC design is focused on supplying continuous power to the system when available from the AC, USB, or battery sources.

The power select pin, PSEL, defines which input source of bq24039 is to be used first (primary source AC or USB). If the primary source is not available, then the IC automatically switches over to the other secondary source if available or the battery as the last option. If the PSEL is set low, the USB input is selected first and if not available, the AC line is selected (if available) but programmed to a USB input limiting rate (100 mA/500 mA max). This feature allows the use of one input connector, where the host programs the PSEL pin according to what source is connected (AC adaptor or USB port).

The bq24039 has replaced the PSEL pin (node now tied high internally AC priority) with the ISET3 pin that allows for twice the standard USB input limiting current levels (200 mA/1000 mA), when set to high. This is a feature for manufacturers that supply their own USB power source that is rated for this higher current level.

The bq24038 replaces USBPG with pin VBSEL, to enable user selection of the charge voltage. In addition, pinACPGwas modified to PG. PG is active low when either ac power or USB power is detected.

The ISET1 pin programs of bq24039 the battery's fast charge constant current level with a resistor. During normal AC operation of bq24039, the input supply provides power to both the OUT (System) and BAT pins. For peak or excessive loads (typically when operating from the USB power, PSEL = Low) that would cause the input source to enter current limit (or Q3 - USB FET limiting current) and its source and system voltage (OUT pin) to drop, the dynamic power-path management (DPPM) feature reduces the charging current attempting to prevent any further drop in system voltage. This feature allows the selection of a lower current rated adaptor based on the average load (I_SYS-AVG + I_BAT-PGM ) rather than a high peak transient load.