Texas Instruments BQ21040DBVR

Description

The BQ21040DBVR device is a highly integrated Li-Ion and Li-Pol linear battery charger device targeted at spacelimited portable applications. The device operates from either a USB port or AC adapter. The high input voltage range with input overvoltage protection supports low-cost unregulated adapters. The BQ21040DBVR has a single power output that charges the battery. A system load can be placed in parallel with the battery as long as the average system load does not keep the battery from charging fully during the 10 hour safety timer. The battery is charged in three phases: conditioning, constant current and constant voltage. 

In all charge phases, an internal control loop monitors the IC junction temperature and reduces the charge current if an internal temperature threshold is exceeded. The charger power stage and charge current sense functions are fully integrated. The charger function has high accuracy current and voltage regulation loops, charge status display, and charge termination. The pre-charge current and termination current threshold are fixed to 20% and 10%, respectively. The fast charge current value is programmable through an external resistor. 

Key Features:

• 1% charge voltage accuracy for consistent and safe battery performance
• 10% charge current accuracy for reliable current control
• Supports programmable charge current up to 800 mA via an external resistor
• Ultra-low battery leakage current: only 1 µA
• Optimized for 4.2-V Li-Ion and Li-Pol cells

• 30-V input tolerance with 6.6-V overvoltage protection
• Dynamic Power Management (DPM) to regulate input voltage under varying conditions
• Thermal regulation at 125°C and shutdown protection at 150°C
• Short-circuit protection on OUT and ISET pins
• NTC thermistor input for battery temperature monitoring
• Fixed 10-hour safety timer to prevent prolonged overcharge

• Charging status indication (Charging/Done)
• Compact SOT-23 package for efficient PCB design

Typical Applications:

• EPOS (Electronic Point of Sale) terminals
• Medical endoscopy equipment
• BLE speakers and wireless headsets
• Low-power handheld devices

Simplified Schematic

Pin Configuration and Functions