Host-Controlled Synchronous Swithc-Mode Li-Ion Charger w/2A FET, 1 or 2 Cell 20-VQFN -40 to 85# BQ24113ARHLRG4 Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The BQ24113ARHLRG4 is a highly integrated single-cell Li-ion and Li-polymer battery charger IC designed for space-constrained portable applications. Key use cases include:
- Smartphones and Tablets : Provides complete charging solution for mobile devices with USB compatibility
- Portable Medical Devices : Enables safe charging for medical monitoring equipment and handheld diagnostic tools
- Wearable Electronics : Compact solution for smartwatches, fitness trackers, and health monitors
- Portable Industrial Equipment : Supports battery charging for handheld scanners, meters, and data collection devices
- Bluetooth Headsets and Accessories : Ideal for small form-factor audio devices requiring efficient charging
### Industry Applications
- Consumer Electronics : Mobile devices, digital cameras, portable gaming systems
- Medical Technology : Patient monitoring devices, portable diagnostic equipment
- Industrial Automation : Handheld terminals, portable measurement instruments
- IoT Devices : Smart home sensors, connected wearable technology
- Automotive Accessories : Aftermarket car electronics, portable navigation systems
### Practical Advantages and Limitations
Advantages:
- High Integration : Combines power MOSFETs, current sensor, and reverse blocking protection in single package
- USB-OTG Support : Can operate in boost mode to power USB peripherals (5V/500mA)
- Thermal Regulation : Automatic charge current reduction to maintain optimal die temperature
- Small Footprint : 3mm × 3mm QFN package ideal for space-constrained designs
- High Efficiency : Up to 92% efficiency with 1.5A charge current capability
Limitations:
- Single-Cell Only : Limited to 4.2V/4.35V battery configurations
- Maximum Input Voltage : 16V absolute maximum, 13.5V recommended operating
- Charge Current : Limited to 1.5A maximum, may be insufficient for high-capacity batteries
- Temperature Monitoring : Requires external NTC thermistor for battery temperature sensing
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Pitfall 1: Inadequate Thermal Management
- Problem : Overheating during high-current charging leading to thermal shutdown
- Solution : Ensure proper PCB thermal vias under exposed pad, use 2oz copper when possible
Pitfall 2: Input Voltage Transients
- Problem : Damage from voltage spikes exceeding absolute maximum ratings
- Solution : Implement TVS diode on input and ensure input capacitor meets voltage derating requirements
Pitfall 3: Battery Connection Issues
- Problem : Intermittent battery connection causing charging faults
- Solution : Use battery connectors with adequate retention force, implement proper strain relief
Pitfall 4: Incurrent Current Setting
- Problem : Incorrect charge current due to resistor tolerance or layout issues
- Solution : Use 1% tolerance resistors for ISET, keep ISET resistor close to IC
### Compatibility Issues with Other Components
Power Management ICs:
- Compatible with most system PMICs but requires careful sequencing
- May conflict with other battery charging circuits in system
Microcontrollers:
- I²C compatible (400kHz) for communication with host processors
- Ensure proper pull-up resistors on SCL/SDA lines (typically 10kΩ)
USB Controllers:
- Compatible with USB 2.0 and USB 3.0 specifications
- Requires proper USB detection circuitry for automatic input current limit setting
Battery Protection Circuits:
- Works with standard battery protection ICs but avoid duplicate protection features
- Ensure protection IC doesn't interfere with charger termination algorithms
### PCB Layout Recommendations
Power Path Layout:
