Overview
The Texas Instruments BQ24745RHDR is a high-efficiency, synchronous battery charger integrated circuit designed for multi-chemistry battery charging applications. It is particularly suited for space-constrained designs, offering a low component count and high regulation accuracies. The BQ24745RHDR supports charging of two, three, or four series Li+ cells and is available in a compact 28-pin, 5-mm x 5-mm QFN package. This IC features dynamic power management (DPM) and input power limiting, which help in optimizing system performance and preventing overloading of the AC adapter.
Key Specifications
| Parameter | Symbol | Min | Typical | Max | Unit | Description |
|---|---|---|---|---|---|---|
| Input Voltage Range | VIN | 7 | 24 | V | Operating input voltage range | |
| Charging Voltage | VCHG | 3.0 | 19.2 | V | Adjustable charging voltage | |
| Charging Current | ICHG | 128 mA | 8.064 A | A | Programmable charging current | |
| Adapter Current Limit | IAC | 256 mA | 11.008 A | A | Adapter current limit DPM DAC | |
| Battery Voltage | VBAT | 19.2 | V | Maximum battery voltage | ||
| Efficiency | η | 95% | % | Typical efficiency at 300 kHz frequency | ||
| Quiescent Current | IQ | 30 | 50 | μA | Quiescent current during charging |
Key Features
- NMOS-NMOS Synchronous Buck Converter with 300-kHz Frequency and >95% Efficiency
- 30-ns Minimum Driver Dead-Time and 99.5% Maximum Effective Duty Cycle
- High-Accuracy Voltage and Current Regulation:
- ±0.5% Charge Voltage Accuracy
- ±3% Charge Current Accuracy
- ±3% Adapter Current Accuracy
- ±2% Input Current Sense Amp Accuracy
- Integration:
- Input Current Comparator with Adjustable Threshold and Hysteresis
- Internal Soft-Start
- Safety:
- Dynamic Power Management (DPM)
- 7-V–24-V AC/DC-Adapter Operating Range
- Simplified SMBus Control Interface:
- Charge Voltage DAC (1.024 V–19.2 V)
- Charge Current DAC (128 mA–8.064 A)
- Adapter Current Limit DPM DAC (256 mA–11.008 A)
- Status and Monitoring Outputs:
- AC/DC Adapter Present with Adjustable Voltage Threshold
- Input Current Comparator with Adjustable Threshold and Hysteresis
- Current Sense Amplifier for Current Drawn From Input Source
- Charge Enable Pin
- < 10-μA Battery Current with Adapter Removed
- < 1-mA Input DCIN Current with Adapter Present and Charge Disabled
- 28-Pin, 5-mm × 5-mm QFN Package
Applications
- Laptop and Ultra-Mobile Computers
- Portable Data-Capture Terminals
- Portable Printers
- Medical Diagnostics Equipment
- Battery Bay Chargers
- Battery Backup Systems
Q & A
- What is the primary function of the BQ24745RHDR?
The BQ24745RHDR is a high-efficiency, synchronous battery charger IC designed for charging two, three, or four series Li+ cells.
- What is the operating input voltage range of the BQ24745RHDR?
The operating input voltage range is 7 V to 24 V.
- What is the efficiency of the BQ24745RHDR?
The BQ24745RHDR has a typical efficiency of >95% at a 300-kHz frequency.
- What are the key features of the BQ24745RHDR's voltage and current regulation?
The IC features high-accuracy voltage and current regulation with ±0.5% charge voltage accuracy, ±3% charge current accuracy, and ±3% adapter current accuracy.
- What safety features does the BQ24745RHDR include?
The BQ24745RHDR includes dynamic power management (DPM) and input power limiting to prevent overloading of the AC adapter.
- What is the purpose of the SMBus control interface in the BQ24745RHDR?
The SMBus control interface allows for the programming of charge voltage, charge current, and adapter current limits using DACs.
- What types of batteries can the BQ24745RHDR charge?
The BQ24745RHDR can charge various battery chemistries including Li+, NiCd, NiMH, and Lead Acid.
- What is the quiescent current of the BQ24745RHDR during charging?
The quiescent current during charging is typically 30 μA.
- What is the package type and size of the BQ24745RHDR?
The BQ24745RHDR is available in a 28-pin, 5-mm × 5-mm QFN package.
- What are some common applications of the BQ24745RHDR?
Common applications include laptop and ultra-mobile computers, portable data-capture terminals, portable printers, medical diagnostics equipment, battery bay chargers, and battery backup systems.
