Overview
The Texas Instruments BQ24745RHDT 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 BQ24745RHDT supports charging of two, three, or four series Li+ cells and is available in a 28-pin, 5-mm x 5-mm QFN package. It features dynamic power management (DPM) and input power limiting to prevent overloading the AC adapter when supplying both the load and the battery charger simultaneously.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Package Type | 28-pin QFN | - |
| Package Dimensions | 5-mm x 5-mm | - |
| Switching Frequency | 300 kHz | - |
| Efficiency | >95% | % |
| Driver Dead-Time | 30 ns | ns |
| Maximum Effective Duty Cycle | 99.5% | % |
| Charge Voltage Accuracy | ±0.5% | % |
| Charge Current Accuracy | ±3% | % |
| Adapter Current Accuracy | ±3% | % |
| Input Current Sense Amp Accuracy | ±2% | % |
| Battery Voltage Range | Up to 19.2 V | V |
| AC/DC Adapter Operating Range | 7 V – 24 V | V |
| Charge Voltage DAC Range | 1.024 V – 19.2 V | V |
| Charge Current DAC Range | 128 mA – 8.064 A | A |
| Adapter Current Limit DPM DAC Range | 256 mA – 11.008 A | A |
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)
- Up to 19.2-V Battery Voltage
- 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 Any Battery Chemistry: Li+, NiCd, NiMH, Lead Acid, etc.
- Charge Enable Pin
- < 10-μA Battery Current with Adapter Removed
- < 1-mA Input DCIN Current with Adapter Present and Charge Disabled
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 BQ24745RHDT used for?
The BQ24745RHDT is a high-efficiency, synchronous battery charger IC used for charging two, three, or four series Li+ cells and other multi-chemistry batteries.
- What is the package type and dimensions of the BQ24745RHDT?
The BQ24745RHDT is available in a 28-pin, 5-mm x 5-mm QFN package.
- What is the switching frequency of the BQ24745RHDT?
The switching frequency is 300 kHz.
- What is the efficiency of the BQ24745RHDT?
The efficiency is greater than 95%.
- What are the key features of the BQ24745RHDT's voltage and current regulation?
The BQ24745RHDT 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 BQ24745RHDT include?
The BQ24745RHDT includes dynamic power management (DPM) to prevent overloading the AC adapter.
- What is the operating range of the AC/DC adapter for the BQ24745RHDT?
The AC/DC adapter operating range is 7 V to 24 V.
- How does the BQ24745RHDT support different battery chemistries?
The BQ24745RHDT can charge various battery chemistries including Li+, NiCd, NiMH, and Lead Acid.
- What is the purpose of the SMBus control interface in the BQ24745RHDT?
The SMBus control interface allows for simplified control and programming of charge voltage, charge current, and adapter current limits.
- What are some typical applications of the BQ24745RHDT?
Typical applications include laptop and ultra-mobile computers, portable data-capture terminals, portable printers, medical diagnostics equipment, battery bay chargers, and battery backup systems.
