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Host-Controlled Multi-Chemistry Battery Charger With Low Input Power Detect
Texas Instruments
Description
The bq24705 is a high-efficiency, synchronous battery charger with integrated compensation and system power selector logic, offering low component count for space-constrained multi-chemistry battery charging applications. Charge current and voltage programming allows high regulation accuracies, and can be either hardwired with resistors, or programmed by the system power- management microcontroller using a DAC or GPIOs. The bq24705 charges two, three, or four series Li+ cells, supporting up to 8 A of charge current, and is available in a 24-pin, 4×4-mm thin QFN package. The bq24705 features Dynamic Power Management (DPM) and input power limiting. These features reduce battery charge current when the input power limit is reached to avoid overloading the AC adapter when supplying the load and the battery charger simultaneously. A highly-accurate current-sense amplifier enables precise measurement of input current from the AC adapter to monitor the overall system power.
Features
NMOS-NMOS Synchronous Buck Converter with 600 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 Internal Loop Compensation Internal Soft-Start Safety Input Overvoltage Protection (OVP) Dynamic Power Management (DPM) with Status Indicator Reverse-Conduction Protection Input FET Supports Two, Three, or Four Li+ Cells 5 – 24 V AC/DC-Adapter Operating Range Analog Inputs with Ratiometric Programming via Resistors or DAC/GPIO Host Control Charge Voltage (4-4.512 V/cell) Charge Current (up to 8 A, with 10-m Sense Resistor) Adapter Current Limit (DPM) Status and Monitoring Outputs AC/DC Adapter Present with Programmable Voltage Threshold DPM Loop Active Current Drawn from Input Source Supports Any Battery Chemistry: Li+, NiCd, NiMH, Lead Acid, etc. Charge Enable 10-µA Off-State Battery Current 24-pin, 4×4-mm QFN Package APPLICATIONS Notebook and Ultra-Mobile Computers Portable Data-Capture Terminals Portable Printers Medical Diagnostics Equipment Battery Bay Chargers Battery Back-Up Systems
Related Datasheets
| Part Number | Description | Category |
| • BQ2000 | Programmable Multi-Chemistry Fast-Charge Management IC (Rev. C) | ICs, Interface |
| • BQ2005 | Fast-Charge IC for Dual-Battery Packs (Rev. A) | ICs, Interface |
| • BQ24105 | Synchronous Switchmode, Li-Ion & Li-Pol Charge Mngmt IC (bqSwitcher) (Rev. L) | ICs, Interface |
| • BQ24125 | Single-Chip Switchmode, Li-Ion & Li-Polymer Charge Mgmt IC w/enhanced EMI Perf (Rev. E) | ICs, Interface |
| • BQ24702 | Multichemistry Battery Charger Controller & System Power Selector (Rev. E) | ICs, Interface |
| • BQ24703 | Multichemistry Battery Charger Controller & System Power Selector (Rev. E) | ICs, Interface |
| • BQ24721C | Adv Multi-Chemistry & Mutli-Cell Sync Switch-Mode Charger & Syst Power Selector (Rev. D) | ICs, Interface |
| • BQ24730 | Advanced Multi-Chem & Multi-Cell Sync Switch-Mode Charger & Sys Power Selector | ICs, Interface |
| • BQ24745 | SMBus-Controlled Level 2 Multi-chemistry Battery Charger With Input Current | ICs, Interface |
| • BQ24751A | Host-controlled Multi-chemistry Battery Charger w/Sys Power Selector (Rev. A) | ICs, Interface |
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