Linear公司的LTC 4012-3是恒流/恒壓電池充電控制器,采用同步準恒定頻率PWM控制架構,不會產生和陶瓷電容有關的可聽見噪音.充電電流由外接電阻設定,并由可編程電阻上的輸出電壓值來監視.可編程電流精度在4%,輸出浮動電壓精度在±0.5%,輸入電壓從6V到28V, 輸出電壓從2V到28V.主要用在筆記本電腦,手提儀器和電池備用系統.本文介紹了LTC 4012-3主要特性,方框圖,典型應用電路,性能測試電路以及12.6V 4A充電器電路圖.
The LTC 4012-3 is a constant-current/constant-voltage battery charger controller. It uses a synchronous quasiconstant frequency PWM control architecture that will not generate audible noise with ceramic bulk capacitors. Charge current is set by external resistors and can be monitored as an output voltage across the programming resistor.
With no built-in termination, the LTC4012-3 charges a wide range of batteries under external control. The LTC4012-3 features fully adjustable output voltage. For charge management and safety, the IC includes an input P-channel MOSFET ideal diode controller, battery (output) overvoltage protection, reverse charge current protection, PWM soft-start and robust non-overlap control for an all N-channel MOSFET PWM power stage.
The device includes AC adapter input current limiting, which maximizes the charge rate for a fi xed input power level. An external sense resistor programs the input current limit,and the ICL status pin indicates reduced charge current as a result of AC adapter current limiting. Ideal diode control at the adaptor input improves charger effi ciency.
The CHRG status pin is active during all charging modes, including special indication for low charge current.
LTC 4012-3主要特性:
General Purpose Battery Charger Controller
Efficient 550kHz Synchronous Buck PWM Topology
±0.5% Output Float Voltage Accuracy
Programmable Charge Current: 4% Accuracy
Programmable AC Adapter Current Limit: 3% Accuracy
No Audible Noise with Ceramic Capacitors
INFET Low Loss Ideal Diode PowerPath Control
Wide Input Voltage Range: 6V to 28V
Wide Output Voltage Range: 2V to 28V
Indicator Outputs for Charging, C/10 Current Detection and Input Current Limiting
Analog Charge Current Monitor
Micropower Shutdown
20-Pin 4mmx4mmx0.75mm QFN Package
應用:
Notebook Computers
Portable Instruments
Battery Backup Systems
圖1.LTC 4012-3方框圖
圖2.LTC 4012-3典型應用
圖3.LTC 4012-3測試電路圖
圖4.采用LTC 4012-3的12.6V 4A充電器電路圖 |
