Datasheet LTC4120, LTC4120-4.2 (Analog Devices)

LTC4120/LTC4120-4.2 Wireless Power Receiver and 400mA Buck Battery Charger
FEATURES DESCRIPTION
n
Dynamic Harmonization Control Optimizes
The LTC®4120 is a constant-current/constant-voltage wire-
Wireless Charging Over a Wide Coupling Range
less receiver and battery charger. An external program- n
Wide Input Voltage Range (12.5V to 40V)
ming resistor sets the charge current up to 400mA. The n
Adjustable Float Voltage (3.5V to 11V)
LTC4120-4.2 is suitable for charging Li-Ion/Polymer batter- n
Fixed 4.2V Float Voltage Option (LTC4120-4.2)
ies, while the programmable float voltage of the LTC4120 n 50mA to 400mA Charge Current Programmed with a accommodates several battery chemistries. The LTC4120 uses a Dynamic Harmonization Control (DHC) technique that Single Resistor n allows high efficiency contactless charging across an air gap. ±1% Feedback Voltage Accuracy n Programmable 5% Accurate Charge Current The LTC4120 regulates its input voltage via the DHC pin. n No Microprocessor Required This technique modulates the resonant frequency of a n No Transformer Core receiver tank to automatically adjust the power received n Thermally Enhanced, Low Profile 16-Lead as well as the power transmitted to provide an efficient (3mm × 3mm × 0.75mm) QFN Package solution for wirelessly charging battery-powered devices. Wireless charging with the LTC4120 provides a method
APPLICATIONS
to power devices in harsh environments without requiring n expensive failure-prone connectors. This allows products Handheld Instruments n to be charged while locked within sealed enclosures, or Industrial/Military Sensors and Devices in moving or rotating equipment, or where cleanliness or n Harsh Environments sanitation is critical. n Portable Medical Devices n Physically Small Devices This full featured battery charger includes accurate RUN n Electrically Isolated Devices pin threshold, low voltage battery preconditioning and bad battery fault detection, timer termination, auto-recharge, All registered trademarks and trademarks are the property of their respective owners. and NTC temperature qualified charging. The FAULT pin provides an indication of bad battery or temperature faults. Once charging is terminated, the LTC4120 signals end-of- charge via the CHRG pin, and enters a low current sleep mode. An auto-restart feature starts a new charging cycle if the battery voltage drops by 2.2%.
TYPICAL APPLICATION Wireless Rx Voltage/Charge Current vs Spacing
26.7nF 40 400 IN INTVCC I RUN FREQ 2.2µF CHARGE 35 MAX 333 10µF BOOST CHARGE CURRENT (mA) V LTC4120 22nF 33µH IN 6.5nF SW 30 267 NOT Tx CIRCUITRY DHC CHGSNS (V) CHARGING NTC 25 200 5µH 47µH FAULT BAT V IN(RX) CHRG 1.01M 20 133 Li-Ion + T FB 4.2V CHARGING GND PROG FBG 1.35M 15 67 3.01k 22µF 10 0 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 4120 TA01a SPACING (cm) 4120 TA01b Rev. G Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Test Circuit Operation Applications Information Package Description Revision History Typical Application Related Parts