Features and Benefits
- Dynamic Harmonization Control Optimizes Wireless Charging Over a Wide Coupling Range
- Wide Input Voltage Range (12.5V to 40V)
- Adjustable Float Voltage (3.5V to 11V)
- Fixed 4.2V Float Voltage Option (LTC4120-4.2)
- 50mA to 400mA Charge Current Programmed with a Single Resistor
- ±1% Feedback Voltage Accuracy
- Programmable 5% Accurate Charge Current
- No Microprocessor Required
- No Transformer Core
- Thermally Enhanced, Low Profile 16-Lead (3mm × 3mm × 0.75mm) QFN Package
The LTC4120 is a constant-current/constant-voltage wireless receiver and battery charger. An external programming resistor sets the charge current up to 400mA. The LTC4120-4.2 is suitable for charging Li-Ion/Polymer batteries, while the programmable float voltage of the LTC4120 accommodates several battery chemistries. The LTC4120 uses a Dynamic Harmonization Control (DHC) technique that allows high efficiency contactless charging across an air gap.
The LTC4120 regulates its input voltage via the DHC pin. This technique modulates the resonant frequency of a receiver tank to automatically adjust the power received as well as the power transmitted to provide an efficient solution for wirelessly charging battery-powered devices.
Wireless charging with the LTC4120 provides a method to power devices in harsh environments without requiring expensive failure-prone connectors. This allows products to be charged while locked within sealed enclosures, or in moving or rotating equipment, or where cleanliness or sanitation is critical.
This full featured battery charger includes accurate RUN pin threshold, low voltage battery preconditioning and bad battery fault detection, timer termination, auto-recharge, 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%.
- Handheld Instruments
- Industrial/Military Sensors and Devices
- Harsh Environments
- Portable Medical Devices
- Physically Small Devices
- Electrically Isolated Devices
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (3)
Demonstration kit DC2386A is a kit of the DC2330A LTC4125EUFD demonstration board, the DC2445A-A/DC2445A-B LTC4120EUD demonstration board, and an assortment of different length standoffs. The DC2330A can deliver up to 1.68W to the receive board with up to 12mm spacing between the transmit and receive coils.
Demonstration circuit 2181A-B features the LTC4120EUD wireless power receiver with 400mA synchronous step-down CC/CV battery charger. The DC2181 is used with the DC1968A wireless power transmitter or the PowerByProxi ProxiPoint transmitter. Either can deliver 2W to the DC2181, with up to 10mm spacing between the transmitter and the receive coil. The basic transmitter doesn’t support foreign metal object detection.
Demonstration circuit 2181A-A features the LTC4120-4.2 wireless power receiver with 400mA synchronous step-down CC/CV (4.2V charge voltage) battery charger. The DC2181 is used with the DC1968A wireless power transmitter or the PowerByProxi ProxiPoint transmitter. Either can deliver 2W to the DC2181, with up to 10mm spacing between the transmitter and the receive coil. The basic transmitter doesn’t support foreign metal object detection.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
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Models for the following parts are available in LTspice:
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.