Features

• Monolithic 5W Wireless Power Transmitter
• AutoResonant^TM Switching Frequency Adjusts to Resonant Capacitance and Transmit Coil Inductance*
• Transmit Power Automatically Adjusts to Receiver Load*
• Input Voltage Range: 3V to 5.5V
• Integrated 100mΩ Full Bridge Switches
• Multiple Foreign Object Detection Methods
• Programmable Average Input Current Limit and Monitor
• NTC Input for System/Component Temperature Qualified Power Transfer
• Wide Operating Switching Frequency Range: 50kHz to 250kHz
• Thermally Enhanced 4mm × 5mm QFN 20-Lead Package

Typical Application

Description

The LTC®4125 is a simple and high performance monolithic full bridge resonant driver capable of delivering over 5W of power wirelessly to a properly tuned receiver. The device controls the current flow in a series connected transmit coil LC network to create a simple, safe and versatile wireless power transmitter.

The LTC4125 automatically adjusts its driving frequency to match the LC network resonant frequency. This AutoResonant switching allows the device to deliver maximum power from a low voltage input supply (3V to 5.5V) to a tuned receiver. To optimize system efficiency, the LTC4125 employs a periodic transmit power search and adjusts the transmission power based on the receiver load requirements. The device stops delivering power during a fault condition, or if a foreign object is detected.

The LTC4125 also includes a programmable maximum average input current limit and an NTC input as additional means for foreign object and overload protection. The LTC4125 is available in a 20-lead low profile (0.75mm) 4mm × 5mm QFN package.