5W AutoResonant Wireless Power Transmitter Offers Foreign Object Detection & Completes LTC's Wireless Charging Solution

News Release  www.linear.com
5W AutoResonant Wireless Power Transmitter Offers Foreign Object
Detection & Completes LTC’s Wireless Charging Solution
MILPITAS, CA – November 30, 2015 – Linear Technology Corporation introduces the
LTC4125, a wireless power transmitter, complementing our wireless receiver ICs for the wireless
charging market. The LTC4125 is a simple, high performance monolithic full bridge resonant
driver, capable of delivering up to 5W of power wirelessly to a companion receiver. It functions
as the transmit circuit component in a complete wireless power transfer system comprised of
transmit circuitry, transmit coil, receive coil and receive circuitry.
The LTC4125 wireless power transmitter improves upon a basic transmitter by providing
three key features: an AutoResonant™ function that maximizes available receiver power, an
Optimum Power Search algorithm that maximizes overall wireless power system efficiency, and
Foreign Object Detection (FOD) to ensure safe and reliable operation when working in the
presence of conductive foreign objects. The LTC4125 automatically adjusts its drive frequency
to match the LC network resonant frequency. This AutoResonant switching enables the device to
deliver maximum power from a low voltage input supply (3V to 5.5V) to a tuned receiver such
as Linear’s LTC4120 wireless receiver and battery charger via loosely coupled coils. Wireless
power receivers can also be designed with the LTC4071 shunt battery charger or the LT3652HV
multi-chemistry battery charger. 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 in a fault condition, or in the case of a detected
foreign object.
5W AutoResonant Wireless Power Transmitter Offers Foreign Object
Detection & Completes LTC’s Wireless Charging Solution
page 2
Simplifying the wireless power system, these transmit power optimization and foreign
object detection features in the LTC4125 do not require any direct communication between the
transmitter and receiver circuits. Without digital communication the LTC4125 can work over a
wide range of transmit-to-receive coil coupling factors and avoid the need for complicated signal
processing hardware and software to support a communication protocol.
The LTC4125 includes a programmable maximum current limit and an NTC input as
additional means of foreign object and overload protection. Applications include handheld
instruments, industrial/military sensors and similar devices in harsh environments, portable
medical devices, and electrically isolated devices. LTC4125-based systems offer robust,
standalone solutions capable of large transmission distances up to 10mm and tolerance of poor
coil coupling due to misalignment.
The LTC4125 is housed in a low profile (0.75mm) 20-pin 4mm x 5mm QFN package
with backside metal pad for excellent thermal performance. The device is specified for operation
from ˗40C to 125C, in both E and I grades. 1,000-piece pricing starts at $4.00 each for the E
grade. For more information, visit www.linear.com/product/LTC4125.
Photo Caption: 5W AutoResonant™ Wireless Power Transmitter
Summary of Features: LTC4125
Monolithic 5W Wireless Power Transmitter
AutoResonant™ Switching Frequency Adjusts to Resonant Capacitor & Transmit Coil
Transmit Power Automatically Adjusts to Receiver Load*
Input Voltage Range: 3V to 5.5V
Integrated 100mΩ Full Bridge Switches
Foreign Object Detection
Programmable Average Input Current Limit & Monitor
NTC Input for System/Component Temperature Qualified Power Transfer
Wide Operating Switching Frequency Range: 50kHz to 250kHz
Thermally Enhanced 4mm × 5mm QFN 20Lead Package
* The AutoResonant and Auto Load Detect features use patent pending circuits and algorithms.
5W AutoResonant™ Wireless Power Transmitter Offers Foreign Object
Detection & Completes LTC’s Wireless Charging Solution
page 3
The USA list pricing shown is for budgetary use only. International prices may differ due to
local duties, taxes, fees and exchange rates. About Linear Technology Linear Technology Corporation, a member of the S&P 500, has been designing, manufacturing and marketing a broad line of high performance analog integrated circuits for major companies worldwide for over three decades. The Company’s products provide an essential bridge between our analog world and the digital electronics in communications, networking, industrial, automotive, computer, medical, instrumentation, consumer, and military and aerospace systems. Linear Technology produces power management, data conversion, signal conditioning, RF and interface ICs, µModule® subsystems, and wireless sensor network products. For more information, visit www.linear.com
, LT, LTC, LTM, Linear Technology, the Linear logo and µModule are registered trademarks and AutoResonant is
a trademark of Linear Technology Corp. All other trademarks are the property of their respective owners.
Press Contacts:
North America / Worldwide
UK & Nordic
John Hamburger, Director Marketing
[email protected]
Tel: 408-432-1900 ext 2419
Alan Timmins
[email protected]
Tel: +44-1-252-629937
Doug Dickinson, Media Relations Manager
[email protected]
Tel: 408-432-1900 ext 2233