By Upal Sengupta and Bill Johns, Texas Instruments
Wireless power systems are emerging as a practical option for conveniently recharging mobile phones and other handheld devices. Implementing an industry standard interface allows a common charging pad (TX) to recharge multiple types of battery-operated devices (RX). The WPC developed the Qi standard for wireless power systems with up to 5W of output power. This allows complete interoperability between transmitters and receivers independent of device manufacturer. This standard defines the means of implementing a number of functions that enhance the utility and efficiency of a wireless power system, for example:
- The charging pad does not consume significant amounts of standby power when idle (no device placed on the pad).
- The TX can detect the presence of an object placed on the pad, and further determine that it is a valid, Qi-compliant RX device.
- Once an object is placed on the charging pad, the transmitter can output a variable power level based on the TX’s requirements.
The RX unit communicates its power needs back to the TX unit over the same magnetic coupling used for power transmission. Read More Here
