Charge Your Phone Without Cables Using Wireless Power

Wireless Power Diagram
Wireless Power – Credit: WPC

The idea behind wireless power is over a century old. The concept and first practical application was developed by Nicola Tesla. It’s come a long way since then and can be found in common household items such as electric toothbrushes, portable drills / saws and in life sustaining devices like artificial hearts.

At it’s core, wireless charging (also know as inductive charging), is quite simple and only requires a transmitter coil and a receiving coil linked by a magnetic field. Applications are limited to about 5W right now, but this is growing as the technology evolves.

For more information and details, visit the Wireless Power Consortium for details, specifications and to find out which companies are developing / manufacturing products.

Cellphone makers are now including this charging method in their new “Qi-Phones”. As the transfer power increases, this will migrate to notepads, laptops and game consoles and all other battery operated devices. Imagine that you’ll no longer need any cables to tether your devices for charging. Simply place the device on a charging pad! Coffee shops (e.g., Starbucks) are looking to embed the chargers in their counter-tops; Automobile designers are figuring out how to incorporate this into the dashboard or center console areas; Furniture makers are developing powered tables and chairs with charging surfaces.

For developers, the two prominent chip vendors that are pursuing this market are TI and IDT. Below is their descriptions for their offerings.

According to a recent IDT press release highlighting their new transmit and receive chips for wireless charging:

The IDTP9030 is the most highly integrated wireless power transmitter available today. It combines the features and functionality of dozens of discrete components into a simplified, cost-effective, and highly efficient solution. The integration drastically minimizes the application footprint and component count, enabling customers to design and deploy more compact, cost-efficient, and conveniently located wireless charging stations. These charging stations may be deployed virtually anywhere, including homes, offices, libraries, stores, public waiting areas, automobiles, airports, and airplane seats.

The IDTP9020 is a high-efficiency single-chip wireless power receiver. In Qi mode, the device delivers up to 5 watts to the system. When used with the IDTP9030 transmitter in a proprietary configuration, it can deliver up to 7.5 watts, making the device suitable for powerful mobile devices, such as tablets, smart phones, digitals cameras, GPS units, and headsets. When used in tandem, the IDTP9030 and IDTP9020 become the industry’s most efficient end-to-end wireless power solution, resulting in reduced energy costs and faster charging time.

The IDTP9020 and IDTP9030 also feature proprietary multi-layered foreign object detection (FOD), utilizing sophisticated multi-parameter algorithms to assure a high level of safety while avoiding FOD false alarms. Coupled with over-temperature, over-voltage, and over-current protection, IDT’s solution offers the most comprehensive suite of protection features on the market, ensuring safe and reliable operation. In addition, the receiver includes support for charging the battery via USB cable when a wireless charging station is not available, eliminating the need for external USB adaptor switches in mobile devices.

For more information and datasheets on the IDT portfolio, please see the IDT Wireless Power homepage .

Texas Instruments (TI) has released their next generation products. They offer three devices for wireless power – bq500211A,bq500410A, and bq5101xB.

The product overview from their websites describes these as:

The bq500211A is a second generation digital wireless power controller that integrates all functions required to control wireless power transfer to a single WPC compliant receiver. It is WPC1.1 compliant and designed for 5-V systems as either a WPC type A5 transmitter with a magnetic positioning guide or as a WPC type A11 transmitter without the magnetic guide. The bq500211A the surrounding environment for WPC compliant devices to be powered, safely engages the device, receives packet communication from the powered device and manages the power transfer. To maximize flexibility in wireless power applications, Dynamic Power Limiting (DPL) is featured on the bq500211A. DPL enhances user experience by seamlessly optimizing the usage of power available from limited input supplies. The bq500211A supports both Foreign Object Detection (FOD) and Parasitic Metal Object Detection (PMOD) by continuously monitoring the efficiency of the established power transfer, protecting from power lost due to metal objects misplaced in the wireless power transfer bath. Should any abnormal condition develop during power transfer, the bq500211A handles it and provides indicator outputs. Comprehensive status and fault monitoring features enable a robust system design.

The bq500410A is a free-positioning digital wireless power controller that integrates all functions required to control wireless power transfer to a WPC compliant receiver. It is WPC 1.1 ready and designed for 12-V systems but applicable to other supply voltages. The bq500410A the surrounding environment for WPC compliant devices to be powered, safely engages the device, reads the packet feedback from the powered device, and manages the power transfer. A charging area of at least 70 mm x 20 mm provides flexible receiver placement on a transmitter pad. The bq500410A supports both Parasitic Metal Detection (PMOD) and Foreign Object Detection (FOD) by continuously monitoring the efficiency of the established power transfer, protecting from power lost due to metal objects misplaced in the wireless power transfer path. Should any abnormal condition develop during power transfer, the bq500410A handles it and provides fault indicator outputs. Comprehensive protection features provide a robust design to protect the system in all receiver placements.

The bq5101xB is a family of advanced, flexible, secondary-side devices for wireless power transfer in portable applications. The bq5101xB devices provide the AC/DC power conversion and regulation while integrating the digital control required to comply with the Qi v1.1 communication protocol. Together with the bq50xxx primary-side controller, the bq5101xB enables a complete contact-less power transfer system for a wireless power supply solution. Global feedback is established from the secondary to the primary in order to control the power transfer process utilizing the Qi v1.1 protocol.

The bq5101xB devices integrate a low resistance synchronous rectifier, low-dropout regulator, digital control, and accurate voltage and current loops to ensure high efficiency and low power dissipation.

The bq5101xB also includes a digital controller that can calculate the amount of power received by the mobile device within the limits set by the WPC v1.1 standard. The controller will then communicate this information to the transmitter in order to allow the transmitter to determine if a foreign object is present within the magnetic interface and introduces a higher level of safety within magnetic field. This Foreign Object Detection (FOD) method is part of the new requirements under the WPC v1.1 specification

All three devices are available in a 48-pin, 7 mm x 7 mm QFN package and operate over a temperature range from –40°C to 110°C.

For more information and datasheets on the TI selection, please see the TI Wireless Power Solutions homepage .

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