Renesas Electronics has partnered with Qualcomm Technologies to integrate 30W wireless charging into mid-range smartphones running the latest Qualcomm Snapdragon 780G 5G platform. The new reference design is based on the P9412 from Renesas. It supports special fast charging modes with authentication and 24KB multi-time programmable non-volatile (MTP) memory. In an interview with EE Times, Amit Bavisi, Vice President and General Manager of Renesas Wireless Power Group, Mobile Infrastructure and IoT Power Business Division at Renesas Electronics, highlighted the ongoing collaboration between the two companies as an important step in expanding integrated wireless power capabilities in 5G smartphones. “The 5G revolution is challenging mobile device designers as the technology delivers higher performance and enables broader user applications and possibly more than its predecessors. As phone manufacturers increase their 5G device lineup as battery sizes expand and more and more features are packed into these smartphones, the design of these smartphones is so exciting. Wireless power requires fast charging that is highly efficient and has a lower thermal footprint,” Paveci said. 5G Wireless Charging A wireless charging system contains a wireless power transmission base station with one or more transmitters that deliver power through DC to AC converters and transmit power to a pair of inductors in a mobile device. A typical system uses near field magnetic induction between the coils and can be a free-position or magnetically driven system. The receiver controls the transmitted power in order to optimize charging. Rx-to-Tx communication uses existing power links over in-band communication for transmission frequencies or also supports out-of-band communication. Wireless power design includes both hardware and software; It is undoubtedly a system play. To achieve a stable and high-performance wireless power solution, a good design must have solid hardware quality and a powerful software algorithm. This goes hand in hand: Wireless power is truly a SoC where hardware and software interact to create an ideal system solution and the scalability needed to solve different dynamic user scenarios,” said Bavisi. Figure 1: Diagram of a typical system (Source: Renesas) Wireless technology is well known Qi is a wireless charging system that uses electromagnetic induction.In the transmitter or base station, which is usually a flat surface, the coil that A changing electric current passes through an oscillating electromagnetic field. In the object to be charged, a similar coil detects this changing field, and due to the known laws of electromagnetism, current flows through it, which then supplies the battery to be charged.” Antennas are generally customized to offer the best fit for receivers Wireless is in the ultimate device form factor. In general, it is common to see 40mm-50mm antennas used in phones,” Paveci said. Qi, for example, provides different coil configurations within wireless chargers so that users don’t have to precisely position the devices to be charged. In theory, The coils should be close together to transmit power, ideally overlapping, but some elements of the Qi standard allow charging even if the coils are a few centimeters apart.) The standard also provides some form of communication between the charger and the charging device: this is done using the same magnetic field as the Charging and allows, among other things, to stop the generation of the magnetic field when charging is complete.Reference Design The reference designs aim to provide integrated solutions to facilitate smartphone manufacturers to rapidly and cost-effectively deploy fast wireless charging on high-end and mid-range smartphones, with the ability to program Multitime (MTP) and OTA updates to simplify software development and the Qi certification process.Pavesi highlighted how Renesas’ 30W solution combined with Qualcomm Technologies’ 5G solution delivers over 85% system efficiency or end-to-end, facilitating the delivery of fast wireless charging technology to the next generation of mid-range smartphones. The wireless power receiver includes the Renesas’ P9412 with a high-voltage capacitor splitter, providing a compact footprint and freeing up the PCB area to include new features. The P4912 is a full low-impedance switching synchronous rectifier with a 32-bit ARM Cortex-M0 processor. “The integrated cover splitter greatly improves system efficiency while reducing solution size for high-power designs. By incorporating a highly efficient (>98%) cover splitter, the wireless power receiver coil now operates at half the current level, significantly reducing total power loss .The integrated solution allows the wireless receiver IC to seamlessly control state transitions during operating mode changes and also simplifies system design.To achieve 85-90% of end-to-end system efficiency (wall adapter for wireless power output in phone battery or battery charger), it must The efficiency of the individual components is high so no hotspots are created.“The high-efficiency cover splitter at 20V (completely integrated) reduces the integration problem for telephone and computer customers, and will make it compatible with traditional battery charging structures,” said Bavisi. WPC 5W and also uses higher power protocols that allow power delivery to be extended beyond the WPC 5W standard.A dedicated high power protocol is built into the device firmware, allowing the system to authenticate power transmission beyond 15W.(Fig. 2).Fig 2: Map i-Block P9412 (Source: Renesas) Wireless power is stored on one or more capacitors connected to the VRECT. The rectifier circuit and control block provide shunts and connections to maintain efficiency at required levels. The internal ADC monitors the voltage at VRECT and the load current, and the P9412 sends instructions to the power transmitter to increase or decrease the amount of power transmitted. .