With the release of the iPhone 12, Apple has stopped including chargers for environmental reasons, and wireless earbuds like AirPods now support wireless charging. Many people are opting for wireless charging for their phones and earbud charging cases, enjoying the convenience it brings by eliminating the hassle of wired connections. Multifunctional wireless chargers have flooded the market, making our lives easier.
As more devices support wireless charging, the market for wireless chargers is expanding rapidly, with many uniquely designed chargers entering the market. Early wireless charging designs required multiple chips and many discrete components, resulting in complex circuits that were difficult to debug and unable to achieve compact designs.
However, modern users expect more than just the ability to charge. Devices that support wireless charging come in various stylish designs. How can we design a compact wireless charger that meets the needs of modern devices?
One Chip Achieves 15W Wireless Charging
Ruiyuan Semiconductor has launched the AT8915 series of wireless charging SoC chips, which integrate PD and fast charging protocol power extraction, wireless charging main control, and wireless charging power stage into a single chip. This single chip can complete the full functionality of a wireless charger, simplifying product development and accelerating time to market. Ruiyuan Semiconductor is one of the few manufacturers in the wireless charging industry with a fully integrated wireless charging SoC chip design.
The founding team of Ruiyuan Semiconductor mainly comes from NXP, TI, and ST, with over 10 years of design and mass production experience in digital and analog power supply fields. Founded in September 2017, Ruiyuan Semiconductor aims to become a globally recognized smart power SoC chip design company, committed to providing high integration and high-performance SoCs for domestic and international customers. Their products are widely used in 3C electronic products, IoT devices, and automotive networking smart hardware.
Ruiyuan Semiconductor has integrated all the functions of a modern wireless charging transmitter into the chip, including fast charging protocol, MCU core, full-bridge driver, and full-bridge MOSFETs. All components required for wireless charging are consolidated into a highly integrated chip. The latest AT8915 series wireless charging SoC chip from Ruiyuan is such a product, requiring only simple external components to complete a full wireless charging product.
Compared to traditional microcontroller plus external MOSFET solutions, Ruiyuan Semiconductor’s latest wireless charging SoC chip integrates the microcontroller, MOSFETs, operational amplifiers, and other large components into a QFN package measuring only 6x6mm. During production, only one chip needs to be placed to achieve the functionality that previously required multiple chips.
Ruiyuan AT8915 Series Parameters
The Ruiyuan AT8915 series consists of three wireless charging chips, all supporting a maximum output of 15W: AT8915, AT8915C, and AT8915S.
AT8915 is a widely applicable high-integration wireless charging SoC that integrates all the necessary functions for a wireless charger, including support for PD and QC fast charging protocols, wireless charging control, and full-bridge MOSFET driver, requiring only a few necessary external components.
AT8915S supports USB PD and QC power extraction, while AT8915C only supports QC power extraction. Both AT8915 and AT8915S integrate a 32-bit ARM core; the core frequency reaches up to 96MHz, with 32KB+4KB of storage, a single-cycle 32-bit hardware multiplier, 32 NVIC interrupt inputs, 4 levels of adjustable interrupt priority, GPIO supporting multiple operating modes, 4 independent PWM outputs, rich and flexible PWM functionality, up to 6 16-bit timer channels, 12-bit resolution ADC, a conversion rate of up to 1.5MHz, and 14 conversion channels, along with built-in temperature detection channels and two ACMP and OPA modules.
AT8915S provides more peripheral resources and is open-source, offering low-level hardware resources and remaining MCU resources for secondary development. Peripheral resources include a 16-bit three-phase motor control module (Motor-PWM), support for SPI / UART / I2C / CAN bus, USB2.0 full-speed interface, etc.
It supports USB-C interface for programming the wireless charging firmware, with support for 100,000 program re-flashes. AT8915S also supports dual fast charging from a single chip, suitable for mobile phone wireless charging dock applications, supporting simultaneous charging of a phone and a watch, or a phone and earbuds, reducing costs and enhancing product competitiveness.
Wireless chargers can be divided into two schemes: one is integrated within the Type-C plug, and the other is placed inside the wireless charger. The high integration of the chip facilitates different product designs.
The AT8915 chip is soldered onto a small Type-C board, with the output wire directly soldered to the coil, resulting in a compact size that allows for more personalized designs. Comparatively, the wireless charging PCBA built with this module is smaller than a one-yuan coin, clearly demonstrating its integration advantages.
With the design of the MagSafe charger, both wireless charging solutions above have very simple peripheral components.
Ruiyuan Releases Three Single-Chip Wireless Charging SoCs
It may be hard to believe that a wireless charger can be made with just one chip, but how does it perform? Below, we present an introduction and testing of the Ruiyuan AT8915 series SoC wireless charging solutions.
Highly Integrated Ruiyuan AT8915
The AT8915 launched by Ruiyuan focuses on high integration, with an integrated fast charging protocol module supporting PD and QC adapters, intelligently adapting to 5/7.5/10/15W wireless charging output based on 5/9/12V input voltage.
The chip integrates PD & QC protocol functions, a BUCK step-down converter, a 3.3V LDO, an MCU core, full-bridge drive, full-bridge MOS, voltage and current demodulation, and Q value detection functions. The minimum number of external resistors and capacitors is only 30, and the MCU’s internal Flash can be programmed via J-link, facilitating product upgrades. Additionally, it supports an input voltage rating of 25V without the need for additional protection components.
The Ruiyuan AT8915 uses a QFN 6×6 48-pin package, completing all wireless charging functions with a single chip, significantly simplifying the wireless charging circuit.
The Ruiyuan AT8915 can wirelessly charge the iPhone 12 Pro, triggering the MagSafe charging animation. Testing with a wireless charging tester shows that the AT8915 supports automatic boost, achieving 15W wireless fast charging output.
High Cost-Performance Ruiyuan AT8915C
The Ruiyuan AT8915C does not support PD protocol power extraction but retains QC power extraction functionality, with all other features consistent with the AT8915.
The Ruiyuan AT8915C uses a QFN 5×5 32-pin package, with simple peripheral components.
Using the Ruiyuan AT8915C for wireless charging of the iPhone 12 Pro, connected via a QC charger and USB-A port, can trigger the MagSafe charging animation. The AT8915C supports automatic boost, achieving 15W wireless fast charging output.
Single Chip Dual Charging Ruiyuan AT8915S
Compared to the AT8915, the Ruiyuan AT8915S offers more GPIO, PWM, ADC, I2C, SPI, and other resources, open to technically capable companies for secondary development, enhancing product differentiation and competitive advantage.
The AT8915S single chip can be configured for dual fast charging, wind-cooled back clips, and other smart home wireless charging product solutions. The AT8915S is pin-to-pin compatible with the AT8915.
The AT8915S can also wirelessly charge the iPhone 12 Pro, triggering the MagSafe charging animation.
Single Chip Dual Fast Charging
The Ruiyuan AT8915S, through its open GPIO and MCU resources, can be configured for single chip dual fast charging. Using one AT8915S chip plus an integrated power stage chip, it can achieve two independent wireless charging outputs, both capable of providing wireless fast charging.
The AT8915S supports USB PD fast charging, allowing for 9V and 12V power supply, and outputs EPP 15W wireless charging. It can also be configured for 7.5W+7.5W or 10W+5W power outputs, suitable for mobile phone wireless charging docks, supporting simultaneous charging of a phone with another phone, a phone with a watch, or a phone with earbuds.
Using the Ruiyuan AT8915S to achieve single chip dual fast charging allows for independent design of PCBA and coils, separating them to dissipate heat and reduce temperature rise. Designing a wireless charger with the AT8915S for single chip dual fast charging reduces the need for an additional wireless charging main control, effectively lowering costs, simplifying design, and enhancing product competitiveness.
Fast and Stable Charging Speed
We used the Power-Z KM001 to monitor the wireless charging curve of the Ruiyuan AT8915 and MagSafe wireless charging pad for the iPhone 12 Pro.
In actual tests, the Ruiyuan AT8915 took 160 minutes to charge from 0-100%, with no interruptions during the wireless charging process.
The original MagSafe wireless charger took 207 minutes to charge from 0-100%, with no interruptions during the wireless charging process.
Charging Head Network Summary
The design of modern electronic products is constantly approaching physical limits. To pursue power density and improve space utilization, chargers have begun to use three or more circuit boards stacked together to minimize unused space inside the charger. Wireless charging is no different; traditional multi-chip designs can no longer meet the demand for smaller designs. Single-chip, highly integrated wireless charging solutions can adapt to more innovative designs, appealing to consumer purchasing desires.
The three wireless charging SoCs launched by Ruiyuan enable single-chip wireless charger designs. Compared to recent high-integration power extraction chips combined with wireless charging chips or microcontrollers combined with full-bridge wireless charging solutions, they save one chip, facilitating cost control and material management for manufacturers. The built-in MCU of Ruiyuan’s wireless charging SoC supports secondary development, allowing for differentiated functional development in products such as in-car wireless chargers, desk lamp wireless chargers, mobile power wireless chargers, and Bluetooth speaker wireless chargers, adding product selling points.
Live Broadcast Announcement
Ruiyuan Semiconductor will hold an online live broadcast on June 4 (Friday) at 14:00, where senior engineers from Ruiyuan Semiconductor will share many highlights of the AT8915 series. Scan the QR code in the image below to register in advance~
Click on the blue text to learn about the following popular topics, or reply with the keywords below in the Charging Head Network WeChat backend to access the special topic.
「Technical Topics」
GaN、SiC、LLC、USB PD、QC、VOOC、DFH、Qi、POWER-Z
「Disassembly Summary」
1500 disassemblies、wireless charging disassemblies、PD charger disassemblies、mobile power disassemblies、PD car charger disassemblies、charging case disassemblies、GaN fast charging disassemblies、100W charger disassemblies、100W power bank disassemblies、mobile fast charging disassemblies、18W PD fast charging disassemblies、20W PD fast charging disassemblies、high-power wireless charging disassemblies、PD power strip disassemblies
「Quality Resources」
Charger factories、GaN fast charging factories、power bank factories、outdoor power supply factories、wireless charging factories、fast charging chips、power chips (with built-in MOS)、step-up/down chips (power banks)、step-up/down chips (car chargers)、multi-port fast charging chips、charging case protocol chips、wireless charging chips、charging case chips (wired)、charging case chips (wireless)、fast charging capacitors、GaN fast charging、20W PD fast charging、30W PD fast charging
「Original Factory Resources」
Yingjixin、Zhirong、Nanchip、Dongke、Xinmaowei、Maoruixin、Silicon Power、Global、Meisidi、Fuman-Yunxi、Yachengwei、Chengxinwei、BiYi、Jiehuate、Qinheng、Xinhai、Tian Deyu、Hengchengwei、Yingnuosike、Namiwei、Weizhao、Weishuo、Nuowei、MDD、Fengbin、Yongming、KeNisheng、Zhouyu Electronics、Baoruike、TeRuixiang、Meixinsheng、Fuda、Beilan、Weiyuan、Xinxian Solutions
「Fast Charging Factories」
Kunxing、Huake Long、Yajingyuan、Oupaiqi、Ruijiada、Pengyuansheng、Gushi、Huakesheng
「Brand Zone」
Apple、Huawei、Xiaomi、OPPO、vivo、Honor、Samsung、mophie、ANKER、Zimi、Baseus、UGREEN、CHOETECH、ZENDURE、Patriot
「Exhibition Reports」
USB PD Asia Exhibition、Wireless Charging Asia Exhibition、Apple Fan Carnival、Hong Kong Exhibition、AirFuel Wireless Charging Conference、CES Exhibition
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