The smart charging case, as an innovative solution in the wearable technology field, not only provides charging functionality but also transforms the way users interact with audio devices. Through Bluetooth technology, it achieves seamless connectivity with headphones and smartphones, becoming a crucial node for information exchange.
The Realtek chip series supports various interfaces such as I2S, USB, ADC, SDIO, SPDIF, and QSPI, offering low power consumption and stable Bluetooth connectivity, thereby enhancing the product's versatility. This provides significant advantages and robust support for a range of smart charging case products, from entry-level to high-end. Additionally, Realtek offers comprehensive development kits and detailed development documentation to assist customers in smoothly completing function development and mass production testing, enabling products to be rapidly and efficiently brought to market.
System Structure
The smart charging case solution based on the RTL8762DT supports both button and touch screen operations and has a built-in speaker function. When the earphones are placed in the charging case, they exchange information quickly and stably through a One-wire UART interface, enabling fast pairing and positioning. When the earphones are removed from the charging case, the case establishes a Bluetooth LE link with the main earphone to monitor the earphone status in real-time and adjust parameters or control functions based on the status.
Additionally, the interaction signaling system of this solution is expandable. Users can refer to the examples in the SDK documentation to independently add or customize functions to meet specific needs. This flexibility not only enhances the earphone functions but also greatly improves the user experience, increasing convenience of use.
The RTL8763EW-VC is an upgraded version of the RTL8762DT, featuring advanced dual-mode Bluetooth functionality and supporting LE Audio, while also incorporating a digital signal processor (DSP). This chip extends a wide range of peripheral interfaces, including USB, SDIO, MIC, and Line-in, and in addition to continuing the Bluetooth LE support of the RTL8762DT, it adds full support for Classic Audio and LE Audio. These enhancements enrich the functionality of smart charging case solutions and improve connectivity performance with Bluetooth headsets, making it suitable for a broader range of applications.
The RTL8773DO-VAI and RTL8773ETP are two advanced models of the RTL8763EW-VC, each optimized in different directions to meet diverse market demands:
RTL8773DO-VAI:
Added support for SPDIF interface.
Enhanced core performance, including higher CPU clock speed and DSP processing rate.
Increased memory (RAM) capacity to support more complex application scenarios.
Suitable for smart charging case solutions requiring SPDIF support and stronger audio processing capabilities.
RTL8773ETP:
It integrates a 2.5D graphics processing unit, significantly enhancing GUI rendering capabilities.
USB and SPDIF support have been removed, but the core performance level remains similar to the previous generation.
Suitable for smart charging case solutions that emphasize interactive experiences.
Practical Application Case
The smart charging case integrates Line-in audio data input and Auracast™ Transmitter. It can synchronously transmit the received audio data stream in broadcast form to multiple user terminals. This innovative feature greatly meets the demand for simultaneous listening by multiple people and is suitable for various scenarios, such as school classrooms, business meetings, and guided tours.
The smart charging case integrates screen touch interaction and Auracast™ Assistant. As an Auracast™ Assistant, it can scan broadcast signals from Auracast™ Transmitters such as TVs and phones in real time, and intuitively display relevant information on the screen, thereby helping users conveniently select the broadcast audio source they wish to listen to.
Advantages of Solution
The smart charging case solution enhances the interaction experience between the user, the charging case, and the earphones by combining diverse display effects with intuitive touch operation.
Simultaneously supports both Auracast™ Transmitter and Assistant, facilitating diverse product development for customers.
A fully functional SDK/HDK development kit along with a complementary mobile app project can effectively reduce the burden of project development and accelerate project implementation.
Start Implementing My Smart Charging Case Application
Clarify functional and performance specifications of the smart charging case through comprehensive analysis of target user demographics and market positioning, establishing clear guidelines for subsequent development.
Select suitable chip solutions based on the target user's needs, and comprehensively evaluate their computational performance, power consumption, cost-effectiveness, and supply chain stability.
Design the software architecture of the smart charging case with modular principles and interface protocols to ensure operational efficiency, maintainability, and scalability.
Collaborate with hardware engineers on circuit and PCB development, optimizing physical layout and thermal management while adhering to Design for Manufacturing (DFM) and assembly requirements.
Reference links: RTL8762DT HDK, RTL8763E HDK, RTL8773D HDK, RTL8773E HDK.
Rely on the hardware platform and software SDK for code implementation and performance optimization to ensure the Bluetooth protocol stack functions properly while the GUI responds quickly.
Reference links: RTL8762DT SDK, RTL8763E SDK, RTL8773D SDK, RTL8773E SDK.
Conduct multi-level verification (unit/integration/system testing) to identify and resolve defects, ensuring final deliverables meet reliability benchmarks.
Build engineering prototypes for scenario-based testing, collect user feedback for iterative refinement, and complete full-process validation prior to mass production.
Recommended Hardware
| RTL8762DT | RTL8763EW-VC | RTL8773ETP | RTL8773DO-VAI | |
|---|---|---|---|---|
| MCU | CM4F 90MHz | Real-M300F 100MHz | Real-M300F 100MHz | CM4F 160MHz |
| DSP | N | HiFi mini 200MHz | HiFi mini 200MHz | •HiFi mini 320MHz •HiFi 4 320MHz |
| MCM Flash Size | N | N | N | 16MB |
| SRAM | 192KB | 600KB | 800KB | 4.3MB |
| GPU | N | N | Y | N |
| BT Version | BLE 5.2 | BR/EDR+ LEA + BLE 5.3 | BR/EDR+ LEA + BLE 5.4 | BR/EDR + LEA + BLE 5.4 |
| I8080 | 20MHz 8080 | 20MHz 8080 | 50MHz 8080 | N |
| QSPI | 45MHz QSPI | 40MHz QSPI | 50MHz QSPI | 80MHz QSPI |
| Max GPIO Number | 37 | 78 | 37 | 64 |
| SPDIF | N | N | N | Y |
| Line In | N | Y | Y | Y |
| MIC Resource | N | Y | Y | Y |
| USB | N | Y | N | Y |
| Package (mm) | QFN56, 7x7 | BGA149, 7x7 | QFN68, 7x7 | BGA184, 4.9x6.0 |
