Due to the built-in lithium battery, TWS earphones require precise internal components for operation assistance and control during the charging and discharging process. This provides a more efficient and safe charging process for the earphone charging box and the earphone body, providing reliable power supply for the earphones and effectively preventing damage to the internal structure of the earphones.

Recently, 52Audio disassembled the Redmi Buds 4 Youth Edition true wireless earphones and found that the earphone box is equipped with a low-power microcontroller with SinhMicro SS880MH integrated power management function and a SinhMicro SS61-C boost IC. The two achieve charging for the earphone box and the earphone itself, forming a complete set of efficient and safe charging operation solutions for the earphones. Let's take a look at the details together.

The Redmi Buds 4 Youth Edition adopts a semi in ear design, and the earphone body is more in line with the curve of the ear for a comfortable wearing experience; The weight of a single earphone is only 3.9g, lightweight and no burden. In addition, the product has added colorful color schemes such as sunset orange and trendy green, using trendy contrasting color combinations. The charging box is made of matte material to avoid fingerprint contamination to a certain extent.

The Redmi Buds 4 Youth Edition is equipped with a 12mm large dynamic double-layer polymer composite diaphragm, with clear and clear high pitched sounds and powerful low pitched sounds; The earphones adopt the new Bluetooth 5.3 technology, which has lower latency and stronger stability; Built in sensitive microphone, effectively reducing environmental noise for clearer vocals; The earphones support IP54 level dust and water resistance, with a single battery life of up to 5 hours. When used with a charging box, the battery life can reach up to 20 hours.

The charging box is equipped with a large capacity lithium battery, and the motherboard is equipped with an integrated lithium protection IC. The SinhMicro SS880MH low-power micro control is used to charge the built-in battery and achieve battery management. The SinhMicro Micro SS61-C synchronous boost converter is used to boost the built-in battery and charge the headphones.

SinhMicro's upgraded micro SS880MH is a low-power microcontroller with integrated power management function. The core of this component is an 8-bit MCU compatible with the 8051 instruction set, with a maximum main frequency of 12MHz. It integrates a power management unit and a charging management unit, supports battery or 5V adapter power supply, and can charge batteries of different specifications and capacities. By combining built-in detection and protection mechanisms for low voltage, overvoltage, overcurrent, and overheating, we provide efficient and safe power solutions for headphones. The VIN pin has withstand voltage treatment, with a maximum withstand voltage of 14V for the low-voltage version and 28V for the high-voltage version.

The SinhMicro SS880X series built-in linear charging management unit can charge single lithium batteries, lithium iron phosphate batteries, and other batteries. In addition, the series also supports five modes: normal, low speed, idle, standby, and sleep. Supports six reset methods: power on, external pins, watchdog timer, VDD low voltage, debugger, and software exceptions.

Schematic diagram of the SinhMicro SS880MH pins.

According to the dismantling of 52Audio, the POWER MCU of SinhMicro has been widely used in over 40 best-selling models under brands such as Manbu, Black Shark, Xiaomi, OPPO, Honor, Redmi, Realme, Nubia, Lenovo, Nokia, HTC, Soundbox, Wanmo, FIIL, 233621, Kugou, JBL, Philips, Skullcandy, Baidu Xiaodu, Leisher, Zimi, Astrid, Lear, and Ait Mingke.

SinhMicro Micro SS61-C boost IC is an efficient synchronous boost converter with ultra-low static current, with a conversion efficiency of up to 94%. The boost IC can output at least 2W of power from a low voltage source, i.e. 0.4A of current at 5V. In addition, the boost IC also has a true turn off function, enabling the disconnection of input and output under shutdown and output short-circuit conditions, without the need for external MOS transistors, and providing strong output overload protection.

Detailed functional features of SinhMicro SS61-C.

 

Summary

Through the dismantling of the Redmi Buds 4 Youth Edition, we have discovered the secret of TWS earphones being able to charge in a safe and stable mechanism - a complete and reliable charging and boosting solution that provides efficient charging experience for the earphones, becoming the fundamental driving force for the normal operation of the earphone's acoustic function.

SinhMicro, also known as Shengsheng Microelectronics, was founded in 2017. It is a company dedicated to developing top-tier processor chips for edge computing applications in the era of artificial intelligence. SinhMicro provides comprehensive solutions by combining digital and analog chips. The company is headquartered in Zhuhai, China, with branch offices in Shenzhen, Chengdu, and Shanghai. 

Our team possesses leading expertise in mixed-signal integrated circuit design, CPU design, low-power power management technology, and the development and application of 8/32/64-bit CPU systems. While focusing on RISC-V CPU architecture and its ecosystem, SinhMicro also excels in designing and developing intelligent control systems for edge computing, including Smart Power, Graphics Processing, Sensor Fusion, and Secure OS. We have in-depth knowledge of operating systems such as RTOS/Linux/Android and are familiar with the intelligent hardware ecosystem and channels.

SinhMicro's high-quality processor chips and highly reliable power chip products have been adopted by numerous renowned domestic and international brands, making us a leading provider of chip solutions in industries such as industrial automation, smart cities, smart homes, healthcare, automotive, and consumer electronics.

With a foundation built on personal growth, SinhMicro is committed to continuous improvement, innovation, and collaboration. We strive for excellence in technology and quality, constantly pushing the boundaries to create a better future together with our partners.

Original：https://www.sohu.com/a/646271556_100193168https://www.sohu.com/a/646271556_100193168