A recent teardown has revealed the SC8723, a highly efficient synchronous buck-boost converter from Southchip Semiconductor. This integrated circuit incorporates four internal switching MOSFETs, supporting scenarios where the input voltage is higher, lower, or equal to the output voltage. It enables stable voltage conversion across wide input and output ranges, making it suitable for applications such as wall chargers, power banks, USB-C hubs, wireless chargers, and industrial power supplies.

The SC8723 utilizes a synchronous four-switch Buck-Boost architecture. It operates with an input voltage range from 2.7V to 22V and an output voltage range from 3V to 22V, supporting a maximum average inductor current of up to 10A. This capability meets the design requirements for high efficiency and high integration in various portable power and small adapter products.

The SC8723 is designed to maintain a stable output even with significant input voltage fluctuations. It operates in buck mode when the input voltage exceeds the output, switches to boost mode when the input is lower than the output, and facilitates smooth transitions via its Buck-Boost architecture when the voltages are close.

In terms of control, the SC8723 employs average current mode control. The output voltage is set using external divider resistors on the FB pin. Its switching frequency is externally configurable, offering flexible adjustment among 250kHz, 500kHz, and 800kHz. This allows engineers to balance power density, efficiency, and peripheral component size based on specific application needs, enhancing design flexibility.

The chip also supports programmable output current limiting and offers selectable Forced PWM and PSM modes. PWM mode is better suited for applications requiring low ripple and fast dynamic response, while PSM mode helps improve light-load efficiency, making it ideal for products sensitive to standby power consumption, such as power banks and portable devices.

The SC8723 integrates multiple protection mechanisms, including input undervoltage protection, input overvoltage protection, output overvoltage protection, FB short-circuit protection, output short-circuit hiccup protection, and overtemperature protection. It also supports EN control and internal soft start, contributing to improved safety and reliability under abnormal operating conditions.

Housed in a compact QFN22 package, the high level of integration helps reduce the number of external components and PCB footprint. This makes the SC8723 well-suited for use in fast-charging power banks, USB-C hubs, wireless charging transmitters, and compact power modules.

In a previous teardown of the OnePlus 45W Liquid Cooler PCV05, the SC8723 was found inside, used to power the water pump. Similarly, the chip was identified in the teardown of the Baseus Tesla Model 3/Y T-Space Expansion Dock BS-TS002, where it managed the buck-boost output for the USB-C port.

The core value of the SC8723 lies in its high integration and wide voltage range. By integrating four MOSFETs internally and supporting a 2.7V-22V input and 3V-22V output with up to 10A average inductor current, it significantly reduces the number of external components and PCB area compared to solutions with external MOSFETs. This is particularly advantageous for space-constrained products like fast-charging power banks, USB-C hubs, and wireless chargers.

As the USB-C ecosystem continues to expand, the demand for multi-voltage input, multi-level output, and high-efficiency conversion in end devices is becoming increasingly evident. Buck-boost converters are becoming key components in fast-charging accessories. The SC8723 not only covers common battery-powered and adapter-powered scenarios but also offers adjustable switching frequency, PWM/PSM mode selection, and multiple protection mechanisms, balancing efficiency, size, reliability, and design flexibility.

For manufacturers, such highly integrated synchronous buck-boost solutions can help shorten development cycles and provide greater flexibility for future product miniaturization and multi-functionality.