Power Adapter Intelligent Power Sharing:

Power Efficiency

Ahsan Zaman Director of Marketing Silanna Semiconductor

Power adapters with multiport power sharing are devices that allow multiple electronic devices to be charged or powered simultaneously. These adapters typically have multiple output ports, each capable of delivering power to different devices including smartphones, tablets, laptops, or other USB-powered consumer electronics, smart home, IT, and industrial equipment products.

Traditional multiport power adapters have limited/no dynamic power sharing ability and power each device with equal or a pre-set power delivery level. All connected ports will receive the same maximum power output, regardless of the type of device and their battery charge levels. For example, a 40W 2C charger will deliver 20W to each device regardless of their battery levels. One of the key features of power adapters with multiport power sharing is the ability to dynamically allocate power among the different output ports based on the actual power requirements. This means that the adapter can intelligently distribute the available power across the connected devices, ensuring that each receives the appropriate amount of power for efficient charging or operation.

Power adapters with multiport power sharing usually come with various charging technologies, such as USB Power Delivery (USB-PD) or Qualcomm Quick Charge, which provide fast charging capabilities for compatible devices. These adapters may also have additional safety features, such as overvoltage protection, overcurrent protection, and short circuit protection, to safeguard the connected devices from potential power-related risks.

The convenience of having multiple output ports in a single power adapter with power sharing capability allows users to reduce clutter and simplify their charging setup, making it ideal for home, office, or travel use. It can also be a cost-effective solution for powering multiple devices simultaneously without the need for individual power adapters for each device.

Multiport Power Sharing Example

The power sharing feature of the SZPL3002A buck converter IC is designed to efficiently distribute power among multiple devices connected to the charger or adapter. As an example, for a 65W multiport adapter, when a single device is plugged in, the PD Controller communicates with the device to determine its power requirements and if the device has a low battery level of 20%, it will receive 100% of the available power.

Fig 1: Adaptive Intelligent Power Sharing

When a second device is added, the PD Controller will communicate with the new device to establish its power needs. For instance, if the second device is a smartphone with a battery level of 30%, the PD Controller will reduce the power allocated to the first device to 57.5W and allocate 7.5W to the smartphone.

Similarly, when a third device is added, the communication loop is repeated to establish the new power requirements. The power allocated to the first and second channels may be further adjusted based on the battery levels of all connected devices. This ensures that the maximum output of multiport adapter is shared among the devices that need power the most, using an adaptive power sharing algorithm.

As the battery level of the first device increases, the power IC allows for power rebalancing without establishing a new contract, allowing for efficient redistribution of available power. For example, the power allocated to the first device may be reduced by 10W, and the additional 10W may be redirected to the second device.

By integrating the buck converter and the PD Controller into a single IC package, the SZPL3002A simplifies the design of 65W fast charger and adapter applications with up to four ports, while ensuring efficient power sharing among connected devices.

The SZPL3002A is a high-efficiency synchronous buck converter with a selectable switching frequency ranging from 667kHz to 2MHz. It has an input voltage range of 7V to 27V and is capable of providing a 3.3V to 21V output at 3.25A, which covers PD (Power Delivery) and PPS (Programmable Power Supply) requirements.

Fig 2: SZPL3002A buck converter IC with a built-in USB PD/FC port controller

One of the unique features of the SZPL3002A is its integrated PD controller, which supports both Type A and C ports. The PD controller enables adaptive power sharing across two, three, or four ports with auto power re-balancing and power throttling at elevated temperatures. This means that when multiple devices are connected to the SZPL3002A for charging, the PD controller communicates with each device to establish their power needs and dynamically adjusts the power output accordingly.

Fig 3: 65W 2C1A high-power-density AnyPort™ Schematic

Furthermore, the SZPL3002A features a high-efficiency buck converter, which ensures that the power delivery is greater than 98%. It also has a selectable soft start time and supports communication through an I2C bus.


Compact and highly integrated semiconductors such as the SZPL3002A are helping to significantly simplify the design of fast chargers. Packaged in a compact 5mm x 5mm QFN package, this is the world’s first buck converter power IC to feature an intelligent, adaptive power sharing integrated PD controller. The innovative, in-built power sharing feature ensures that available power is shared among the connected devices based on their power needs, maximizing charging efficiency and optimizing overall system performance.