Portable devices such as Bluetooth speakers have the ability to benefit from USB-C by allowing their product to charge and power connected peripherals from a single port, giving users the ability to turn their portable product into a power bank. Figure 55 and Figure 56 show two typical block diagrams for a Bluetooth speaker, which are often applicable to other portable battery-powered devices.

There are two potential power architectures when designing a Bluetooth speaker or any portable battery-powered device:

• Two separate power paths for sinking and sourcing power from the system.
• A single power path where the battery charger also acts as the source in on-the-go mode.

Instances when the first option make sense include if there is a common 5V rail used across multiple devices within Bluetooth speaker, and designer would prefer to have the sink power path isolated from the rest of the power architecture. The second option may be better for systems that want to sink and source voltages greater than 5V. In order for a system to source 9V from the USB-C port, you must implement a variable DC/DC that has the ability to start at 5V and then transition to 9V. Instead of having to implement a separate variable DC/DC for this functionality, you can use the on-the-go functionality integrated in many battery chargers.