Power management techniques are disclosed. For instance, an apparatus may include a bidirectional voltage converter circuit, and a control module that selectively operates the bidirectional voltage converter circuit in a charging mode and a delivery mode. The charging mode converts a voltage provided by an interface (e.g., a USB interface) into a charging voltage employed by an energy storage module (e.g., a rechargeable battery). Conversely, the delivery mode converts a voltage provided by the energy storage module into a voltage employed by the interface.