The LM51770x is a four switch buck-boost controller. The device provides a regulated output voltage if the input voltage is higher, equal, or lower than the adjusted output voltage. In power save mode, the device supports high efficiency with low output loads due to its low quiescence currents. In power save mode, the device supports high efficiency close to 99% efficiency over the full range of the output current. The LM51770x runs at a fixed switching frequency, which is set through the RT or SYNC pin. The switching frequency remains the same during buck, boost, and buck-boost operation. The integrated and optional average current monitor helps monitor and limit input and output current of the LM51770x. This feature also supports charging backup power elements, like batteries or capacitors, with constant current (CC) and constant voltage (CV).