The power and clock management system automatically ensures maximum power efficiency.
The nRF9160 provides a total of three power modes; two internal (automatically handled by the device), and one external (driven by the ENABLE pin and overriding internal ones).
The core of the automatic power and clock management is the power management unit (PMU) illustrated in the following image.
Figure 1. Power management unit
When the device is powered and enabled, the PMU automatically tracks the power and clock resources required by the different components in the system. It then starts/stops and chooses operation modes in supply regulators and clock sources, without user interaction, to achieve the lowest power consumption possible.