Shown here are some of the functions that make the Si10xx a good choice for this type of application. The ADC can operate autonomously from the CPU, reducing power. It also has a very fast settling time so the measurement can be taken and put back to sleep before other devices even settle the analog system. With the integrated single cycle CPU, any computations can be completed quickly and the CPU can go back into the sleep mode. The effect of integrating the DC/DC converter can also be seen. By adding the DC/DC converter the supply voltage and the supply current to the Si10xx are held constant. This resolves the power curve to a single point instead of varying as battery voltage changes which forces a constant supply voltage and current. DC/DC converter output voltage can be held to a voltage that minimizes the power consumption regardless of the battery voltage (e.g. always operate at 1.9 V). This can be seen in the plot denoted by the star. When the battery is fully charged the system consumes the minimum amount of power.