How to calculate the power consumption of microcontroller

The power consumption of a microcontroller is very difficult to calculate, and at high temperatures, the power consumption of a microcontroller is still a particularly important parameter.
For the time being, the power consumption of a microcontroller is divided as follows.
1. Internal power consumption (related to frequency)
2. Power consumption of digital input and output ports
2.1 Input port
2.2 Output high
2.3 Output low
3. Power consumption of analog input ports
Some basic parameters can be obtained from the table below:




First, we calculate the internal power consumption
The power consumption of a microcontroller is generally related to the operating frequency. At a fixed frequency, it is related to the function. There are two ways to calculate it.
The first is a fixed frequency, and the increase or decrease function causes current changes:




The second is a frequency change, regardless of the use of the module:




Next, calculate the power consumption of the digital port:




Digital output port, according to the data in the table, the internal Rdson is obtained, and the internal power consumption of output high and output low can be calculated.
It should be noted here that the power consumption of the input port is generally not large, but the power consumption is large when the designed IO port has current injection. At this time, the embedded diode is working, and pay attention to this part of the power consumption.




P=I.inject*Vf_diode
Input power consumption is relatively small when there is no clamping. If the input voltage is too high or too low, it will cause many problems.




The total power consumption of the MCU is the sum of the three parts.
P.MCU=P.internal+P.IO+P.Analog