How to calculate the "power consumption" of a 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 the 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. Analog input port power consumption

Some basic parameters can be derived from the following table:

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 calculation methods.

The first one is fixed frequency, and the increase and decrease functions cause current changes:

The second type, frequency change, does not consider the use of modules:

Next, calculate the digital port power consumption:

For the digital output port, according to the data in the table, the internal Rdson is obtained, and the internal power consumption of high output and low output can be calculated.

What needs to be noted here is that the power consumption of the input port is generally not large, but the power consumption of the designed IO port is large when current is injected. At this time, the clamping diode is working, so pay attention to this part of the power consumption.

P=I.inject*Vf_diode

Input power consumption is relatively small when there is no Clamped. If the input voltage is too high or too low, it will cause many problems.

All power consumption of the MCU is the sum of the three parts.

P.MCU=P.internal+P.IO+P.Analog