[Solved] How to Reduce the Power Consumption of MCU 2023

Reducing MCU power consumption is very important for an electronic product that needs to be powered by a battery. Not only do MCU development engineers need to design a reasonable circuit and choose the right electronic devices to strictly control the power consumption of MCU. So what are the aspects of reducing MCU power consumption?

So what is a low-power MCU chip?

Strictly speaking, there is no audit standard for low-power MCU chips, because every MCU manufacturer will advertise low power consumption when developing and producing chips. But in the end is not low power consumption, it is necessary to test the use of data before being able to conclude.

Ways to Reduce MCU Power Consumption

1. Reduce the power consumption of the MCU chip when running in active mode can reduce the energy consumption of the MCU chip, the MCU should be selected so that it runs at the lowest possible clock speed, and then run them at the lowest possible voltage according to the selected clock frequency.

If the MCU can be programmed clock rate, a good program should be written to clarify the load in all modes of operation and run the MCU at the lowest possible rate in each mode.

2. During MCU chip development, the code setup is as concise as possible to make the microcontroller spend less time in operation. In addition, 32-bit microcontroller cores process data more efficiently than 8-bit or 16-bit microcontrollers because they can operate on large blocks of data in a single clock cycle.

Moreover, 32-bit microcontrollers will likely be manufactured using more advanced semiconductor process technologies, and these technologies, if used properly, are expected to reduce operating power consumption.

Further Reading: MSP430 Low Power Consumption Principle and its Application of Sea Temperature Measurement

The Specific Six Methods to Reduce MCU Power Consumption are as follows

1. Peripheral component selection

Some 8-bit MCU power of a few tens of microamps, sleep mode for about 1uA, become the preferred. The most likely problem with this type of MCU is the limited resources and the small number of pins, such as an ICROM only 1K,RAM 32 bytes, so the final software implementation may be difficult.

2. Sleep mode

MCU can sleep in sleep mode, or in module sleep mode. When the MCU external trigger wakes up, the MCU then wakes up the module that consumes more power, and immediately goes to sleep after completing the function or communication, in short, it is natural to enter the sleep state to save power. Some modules use a variety of sleep modes, the purpose is to reduce power consumption more flexibly without affecting the function.

3. Shut down the unused resources

When using a slightly more complex MCU, it comes with its own peripherals, which must be turned off when not in use. When using a simple MCU, all possible functions, such as IIC,SPI,Uart and so on, but also note that before starting sleep, you should turn off the corresponding devices, such as sensors, or let it enter PowerDownMode, after waking up, before initializing the configuration.

4. Reduce the main frequency

We all know that the higher the main frequency of the chip, the greater the power consumption. Frequency reduction program generally does not use external crystal oscillator, using internal crystal oscillator, frequency selection commonly used 32768Hz although low, but can only get seconds of accuracy, to get ms or us-level accuracy, more than 1M frequency is rare.

5. The principle of intermittent work.

The so-called intermittent work, refers to the combination of work and rest, alternating work rest, using intermittent power supply, intermittent switching mode, so that the power consumption of the device is reduced by half. If a device is powered on, it needs to warm up for a period of time, this method does not work.

There are also some level-driven components, give the pulse a certain duty cycle can work, but also according to the voltage to adjust the duty cycle, balance the load to achieve the maximum utilization of power, but this is also a complex task.

6. The IO interface configuration.

In the above mentioned sleep before turning off external devices, you think this can be, in fact, not necessarily. If some pins are connected externally to pull-up resistors, and the MCU is sleeping when the pin is placed lower, so that there is a voltage difference, there is a resistance, the formation of unnecessary power consumption. This problem is easy to ignore, so each pin must be configured reasonably according to the external circuit.

Therefore, the definition of "low-power MCU chip" is often a variety of factors, whether it is the internal architecture layout or the actual experience of production, to meet the requirements of low power consumption, in order to be called "low-power MCU chip".