Home Consumer Electronics Understanding the Six Energy Modes for Most Effectivity on NXP’s LPC55S69 MCU  –...

Understanding the Six Energy Modes for Most Effectivity on NXP’s LPC55S69 MCU  – Trade Articles


When searching for the proper microcontroller, it’s vital to know all of its key options to make sure the right execution throughout any challenge. Luckily, there are various microcontrollers available on the market that provide quite a lot of options to fulfill the wants of demanding purposes. NXP’s LPC5500 sequence of microcontrollers might be utilized to many real-world purposes, together with industrial and industrial, providing energy consumption advantages, amongst many different issues, which might be mentioned on this article. 

A earlier article, Leveraging the LPC55S16-EVK for Industrial Applications, investigated the facility consumption and clock pace of one other member of the LPC5500 sequence of microcontrollers, the LPC55S16 MCU, a helpful board for industrial purposes as a consequence of its number of interfacing choices. This text explores the facility rails and energy modes of the LPC55S69 and investigates how the modes have an effect on the MCU in numerous purposes.


Determine 1. The NXP LPC55S69-EVK


How A lot Present Does the LPC55S69 MCU Draw?

The ultra-efficient 40nm flash expertise, mixed with a singular structure, makes it potential for the LPC55S69 system to solely devour round 32µA/MHz. Subsequently, the chip ought to theoretically solely devour round 4.8mA when it operates with its most frequency of 150 MHz. Nonetheless, that’s below the idea that the code is working in RAM and that the applying is extremely optimized. Realistically, in lots of instances, the present consumption might be round 10mA.

Earlier than figuring out the facility consumption of the MCU, it is vital to try its energy provide. On the LPC55S69 system is organized as proven in Determine 1. 

The 2 energy rails of curiosity for this experiment are marked with blue circles within the determine above. VDD is the facility provide that drives all of the GPIO pins, whereas VBAT_PMU and the VBAT_DCDC rails kind the principle provide that powers the logic of the chip. So, the mixed present consumption of all these rails have to be considered to seek out the general present that the MCU attracts in a practical setting.

Working with the utmost clock pace of 150MHz, the mixed present draw is round 7.54mA. Contemplating the MCU’s clock, the chip has a present consumption of round 50µA/MHz.

Even with a barely increased present consumption than theoretically potential, the MCU requires little or no energy to function, particularly when contemplating that it runs at 150MHz. The outcomes might additionally range dramatically when the code is optimized, executed from RAM, and when extra exact measuring gear is used.

These properties make the LPC55S69 MCU perfect in all situations that require important processing energy and effectivity.


Energy Modes of the LPC55S69 MCU

To additional mitigate the facility consumption of the MCU, the LPC55S69 system helps six energy modes that disable sure elements of the chip to save lots of energy. To exhibit how the completely different energy modes have an effect on an Okdo E1 growth board, which makes use of an LPC55S69 MCU, the setup proven in Determine 3 is used.


Determine 2. The setup used to exhibit how the completely different energy modes have an effect on an Okdo E1 growth board. 


A 200mAH CR2032 coin-cell battery is immediately linked to the VDD_TARGET pin of the event board to energy it. Moreover that, it’s additionally hooked as much as a small e-ink show, which can output the clock pace of the microcontroller. A demo utility manages the facility mode that the LPC55S69 system is in. The mode might be modified utilizing the wake button on the right-hand facet of the Okdo E1 board.

Utilizing this setup, the microcontroller was put into completely different energy modes, and the next desk highlights the measured present in every mode:



Word that the measured present contains all of the peripherals linked to the Okdo E1 board.

In full-speed mode, the MCU operates with a frequency of as much as 150 MHz. Subsequently, this mode is finest fitted to purposes that require quick processing, whereas power-efficiency isn’t of utmost significance.

The run mode will decrease the MCU’s clock frequency to 12 MHz, which helps cut back energy consumption whereas nonetheless making certain quick response instances when performing complicated calculations. This mode represents a very good mixture of processing energy and energy effectivity.

The primary low-power mode is the sleep mode — think about it as a nap mode for the microcontroller the place the core clock is stopped, however all of the peripherals stay operational. Because the setup on this experiment consists primarily of peripherals, the advance in present consumption is quite small when switching from run mode into the primary sleep mode. On this demo, the MCU might be woken up by utilizing one of many person buttons on the Okdo E1 board.

In deep-sleep mode, the core is stopped like in sleep mode. Nonetheless, right here, lots of the peripherals additionally shut down to scale back the present consumption of the system. Urgent a user-button will, once more, wake the MCU up.

The ability-down mode additional reduces the present consumption by disabling the DCDC converters, turning off the digital logic, and stopping the clock pace. There’s an choice to retain the contents of the RAM and preserve one or two asynchronous peripherals working. Urgent the ISP button on the Okdo E1 board will get up the core.

In deep-power-down mode, the digital logic, DCDC converters, and many of the chip are turned off. Solely the real-time-clock stays lively, which can wake the MCU after a 10-second delay and reset the MCU to the run mode on this utility.

Word that the desk isn’t consultant of the present consumption of the microcontroller itself because of the peripherals and the added present draw of the Okdo E1 growth board which requires round 5.7mA. Subsequently, the MCU solely attracts a couple of micro Amperes of present within the deep-power-down mode. Nonetheless, in follow, it’s unlikely that the MCU would be the solely part in a circuit. Subsequently, this experiment illustrates how the MCU behaves in its completely different energy modes in a practical setting.


The LPC55S69: A Low-Value, Extremely-Environment friendly MCU

The LPC55S69 MCU requires little or no energy to run, particularly contemplating that it accommodates numerous co-processors, DSPs, and security-features. These traits allow the LPC55S69 for use in all kinds of various purposes starting from hobbyists initiatives to processing on-the-edge to industrial and industrial merchandise. This text launched the six energy modes of the MCU and demonstrated how they have an effect on the operation and the present consumption of the general system. 

In a median utility, working at 150MHz, the MCU will devour round 10mA normally. In its deep-power-down mode, the chip’s present consumption is within the micro Ampere vary. NXP’s neighborhood web page affords an inventory of utility notes, tutorials, and movies primarily based on the obtainable MCUs, which might be useful to higher perceive their capabilities. 

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