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[STM32] Why does the LCD current gradually increase and then decrease gradually?

Associate II

I use STM32L496

To save current to a minimum, It briefly enters NOMAL mode (0.2mA ~ 6.3mA) and updates the LCD numbers, then stays in STOP mode (0.2mA) for about 1 second and then wakes up with RTC.
I keep repeating this.

However, in STOP mode, it always consumes 0.2mA, but in NOMAL mode, the current gradually increases from 0.2mA, and when it reaches about 6.3mA, it gradually decreases again to 0.2mA.

(I think one cycle lasts about 80 seconds.)

(It does not rise and fall quickly like noise, but gradually increases and gradually decreases (like a sin wave))

The goal is to achieve 0.2mA in NOMAL mode.

For reference, if you turn off the LCD, this problem will not occur ( = LCD problem for sure)

I wonder what causes this to happen. Is there any solution??

ST Employee

Well, no one can understand what exactly is happening until you give more information about your setup. We don't know your hardware and software settings for clock, GPIOs or other settings. Especially in ultra low power applications there are some things to keep in mind to keep the power consumption as low as possible even in run mode, see e.g. How to minimize the power consumption in low power mode.


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