Today I got brand new iPhone 13 mini (iOS 17.6) just to check its impact on my vision.

…and I was wondered it has almost zero negative impact. Then I decided to measure PWM frequency and I was wondered even more. The PWM frequency is in the range 28-29kHz.

Most bloggers/public sources report iPhone 13 mini PWM frequency is in the range of 480-510Hz but results I got are much better.

To measure PWM, I used an oscilloscope (with 70 Mhz BW) and self made photosensor based on the BPW32S photodiode and OPA381 amplifier. Additionally I verified (by LED and Rpi 4) it perfectly works in the range 0-150kHz.

The question is how PWM was measured by bloggers as I don't believe I got an iPhone sample driven by special high frequency PWM backlight.

Soon, I will share pictures captured by the oscillosope using different brightness level on the target device.

I bet you got a iphone with a lcd replacement. if you display a black image it should not be lit if its oled. if its lcd itll have a glow

dev