You can modulate the brightness without flicker, you can try it yourself with a lab power supply. It is just that filtering the output of the regulator is “exp

You can modulate the brightness without flicker, you can try it yourself with a lab power supply. It is just that filtering the output of the regulator is “expensive” as you need a relatively large capacitor. If this is omitted in combination with a low frequency PWM, you will experience flicker.