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TPS929240-Q1: PWM dimming and analog dimming

Ivy Jin
Expert 4625 points
Part Number: TPS929240-Q1

Tool/software:

Hi Team,

May I know under what scenarios PWM dimming is more recommended and under what scenarios analog dimming is recommended?

What are the advantages and disadvantages of PWM dimming and analog dimming? Thank you!

Regards，

Ivy

  • +1
    TI__Prodigy 490 points

    Hello Ivy,

    PWM dimming will have better linearity and control at low brightnesses. This is due to PWM holding a constant maximum current for a short duration. Analog dimming will have no noise due to switching and will be more efficient due to the current amplitude being varied. Analog dimming struggles at a low brightness because the IC may not maintain a low constant current. 

    The TPS929240-Q1 has only 6 bits of accuracy to control the analog dimming for each output using the IOUTXn register while PWM has 12 bits of accuracy when writing to the PWMMXn and PWMLXn registers.

    Analog dimming and PWM dimming are intended to be used together for this chip. The analog dimming is used for dot correction to calibrate the LEDs to the same intensity while the PWM dimming allows for accurate and smooth commands.

    On their own, PWM dimming should be used for smooth animations or an accurate LED brightness, while analog dimming is needed if efficiency and low noise is required.

    Kind regards,

    Nicholas Alexander