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TPS92390: Analog dimming with PWM control

Kai Nomiyama
Expert 5355 points
Part Number: TPS92390

Hi Team,

Could I ask how to set the TPS92390 to meet following requirement?
[Requirement]
1. control the LED current by I2C(Analog dimming)
2. control the LED current ON/OFF(analog dimming current or 0%) by PWM input(PWM dimming)
Key care about: fastest ON/OFF control

TPS92390 "Current Dimming Mode" might be Analog dimming with I2C so I think we can meet above requirement with following setting.
PWM ON/OFF control should be faster than I2C BRT control so I use PWM INPUT to pin12/PWM.
Mode: Current Dimming Mode
Analog dimming: BRT_CONTROL Register by I2C
PWM dimming: PWM input ON/OFF(analog dimming current or 0%) to pin12/PWM by external GPO
> PWM frequency is decided by R_PWM_FSET so the end of PWM input should follow LED PWM frequency to meet 100% duty or 0% duty.

No comment in datasheet that Current Dimming Mode supports both BRT_CONTROL(analog dimming) and PWM INPUT(PWM dimming) so not sure both are supported.
If there are any other fastest way to meet above requirement, could you share it with me?

Regards,
Kai

  • 0
    TI__Genius 9630 points

    hello Kai, sorry for the late reply.

    Per my understanding, current dimming mode is analog dimming. So from the requirement, if you want to realize both analog dimming and PWM dimming, hybrid mode can support this, and in this mode PWM dimming is used for low brightness range, current dimming is used for high brightness levels.