LED driver PCA9635 and PCA9685BS,118

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LED driver PCA9635 and PCA9685BS,118

Contributor I


we have application to turn ON the LEDs during power ON stage and same for some other LEDs to turn OFF.

For that we have selected PCA9635 and PCA9685.  After power on processor will take control but we need the state during power on / default condition some ON/OFF.

Please suggest if selected device work with the application.

I have also attached schematics for your review.



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NXP Employee
NXP Employee

From the datasheet: "The Software Reset (SWRST) Call allows the master to perform a reset of the PCA9635
through the I2C-bus, identical to the Power-On Reset (POR) that initializes the registers to
their default state causing the outputs to be set HIGH (LED off). This allows an easy and
quick way to reconfigure all device registers to the same condition."

  • The Power-On Reset (POR) default state of LEDn output pins is LOW in the case of PCA9685. It is HIGH for PCA9635

So if you are suggesting you will use one for the LEDs that need to be on after reset and the other for LEDs that need to be off, it appears that would work.

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