Hi
Please see my comment for your questions:
1：Does PCA9685 have the function that is near to PCA9635?In addition?
[gw]Yes
2:how different are PCA9685 and PCA9635?
[gw]Please see PCA9685 datasheet page 1 for your question
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Although the PCA9635 and PCA9685 have many similar features, the PCA9685 has
some unique features that make it more suitable for applications such as LCD or LED
backlighting and Ambilight:
• The PCA9685 allows staggered LED output on and off times to minimize current
surges. The on and off time delay is independently programmable for each of the
16 channels. This feature is not available in PCA9635.
• The PCA9685 has 4096 steps (12-bit PWM) of individual LED brightness control. The
PCA9635 has only 256 steps (8-bit PWM).
• When multiple LED controllers are incorporated in a system, the PWM pulse widths
between multiple devices may differ if PCA9635s are used. The PCA9685 has a
programmable prescaler to adjust the PWM pulse widths of multiple devices.
• The PCA9685 has an external clock input pin that will accept user-supplied clock
(50 MHz max.) in place of the internal 25 MHz oscillator. This feature allows
synchronization of multiple devices. The PCA9635 does not have external clock input
feature.
• Like the PCA9635, PCA9685 also has a built-in oscillator for the PWM control.
However, the frequency used for PWM control in the PCA9685 is adjustable from
about 24 Hz to 1526 Hz as compared to the typical 97.6 kHz frequency of the
PCA9635. This allows the use of PCA9685 with external power supply controllers. All
bits are set at the same frequency.
• The Power-On Reset (POR) default state of LEDn output pins is LOW in the case of
PCA9685. It is HIGH for PCA9635.
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Thanks!
BR
guowei
