PCF1545 PWM Dimming Behavior Analysis on Embedded Boards

jeremiranner — Thu, 14 May 2026 19:54:21 GMT

I have been testing PWM dimming behavior with the PCF1545 on a small embedded LED control board and noticed some interesting behavior at lower brightness levels.

The setup currently uses:

MCU: Cortex-M based controller
Communication: I2C
LED load: multi-segment indicator array
Supply voltage: 3.3V

At higher PWM duty cycles, brightness transitions appear smooth and stable. However, when reducing brightness below roughly 15–20%, slight flickering becomes visible depending on the LED type and refresh timing.

A few observations so far:

Increasing the PWM refresh frequency reduced visible flicker.
Different LED colors behaved differently, especially blue LEDs.
Timing jitter from other RTOS tasks slightly affected consistency.
Power rail noise also influenced low-brightness stability.

I am currently experimenting with:

adjusting scan/update intervals
optimizing I2C transaction timing
using separate power filtering for the LED section
synchronizing PWM updates with the main refresh loop

Has anyone else analyzed PWM dimming characteristics on the PCF1545 in embedded applications?

I would be interested in:

recommended PWM frequency ranges
best practices for low-brightness stability
techniques to reduce flicker during dynamic updates
observations when using RTOS environments vs bare-metal systems

Any practical insights or scope captures would be greatly appreciated.

Other NXP ProductsのトピックPCF1545 PWM Dimming Behavior Analysis on Embedded Boards

PCF1545 PWM Dimming Behavior Analysis on Embedded Boards