This application note provides a detailed description of LED dimming implemented on the STM32 microcontroller in combination with the STP24DP05 LED driver. It describes the general principles of LED dimming, with a focus on the use of pulse width modulation (PWM) for digital dimming, and compares the most common design approaches. The conclusion helps developers choose the best approach for their LED dimming application.
This document details the principles of digital LED dimming, specifically focusing on Pulse Width Modulation (PWM). It compares different design approaches for driving multiple LEDs, including dedicated pins and serial-parallel conversion.
The note provides a specific implementation guide using an STM32 microcontroller combined with the STP24DP05 24-bit constant current LED sink driver. It analyzes various data transfer methods such as dynamic preparation, static lookup tables, and interrupt/DMA configurations to help developers choose the optimal approach for their application.
| PWM frequency for non-flickering light | > 100 Hz |
|---|---|
| Document revision date | November 2008 |
The specific application example uses an STP24DP05 24-bit constant current LED sink driver.
The PWM frequency must be higher than 100 Hz for the light to appear non-flickering.
Using a 4-bit PWM resolution allows for 16 different light intensity values.
The STP24DP05 is a 24-bit constant current LED sink driver.