LED Driver ICs vs Direct GPIO

Driving LEDs directly from a GPIO pin is fine for indicator LEDs drawing under 5mA. For any application requiring consistent brightness, multiple LEDs, or high current, a dedicated driver IC is the correct choice.

Why not GPIO: GPIO output voltage varies with supply voltage and load. LED forward voltage varies with temperature. The combination means GPIO-driven LED brightness varies significantly with operating conditions — visually noticeable for indicator arrays.

Constant-current LED drivers like the TLC5947 (24 channels, 12-bit PWM, SPI control) maintain constant current regardless of supply voltage variations. The current is set by a single external resistor for all channels. For high-power LEDs, dedicated drivers like the AL8843 handle heat and efficiency. The cost delta over GPIO plus resistors is under $1 per driver IC for small quantities.