THL3526 is a 24-channel LED driver IC with switchable constant-current output/open-drain output. Different current values can be set for each of the three groups of constant-current outputs using external resistors. The oscillator and PWM circuit are built-in, and LED brightness can be set individually for each channel in up to 256 steps. The serial interface can be selected from 3-wire/2-wire serial bus or I2C bus with the setting pin. When multiple THL3526 units are used, cascade connection using the built-in serial interface buffer circuit enables stable serial communication.