The TLC5904 is a constant current driver incorporating shift register, data latch, and constant current circuitry with current value adjustable and a 256 gray scale display using pulse width control. The output current can be selected as maximum 80 mA with 16 bits or 120 mA with 8 bits, and the current value of constant current output can be set by one external resistor. After this device is mounted on a PCB, the brightness deviation between LED modules (ICs) can be adjusted by external data input, and the brightness control for the panel can be accomplished by the brightness adjustment circuitry. Also, the device incorporates the output voltage monitor (OVM) used for LED open detection (LOD) by monitoring the constant current output. Moreover, the device incorporates watchdog time (WDT) circuitry, which turns the constant current output off when a scan signal is stopped at the dynamic scanning operation, and thermal shutdown (TSD) circuitry, which turns the constant current output off when the junction temperature exceeds the limit.