The U6809B is designed to support the fail-safe function of safety-critical systems such as ABS. It includes a relay driver, two independent short-circuit-protected lamp drivers which are supplied by redundant ground lines, two monitoring circuits for the lamp driver output voltage and output current, a watchdog controlled by an external RC network and a reset circuit initiated by an over- and undervoltage condition of the 5-V supply providing a positive and a negative reset signal.