AUTOMATIC DAYTIME RUNNING LIGHT SYSTEM

摘要

An automatic daytime running light system for a vehicle having an engine, an electrical power source (+12V), a starter motor circuit (P3) for the engine, external running lights including headlights (HL) and parking lights (PL), and input switches (P1, P2) for ignition circuit and the external running lights, the system being responsive to the input switches and the starter motor cuicuit automatically control the operation of the external running lights, and the system including digital logic timer circuit means (U5, U6) for automatically controlling the operation of the external running lights, and MOSFET output switching devices (Q3, Q4), which thereby provide high reliability and safety, redundant circuitry (Q2, U6, Q3) to thereby provide a higher level of reliability and failsafe operation of the system, and MOSFET fault current monitoring circuitry (U5, Q4) which monitors the drain to source fault currents of the MOSFET output switch means (Q4), whereby upon detection of fault currents, the digital logic timer (U5) controls a fault current indicator (27) to provide an indication of a fault current condition.