A fail-safe scan circuit and a multibeam sensor.

摘要

A fail-safe scan circuit sequentially and periodically drives and scans objective devices. The scan circuit has a failure detector that provides, upon detecting a failure, a signal of logical value 0 to inform of the failure. Adjacent input signals to the failure detector have a phase difference of pi . This phase difference results in simplifying the structure of the failure detector. The fail-safe scan circuit is employable to drive and scan many photosensors of a fail-safe multibeam sensor.