To provide a fail safe type DC digital output circuit with which the spread of fault or the like can be prevented by diagnosing the fault of an output element by itself.
Mutually serially connected output elements 1 and 2 are provided between a DC power source for load drive for directly driving a load and that load, 1st and 2nd output control circuits 10 and 20 are provided for controlling the drive of the respective output elements 1 and 2, and a hit pulse generating circuit 28 is provided for instantaneously hitting the driving output of the output element 2. The output states of output elements 1 and 2 detected by 1st and 2nd monitor input circuits 16 and 26 are compared with the driving outputs of output elements 1 and 2 by 1st and 2nd comparator circuits 12 and 22 and when the both are different, the self-diagnosis of faults at the output elements 1 and 2 is performed. At the same time, the pulse output of the hit pulse generating circuit 28 is directly compared with the output state of the output element 2 by the 2nd comparator circuit 22 and when the both are different, the self- diagnosis of a short-circuiting fault at the output element 2 is performed. When the fault at any one of output elements 1 and 2 is diagnosed, the driving outputs of both the elements are turned off.
| WO/2013/011913 | SWITCHING DEVICE |
| JP4244971 | Robot control device |
ITOU KAORU
MAKISHIMA AKIO
KOMINE TOSHIYUKI
HIGASHI NIPPON RYOKAKU TETSUDO