JPS6429023A - Signal converter - Google Patents

Abstract

PURPOSE:To detect a fault, and at the same time, to protect an output signal at the time of the fault by assigning one input signal simultaneously to two signal conversion circuits, and comparing the outputs of them. CONSTITUTION:N-number of the input signals 1 are assigned to N-number of signal conversion circuits 8 respectively by an input control circuit 7, and at the same time, the same input signal as the input signal, assigned to the signal conversion circuit 8 to detect the fault, is assigned to the N+1-th signal conversion circuit 8. Here, two outputs from an output selecting circuit 10 are compared by a comparing circuit 11, and a result is outputted to a control circuit 13. Then, time since the assignment of the input signal is changed until the internal state of the signal conversion circuit 8 settles is measured by a timer circuit 12, and afterwards, the output of the comparison circuit 11 is checked by the control circuit 13, and the fault is detected. At the same time, from the result, by changing the output of the signal conversion circuit 8, in which the fault exists, to the output of the normal signal conversion circuit 8, the output signal 2 at the time of the fault is protected.