Fault diagnosis device for multiplexer

摘要

The fault diagnosis device is for a multiplexer having inner channels selectable by a selection signal. At least two of the inner channels are assigned with input channels. Two of the inner channels in a mutually exclusive relationship are assigned with first and second diagnostic channels. Input voltages of the first and second diagnostic channels are applied with first and second diagnostic voltages, respectively. The fault diagnostic device includes a voltage detection section configured to detect a first detection voltage appearing at the output channel when the first diagnostic channel is selected and a second detection voltage appearing at the output channel when the second diagnostic channel is selected, and a diagnosis section configured to determine that the multiplexer is faulty upon detecting that the first detection voltage is different from the first diagnostic voltage or the second detection voltage is different from the second diagnostic voltage.

主权项

1. A fault diagnosis device for a multiplexer which includes at least two input channels, an output channel, and a selection circuit that connects a selected one of the input channels to the output channel in accordance with multi bit signals supplied from outside the multiplexer,
two of the selectable input channels which are associated with two of the multi-bit signals that are in an inverted relationship in logic state being assigned with diagnostic channels, input voltages of the diagnostic channels being set to diagnostic voltages, the fault diagnosis device comprising a computer processor, the fault diagnosis device being configured at least to perform:
a voltage detection for detecting voltage appearing at the output level, anda diagnosis for performing, when the two diagnostic channels are selected in succession to be connected to the output channel, a process in which the multiplexer is determined to be faulty upon detecting that one of an output voltage of the output channel detected in the voltage detection when either one of the two diagnostic channels is selected and an output voltage of the output channel detected in the voltage detection when the other is selected differs from the diagnostic voltage.