| 摘要 |
PURPOSE:To monitor a short-circuit fault of a diode all the time by detecting a voltage when the diode short-circuits, by providing a voltage nonitoring point corresponding to every column of a diode matrix. CONSTITUTION:A scanner consists of row drivers Q1 and Qn, monitoring points SP00 and SPnm, a diode matrix, and sense amplifiers SA0 and SAm. When a row 0 is specified, a row driver Q0 turns on and the sense amplifier SA0 and SAm read whether contacts (a) are closed or not at monitoring points SP00 and SP0m. Inputs to the sense amplifiers SA0 and SAm are connected to voltage comparators DET-B and DET-G and if a diode DS short-circuits, a battery -E at a monitoring points SP is detected; if a diode DP short-circuits, the earth potential is detected when the contact (a) of the monitoring point SP is closed. Thus, short-circut faults of the diodes DS and DP are monitored all the time. |
