| 摘要 |
PROBLEM TO BE SOLVED: To interrupt a main power supply circuit by reliably detecting a complete short-circuit and an incomplete short-circuit of an upstream side of a semiconductor relay. SOLUTION: This controller is provided with a 1st comparator circuit CMP1, that compares the difference between the source voltages of 1st and 2nd overheat self-interrupt type semiconductor switches QA, QB with a prescribed overcurrent criterion value to discriminate the occurrence of an overcurrent and with a 2nd comparator circuit CMP2 that compares the difference between the source voltages of 1st and 3rd overheat self-interrupt type semiconductor switches QA, QC with a prescribed overcurrent criterion value to discriminate an undervalue current. When the comparison result of the 1st comparator circuit CMP1 indicates that a current in excess of the prescribed current criterion value flows to the 1st overheat self-interrupt type semiconductor switch QA, the comparison result of the 2nd comparator circuit CMP2 indicates that a current below the prescribed current criterion value flows to the 1st overheat self-interrupt type semiconductor switch QA, the 1st overheat self-interrupt type semiconductor switch QA is turned off.
|
