| 摘要 |
PROBLEM TO BE SOLVED: To protect the operation of a current amplifier circuit in a wide range from low frequency side to high frequency side, by protecting the current amplifier circuit even for the operation of higher speed than the reset time of a relay device, in the protective device of a current amplifier circuit.SOLUTION: A protective device 30 includes a detection circuit 32 for detecting the abnormal current value of a current amplifier circuit 14 and outputting a first abnormality detection signal, outputs a second abnormality detection signal continuously for a predetermined maintenance time starting from the output timing of the first abnormality detection signal, squeezes the input voltage value to the current amplifier circuit, at the reception timing of the second abnormality detection signal, and outputs a cut-off command signal to a relay device 36 at the same timing. The detection circuit 32 has a load line detector 42 where the current value on the load line is the abnormality detection operating point, and a pulse response characteristics changing section 44 for changing the frequency characteristics of abnormality detection operation by load line detector.SELECTED DRAWING: Figure 1 |
