| 摘要 |
<p>PROBLEM TO BE SOLVED: To adjust a phase compensation amount in an operational amplifier by an external circuit of the operational amplifier for reducing the delay of a detected current signal, in a current detection device using a general-purpose operational amplifier of low speed.SOLUTION: A current detection device 5 includes: a shunt resistance 11 for converting an instantaneous current into a detection current signal which is a voltage signal; a first filter 12 for reducing surge noise superimposed on the detection current signal; an operational amplifier 17 for amplifying the detection current signal; a third filter 19 which reduces a ringing signal due to the surge noise of the detection current signal amplified by the operational amplifier 17 and outputs the same to an A/D converter 6a; and a second filter 13 which reduces the surge noise which becomes a ringing-shaped waveform of the detection current signal inputted from the first filter 12 and outputs the same to the operational amplifier 17. A time constant of the second filter 13 is smaller than a time constant of the third filter 19, and a capacity of a capacitor 13b is larger than that of a capacitor 19b.</p> |
