| 摘要 |
<p>PURPOSE:To increase reliability with a simple construction, small size and less number of connection by providing a 1st, 2nd current detectors and inversion adding circuit. CONSTITUTION:Currents of two phases are detected by two current detectors 1 and 2 to obtain conversion outputs I01 and I02, and the conversion output I03 for the remaining phase is so arranged as obtaining by the inversion adding circuit 30 in which aforementioned two outputs are inputted to invert with adding or add with inversion. That is, by performing the inversion adding 30 with the outputs of the detectors 1, 2 as the input, one corresponding to the detecting output of the current on the remaining one phase is outputted according to a balancing theory for the 3-phase AC. It is the same which current among three phases is detected and which current detector is used for the detection to output the conversion output. Also, this circuit can be shared for a power supply and grounding, so the total number of connector pins is 6, i.e. 2 pins PS for power supply, 1 pin PG for grounding and 3 pins P1-P3 for output terminals with 1 pin for each phase, thus, the number of pins can be reduced to a half as compared with a conventional method.</p> |
