| 摘要 |
PROBLEM TO BE SOLVED: To provide an encoder for a motor capable of lifetime elongation, miniaturization and cost reduction of a backup power source, even when an element requiring a large power consumption is used. SOLUTION: This encoder 1 having an A-phase Hall IC 7a for outputting an A-phase pulse signal following rotation of a rotor 25, a B-phase Hall IC 7b for outputting a B-phase pulse signal having a phase which is different by 90 degrees from the A-phase pulse signal following rotation of the rotor 25, and a multi-rotation counter 3 for outputting a multi-rotation count value based on output signals from each Hall IC 7a, 7b, and driving each Hall IC 7a, 7b and the multi-rotation counter 3 by using a power source 8 for normal operation and the backup power source 9, is equipped with a supply voltage monitor circuit 22 for detecting the ON/OFF state of the power source 8 for the normal operation; and an operation control part 4 for setting each Hall IC 7a, 7b into an intermittent operation state, when the supply voltage monitor circuit 22 detects the OFF state of the power source 8 for the normal operation. COPYRIGHT: (C)2009,JPO&INPIT
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