APPARATUS FOR THE CONVERSION OF DIRECT CURRENT SIGNAL IN PROPORTION OF THE MAGNITUDE OF THREE-PHASE BACK ELECTROMOTIVE FORCE

摘要

PURPOSE: A device for converting direct signals proportional to a size of 3-phase counter electromotive voltage signals is provided to determine a forward direction of a BLDC(Brushless Direct Current) motor at a maximum point of counter electromotive voltage, thereby having a property strong to noise. CONSTITUTION: A differential amplification circuit(110) removes the common-mode noise of a BLDC motor. A phase selector(120) selects each phase by using hole sensor signals(H1,H2,H3) of the BLDC motor. A wave rectifier circuit(130) wave-rectifies counter electromotive voltage output by the selector, thereby generating wave rectified output voltage. An amplification/counter amplification function circuit(140) amplifies or counter-amplifies the generated wave rectified output voltage. A phase and forward/reverse direction determining device(150) obtains a forward/reverse direction determining logic circuit determining the forward/reverse direction of the BLDC motor. [Reference numerals] (11) BL 3-phase counter electromotive voltage generator; (110) Differential amplification circuit; (12) Hall sensor signal generator; (120) Phase selector; (130) Wave rectifier circuit; (141) Amplifier; (142) Inverted amplifier; (150) Phase and forward/reverse direction determining device; (160) Forward/reverse direction selecting device; (170) Lower frequency filter; (180) Offset regulating circuit