MOTOR DRIVING DEVICE
First Claim
1. A motor driving device for driving a three-phase brushless motor without using a hall sensor, comprising:
- a filter circuit which receives coil terminal voltages of each phase of the three phase coils of said three-phase brushless motor and a center tap voltage of said three-phase coil so as to remove a voltage component resulting from a current ripple included therein; and
a voltage comparing portion including a comparator which compares a coil terminal voltage of each phase after filtering the coil terminal voltage of said each phase with a center tap voltage after filtering of said center tap voltage, whereinsaid comparator sets a comparison voltage with said coil terminal voltage of each phase after filtering based on an offset signal to a value supplied with a higher offset voltage than said ripple voltage after filtering.
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Accused Products
Abstract
An object of the present invention is to provide a motor driving device capable of outputting an accurate rotation signal while preventing a false detection of B-EMF in a position detecting comparator. The motor driving device includes an output circuit, filter circuit, comparison circuit, current zero ampere detecting circuit, position detecting circuit, sensorless drive arithmetic operation circuit, noise reduction current waveform generating circuit, signal synthesizing circuit, and output transistor control circuit, the comparison circuit including a comparator, polarity switching portion connected to a +terminal and −terminal of the comparator and signal switching portion, the comparator being structured to be able to set and release an offset having a predetermined voltage value set preliminarily.
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Citations
4 Claims
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1. A motor driving device for driving a three-phase brushless motor without using a hall sensor, comprising:
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a filter circuit which receives coil terminal voltages of each phase of the three phase coils of said three-phase brushless motor and a center tap voltage of said three-phase coil so as to remove a voltage component resulting from a current ripple included therein; and a voltage comparing portion including a comparator which compares a coil terminal voltage of each phase after filtering the coil terminal voltage of said each phase with a center tap voltage after filtering of said center tap voltage, wherein said comparator sets a comparison voltage with said coil terminal voltage of each phase after filtering based on an offset signal to a value supplied with a higher offset voltage than said ripple voltage after filtering. - View Dependent Claims (2, 3, 4)
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Specification