| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor drive circuit that obtains signals of a uniform excitation angle interval and thus phase current output regardless of the non-uniformity of Hall output signals in a Hall signal processing in a brushless motor. <P>SOLUTION: The motor drive circuit comprises: a comparator 4 that compares the non-inversion output 2a with the inversion output 3a with respect to the output of a Hall signal and produces a binary output; a first counter 6 that obtains period time information by counting the one-period time of the output of the comparator 4; an oscillator 14 and a frequency divider 15 that input a certain frequency for increasing or decreasing the signal of the first counter 6; a latch circuit 8 that temporarily stores counter information; and a second counter 10 that counts latch information with N-times frequency. Thus, a three-phase current waveform that is excellent in symmetry and continuous is formed, and thereby uneven rotation and noise are reduced, and the efficiency is enhanced. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
