FAN MOTOR DRIVE DEVICE, DRIVE METHOD, COOLING DEVICE EMPLOYING THE SAME, AND ELECTRONIC APPARATUS

摘要

PROBLEM TO BE SOLVED: To suppress rise of a power supply voltage or an output voltage and/or to improve efficiency and torque characteristics.SOLUTION: A speed detection circuit 210 generates a speed detection signal S2 of a cycle corresponding to a rotational speed of a single-phase motor 102. A current monitoring circuit 208 asserts a zero current detection signal S5 when inversion of a direction of a coil current flowing to a motor coil 103 is detected. A shift trigger circuit 220 includes a first counter 222 which is reset for each edge of a Hall detection signal S1 and performs a counting operation while defining a pulse signal S4 indicating that a rotor is rotated at a predetermined electric angle, as a clock and when a count value CNT1 is matched with an advance angle setting value S6, a shift pulse S7 is asserted. On the basis of at least the shift pulse S7, a logic circuit 204 shifts an H bridge circuit 206. An advance angle controller 230 adjusts the advance angle setting value S6 in accordance with the timing in which the zero current detection signal S5 is asserted.SELECTED DRAWING: Figure 3