| 摘要 |
PURPOSE:To facilitate a low speed rotation drive by energizing two phases of a motor driving coils to drive a rotor at the time of rotating at a high speed and energizing one phase of the coil at the time of rotating at a low speed. CONSTITUTION:Currents are supplied to motor drive coils(MC) L1, L2 at the time of high speed rotation, and an H/L signal is output from a comparator IC1 in response to a pole of a rotor. At the time of the H signal, a transistor(Tr) Q1 is turned ON. Thus, a current flows to the MC L1, and a rotary force is applied to the rotor by an electromagnetic force. Then, at the time of the L signal, the Tr Q1 is turned OFF, and no current flows to the MC L1. In this case, a Tr Q2 is turned ON. Thus, a current flows to the MC L2, and a rotary force is applied to the rotor by an electromagnetic force. At the time of rotating at a low speed, when the H signal is input to an input terminal T1, a Tr Q3 is turned ON, and no current flows to a base of the Tr Q2. Accordingly, only the Tr Q1 is solely operated, and the MC L1 is intermittently energized according to the rotation of the rotor. |
