| 摘要 |
PURPOSE:To enhance the driving capacity of a motor by providing a first level shifter between the emitter and the output of a transistor which receives differential inputs of a plurality of phases. CONSTITUTION:A driver of a 3-phase brushless motor is composed of an upper stage having driver 1 transistors (Tr) Q1-Q6, resistors R1-R4, and a lower stage driver 4 having Trs Q7-Q12 and resistors R5-R8. The Trs Q2 and Q3, Trs Q8 and Q9 respectively form current mirror circuits. In this case, a level shifting diode D1 is inserted between the emitter and the output terminal 3 of the Tr Q7. Thus, since the diode D1 sets the emitter potential of one Tr Q7 of a push-pull type to a potential higher than the output, the voltage drop of the driver is reduced, thereby raising a voltage applied to both ends of a motor coil. |
