| 摘要 |
PURPOSE:To obtain a motor current detecting circuit requiring no reverse current blocking diode by connecting a current detecting resistor to the joint of each emitter of phase switching transistor and a ground resistor. CONSTITUTION:Current detecting resistors R2-R4 are disposed between respective emitters of transistors Q4-Q6 and a ground resistor GND, and resistors R5-R7 for converting into an average current and detecting current flowing through armature winding are disposed at the common joints of the emitters and the resistor. Current flowing from point A through armature windings (a), (b) to point B passes through the transistor Q5, the resistor R3 and D7. Current is determined at current detection terminal DET by utilizing the fact that two of three resistors R5, R6, R7 have 0V. The resistors R2-R4 function to detect current when forward current is fed through the transistor whereas function to disable an inner diode when a voltage is applied reversely. |
