| 摘要 |
PURPOSE:To secure a sufficient dynamic range and to reduce power consumption by operating a transistor (TR) part which is supplied with a low source voltage in the driving circuit of the actuator during normal servo operation, and operating a transistor part supplied with a high source voltage during fast response operation. CONSTITUTION:An error signal applied to an input terminal IN during stationary focusing and tracking servo operation is passed through an operational amplifier OP and an electronic changeover switch SW controlled with a control voltage applied to INc to turn on Tr11 and Tr22, driving the actuator C. Those power parts are supplied with low source voltages + or -B22, so the power consumption is small. When high-speed response is required, high source voltages + or -B3 are supplied from the output of the amplifier OP through the switch SW to operate Tr33 and Tr34, obtaining the sufficient dynamic range.
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