| 摘要 |
PURPOSE:To improve control characteristics by controlling the maximum value of output currents by a control input apart from a servo signal. CONSTITUTION:An output from a servo IC is applied to a differential amplifier 30, bias voltage VB is subtracted, and currents I4 corresponding to a differential output are made to flow through a current mirror circuit 34. An output circuit 12 is supplied with output currents I2 corresponding to currents I4 from a transistor 102 through a current mirror circuit 34. Transistors 40, 42 constitute a comparator, the voltage VTL of a control input terminal 44 and the voltage V36 of a resistor R3 are compared, and the transistor 40 is turned ON when VTL>V36 holds and the transistor 42 when VTL<V36 holds. Consequently, the base potential of a transistor 4 is subject to the effect of the ON of the transistor, and output currents Iout can be limited when VTL<V36 holds. Iout=0 can be brought especially when VTL=0 holds. |
