| 摘要 |
Here is disclosed an IC for controlling the spindle motor of a small hard disk drive unit, characteristic in being provided with a voltage detection circuit for a control circuit driving power source, responsive to the voltage at the connecting terminal of the control circuit driving power source for generating a signal to control the operation of the spindle motor; a voltage detection circuit for a motor driving power source, responsive to the voltage at the connecting terminal of the motor driving power source for controlling the operation of the motor; and further provided with a logic circuit for keeping valid the output signal of the voltage detecting circuit for said motor driving power source from the time the voltage at the motor driving power source terminal rises above a prescribed voltage higher than the upper limit of the prescribed voltage range of the control circuit power source until the time it falls below another prescribed voltage lower than the lower limit of said prescribed voltage range. The IC can be used in a single voltage mode, in which a single voltage power source corresponding to the control circuit driving power source is connected to the control circuit power source terminal and the motor driving power source terminal, or in a dual voltage mode, in which power sources of two different voltages can be connected to these power source terminals, it increases the freedom of design.
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