Abstract: The present invention provides a level shift circuit having low possibility of malfunction by noise, and can operate with low power.

Abstract: A level shift circuit of an embodiment includes first and second MOSFETs using signals with phases same as and opposite to the phase of an input signal as gate inputs; first and second resistance elements, each having one end connected to a shift level power terminal that supplies high-level output voltage of a level-shifted output signal, and each having the other end connected to a corresponding drain of the first and second MOSFETs; a comparator having a pair of differential input terminals, individually connected to respective drains of the first and second MOSFETs; and a current control circuit that controls an amount of first current flowing through the first MOSFET via the first resistance element and an amount of second current flowing through the second MOSFET via the second resistance element in synchronization with a rising and a falling of a signal level of the input signal.

Abstract: A voice coil motor driving circuit 10 with retracting function used in a disk drive unit for driving a read/write head by means of a voice coil motor VCM, comprising a voltage up-converter 12; a voice coil motor control circuit 16 for driving the voice coil motor during normal operation; a retract power source Vrr for supplying a retract current to the voice coil motor during head retract action; a retract control circuit 24 for allowing the retract current from the retract power source to the voice coil motor in response to a retract signal. The driving circuit also includes a capacitor C for providing an uninterrupted supply of voltage to the retract control circuit 24 during head retract action.