Single phase motor driving unit

Abstract

A single phase motor driving unit includes: a first driving transistor supplying a single phase coil with a driving electric current in a certain direction; a second driving transistor supplying the single phase coil with a driving electric current in the opposite direction; a comparison section comparing an intensity of a sine wave signal obtained from a Hall device detecting a rotational position of a single phase motor and a reference value, and generating a timing signal in a predetermined period starting immediately before and ending immediately after a point at which the direction of the driving electric current for the single phase coil changes; and a recirculating section recirculating the driving electric current by controlling ON-OFF timings of the first and the second driving transistors in the predetermined period in which the timing signal is generated such that, within a given period in which the first and the second driving transistors on the side to which the driving electric current flows out from the single phase coil are ON, the first and the second driving transistors on the side from which the driving electric current is supplied to the single phase coil each becomes ON for a period that is shorter than the given period.