Motor lock detection circuit

Abstract

A motor lock detection circuit for detecting lock of a motor, comprising: a binarizing circuit to binarize a signal, obtained from the motor, having a frequency corresponding to rotation speed of the motor, to generate a binary signal; an edge detecting circuit to generate an edge detection signal when detecting an edge of the binary signal; a first counter to count based on a first counter clock, be reset according to the edge detection signal generated by the edge detecting circuit, and generate a count signal when counting for a first count period longer than an interval between edges of the binary signal; and a second counter to count based on a second counter clock, be reset according to the count signal, and generate a motor lock detection signal indicative of detection of lock of the motor when counting for a second count period longer than the first count period.