Patent ID: 6384556
Filing Date: 2002-05-07
Classification: H02P

Abstract:
A motor driving circuit having a plurality of pairs of a source-side transistor and a sink-side transistor being serially connected between a first power source and a second power source, wherein a source-side transistor and a sink-side transistor which belong to different pairs are sequentially switched on to supply a driving current to a motor coil connected between connections each between a source-side transistor and a sink-side transistor constituting a pair, the motor driving circuit comprising:a detection circuit for detecting a motor driving current; and a control circuit for periodically switching on and off at least a source-side transistor and a sink-side transistor respectively of different pairs through which the motor driving current flows, in a predetermined cycle when the motor driving current detected by the detection circuit is more than a predetermined value, wherein (i) a source-side transistor of a first pair is on and a sink-side transistor of a second pair is periodically on and off to rotate the motor, and (ii) during the situation recited in (i), the following action is performed when a braking instruction is generated: (a) said source-side transistor of the first pair and said sink-side transistor of the second pair is off, and (b) a sink-side transistor of said first pair and a source-side transistor of said second pair is periodically on and off when the driving current is more than a predetermined value.