A current driver includes a gate line having a first and second nodes, K driving transistors, a terminal and a voltage generation section. Unlike conventional cognitive radios that utilize spectrum holes only, the proposed method can also utilize spectrally correlated frequency components where primary-user signals are present. Stall avoidance is accomplished by determining whether a stall condition exists with respect to receiving a missing data unit. The bias control circuit provides the bias voltage for the amplifying circuit and is deactivated when the second power down signal is asserted. The respective rise and fall digital outputs have state change timings that indicate rise and fall times of said motor phase signals.