Motor controller circuit having stable speed controlling mechanism

A motor controller circuit having a stable speed controlling mechanism, which is applicable to a motor, the motor controller circuit comprising:

• a duty cycle determining circuit, wherein the duty cycle determining circuit is configured to determine that a plurality of waveforms of each of a plurality of first waveform signals are generated respectively within a plurality of time intervals, the duty cycle determining circuit is configured to determine that each one of the plurality of waveforms of each of the plurality of first waveform signals is generated within one of the plurality of time intervals, and the duty cycle determining circuit is configured to determine a plurality of duty cycles of the plurality of waveforms respectively of the plurality of first waveform signals within each of the plurality of time intervals to output a duty cycle instructing signal, according to a target duty cycle corresponding to a target rotational speed of the motor;
• a signal generating circuit connected to the duty cycle determining circuit, configured to output the plurality of first waveform signals according to the duty cycle instructing signal, and configured to output a second waveform signal;
• a motor control circuit connected to the signal generating circuit, and configured to output a plurality of on-time signals according to the plurality of first waveform signals and the second waveform signal, wherein the motor controller circuit outputs each one of the plurality of on-time signals according to one of the plurality of first waveform signals and the second waveform signal;
• and
• a motor driving circuit connected to the motor control circuit, and configured to operate and drive the motor to rotate according to the plurality of on-time signals.