Patent ID: 8847537

Claim:
A motor driving circuit for adjusting motor speed, comprising: a pulse width modulator (PWM) converting circuit includes a first input end, a second input end, a third input end and an output end, wherein the first input end is connected to a controlling signal, the second input end is connected to an adjustable highest setting voltage signal (VH), the third input end is connected to an adjust lowest setting voltage signal (VL) and the output end is to output an analog signal, and the analog signal is changeable in accordance with the controlling signal, the adjustable highest setting voltage signal (VH) or the adjust lowest setting voltage signal (VL); an oscillator configured to generate a triangular signal; and a comparator including a first input, a second input and an output, and the first input is connected to the triangular signal generated by the oscillator, the second input is connected to analog signal generated by the PWM converting circuit and the output end is to generate a driving signal.