Abstract: A ringer circuit comprising a rectifier circuit, a voltage regulator and a ringer generation circuit is provided. The rectifier circuit generates a DC voltage signal at an output terminal and has an input terminal adapted to receive a ring input signal and a ground terminal. The voltage regulator generates a voltage signal, responsive to the DC voltage signal. The ringer generation circuit outputs a ring audio, responsive to the voltage signal. As a voltage level of the ring input signal exceeds a predetermined value, the voltage signal substantially equals to a fixed value, and as the voltage level of the ring input signal does not exceed the predetermined value, the voltage signal substantially equals to the DC voltage signal.