Patent ID: 7701179

Claim:
A control circuit of a multi-mode buck-boost switching regulator, wherein the multi-mode buck-boost switching regulator comprises a first switch, a second switch, a third switch, a fourth switch, an inductor, and a capacitor, the first switch receives an input voltage, the second switch is coupled between the first switch and a ground terminal, the inductor is coupled to the first switch and the second switch, the fourth switch is coupled between the inductor and the ground terminal, the third switch is coupled to the inductor and the fourth switch, the capacitor is coupled between the third switch and the ground terminal, the capacitor provides an output voltage of the multi-mode buck-boost switching regulator, the control circuit comprises: a comparator, for outputting a control signal according to an error between a feedback voltage and a reference voltage, wherein the feedback voltage is generated according to the output voltage, and the feedback voltage is in direct proportion to the output voltage; a triangle wave generator, for providing a first triangle wave and a second triangle wave, wherein at a first time point, the first triangle wave is larger than the second triangle wave, and at a second time point, the first triangle wave is smaller than the second triangle wave, the first and the second triangle waves are mutually crossed, the maximum value of the first triangle wave is larger than that of the second triangle wave, the maximum value of the second triangle wave is larger than an average value of the first triangle wave and the second triangle wave, the average value is a DC level and larger than the minimum value of the first triangle wave, and the minimum value of the first triangle wave is larger than that of the second triangle wave; and a logic circuit, for controlling the switching timing of the first switch, the second switch, the third switch, and the fourth switch according to a comparing result between the control signal, the first triangle wave, and the second triangle wave.