Patent ID: 9225248
Filing Date: 2015-12-29
Classification: H02M

Abstract:
1. A synchronous direct current (DC)-DC buck converter, the synchronous DC-DC buck converter generating a stepped-down output voltage using a first switch configured to apply an input voltage to an inductor during on-duty time of a first switching signal and a second switch configured to switch in response to a second switching signal complementary to the first switching signal, the synchronous DC-DC buck converter comprising: a sawtooth generation unit configured to generate a sawtooth wave based on a frequency according to a frequency setting signal; a driver oscillating signal generation unit configured to generate an error voltage between the output voltage and a reference voltage and to compare the sawtooth wave with the error voltage, so as to generate a driver oscillating signal having a duty ratio corresponding to a magnitude of the error voltage; a switching signal generation unit configured to generate each of the first and second switching signals to have respectively a waveform obtained by applying dead time to on-duty time of the driver oscillating signal; and a phase tracking unit configured to generate the frequency setting signal based on a sum signal obtained by summing an active time length signal of a pulse, corresponding to a phase difference between the driver oscillating signal and a reference clock signal, and a frequency variation signal based on a spread spectrum clock setting voltage.