A Novel Multi-Phase Buck Converter for Lap-top PC

We propose a novel multi-phase buck converter with a simple gate drive circuit, which is suitable for mobile microprocessors of lap-top computers. In case of the three-phase construction, the duty-cycle of this converter is extended to three times of that of the typical buck converter because the voltage conversion ratio is given as V0/Vi = D/3. The switching loss and switching stress are reduced sufficiently because the switching operation is achieved by one-third of the input source voltage (Vi/3). The current ripple of the output smoothing capacitor is the same as that of conventional five-phase buck converter. The current unbalance between the respective phases is removed automatically and completely without any current sensing means. The above fine characteristics are simply achieved with two additional capacitors.