Improving the efficiency of mixed-structure charge pumps by the multi-phase technique

In this paper, a new design for efficiency enhance switching-capacitor DC-DC voltage converter based on combination of traditional charge-transfer-switch charge pump and cross-coupled output stage. In order to get a high output power and pump-efficiency. By using multi-phase technique, its can increase both of pump-efficiency and power-efficiency. The propose multi-phase mixed-structure charge pump can operate at 1 MHz switching-frequency on the 0.1 μF pump-capacitors. After the simulation by using HSPICE 0.35 μm TSMC process, our work can converter the input low DC-voltage (V_DD = 1.5 V) up near to 5 times of it (V_OUT = 7.4688), the pump-efficiency can reaches to 99.58%, and the output power can be increased. The new proposed charge pump circuit is suitable for low-voltage applications in CMOS process because there is no threshold voltage drop in every stage even at the output stage. A great achievement has been obtained.