Research And Design Of An Auto-mode-adjustable Charge Pump

As the development of sub-micron technologies and the use of high value multi-layer ceramic capacitors, the efficiency of charge pump is improved which make charge pumps widely used in higher output currents condition DC/DC converter. But the voltage gain of common charge pump is a fix value, the transition efficiency will become lower and lower along with the input voltage rising.To solve the problem, an auto-adjustable charge pump circuit which was used as a DC/DC converter was designed in this thesis. The charge pump in this thesis can change its voltage gain and choose whether stop switching or not automatically in order to improve transition efficiency and reduce power dissipation.Based on fundamental principle and basic topology of charge pump circuit, whole framework and sub-blocks of 1.5×/2×high-efficiency, auto-adjustable charge pump circuit are designed, and some performance parameters are analyzed in details. Then we analyze some important modules in details such as input bandgap, mode change, oscillator and thermal shutdown, etc.At last, we simulated all the sub-blocks and whole circuit by Hspice, the results show that the circuit has achieved the expectation.