A CTS pump with a crossed-coupled output for higher conversion efficiency

In this paper, a novel switching-capacitor DC-DC voltage converter with higher efficiency will be presented. This circuit was designed by modifying the output stage of the conventional static charge-transfer-switch (CTS) charge pump in a cross-coupled configuration. In this design, a control scheme to overcome both the reverse charge sharing and the threshold drops in the CTS pump was also employed. In this study, the capacitances for all the pumping capacitors were selected the same as 0.1 μF. With this design, our circuit can operate with a clock rate up to 1 MHz. The performance of this circuit was first evaluated by simulation by HSPICE with the 0.35-μm technology of TSMC. The results showed that this circuit can pump the low input of 1.5V nearly 5 times at the output. The conversion gain can be around 95%. The performance of the real chip manufactured by TSMC was measured and will be compared with the simulation results