Abstract
In this paper, we design a power management IC (PMIC) with fast dynamic voltage scaling capability. The output voltage of this PMIC can be adjusted by controlling signals for different load requirements. With this technique, the overall conversion efficiency can be increased to extend the battery life in portable electronics. Moreover, this PMIC with high efficiency and low output voltage ripple supplies a stable output voltage to sensitive loads. This PMIC topology is a switching type power converter cascading a linear regulator. The switching converter uses a constant on-time control method. And in the linear regulator circuit, an N-channel MOSFET is chosen in our design for high PSRR and low dropout voltage. From simulation results, cascading a linear regulator would decrease the output voltage ripple to 2.74%, raise the maximum efficiency to 87%, and cut down the average tracking speed to about 11.6us/0.3V. This power management IC is implemented by TSMC 0.35 um 2p4m process. The measurement results are not as predicted by simulation because of the possible single hysteresis effect in the comparator, which is verified by simulation.