Load Optimized Gate Driving for Charge Pumps

This paper presents a method for efficiency optimization for charge pumps using a negative feedback loop to control the gate driving voltage in each transistor. Switching losses can be significantly lowered by reducing the gate voltage swing while only slightly increasing the conduction losses, thus improving the performance of the switched capacitor dc-dc converter. By setting a target output voltage it is possible to use a feedback loop that controls the voltage swing in each power switch where, by reducing their driving voltage, the output resistance is increased, regulating the output voltage to the target value. The proposed methodology is used to optimize the efficiency of a power management unit (PMU) designed by Silicongate in the scope of the pAvIs project.