A reconfigurable Buck-Boost Cross-Coupled charge Pump

Abstract

This paper presents a reconfigurable buck-boost Charge Pump (CP) based on the cross-coupled topology. The proposed CP is a switched capacitor (SC) converter merging different ratios and operation modes in one topology. The converter is able to step-up or step-down the input voltage at the output only by controlling the external connections of the circuit. By achieving various conversion ratios and operation modes, higher efficiency levels are performed maximizing the power that is delivered to the load. The reconfigurable buck-boost CP has been designed in 65 nm TSMC CMOS technology and covers an input voltage range from 1.6 V to 3.2 V and an output voltage range also from 1.6 V to 3.2 V in the boost mode and an input voltage range from 2.6 V to 3.6 V and an output voltage range from 1.4 to 1.8 V in the buck mode. In addition, efficiency estimation analysis is presented and proves how parasitic capacitances of flying capacitors affect the overall efficiency of a multi-ratio converter. The converter indicates peak efficiency equal to 77 % and delivers up to 4 mA load current.