An Efficiency-Enhanced Auto-Reconfigurable 2 $\times$ /3 $\times$ SC Charge Pump for Transcutaneous

An auto-reconfigurable 2×/3× switched-capacitor charge pump (SC-CP) for transcutaneous power transmission is presented in this paper. The proposed SC-CP can automatically configure its own voltage conversion ratio according to different input voltages by using the adaptive control circuitry such that the DC/DC regulator can maintain high power efficiencies under coupling variations. In addition, a dynamic dead-time control scheme and a minimum capacitance selection strategy are developed to improve the power efficiency of the proposed SC-CP through minimizing the shoot-through current and maximizing its average output voltage, respectively. Implemented in a standard 0.35-μm n-well CMOS process, the proposed SC-CP achieves peak power efficiencies of 95% (2 ×) and 92% (3 ×). The quiescent current consumption of the charge pump has been reduced by 1.6 times (2 ×) and 2.3 times (3 ×) with the dynamic dead-time control. The power efficiency of the DC/DC regulator with the proposed SC-CP is also improved by > 25%, compared to that using the conventional 3×SC-CP, when the input voltage varies from 1.6 V to 2.4 V.