A 97% Maximum Efficiency Fully Automated Control Turbo Boost Topology for Battery Chargers

Abstract

In this paper, the proposed topology of a fully automated control (FAC) battery charger that provides turbo-boost operation and fully automated detection without any feedback from the system is discussed. It uses closed-loop control for automatic system load detection and automatically adjusts the battery discharge current. The advantages include shortened battery discharge time and maximum power provided by the adapter. Therefore, the FAC technique is flexible for any load system that is limited to battery chargers with the turbo boost mode support. In addition, to avoid over discharge, a battery protection circuitry is also included. The test chip is fabricated using a 0.25- $\mu \text{m}$ CMOS process, with a maximum efficiency of 94.58 & x0025; when the charger operates in the turbo boost mode, and achieves 97 & x0025; maximum efficiency when the charger operates in buck charge mode.