Li-Ion Battery Charging with a Buck-Boost DC–DC Converter for a Portable Device Power Management

In this paper, a Li-ion battery charging buck-boost DC–DC converter for a portable device power management is proposed. The battery is charged using a non-inverting synchronous buck-boost DC–DC power converter. The system operates in buck, buck-boost, or boost mode, according to the supply voltage conditions. To overcome the limitations presented by the architectures of buck, boost and single-ended-primary-inductance (SPEIC) we will propose an integral architecture based on a non-inverter buck-boost DC–DC converter. The proposed battery charger consists of a current feedback loop (CFL) circuit, a voltage feedback loop (VFL) circuit, and a control logic circuit with a digital phase frequency detector (PFD). The battery charger has been designed and implemented in TSMC 130 nm CMOS technology with LDMOS transistors, which have very low on-resistance. The input range of the converter is 3.6–5 V, and it can supply up to 996 mA load current. The maximum efficiency is 95% and the chip area is only 1.5 mm².