Lithium-Ion Battery Charge Controller IC with Support For Large-Current Rapid Charging

Renesas Electronics Corp. has developed of the R2A20057BM Li-Ion battery charge controller IC for mobile devices employing one cell Li-Ion batteries, such as digital still cameras and smartphones. The R2A20057BM integrates a step-down DC-DC converter and supports 2 A large-current charging in very small package in the world’s smallest class.

As digital still cameras, smartphones and other mobile devices gain higher levels of functionality, their current usage increases, requiring bigger capacity of Li-Ion batteries, and larger currents for charging these batteries. However, systems for large-current charging employ multiple power metal-oxide-semiconductor field-effect transistors (MOSFETs) and discrete passive components, and large-scale heat emission structure under large-current handling, while they need mounting area compactness especially for mobile devices.

To solve these problems, the R2A20057BM reduces the mounting area by integrating multiple power MOSFETs and charging circuits in a single chip, using a wafer-level package, a packaging technology that can also supply large amounts of current due to reduced package resistance. In addition, it incorporates a highly efficient on-chip step-down DC-DC converter to realize large-current charging while keeping heat generation to a minimum.

The use of a very finer high-voltage-tolerance wafer process and wafer-level package allows Renesas to achieve a compact chip size in the world’s smallest class of 2.47 mm by 2.47 mm. In addition, the integrated 2 MHz high-frequency step-down DC-DC converter enables a use of compact multi-layer-chip inductors as the external devices. The 25 V on-chip, high-input voltage-tolerance enables a built-in overvoltage protection circuit and eliminates an external overvoltage protection circuit, contributing to a substantial reduction in the mounting area.

The R2A20057BM automatically identifies six USB port types including the three types stipulated in the USB Battery Charging Specification, Revision 1.2, and sets the input current limit value automatically.

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