The Front-ended Design Of A Battery Protection Chip For The Mobilphone With Multifunction

The development of portable products improves the miniaturization of electronic production, and drives the evolution of the mini power. As a wonderful battery, the lithium-ion battery is more and more widely used in all sorts of portable instruments, specially used in mobil telephone, because of its light weight, small size, long life and so on. The battery protection chip for mobilphone with low-power consumption is absolutely necessary to ensure its security, reduce the lose of its capacity during the discharging and charging circle, and prolong the time of its work.In this paper, the front-ended design of a protection chip with low power consumption for the mobilphone battery is presented. Firstly, the working modes of the chip are defined based on the battery's electrochemical characteristic. Then, the bias, reference circuit and the sub-module circuits based on the working modes are planed by the"Bottom-to-up"methodology, considering the implement of low power consumption in the system. Finally, the sub-block analog circuits and whole chip have been stimulated in HSpice. The emphasis of this paper is to accomplish the low power consumption design by advancing the analog circuit working on the sub-threshold region and exerting the asynchronical mode used in digital circuit into the analog design. In the same time, the chip includes the technology of sluggish and delaying comparation and the fuctions of 0 V battery charging unavailable and charger detection in order to enhance the performance of the chip.With 0.6μm, N well CMOS technology, this front-ended design of the chip has been stimulated successfully in HSpice by the result showing that the battery can be protected by over-voltage, under-voltage, and over-current, and the power consumption of the whole chip is less than 10μW.