Li Ion Polymer Battery Charger Using LTC4098

Using the LTC4098 USB Power-Path controller you can design an high efficiency , full-featured Li-Ion Polymer battery charger using few external electronic components . This Li-Ion Polymer battery charger circuit can be used with many power distribution sources like: USB, wall adapter, automotive, Firewire or other high voltage DC/DC converters, and a Li-Ion/Polymer battery.

Li-Ion Polymer Battery Charger Circuit diagram

For automotive and other high voltage applications, the LTC4098 interface with a Linear Technology external switching regulator to provide a high efficiency high voltage power path. An overvoltage circuit protects the LTC4098 from high voltage damage on the USB/wall adaptor inputs with an N-channel FET and an resistor .

The voltage on the pin7 (Prog) pin always represents the actual charge current by using the following formula: IBAT =(VPROG/RPROG)x1030 The charge current is programmed using a single resistor from PROG to ground.The program resistor and the charge current are calculated using the following equations :RPROG =1030V/ICHG ; ICHG =1030V/RPROG . The charge voltage will be 4.2V with 0.5 accuracy . As you can see in the schematic circuit this charger is very simple an you need to apply just few easy equations to design a high efficiency Li-Ion Polymer charger .

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Designing A Li Ion Battery Charger with Load Sharing MCP73837

Batteries often serve as the main energy source for portable electronic devices. Although they depend on batteries, portable consumer electronic products, such as GPS devices and multi-media players, often consume energy directly from an ac-dc wall adapter or accessory power adapter (or “Auto Adapter”) when the battery is low or the device is in a stationary mode. Due to their cost effectiveness over their useful life, rechargeable batteries are often used for the power source of the portable electronic device.

Attributes such as “relatively high energy density” and “maintenance free” make Lithium-Ion (Li-Ion) batteries popular in the portable consumer electronic products. Refer to the application note, AN1088, “Selecting the Right Battery System For cost Sensitive Portable Applications While maintaining Excellent Quality” (DS01088) for characteristics of Li-Ion batteries. Some examples of how to properly design with Li-Ion batteries will be discussed in this application note. [Link] 

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