CS5918 Switching Type 2A Single Cell 4.2V Li-ion Battery Charge Management IC Solution

introduction

Lithium batteries are widely used in various mobile electronic devices, such as portable digital products, lamps, toys, small household appliances and power tools. The shipment volume of charging chips used for single-cell lithium batteries is very large.

Charging chips are divided into linear charging and switching charging management. Linear charging chips are small in size, easy to use, free of noise and radiation conduction interference, and low in cost. The more familiar and common models on the market are 4054 and 4056; however, they are inefficient and generate a lot of heat, and cannot meet high-current charging applications above 1A. Switching charging chips are known for their high efficiency and can output larger charging currents in small SMD packages. However, compared with linear charging chips, peripheral inductors require larger circuit board space, increasing BOM costs and design complexity, and EMI radiation interference needs to be considered.

The type of charging chip to be selected mainly depends on the battery capacity and charging time requirements. Generally, linear charging chips are preferred for small PCB size, simple design and lower cost, small battery and low charging current applications such as wearable devices and the Internet of Things (IoT). Switching type charging management chips will be preferred for large capacity and multi-battery parallel applications such as smartphones, tablets and small appliances.

Aiming at the application of large-capacity single-cell lithium batteries, Shenzhen Yongfukang Technology Co., Ltd. is now vigorously promoting the industry's first switching 2A single-cell 4.2V lithium battery charging chip - CS5918, which uses a simple SOT23-6 package. The chip has few peripheral components, simple application, high cost performance, and has broad market application prospects.

overview

CS5918R is a 5V input step-down charging management IC that supports single-cell lithium battery or lithium-ion polymer battery. CS5918R integrates power MOS and adopts synchronous switch architecture, which requires only a few peripheral devices when applied, effectively reducing the overall solution size and BOM cost. CS5918R converter has a charging current capability of 2A, and the charging current can be flexibly adjusted through external resistors.

The CS5918R has four built-in loops to control the charging process, namely the constant current (CC) loop, the constant voltage (CV) loop, the chip temperature regulation loop, and the intelligently adjustable charging current to prevent the adapter output from being pulled down, and to match the input adaptive loop of all adapters.

CS5918R has complete protection functions, including input undervoltage/overvoltage protection, battery overvoltage and short circuit protection, and chip temperature protection. In addition, the chip monitors the entire charging process through an external LED indicator.

CS5918R provides a small SOT23-6L package type for customers to choose.

The temperature range is -40℃ to 85℃.

describe

Synchronous buck charging

Charging current externally adjustable

±0.75% battery constant voltage accuracy

Input adaptive current limit to prevent adapter output from collapsing

Maximum charging time limit

Built-in power MOS

Charging status indicator

Chip over-temperature protection, chip temperature adaptive adjustment

Input undervoltage and overvoltage protection

Battery short circuit and overvoltage protection

CS5918 Application Information

1. CS5918 pinout

2. CS5918 pin description

3. CS5918 DEMO board schematic diagram

4. CS5918 DEMO board PCB top-level design diagram

5. CS5918 DEMO board PCB bottom design diagram

6. CS5918DEMO board patch diagram

7. CS5918DEMO board bill of materials

8. CS5918DMEO board physical picture