Product Introduction

Product parameters

Funtion:5A, Standalone Li-ion Battery Charger

Opration Mode:Switch

Battery:1 or multi-cell lithium ion batteries or LiFePO4 batteries

Vout Range:0V-25V

Vin Range:7.5V-28V

Max Charge Current:5A

Operating Current:1.55mA

Solar Panel charge:No

Chip Temperature Regulation:No


Switching Frequency:300kHz

Chip Enable:No

On-chip Power MOSFET:No

General Descriptions:

The CN3705 is a PWM switch-mode battery charger controller for 1 or multi-cell lithium ion batteries or LiFePO4 batteries in a small package using few external components.

The CN3705 is specially designed for charging lithium ion batteries or LiFePO4 batteries with constant current and constant voltage mode. In constant voltage mode, the regulation voltage is set by the external resistor divider. The constant charging current is programmable with a single sense resistor.

Deeply discharged batteries are automatically trickle charged at 15% of the programmed constant charging current until the cell voltage exceeds 66.7% of the regulation voltage in constant voltage mode. The charge cycle is terminated once the charging current drops to a level set by an on-chip resistor and an external resistor, and a new charge cycle automatically restarts if the battery voltage falls below 91.1% of the regulation voltage in constant voltage mode. CN3705 will automatically enter sleep mode when input voltage is lower than battery voltage.

Other features include undervoltage lockout, battery temperature monitoring and status indication, etc.

CN3705 is available in a space-saving 16-pin TSSOP package.


l  LiFePO4 Battery Charger

l  Electric Tools

l  Battery-Backup Systems

l  Portable Industrial and
Medical Equipment

l  Standalone Battery Chargers


l  Wide Input Voltage: 7.5V to 28V

l  Complete Charger Controller for 1 or multi-cell Lithium-ion Battery or LiFePO4 Battery

l  Charge Current Up to 5A

l  High PWM Switching Frequency: 300KHz

l  Constant Charging Voltage Set By the External Resistor Divider

l  Charging Current is programmed
 with a sense resistor

l  Automatic Conditioning of Deeply Discharged Batteries

l  End-of-Charge Current can be set
 by an external resistor

l  Battery Temperature Monitoring

l  Automatic Recharge

l  Charger Status Indication

l  Soft Start

l  Battery Overvoltage Protection

l  Operating Ambient Temperature
40 to 85

l  Available in 16 Pin TSSOP Package

l  Pb-free , RoHS Compliant,
and Halogen Free

Tools and Documents




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