Overview: The CN3791 is a PWM step-down mode single-cell lithium battery charge management integrated circuit that can be powered by a solar panel. It independently manages the charging of single-cell lithium batteries and offers advantages such as a small package, fewer external components, and ease of use. The CN3791 features trickle, constant current, and constant voltage charging modes, making it very suitable for lithium battery charge management. In constant voltage charging mode, the CN3791 modulates the battery voltage to 4.2V; in constant current charging mode, the charging current is set by an external resistor. When the current output capability of the input power supply decreases, the internal circuit can automatically track the maximum power point of the solar panel. Users do not need to consider the worst-case scenario, as it maximizes the utilization of the solar panel's output power, making it very suitable for solar panel powered applications. For deeply discharged lithium batteries, when the battery voltage is below 66.5% (typical value) of the constant voltage charging voltage, the CN3791 trickle charges the battery with 17.5% of the set constant current charging current. During the constant voltage charging phase, the charging current gradually decreases, and charging ends when the charging current drops to 16% of the constant current charging current. In the charge termination state, if the battery voltage drops to 95.5% of the constant voltage charging voltage, a new charging cycle automatically begins. When the input power supply is cut off or the input voltage is lower than the battery voltage, the CN3791 automatically enters sleep mode. Other functions include input undervoltage lockout, battery overvoltage protection, and charge status indication. The CN3791 adopts a 10-pin SSOP package.

Product Parameters

Main Functions: PWM step-down mode single-cell lithium battery charging management integrated circuit that can be powered by solar panels

Operating Mode: Switching

Battery Type: Lithium battery

Number of Batteries: 1

Output Voltage Range: 0V-4.2V

Input Voltage Range: 4.5V-30V

Maximum Charging Current: 4A

Operating Current: 1mA

Solar Power Supply: Yes

Thermal Modulation: No

Packaging Type: SSOP10

Switching Frequency: 300kHz

Built-in Power Tube: No

Applications ：

l Mobile Power Supply

l Handheld Devices

l Backup Battery Applications

l Portable Industrial and Medical Instruments

l Power Tools

l Independent Battery Chargers

Features ：

l Solar Panel Maximum Power Point Tracking Function

l Wide Input Voltage Range: 4.5V to 28V

l Complete charging management for single-cell lithium batteries

l Charging current up to 4A

l PWM switching frequency: 300KHz

l Constant voltage charging voltage: 4.2V±1%

l Constant current charging current set by external resistor

l Trickle charging for deeply discharged batteries

l Automatic recharging function

l Charging status and charging completion status indication

l Soft start function

l Overvoltage protection at the battery terminal

l Operating temperature range: -40°C to +85°C

l Uses 10-pin SSOP package

l Lead-free product, RoHS compliant, halogen-free