Overview: CN3305 is a PFM boost type multi-cell battery charge control integrated circuit operating at 2.7V to 6.5V. CN3305 uses constant current and quasi-constant voltage mode (Quasi-CVTM) to manage battery charging. It integrates a reference voltage source, inductor current detection unit, control circuit, and external field-effect transistor drive circuit, etc., with advantages such as fewer external components and simple circuitry. When the input power is turned on, CN3305 enters the charging state, controlling the external N-channel MOSFET to turn on, and the inductor current rises. When it rises to the upper limit set by the external current detection resistor, the external N-channel MOSFET turns off, and the inductor current decreases, transferring the energy in the inductor to the battery. When the inductor current drops to the lower limit set by the external current detection resistor, the external N-channel MOSFET turns on again, and this cycle repeats. When the FB pin voltage first reaches the internally set 1.205V (typical value), CN3305 enters quasi-constant voltage charging mode and charges the battery with a smaller current. Only when the FB pin voltage reaches 1.205V for the second time does the charging process end, and the external N-channel MOSFET remains off. When the FB pin voltage drops to the recharge threshold, CN3305 enters the charging state again. The maximum operating frequency of CN3305 can reach 1MHz, and the operating temperature range is from -40°C to +85°C. When the battery voltage is lower than the input voltage or the battery is short-circuited, CN3305 continues to charge the battery with a smaller current under the combined action of the external N-channel MOSFET and P-channel MOSFET, protecting the battery. Other functions include a CMOS status indication output terminal, etc. CN3305 uses an 8-pin SOP8 package.

Product Parameters

Main Functions: A PFM boost type multi-cell battery charge control integrated circuit operating at 2.7V to 6.5V

Operating Mode: Switching

Battery Type: Lithium-ion battery, Lithium iron phosphate battery

Number of Batteries: 2-4

Output Voltage Range: 0-18V

Input Voltage Range: 2.7V-6.5V

Operating Current: 280uA

Solar Power Supply: Yes

Thermal Modulation: No

Packaging Form: SOP8

Maximum Output Power: 35W

Built-in Power Tube: No

Applications:

l Multi-cell battery charge control

l Suitable for lithium batteries, lithium iron phosphate batteries, and lead-acid batteries, etc.

l Various small household appliances

l POS machines, audio equipment, etc.

l Independent charger

Features:

l Input voltage range: 2.7V to 6.5V

l Operating current: 280μA @VIN=5V

l Inductor current detection

l Up to 1MHz switching frequency

l Quasi-constant voltage charging mode compensates for voltage loss caused by battery internal resistance and battery connection line resistance

l Automatic recharging function

l Up to 35W output power

l When the battery voltage is lower than the input voltage or the battery is short-circuited, charge at a lower current.

l Adaptive function of input power supply

l Overvoltage protection at the battery terminal

l Status indication output

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

l Suitable for lithium batteries, lithium iron phosphate batteries, and lead-acid batteries, etc.

l 8-pin SOP8 package

l Lead-free product, meets RoHS directive requirements, halogen-free