CN3300

CN3300 is a PFM boost-type battery charge controller IC operating from 4V to 28V. It integrates an internal voltage reference, a +5V voltage regulation unit, an inductor current sensing unit, a battery voltage detection circuit, and an external N-channel MOSFET driver circuit, making it ideal for charging lithium, LiFePO₄, and lead-acid batteries. It features minimal external components and a simple circuit design. When input power is applied, CN3300 enters the charging state, turning on the external N-channel MOSFET, causing the inductor current to rise and transferring energy from the output capacitor to the battery. When the inductor current rises to the upper limit set by the external current sense resistor, the external N-channel MOSFET turns off, the inductor current falls, and energy stored in the inductor is transferred to the output capacitor and battery. When the inductor current falls to the lower limit set by the external current sense resistor, the external N-channel MOSFET turns on again, and this cycle repeats. The battery voltage is fed back to the FB pin through a resistor divider network. When the FB pin voltage reaches 1.205V (typical), the charging process ends, the external N-channel MOSFET turns off, and CN3300 enters the end-of-charge state. In the end-of-charge state, no current flows from the input to the battery. When the FB pin voltage drops to the recharge threshold of 1.155V (typical), CN3300 re-enters the charging state. CN3300 supports a maximum operating frequency of up to 1MHz.

Applications

• Lithium battery charge control
• LiFePO₄ battery charge control
• Lead-acid battery charge control
• Standalone charger

Key features

• Input voltage range: 4V to 28V
• Inductor current sensing
• Battery voltage monitoring
• Switching frequency up to 1MHz
• Automatic recharge function
• Output power up to 25W
• 5V, 5mA internal regulator
• Operating temperature range: -40°C to 85°C
• 6-pin SOT23 package
• Lead-free, RoHS compliant, halogen-free