CN3303

CN3303 is a PFM boost-type charge controller IC for three-cell lithium battery applications. The input voltage range is 2.7V to 6.5V. It integrates a voltage reference, inductor current sensing unit, battery voltage detection circuit, output overvoltage protection circuit, battery undervoltage protection unit, control unit, and off-chip MOSFET gate driver. Ideally suited for 5V input three-cell lithium battery charging applications, it features minimal external components, rich functionality, and simple circuitry. When input power is applied, CN3303 enters the charging state, the STAT pin outputs a high level, the off-chip N-channel MOSFET turns on, inductor current rises, and energy from the output capacitor is transferred to the battery. When the inductor current rises to the upper limit set by the external current sense resistor, the off-chip N-channel MOSFET turns off, the inductor current falls, and the 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 off-chip N-channel MOSFET turns on again, and the cycle repeats. The battery voltage is fed back to the voltage comparator through an internal resistor divider network. When the BAT pin voltage reaches 12.6V (typical) for the first time, after a debounce delay, CN3303 enters a quasi-constant-voltage charging state, and the input current drops to 60% of the constant-current value, resulting in a reduced charging current. When the battery voltage reaches 12.6V for the second time, after a debounce delay, the charging process ends, the off-chip N-channel MOSFET turns off, and CN3303 enters the charge termination state with the STAT pin outputting a low level. In the charge termination state, no current flows from the input to the battery. When the BAT pin voltage drops to the recharge threshold of 12.142V (typical), CN3303 re-enters the charging state. CN3303 supports a maximum operating frequency of up to 1MHz. CN3303 is a boost-type charge controller IC; under normal conditions, the battery voltage is higher than the input voltage. In certain situations where the battery voltage falls below the input voltage or even a battery short circuit occurs, the off-chip N-channel MOSFET turn-off time is extended and the charging current is reduced, providing protection for the battery. Additional features include a chip enable input and BAT pin overvoltage protection.

Applications

• Massage machines, fascia guns, etc.
• Audio systems
• Standalone chargers

Key features

• Input voltage range: 2.7V to 6.5V
• Operating current: 280µA @ VIN = 5V
• Inductor current sensing
• Switching frequency up to 1MHz
• Quasi-constant voltage charging mode to compensate voltage drop caused by battery internal resistance and battery connection wire resistance
• Automatic recharge function
• Output power up to 35W
• Trickle charging when battery voltage is below input voltage or battery short circuit occurs
• Adaptive input power supply function
• Chip enable input
• Battery terminal overvoltage protection
• Status indicator output
• Operating temperature range: -40°C to 85°C
• 8-pin SOP8 package
• Lead-free, RoHS compliant, halogen-free
• Three-cell lithium battery charge control