CN3302

Is a boost-type two-cell lithium battery charge control IC. The input voltage range extends to 6.5V. It integrates an internal voltage reference, inductor current sensing unit, battery voltage detection circuit, output overvoltage protection circuit, over-temperature protection unit, battery undervoltage protection unit, control unit, and off-chip FET driver circuit. It is well suited for two-cell lithium battery charge control applications, featuring few external components, rich functionality, and simple circuitry. In addition to adapter power supply, it also supports solar panel input. When the input power is connected, the device enters the charging state. The pin outputs a high level, the off-chip N-channel FET turns on, the inductor current rises, and energy in 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 FET 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 FET turns on again, and this cycle repeats. The battery voltage is fed back to the voltage comparator through an internal resistor divider network. When the pin voltage reaches the typical value for the first time, after a debounce delay, the device enters quasi-constant-voltage charging mode, and the input current drops to 25% of the constant-current value, so the charging current also decreases. In quasi-constant-voltage charging mode, when the battery voltage reaches the threshold for the second time, after a debounce delay, the charging process ends, the off-chip N-channel FET turns off, and the device enters the end-of-charge state, with the pin outputting a low level. In the end-of-charge state, no current flows from the input to the battery. When the pin voltage drops to the recharge threshold typical value, the device re-enters the charging state. The maximum operating frequency can reach. As a boost-type charge control IC, under normal conditions the battery voltage is higher than the input voltage. In certain situations where the battery voltage is lower than the input voltage, or even in the event of a battery short circuit, the off-time of the off-chip N-channel FET is extended and the charging current is reduced, providing battery protection. Other features include a chip enable input, die over-temperature protection, current-sense resistor short-circuit protection, and pin overvoltage protection.

Applications

• POS terminal
• Electric fan
• Audio system
• Standalone charger

Key features

• Input voltage range: to
• Operating current: microamps VIN = 5V
• Input power adaptive function
• Solar power supply support
• Inductor current sensing
• Switching frequency up to
• Quasi-constant voltage charging mode compensates for voltage drop caused by battery internal resistance and battery connection wire resistance
• Auto-recharge function
• Output power up to
• Charges with reduced current when battery voltage is below input voltage or battery is short-circuited
• Chip enable input
• Die over-temperature protection
• Battery terminal overvoltage protection
• Status indicator output
• Operating temperature range: -40°C to 85°C
• Pin package
• Lead-free product, compliant with directive requirements, halogen-free