The CN3302 is a PFM boost type dual battery charging control integrated circuit operating from 2.7V to 6.5V. CN3302 adopts constant current and quasi-constant voltage mode (Quasi-CVTM) to charge the battery, and integrates the reference voltage source, inductance current detection unit, battery voltage detection circuit and off-chip field effect transistor drive circuit, which has the advantages of fewer external components and simple circuit.
    When the input power is connected, CN3302 enters the charging state, the control off-chip N-channel MOSFET is on, and the inductor current rises. When it rises to the upper limit set by the external current detection resistance, the off-chip N-channel MOSFET is cut off, the inductor current drops, and the energy in the inductor is transferred to the battery. When the inductor current drops to the lower limit set by the external current detection resistance, the off-chip N-channel MOSFET is switched on again, and so on. When the BAT pin voltage reaches the 8.4V(typical value) set internally for the first time, the CN3302 enters the quasi-charging mode and charges the battery with a small current. Only when the BAT pin voltage reaches 8.4V for the second time, the charging process ends, and the off-chip N-channel MOSFET remains in the cut-off state. When the BAT pin voltage drops to the recharging threshold, CN3302 enters the charging state again.
    The CN3302 has a maximum operating frequency of 1MHz and an operating temperature range from -40℃ to +85℃.
    When the battery voltage is lower than the input voltage or the battery is short-circuited, the CN3302 continues to charge the battery with a small current under the combined action of the off-chip N-channel MOSFET and P-channel MOSFET, which plays a protective role for the battery.
    Other functions include chip enable input, status indicator output, etc.
    The CN3302 comes in an 8-pin SOP8 package.

Input voltage range: 2.7V to 6.5V
Working current: 280 microamper@VIN =5V
Inductive current detection
Up to 1MHz switching frequency
The quasi-constant voltage charging mode compensates for the voltage loss caused by the internal resistance of the battery and the resistance of the battery connection line
Automatic recharging function
Up to 35W output power
When the battery voltage is lower than the input voltage or the battery is short-circuited, charge with a small current.
Can be widely adapted to the load capacity of the input power supply
The chip enables the input terminal
Battery end overvoltage protection
Status indicating output
Operating temperature range: -40℃ to 85℃
8 Pin SOP8 package
The product is lead-free, meets the requirements of rohs directive, and contains no halogen

Dual lithium battery charging control
POS machine, electric fan
sound
Individual charger