Datasheet CN3165 (Consonance) - 6

CONSONANCE Detailed Description
The CN3165 is a linear battery charger IC designed primarily for charging single cell lithium-ion or lithium-polymer batteries. Featuring an internal P-channel power MOSFET, the charger uses a constant-current/constant-voltage to charge the batteries. Continuous charge current can be programmed up to 1A with an external resistor. No blocking diode or sense resistor is required. The on-chip adaptive cell can adjust charging current automatically based on the output capability of input power supply, so CN3165 is ideally suited for the solar-powered systems, or the applications that need to charge lithium-ion battery or lithium polymer battery with an input power supply whose output capability is limited. The open-drain output and indicates the charger’s status. The internal thermal regulation circuit reduces the programmed charge current if the die temperature attempts to rise above a preset value of approximately 130℃. This feature protects the CN3165 from excessive temperature, and allows the user to push the limits of the power handling capability of a given circuit board without risk of damaging the CN3165 or the external components. Another benefit of adopting thermal regulation is that charge current can be set according to typical, not worst-case, ambient temperatures for a given application with the assurance that the charger will automatically reduce the current in worst-case conditions. The charge cycle begins when the voltage at the VIN pin rises above the UVLO level, a current set resistor is connected from the ISET pin to ground. The pin outputs a logic low to indicate that the charge cycle is ongoing. At the beginning of the charge cycle, if the voltage at FB pin is below 70% of the regulation voltage, the charger is in precharge mode to bring the cell voltage up to a safe level for charging. The charger goes into the fast charge constant-current mode once the voltage on the FB pin rises above 70% of the regulation voltage. In constant current mode, the charge current is set by RISET. When the battery approaches the regulation voltage, the charge current begins to decrease as the CN3165 enters the constant-voltage mode. When the current drops to charge termination threshold, the charge cycle is terminated, is pulled low by an internal switch and pin assumes a high impedance state to indicate that the charge cycle is terminated. The charge termination threshold is 10% of the current in constant current mode. To restart the charge cycle, just remove the input voltage and reapply it. The charge cycle can also be automatically restarted if the charge current rises above the recharge threshold. The on-chip reference voltage, error amplifier and the resistor divider provide regulation voltage with 1% accuracy which can meet the requirement of lithium-ion and lithium polymer batteries. When the input voltage is not present, the charger goes into a sleep mode, dropping battery drain current to less than 3uA. This greatly reduces the current drain on the battery and increases the standby time. The charging profile is shown in the following figure: www.consonance-elec.com 6 REV 1.0