The cxlb7478b is a complete system integrated circuit that manages the charging function of lithium battery. It can provide fast charging and maximize battery life. The cxlb7478b monitors the condition of the battery and decides whether it needs to be precharged if the battery voltage is lower than 2.9v. Precharge current can be set in any range from 7.5ma to 120mA through external resistance. Precharge will keep the battery in good condition and prolong the battery life. Once the battery voltage reaches 2.9v, the cxlb7478b will automatically convert to a constant current (CC) charging cycle. The internal current is set to more than 6 times the current at precharge. The constant current cycle function reduces the charging time to the shortest. When the battery is nearly fully saturated, about 4.15V, the cxlb7478b will automatically convert to the constant voltage (CV) charging cycle. In the constant voltage charging cycle, the charging current will reduce the risk of making the battery gradually saturated without over saturation, which is necessary, because the lithium battery cannot be over saturated with 50mV, otherwise there is a risk of explosion. The cxlb7478b ensures that the lithium battery is fully charged, but does not go into an oversaturated state. After charging, the cxlb7478b will enter the off mode, reducing the internal power consumption to less than 35ua. This feature enables the cxlb7478b to be applied to the interior of portable devices and consumes almost no energy when the device is not working. The cxlb7478b also provides on-chip temperature protection.