Lithium battery 1.5A linear charger BQ2407X with power path management

1. The switch mode has high efficiency and is suitable for high-current applications. Our commonly used fast charging solutions are usually switch mode; the application of switch mode charging management chips is also flexible, and can be designed as buck, boost or boost as needed. The BQ25895/BQ25703/BQ24715 that everyone is familiar with are very typical switch-mode charge management chips.

2. The switched capacitor mode can achieve a maximum efficiency of more than 97%, but due to the structure, the output voltage and the input voltage are usually in a fixed proportional relationship, and the application scenarios are relatively limited. BQ25970 is a typical switched capacitor type charge management chip.

3. However, some low-power portable electronic products do not have high requirements on charging current and efficiency, usually not higher than 1A, but have higher requirements on volume and cost, so they are suitable for charging management chips using linear switching mode, BQ2400X/BQ2404X is one of the typical chips.

The BQ2407X series charging management chip that I recommend to you today is in linear mode, but the charging current can reach up to 1.5A, which is suitable for portable devices, smart locks, electronic cigarettes, TWS charging boxes and other fields. The BQ2407X has the following features:

1. Fully Compliant with USB Charger Standard
2. Input-based dynamic power management (VIN-DPM) to protect against bad USB power
3. Integrated Dynamic Power Path Management (DPPM) function to simultaneously power the system and charge the battery
4. Charge current can be set and current monitoring (ISET) can be performed
5. With SYSOF pin, the battery can be disconnected from the system by software
6. Complete protection function:

• With input overvoltage, reverse current, overcurrent, short Circuit protection
• Programmable pre-charge and fast-charge safety timers
• Battery over temperature, low temperature chip thermal protection
• Proprietary startup sequence limits inrush current

The typical application circuit diagram of BQ2407X is as follows:

The BQ2407X series includes the following chips to choose from:

(For detailed specifications, please refer to the following link: https://www.ti.com.cn/product/cn/BQ24072)

BQ24072/3/4 are suitable for applications where the full charge voltage of lithium batteries is 4.2V. They are compatible with each other and can be replaced without special requirements. Available in stock: https://www.ti.com.cn/product/cn/BQ24072). Under the condition that the adapter is inserted and the lithium battery is in the charging state, the system output voltage of the BQ24072 can track the battery voltage change to provide the best system efficiency and reduce the voltage difference between the system voltage and the battery voltage during the constant current charging stage. For the lithium battery with a full charge voltage of 4.2V, when the battery is fully charged and the battery voltage is 4.2V, the maximum voltage of the system is 4.425V (equivalent to BQ24073/4), which will not affect the withstand voltage of the system. affect. One advantage of BQ24074 is that customers can set a relatively small charge cut-off current, which helps to ensure that the lithium battery is fully charged, but correspondingly, the charging completion time will be longer; the charge cut-off current of BQ24072/3 is the charging current 10%, which can basically meet the needs of practical applications. When the adapter is not plugged in and the battery is in a discharged state, the BQ24072/3/4 perform exactly the same.