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The BQ2408x series is a highly integrated lithium-ion battery

Release on : Jul 30, 2019

BQ24086, BQ24088, BQ24085 are BQ2408x series are highly integrated lithium-ion batteries, ideal for low-dropout design of single-cell LiLi-Pol linear chargers, space-constrained Ion or Li for space-constrained applications -Pol package. The BQ2408x series provides a current and a constant voltage. Charge termination ±0.5% voltage regulation accuracy is based on minimum current. An internal dynamically adjusts the time phase during thermal regulation. The BQ2408x will automatically restart charging. If the battery voltage is below the internal threshold, use the safety timer for pre-charge adjustment; indicating that the charge, fault, and power good outputs have been removed. Multiple versions of the device family implement low power terminal AC adapters.

 

Features

 

Integrated power FETs and current sensors provide a variety of protection features and function options.

Reverse leakage protection prevents the battery from being charged in a small package and the battery is charged three times.

Thermal regulation maximizes charge rate The programmable charge timer provides backup.

The protection function by terminating and terminating the charging with minimum current charging dynamically adjusts the time during thermal regulation.

The status output setting of the LED or system interface sleep mode when the external input power is on.

Short-circuit and thermal protection make it easy to design the bq2408x in the base charger or in a terminal device while using low-cost or high-automatic sleep mode for low power consumption.

Small 3 x 3 mm MLP package device information (1).

Optional battery insert and battery missing part number package size (NOM).

Input overvoltage protection (1) for all available packages.

 

Typical application circuit diagram

 

 

Pin configuration and function

BQ24086 and BQ24088 DRC package 10-pin VSON top view

 

 

BQ24085 DRC package 10 pin VSON top view

 

 

BQ24087 DRC package 10 pin VSON top view

 

 

Detailed description:

 

Overview: The charging current can be programmed using an external component (RISET resistor). The external input power supply is connected to the system at the beginning of the charging process. The charger is enabled by CE = LO, the battery voltage is below the recharge threshold, and V(BAT) < V(RCH). When the charge cycle begins, the safety timer is activated if the safety timer function is enabled. The safety timer timeout value is set by the external resistor connected to the TMR. When the charger is enabled, the two control loops adjust the battery switch drain to source impedance to limit the BAT pin current to the programmed charge current value (charge current loop) or to adjust the BAT pin voltage to the programmed charge voltage value (charge) Voltage loop). If V(BAT)<V(LOWV) (typically 3 V), the BAT pin current is internally set to 10% of the programmed charge current value. The typical charging curve for operating conditions does not cause the IC junction temperature to exceed TJ (REG), (typically 112 °C), as shown in the following figure.

 

 

Use TJ (REG) charging profile

If the operating conditions cause the IC junction temperature to exceed TJ (REG), modify the activation of the charge cycle integrated thermal control loop. The internal connection activates the thermal control loop temperature monitoring voltage below a fixed, temperature-stable internal voltage. The temperature monitoring voltage at the junction is inversely proportional to the IC junction temperature. The thermal cycle covers the other charger control loops and reduces the charging current until the IC junction temperature returns to TJ (REG), effectively adjusting the IC junction temperature.

 

Thermal regulation circuit diagram

 

 

The hot ring effectively modifies the charging cycle as shown in the figure below.

 

 

Charging curve, thermal cycle activation

Functional block diagram