BQ25751: If BQ25751 can detect battery absent and close its charging function when battery is too hot?

Hello Sun,

sun qiyun said:

When the battery is absent, what state is BQ25751?

The device will be in Float Charge(CVmode), since it charged up the output caps. The BQ25751 does not have battery absent detection.

sun qiyun said:

 The lead acid battery is 24V in my design, how should I choose the parameter VBATREG? 24V? or 28.8V?

The VBATREG is the float voltage, the manufacturer of the battery is the best place to get the recommended float voltage.

sun qiyun said:

For TS function, without host, if the battery is too hot, could the management can close its charging function only by the hardware design? What is its reference? 

I recommend refering to section 7.3.4.5.1 Temperature Compensated charging in the datasheet:

Best Regards,

Christian.

Hello Sun,

sun qiyun said:

If I want to judge the battery absent by detecting the battery voltage of below point, it would be the float charge voltage from the charger, right? 

The BQ25751 does not have battery detection. The device will be in Float Charge(CVmode) when battery is absent, but the device is also in Float Charge(CVmode) when battery done charging. So you can't rely on this status register to determine if batery is missing. If this feature is required, I recommend paring with a battery monitor.

sun qiyun said:

From this reference, it seems it must use register to set and enable this function. Could I use this function in hardware mode without IIC setting? If not, is there any other function to support temperature detection?

This function is enabled by default.

Best Regards,

Christian.