ZHCSJD3B July 2018 – February 2019 BQ25150
The BQ25150 IC integrates a linear charger that allows the battery to be charged with a programmable charge current of up to 500mA. In addition to the charge current, other charging parameters can be programmed through I2C such as the battery regulation voltage, pre-charge current, termination current, and input current limit current.
The power path allows the system to be powered from PMID, even when the battery is dead or charging, by drawing power from IN pin. It also prioritizes the system load connected to PMID, reducing the charging current, if necessary, in order support the load when input power is limited. If the input supply is removed and the battery voltage level is above VBATUVLO, PMID will automatically and seamlessly switch to battery power.
There are several control loops that influence the charge current: constant current loop (CC), constant voltage loop (CV), input current limit, VDPPM, and VINDPM. During the charging process, all loops are enabled and the one that is dominant takes control regulating the charge current as needed. The charger input has back to back blocking FETs to prevent reverse current flow from PMID to IN. They also integrate control circuitry regulating the input current and prevents excessive currents from being drawn from the IN power supply for more reliable operation.
The device supports multiple battery regulation voltage regulation settings (VBATREG) and charge current (ICHARGE) options to support multiple battery chemistries for single-cell applications.
A more detailed description of the charger functionality is presented in the following sections of this document.