ZHCSJ56C February 2018 – September 2019 BQ25882
PRODUCTION DATA.
The device supports buck converter operation to deliver power from the battery to other portable devices through USB port. The buck mode output current rating meets the USB On-The-Go 500-mA (OTG_ILIM bits = 000) output requirement. The maximum output current is up to 2.0 A. The buck operation can be enabled if the following conditions are valid:
In buck mode, the device employs 1.5-MHz step-down switching regulator based on system requirements. During buck mode, the status register VBUS_STAT bits are set to 111, the VBUS output is 5.1 V by default (selectable via OTG_VLIM register bits) and the output current can reach up to 2.0 A, selected via I2C (OTG_ILIM bits). The buck output is maintained when BAT is above VOTG_BAT threshold, and VBUS is above VVBUS_PRESENT threshold.
In order to improve light-load efficiency, the device switches to PFM control at light load. During the PFM operation, the switching duty cycle is set by the ratio of SYS and VBUS. PFM operation may be disabled by the host using the PFM_DIS bit. PFM operation also includes an out-of-audio (OOA) feature to prevent the converter from switching within the audible range (< 20 kHz) at no load conditions. This feature may be disabled by the host using the PFM_OOA_DIS bit.