SLUSFR7 August 2025 BQ24810
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
With sufficient charge current, the inductor current does not cross 0, which is defined as CCM. The controller compares SRP-SRN (CC charging) or SRN (CV charging) to a reference value as set in ChargeCurrent() REG0x14 and ChargeVoltage() REG0x15. This error is integrated in the error amplifier and the error amplifier output (EAO) is compared to a ramp voltage. As long as EAO voltage is above the ramp voltage, the high-side MOSFET (HSFET) stays on. When the ramp voltage exceeds EAO voltage, HSFET turns off and low-side MOSFET (LSFET) turns on. At the end of the cycle, ramp gets reset and LSFET turns off, ready for the next cycle. There is always break-before-make logic during transition to prevent cross-conduction and shoot-through. During the dead time when both MOSFETs are off, the body-diode of the low-side power MOSFET conducts the inductor current.
During CCM, the inductor current always flows and creates a fixed two-pole system. Having the LSFET turn-on keeps the power dissipation low and allows safe charging at high currents.