The assumption could be different for the design criteria.

" sleep mode does not inhibit full power" rather sleep mode plus full SoC inhibits all charger power.

The charger is dumb and the laptop monitors both battery charge state, voltage and current demand and active load demand and shares the maximum current available to do both such that it never demands more than the designed max. expected.

So the charge controller takes whatever current is left over from the unit power demands using a current summing limiter.

For example, a 3.5A charger @ 19.5V might take up to 2.5A at max LCD brightness and CPU & HDD load, leaving the battery CC/CV circuit use a maximum of 1A.

Current sensors may be high or low side and often limited to 50mV drop for efficiency with a precision gain amplifier to convert to voltage and compare with a Band gap ref.

The assumption could be different for the design criteria.

" sleep mode does not inhibit full power" rather sleep mode plus full SoC inhibits all charger power.

The charger has OCP but does not regulate current. It is always done by the load. The laptop has 2 separate regulators for DC-to many DC for MOBO and shares the maximum current available to do both such that it never demands more than the designed max. expected. The battery charger will have an algorithm for CCC-CV-float- hysteresis and back to CC-CV in some efficient slow response .

So the charge controller takes whatever current is left over from the unit power demands using a current summing limiter.

For example, a 3.5A charger @ 19.5V might take up to 2.5A at max LCD brightness and CPU & HDD load, leaving the battery CC/CV circuit to use a maximum of 1A.

Current sensors may be high or low side and often limited to 50mV drop for efficiency with a precision gain amplifier to convert to voltage and compare with a Bandgap ref.