The TPS25750EVM comes with an integrated battery charging solution using a BQ25731 buck/boost charger. The charger allows the EVM to operate as a source or sink from 5 to 20 volts at up to 3 amps. When acting as a sink, the TPS25750 negotiated the appropriate PD contract and enables the PPHV power path supplying power to the BQ. The BQ will then buck or boost the voltage to ensure the output is 12 volts (charging a 3S battery). When acting as a source, the BQ is powered by the barrel jack through the TPS56637 buck converter which simulates a 3S battery connection. The BQ will then buck or boost the 12 volts supplied from the TPS56637 to the desired output voltage which was negotiated in the PD contract.