To implement these key requirements for a solar charger, we need a charger that:

1. Can disable its input
2. Can measure the OCV
3. Can set the K-factor
4. Can hold the input voltage at the MPP

The BQ25798 is the perfect candidate and meets all of these requirements. First, it has a Hi-Z mode that allows disabling of the input. Second, it has an ADC that can measure the OCV. Third, it has an I2C register to set the K-factor. Last, it has flexible Input Voltage Dynamic Power Management (VINDPM) to hold the solar panel voltage at the MPP voltage. See Figure 2-1 for BQ25798 features that enable MPPT.

Figure 2-1 BQ25798 Integration and Features