A switched-mode power supply (SMPS) chip and system are disclosed, which are used for determining a maximum power output of a solar photovoltaic panel connected to the SMPS chip. The SMPS chip includes a sampled current comparator module, a logic control module connected to the sampled current comparator module, and a charge/discharge control module connected to the logic control module. According to the present invention, an output current from the SMPS system to an external load is detected and serves as a basis for incrementally adjusting a minimum input voltage of the SMPS chip and hence an output voltage of the solar photovoltaic panel. In this way, an output voltage level of solar photovoltaic panel corresponding to the maximum power output thereof under a given condition can be determined. Through keeping the solar photovoltaic panel operating at that output voltage level, it is ensured that the solar photovoltaic panel provides the maximum power output under the given condition.