Embodiments of the disclosure provide a power supply circuit for powering an OLED panel and a display panel. The power supply circuit for powering the OLED panel reduces the voltage outputted by the DC-DC conversion circuit in the power supply circuit based on a target current. Moreover, the maximum value of the current that can be outputted by the DC-DC conversion circuit when outputting the reduced voltage is not less than the target current. The target current may be a current outputted by the DC-DC conversion circuit to the OLED panel at a time before a K-th preset duration counting from the latest preset duration for receiving the preset pulse signal.