Power saving in OLED displays with multiple refresh rates

A display panel comprising:

• a plurality of pixels arranged in an array, the array including rows and columns, each pixel of the array including at least one OLED light-emitting device;
• a plurality of pixel circuits, each pixel circuit associated with one of the OLED light-emitting devices and configured to drive its associated OLED light-emitting device;
• a plurality of scan lines configured for selecting the pixel circuits associated with each row of the pixels;
• a plurality of column data lines configured for controlling the pixel circuits associated with each column of the pixels;
• a plurality of emission lines configured for supplying signals to pixel circuits associated with each row of the pixels to cause the pixel circuits to supply driving current to anodes of OLED pixels of the row;
• a device driver configured to supply signals to the scan lines, the column lines and the emission lines to cause the display panel to render images on an active area of the display panel with a plurality of different frame rates, including:
• (i) for a plurality of frame rates that match or are above a threshold frame rate, performing an image refresh operation once per frame period and not performing a self-refresh operation during the frame period;
• (ii) for a lower frame rate that is lower than the threshold frame rate and when a brightness of the active area of the display panel is lower than a threshold brightness, performing an image refresh operation once per frame period and performing a self-refresh operation at least once during the frame period;
• and
• (iii) for the lower frame rate that is lower than the threshold frame rate and when a brightness of the active area of the display panel is higher than the threshold brightness, performing an image refresh operation once per frame period and performing no self-refresh operation during the frame period.