Apple Inc.
System on a Chip that Drives Display when CPUs are Powered Down

Abstract:

In an embodiment, a system may include one or more processors forming central processing units (CPUs) in the system, a display controller configured to display frames on a display device, a memory controller configured to control a memory, and a power management circuit. The power management circuit may be configured to establish one of a plurality of power states in the system. In a first power state, the display controller and the memory controller are powered on while the CPUs are powered off. The display controller may be configured to read a plurality of prerendered frames from the memory and display the plurality of prerendered frames at times specified for each of the plurality of prerendered frames.