US Patent 7778064 Accessing a phase change memory

A memory employs a low-level current source to access a phase change memory cell. The current source charges an access capacitor in order to store sufficient charge for an ensuing access. When a memory cell is accessed, charge stored on the capacitor is discharged through the phase change memory, supplying a current to the phase change memory cell that is sufficient for the intended access operation and greater than that provided directly by the current source.