A refresh voltage control engine selectively applies different high voltages to use in refresh operations. The control engine can detect that a portion of a memory device needs to be refreshed, and determine that the refresh cycle time is too short for a state of the portion of the memory device. The memory device typically has an associated refresh cycle time or time between refreshes based on the device and system architecture. The control engine can generate one or more control signals to cause the system to apply an overcharge refresh to overcharge the portion of the memory device with a refresh operation to extend the refresh cycle time for the portion of the memory device.