Apparatus for controlling NAND flash memory device and method for controlling same

A power supply device, comprising:

• a memory;
• a converter connected the memory and converting an input voltage of a supply power to supply an output voltage to the memory;
• an input voltage detector connected to the converter and detecting a level of the input voltage;
• a controller connected to the memory and controlling access to the memory based on the level of the input voltage;
• and
• an auxiliary power unit connected to the memory and the controller and supplying a driving voltage to the memory and the controller for a preset time,
• wherein the controller is configured to:
• generate a command signal to program, read, and erase data in the memory when the level of the input voltage is greater than or equal to a first level,
• control the auxiliary power unit so that the driving voltage for driving the memory and the controller is maintained for a first time period from a first time point at which the level of the input voltage becomes less than or equal to a second level,
• block the command signal for the first time period, and
• block power from being supplied to the memory regardless of a level of the input voltage for at least a second time period from a second time point after the first time period has elapsed, and
• wherein when the level of the input voltage is greater than or equal to the first level before the second time period elapses from the second time point, the controller blocks power from being supplied to the memory.