Memory system that carries out temperature-based access to a memory chip

A memory system connectable to a host, comprising:

• a plurality of memory chips, each of which includes a nonvolatile semiconductor memory cell array;
• a memory controller;
• a first temperature sensor positioned to measure a first temperature, which is representative of a temperature of the memory controller;
• and
• a plurality of second temperature sensors, each of which is positioned to measure a second temperature representative of a temperature of one of the memory chips, wherein
• the memory controller is configured to, prior to performing a read access to the memory chips, compare the first temperature against a first threshold temperature and a second temperature against a second threshold temperature, and perform a heating operation while preventing the read access to the memory chips when neither the first temperature is greater than the first threshold temperature nor at least one of the second temperatures is greater than the second threshold temperature.

A method for operating a memory system including a memory chip having a nonvolatile semiconductor memory cell array, and a memory controller, the method comprising:

• detecting a first temperature of the memory controller;
• detecting a second temperature of the memory chip;
• comparing the first temperature of the memory controller against a first threshold temperature;
• comparing the second temperature of the memory chip against a second threshold temperature;
• accessing the memory chip to carry out an operation in response to a read command from a host, when either the first temperature is greater than the first threshold temperature or the second temperature is greater than the second threshold temperature;
• and
• performing a heating operation in response to the read command from the host while preventing a read access to the memory chip, when neither the first temperature is greater than the first threshold temperature nor the second temperature is greater than the second threshold temperature.