Patent ID: 8462560

Claim:
A semiconductor device comprising: a temperature sensor that performs temperature sensing; a measurement controller that controls the temperature sensor so that a temperature measurement is performed once for each of a plurality of different reference temperatures for a preset number of times of refresh operations; a plurality of latch circuits that hold results of temperature measurement by the temperature sensor at each of the different reference temperatures; a logic circuit that receives outputs of the latch circuits and generate a result of temperature detection; a refresh period of a memory cell provided in the semiconductor device being set based of the result of temperature detection; a comparator that compares a voltage obtained on resistance division of a reference voltage with an output voltage of the temperature sensor, the voltage obtained on resistance division corresponding to the reference temperature; a plurality of the latch circuits that respectively latch the results of comparison by the comparator; an address detection circuit that detects a circulation of refresh addresses of the memory cell; and a logic circuit that generates the signal of temperature detection from a plurality of the results of temperature measurement respectively held by the latch circuits; the measurement controller exercising control of: selecting a first one of a plurality of conditions for temperature measurement, based on the result of detection the circulation of the refresh addresses by the address detection circuit; causing comparator to compare an output of the temperature sensor with a voltage of a reference temperature associated with the first condition of temperature measurement; causing a first one of the latch circuits associated with the first condition of temperature measurement to hold the result of the comparison by the comparator; sequentially selecting a second condition of temperature measurement different from the first condition of temperature measurement in response to the result of detection of the circulation of the refresh addresses by the address detection circuit; causing comparator to compare an output of the temperature sensor with a voltage of a reference temperature associated with the second condition of temperature measurement; and causing a second one of the latch circuits different from the first latch circuit to hold the result of comparison by the comparator.