Auto refresh limiting circuit for semiconductor memory device

An auto refresh limiting circuit comprising:

• an oscillating signal generating part that generates an internal oscillating signal, the internal oscillating signal being a pulse having a period reflecting an internal temperature of a semiconductor memory device;
• a masking signal generating part that generates a masking signal by using an auto refresh command signal and the internal oscillating signal, the auto refresh command signal being provided from an outside and generated in a form of a pulse, the masking signal being deactivated during a period corresponding to an allowable ratio, the allowable ratio being a number of pulses of the internal oscillating signal with respect to a number of pulses of the auto refresh command signal;
• and
• an auto refresh masking part that converts the pulse of the auto refresh command signal into the pulse of an auto refresh driving signal, the conversion of the pulse of an auto refresh driving signal being masked according to an activation of the masking signal.

A semiconductor memory device comprising:

• an auto refresh limiting circuit comprising:
• an oscillating signal generating part that generates an internal oscillating signal, the internal oscillating signal being a pulse having a period reflecting an internal temperature of the semiconductor memory device;
• a masking signal generating part that generates a masking signal by using an auto refresh command signal and the internal oscillating signal, the auto refresh command signal being provided from an outside and generated in a form of a pulse, the masking signal being deactivated during a pulse of the auto refresh command signal, the pulse of the auto refresh command signal being first generated after the pulse of the internal oscillating signal is generated;
• and
• an auto refresh masking part that converts the pulse of the auto refresh command signal into a pulse of an auto refresh driving signal, the conversion of the pulse of the auto refresh driving signal being masked according to an activation of the masking signal.