Internal voltage generation circuit having stable operating characteristics at low external supply voltages

摘要

An internal voltage generation circuit is provided which can stably generate an internal supply voltage even if an external supply voltage decreases. The internal voltage generation circuit includes first and second level shifters, a differential amplifier and a driver. The first level shifter is connected to an internal supply voltage terminal and lowers the internal supply voltage to a predetermined voltage level. The second level shifter is connected to a reference voltage terminal and lowers a reference voltage to a predetermined voltage level. The differential amplifier compares the output voltage of the second level shifter with the output voltage of the first level shifter and amplifies the difference between the two output voltages. The driver generates the internal supply voltage in response to the output of the differential amplifier. The first and second level shifters may be source followers that decrease the internal supply voltage and the reference supply voltage, respectively, by a threshold voltage. Accordingly, the internal voltage generation circuit may stably generate the internal supply voltage even if the level of the external supply voltage is lowered, and restores the level of the internal supply voltage to its original level equal to the reference voltage even when the level of the internal supply voltage drops.