US 5,850,363 A · Voltage boosting circuit having dual precharge circuits in semiconductor memory device

Abstract

A voltage boosting circuit for a semiconductor memory device provides good set-up characteristics and reduces excessive voltage levels by utilizing a first precharge circuit during a first time interval after power is applied and second precharge circuit during a second time interval. The circuit includes a voltage boosting means having an output terminal for outputting a boosted voltage signal. The first precharge circuit is coupled between an internal power supply and the output terminal and includes a diode connected transistor. The second precharge circuit is coupled between an external power supply and the output terminal and includes a plurality of diode connected transistors connected in series. During the first time interval, the voltages of the internal and external power supplies are equal and the first precharge circuit, which has a relatively low turn-on voltage, precharges the output line, thereby providing good set-up characteristics. During the second and subsequent time intervals, the voltage of the external power supply is greater than the voltage of the internal power supply and the second precharge circuit, which has a relatively high turn-on voltage, precharges the output line to provide good set-up characteristics, but prevents the voltage level of the output line from becoming excessive, thereby enhancing the reliability of the gate oxide layer of a transistor that is coupled to the output line.

Claims16

Dependent claims

A voltage boosting circuit for a semiconductor memory device comprising:

voltage boosting means for receiving a first supply voltage and outputting a boosted voltage higher than said first supply voltage;
first precharge means for receiving said first supply voltage and precharging an output terminal of said voltage boosting means;
and
second precharge means for receiving a second supply voltage and precharging the output terminal of said voltage boosting means;
wherein said first precharge means includes at least one diode connected in series between said first supply voltage and the output terminal of said voltage boosting means, and said second precharge means includes a plurality of diodes connected in series between said second supply voltage and the output terminal of said voltage boosting means;
and
wherein the number of diodes in said second precharge means is greater than the number of diodes in said first precharge means.

4 more elements

Dependencies are inferred from the claim text.

Voltage boosting circuit having dual precharge circuits in semiconductor memory device

Life of this patent

Voltage boosting circuit having dual precharge circuits in semiconductor memory device

Life of this patent

Abstract

Claims16