Apparatus for generating high voltage signal

Abstract

A high voltage generator provides a high voltage signal for compensating a threshold voltage loss in a semiconductor memory device. The high voltage generator includes: a level detection unit for detecting a voltage level of the high voltage signal to generate a high voltage enable signal when the voltage level of the high voltage signal reaches a predetermined target value; an oscillation unit, in response to the high voltage enable signal, for generating a plurality of clocks, the clocks including a first to a fourth clocks; a high-voltage charge pump unit, in response to the clocks, for increasing a voltage level of an external power signal to generate the high voltage signal to a high voltage node; and a power-on precharging unit, in response to a control signal, for initializing the high voltage node to a predetermined level.