supply voltage vcc the discharge transistor 240 may be turned on by the activation of the discharge signal disch and the voltage of the control node sw_gate may fall to the level of the negative voltage vneg by which the high voltage switch 201 may be turned off at this time the transistors 210 220 and 230 may be turned off in accordance with an exemplary embodiment of the present invention the power supply voltage vcc may not be involved in turning on and off of the transistors 210 220 and 230 of the high voltage switch circuit configured as shown in fig2 and therefore the high voltage switch 201 may be reliably turned on and off even though the level of the power supply voltage vcc falls also the control node sw_gate may rise directly to the level of the first high voltage vpp without precharge of the control node sw_gate and therefore the high voltage switch 201 may be quickly turned on without the element for example the high voltage nmos transistors 130 described with reference to fig1 for the precharge of the control node sw_gate fig3 is a configuration diagram of an example of the first level shifter 250 shown in fig2 referring to fig3 the first level shifter 250 may include a first nmos transistor n 1 which pull down drives the activation signal enh in response to the inverted preliminary activation signal en_n a second nmos transistor n 2 which pull down drives the inverted activation signal enh_n in response to the preliminary activation signal en a first pmos transistor p 1 which drives the activation signal enh to the level.