Multi-level voltage generator

1. A multilevel voltage generator comprising:

a first positive voltage generator generating a first output voltage corresponding to two times of a reference voltage by using a first capacitor which receives a reference voltage and is switched according to a control signal to be charged to a voltage level of the reference voltage applied to two terminals of the first capacitor;

a second positive voltage generator generating a second output voltage and a third output voltage using a second capacitor and a third capacitor which receive the first output voltage and are charged to voltage levels corresponding to predetermined multiples of the reference voltage; and

a negative voltage generator generating a fourth output voltage having predetermined negative voltage levels using a fourth capacitor which receives the reference voltage, the second output voltage, or the third output voltage and is charged to a voltage level corresponding to a negative voltage of the second or third output voltage;

wherein the first positive voltage generator comprises:

a first switch transferring the reference voltage to a first node in response to a first control signal;

the first capacitor connected between the first node and a second node and charged to the reference voltage that is transferred to the first node;

a first level transfer portion transferring a ground voltage or the reference voltage to the second node in selective response to the first control signal and a second control signal; and

a second switch transferring a voltage level of the first node to a first output in response to a third control signal;

wherein the first level transfer portion comprises:

a third switch transferring the ground voltage to the second node in response to the first control signal; and

a fourth switch transferring the reference voltage to the second node in response to the second control signal;

wherein the second positive voltage generator comprises:

a fifth switch transferring the first output voltage to the second output voltage in response to a fourth control signal;

the second capacitor connected between the second output voltage and a third node and charged to the second output voltage; and

a second level transfer portion transferring the ground voltage, the first output voltage, or the reference voltage to the third node in response to the fourth control signal, a fifth control signal, and a sixth control signal;

wherein the second level transfer portion comprises:

a sixth switch transferring the ground voltage to the third node in response to the fourth control signal;

a seventh switch transferring the first output voltage to the third node in response to the fifth control signal; and

an eighth switch transferring the reference voltage to the third node in response to the sixth control signal;

wherein the second positive voltage generator comprises:

a ninth switch transferring the second output voltage to a fourth node in response to a seventh control signal;

the third capacitor connected between the fourth node and a fifth node and charged to the second output voltage that is transferred to the fourth node;

a third level transfer portion transferring the ground voltage or the first output voltage to the fifth node in response to the seventh control signal or an eighth control signal;

a tenth switch transferring the second output voltage to a third output in response to a ninth control signal; and

an eleventh switch transferring a voltage level of the fourth node to the third output in response to a tenth control signal;

wherein the third level transfer portion comprises:

a twelfth switch transferring the ground voltage to the fifth node in response to the seventh control signal; and

a thirteenth switch transferring the first output voltage to the fifth node in response to the eighth control signal;

wherein the negative voltage generator comprises:

a fourteenth switch transferring the reference voltage to a sixth node in response to an eleventh control signal;

a fifteenth switch transferring the ground voltage to the sixth node in response to a twelfth control signal;

the fourth capacitor connected between the sixth node and a seventh node and charged to the reference voltage or the ground voltage that is transferred to the sixth node;

a fourth level transfer portion transferring the third output voltage, the second output voltage, or the ground voltage to the seventh node in selective response to a thirteenth control signal, a fourteenth control signal, or a fifteenth control signal; and

a sixteenth switch transferring a voltage level of the sixth node to the fourth output in response to a sixteenth control signal.

2. The multilevel voltage generator of claim 1 , wherein the fourth level transfer portion comprises:

a seventeenth switch transferring the third output voltage to the seventh node in response to the thirteenth control signal;

an eighteenth switch transferring the second output voltage to the seventh node in response to the fourteenth control signal; and

a nineteenth switch transferring the ground voltage to the seventh node in response to the fifteenth control signal.