Negative voltage generator, operation method thereof and electronic device including the same

A method of operating a voltage generator including a first output node and a second output node, the method comprising:

• generating, based on a first input voltage, a first output voltage at the first output node and the second output node;
• charging a first capacitor with electric charges corresponding to the first input voltage, and charging a second capacitor with electric charges corresponding to a sum of the first input voltage and a second input voltage;
• and
• generating the first output voltage at the first output node and generating a second output voltage at the second output node,
• wherein the first output voltage is equal in magnitude to the first input voltage, and opposite in sign to the first input voltage.

A display driver integrated circuit (IC) (DDI) comprising:

• a start-up stage circuit configured to generate, based on a first input voltage, a negative first input voltage;
• a first stage circuit configured to generate, based on the first input voltage and the negative first input voltage, a first output voltage;
• and
• a second stage circuit configured to generate a second output voltage based on a second input voltage and the negative first input voltage.