High voltage generating circuit and method of operating the same

A method of operating a high voltage generating circuit comprising:

• generating an output clock signal;
• generating a first clock signal by delaying the output clock signal by a first delay time;
• generating a second clock signal by delaying the first clock signal by a second delay time;
• and
• generating a voltage in response to the output clock signal, the first clock signal, and the second clock signal,
• wherein a sum of the first and second delay times is less than or equal to a period of the output clock signal.

A high voltage generating circuit for generating an output voltage having a voltage level higher than a power supply voltage, the high voltage generating circuit comprising:

• an oscillator comprising an adjustable oscillator and an adjustable delay block, the adjustable oscillator being configured to output a first pumping clock signal and the adjustable delay block being configured to output a second pumping clock signal by delaying the first pumping clock signal by a first delay time;
• a high voltage pump comprising first and second high voltage pump circuits, the first high voltage pump circuit being configured to perform a first charge pumping operation in response to the first pumping clock signal and the second high voltage pump circuit being configured to perform a second charge pumping operation in response to the first pumping clock signal, the high voltage pump outputting the output voltage based on the first and second charge pumping operations;
• and
• a level detector configured to detect the voltage level of the output voltage, the oscillator being controlled to adjust at least a clock period of the first pumping clock signal when the detected voltage level of the output voltage differs from a target voltage.