US Patent 11837282 Charge pump apparatus and calibration method thereof

A charge pump apparatus includes a first charge pump system, a second charge pump system, a switch transistor, and a voltage regulation circuit. The first charge pump system converts a first supply voltage into a first boost voltage. The second charge pump system converts a second supply voltage into a second boost voltage. The switch transistor is coupled to the first charge pump system and the second charge pump system, and outputs an output voltage according to the second boost voltage. The switch transistor includes a control terminal receiving the second boost voltage, a first terminal receiving the first boost voltage, and a second terminal outputting the output voltage. The voltage regulation circuit successively adjusts a code of a voltage regulation signal according to the output voltage, in order to control the second charge pump system to successively adjust the second boost voltage according to the voltage regulation signal.