DRIVE CIRCUIT OF CHARGE PUMP CIRCUIT, POWER SUPPLY AND LIGHT EMITTING DEVICE

摘要

A drive circuit of a charge pump circuit in which efficiency is improved. In the drive circuit (20) of a charge pump circuit (10) capable of switching the step-up rate, a control section (24) controls the charge pump circuit (10). A first oscillator (26) outputs a first period signal required for controlling the step-up operation of the charge pump circuit (10) through the control section (24). A second oscillator (28) outputs a time measuring second period signal having a frequency set lower than that of the first period signal. The control section (24) monitors the states of the drive circuit (20) itself or the charge pump circuit (10) and switches the step-up rate of the charge pump circuit (10) when a predetermined state sustains for a predetermined time or longer. The control section (24) turns on only the first oscillator (26) when the step-up rate is larger than 1, performs step-up operation control and time measurement based on the first period signal, turns on only the second oscillator (28) when the step-up rate is 1, and performs time measurement based on the second period signal.