Voltage boosting circuit, voltage boosting/dropping circuit and LCD

摘要

A voltage boosting circuit performs variable frequency control that gradually increases frequencies of clock signals from a low frequency to a high frequency during a boosting operation period for which a low output voltage of a DC-DC converter when the power is turned on is boosted up to a predetermined voltage. Thus, the frequencies of clock signals may be set according to the boosting operation of the DC-DC converter. Consequently, the operation of the DC-DC converter may be stabilized until the stable operation period is performed after the DC-DC converter starts to operate.