DC-DC CONVERTER WITH AUTO-SWITCHING BETWEEN PWM AND PFM AND OLED DISPLAY USING THE SAME

摘要

A DC-DC converter with auto-switching between pulse width modulation (PWM) and pulse frequency modulation (PFM) is used in an organic light emitting diode (OLED) display and judges power consumption of an OLED array of the display according to display data of the display and thus determines a switching time between PWM and PFM. The converter comprises a content statistic unit, an auto-switching control unit, a PWM controller, a PFM controller and a power generator. The content statistic unit receives and accumulates the display data of the OLED display and then outputs a statistic value. The auto-switching control unit outputs a control signal according to the statistic value to control the PWM controller and the PFM controller and to switch to a PWM mode or a PFM mode.