PULSE FREQUENCY MODULATION MODE CONTROLLER WITH FIXED CONTINUITY TIME, USING A TRIANGULAR-WAVE GENERATOR DETECTING THE LOAD CURRENT VALUE OF A PULSE WIDTH MODULATION MODE AND A PULSE FREQUENCY MODULATION MODE

摘要

PURPOSE: A pulse frequency modulation(PFM) mode controller with fixed continuity time is provided to be adapted to a high efficiency DC-DC buck converter with a wide load current range using the current source of triangular-wave generating circuit.;CONSTITUTION: A continuity time generating unit generates a fixed continuity time controlling signal for a PFM mode. A mode operation controlling switch unit performs operation controls for each mode. A pulse width modulation(PWM) mode and a PFM mode are converted by the mode operation controlling switch unit. A state controlling unit(501) generates a state signal for determining a state in the PFM mode. A load current detecting unit detects a load current in the PFM mode.;COPYRIGHT KIPO 2011