Light emitting diode driving apparatus and method for holding driving voltage thereof

摘要

A light emitting diode (LED) driving apparatus is disclosed. The LED driving apparatus includes a power converter, a voltage sample-and-hold and comparison circuit, and a pre-charge clock generator. The power converter has a power transistor switch for processing power conversion and outputs a driving voltage at an output terminal. The voltage sample-and-hold and comparison circuit enters a sample-and-hold mode or a comparing mode according to a dimming status signal. The voltage sample-and-hold and comparison circuit samples and holds a feedback voltage to obtain a pre-storage voltage during the sample-and-hold mode and compares the pre-storage voltage with the feedback voltage to obtain a comparison result during the comparing mode. The voltage sample-and-hold and comparison circuit generates a pre-charge enable signal according to the comparison result. The pre-charge clock generator generates a pre-charge clock signal to control the power transistor switch according to the pre-charge enable signal and a clock signal.