Avoiding Audible Noise at Light Loads When Using Leading Edge Triggered PFC Converters
When using a leading edge triggered PFC the designer may find that the converter, under extremely light-load conditions, will encounter an audible low noise. The unit under these conditions can go into the Over Voltage Protection (OVP) state because of the extremely light load. When this happens, the output of the current error amplifier can fall to ground because of the input offset voltage variations and the residual current from MOUT. This application note applies to the TI average current mode, leading edge modulation PFC controllers.
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