A shutter circuit is provided for a multi-channel converter to blank the switching noise produced by the switching of the converter. The shutter circuit monitors the switching of the switches in the output stages of the converter, and when one channel performs switching, the shutter circuit will send a signal to other channels to block the current sensors thereof. The current sensors are so blocked for a period not to sense the switching noise. The mutual interference between the channels due to the switching noise of the converter is eliminated.