The audible noise reduction circuit can be disabled when {HEAD ~ the detected switching frequency} is within {TAIL ~ a lower audible frequency range}, e.g., 20 Hz 200 Hz, that is at the lower threshold of the audible frequency range 
The audible noise reduction circuit can be disabled when { HEAD ~ the detected switching frequency } is within { TAIL ~ a lower audible frequency range } , e.g. , 20 Hz 200 Hz , that is at the lower threshold of the audible frequency range
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH