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