The LED driver circuits on the LC4500 controller may generate audible noise which is normal and not an indication of any malfunction.  The noise is louder if the LED drivers are not connected to LEDs, which is often the case for applications using the LC4500-EKT standalone controller.

If not using the LED drivers or the LED enable signals then it is possible to eliminate this noise by installing a jumper on J39.  J39 is a 2mm jumper header immediately adjacent to the pushbutton switch on the opposite side of the driver board from the LED connectors.

Installing J39 will reduce the overall electrical switching noise on the controller board so it may also improve reliability when operating in adverse conditions.