LNK3204D No Load Audible Noise

I used an LNK3204D and designed a 12V/0.12A power supply.

When there is no load, the assembly PCB board makes quite a loud audible noise.

I have checked the operating current of the power inductor. Its frequency is only near 2KHz no what it can be heard.

How can I make the frequency beyond audible range, ie >20KHz Then the circuit board can be totally quiet.