i made a 24V switch mode power and it is suppoed to output the current of 2A ,but ,after i did some experiments,i found the Volt drop down to 22V when the LOAD is 12ohm. (there is weird sound -ZiZi) (pdf 's left upon part is the power supply unit) ,i think the circuit around OPA or tl431 is the key ,however, i just cant adjust it properly.
my SchDoc Pdf
my PCB Doc
hope the problem solved
