A power supply conversion circuit includes a PWM chip and many sub-circuits. Each sub-circuit includes an inductor, a first capacitor connected to ground, a first resistor connected in series with the first capacitor to form a branch parallel to the inductor, a differential pair having a first differential signal trace and a second differential signal trace, a second resistor, and a second capacitor. The first trace is connected between the connection of the first resistor and the first capacitor and the PWM chip. The second resistor is connected between the connection of the first resistor and the inductor and the second capacitor. The second trace is connected between the connection of the second resistor and the second capacitor and the PWM chip. The ratios of the capacitances of each two second capacitors are the same as that of the lengths of the traces of each two corresponding differential pairs.