Signal conversion circuit and refrigeration equipment

The utility model provides a signal conversion circuit and refrigeration equipment. The signal conversion circuit comprises an input end; a first pin of a primary side of the optical coupler is connected with the input end through a first resistor, and a second pin of the primary side of the optical coupler is grounded; the secondary side first pin is connected with the power supply through the second resistor; the positive electrode of the first capacitor is connected with the secondary side second pin of the optical coupler, and the negative electrode is grounded; one end of the third resistor is connected with the secondary side second pin of the optical coupler, and the negative electrode of the third resistor is grounded; one end of the output end is connected with the secondary side second pin of the optical coupler, and the other end of the output end is connected with the analog-to-digital converter. Under the condition that the chip port resource does not meet the use requirement, the pulse width mod