Patent ID: 7239042

Claim:
An electronic device comprising: a circuit board having a power supply circuit for generating a DC voltage using a commercial AC power source, and a switching element for switching AC power from the commercial AC power source to a load connected to said circuit board, wherein said circuit board is configured to output an analog signal using the DC voltage generated by the power supply circuit, and wherein a level of the analog signal corresponds to a type of the commercial AC power source; and a control circuit connected to said circuit board and configured to control the switching element depending on the type of the commercial AC power source in accordance with the analog signal from said circuit board, so as to control switching of the AC power from the commercial AC power source to the load in accordance with the type of the commercial AC power source, wherein the analog signal is obtained by dividing the DC voltage generated by the power supply circuit by a ratio corresponding to the type of the commercial AC power source.