Patent ID: 8461808

Claim:
A DC-DC converter comprising: a transformer including primary and secondary windings, wherein the secondary windings comprise a power supply winding externally supplying a power, and a feedback winding generating a voltage proportional to voltages induced in the secondary windings; a switching element that drives the primary winding; a comparator that compares the voltage from the feedback winding with a predetermined voltage to detect that the voltage is outside a predetermined voltage range to output a logic level indicating a high voltage error in the voltage from the feedback winding on a secondary side of the transformer when the voltage from the feedback winding is outside the predetermined voltage range; and a controller that is on a primary side of the transformer and supplied with the logic level and stops a repeated turning-on-and-off switching operation of the switching element when the logic level indicates the high voltage error in the voltage from the feedback winding on the secondary side of the transformer to avoid the high voltage error, wherein the comparator compares the voltage from the feedback winding that is electrically insulated from the power supply winding.