Leakage current reduction circuit and power supply employing the same

A power supply which converts an input AC voltage to a DC voltage, supplies the DC voltage to the primary side of a transformer intermittently, converts and AC voltage obtained on the secondary side of the transformer to a DC voltage, and outputs the obtained DC voltage, said power supply comprising:

• a first capacitor;
• a second capacitor, said first capacitor and said second capacitor being connected in series between two AC input lines which are connected to an input AC cable of the power supply;
• and
• a third capacitor for the prevention of EMI (Electro-Magnetic Interference) being provided between a grounding line on the secondary side of the transformer and the connection point between the first capacitor and the second capacitor, wherein the capacitance of the second capacitor is set larger than the capacitance of the first capacitor and the second capacitor having the larger capacitance is connected to one of the two AC input lines that is connected to a neutral line of the input AC cable.

A power supply converting AC input power into DC power, said AC input power provided on a first line and a second line, said second line being connected to a neutral, said power supply comprising:

• a transformer having a primary side and a secondary side, said primary side receiving said input AC power, said secondary side providing said DC power and having a ground terminal;
• a first capacitor;
• a second capacitor, said first capacitor and said second capacitor connected in series between said first line and said second line;
• and
• a third capacitor connected between said ground terminal and the connection point between the first capacitor and the second capacitor, wherein a capacitance of the second capacitor is set larger than a capacitance of the first capacitor, and the second capacitor is connected to said second line.

An electronic device having a power supply to convert AC input power into DC power, said AC input power being provided on a first line and a second line, said second line being connected to a neutral, said power supply comprising:

• a transformer having a primary side and a secondary side, said primary side receiving said input AC power, said secondary side providing said DC power and having a ground terminal;
• a first capacitor;
• a second capacitor, said first capacitor and said second capacitor connected in series between said first line and said second line;
• and
• a third capacitor connected between said ground terminal and the connection point between the first capacitor and the second capacitor, wherein a capacitance of the second capacitor is set larger than a capacitance of the first capacitor and the second capacitor is connected to said neutral.