Power supply circuit for supplying power to electronic device such as image forming apparatus

An image forming apparatus comprising:

• a power supply circuit;
• a developing member to which a voltage supplied from said power supply circuit is applied;
• an image carrier which bears an electrostatic latent image that is developed with a developing agent supplied from said developing member;
• and
• a transferring member which transfers a developing agent image from the image carrier onto a printing medium,
• said power supply circuit including:
• an alternating current voltage generation unit which generates an alternating current voltage having a shape of a rectangular wave;
• a voltage conversion unit which converts the alternating current voltage generated by said alternating current voltage generation unit into a predetermined output voltage;
• and
• an adjustment unit which monitors the output voltage and adjusts a driving pattern for driving said alternating current voltage generation unit in accordance with a waveform distortion generated in a rectangular wave of the output voltage,
• wherein the driving pattern is a pattern having, in a half cycle of the rectangular wave of the alternating current voltage, a first ON period during which the alternating current voltage is applied to said voltage conversion unit, an OFF period during which the alternating current voltage is not applied to said voltage conversion unit, and a second ON period during which the alternating current voltage is applied to said voltage conversion unit, and
• said adjustment unit adjusts a ratio of the first ON period, the OFF period, and the second ON period so that the waveform distortion decreases.