Power supply device and image forming apparatus including the power supply device

A power supply device comprising:

• an AC generation part including
• a sinusoidal wave generation part that generates a first sinusoidal wave signal;
• an integrator that integrates a difference between the first sinusoidal wave signal and a feedback signal,
• a triangular wave generation part that generates a triangular wave signal,
• a comparator that compares an output of the integrator and the triangular wave signal and outputs a PWM signal,
• a switching drive part that amplifies the PWM signal and outputs an amplified PWM signal,
• a filter that converts the amplified PWM signal into a second sinusoidal wave signal,
• a transformer that increases a voltage of the second sinusoidal wave signal and outputs an AC voltage, and
• a voltage divider that divides the AC voltage and generates the feedback signal;
• and
• a DC generation part that generates a DC voltage;
• wherein the power supply device is configured to superimpose the AC voltage and the DC voltage and output a superimposed voltage,
• wherein the sinusoidal wave generation part includes
• a table configured to retain data of a plurality of bit patterns corresponding to a ¼ cycle of the first sinusoidal wave signal,
• an operator that contains a counter and that is configured to read out the data of the plurality of bit patterns corresponding to the ¼ cycle of the first sinusoidal wave signal, calculate a bit string of 3 subsequent cycles of the first sinusoidal wave signal based only on the read out data of the plurality of bit patterns corresponding to the ¼ cycle of the first sinusoidal wave signal, and output a calculation result, and
• a D/A converter configured to convert the calculation result into analog data signals.