Discharge lamp ballast apparatus comprising DC/DC converters having at least two transformers and outputting two kinds of voltages

A discharge lamp ballast apparatus comprising:

• a plurality of DC/DC converters which include transformers for boosting a power supply voltage, and are connected in parallel;
• control unit for controlling operation of the transformers of said DC/DC converters;
• and
• a voltage-multiplier rectifier circuit that generates a high voltage to start a discharge lamp by utilizing a potential difference between output voltages of the transformers, wherein
• said control unit controls the transformers in a manner as to shift operation phases of the transformers of said DC/DC converters;
• and further wherein
• said control unit adjusts the operation phases and duty of the transformers of said DC/DC converters in a manner as to increase the potential difference to be supplied to said voltage-multiplier rectifier circuit.

A discharge lamp ballast apparatus comprising:

• a plurality of DC/DC converters which include transformers for boosting a power supply voltage, and are connected in parallel:
• control unit for controlling operation of the transformers of said DC/DC converters;
• and
• a voltage-multiplier rectifier circuit that generates a high voltage to start a discharge lamp by utilizing a potential difference between output voltages of the transformers, wherein
• said control unit controls the transformers in a manner as to shift operation phases of the transformers of said DC/DC converters;
• and further wherein
• said control unit halts voltage outputs of the transformers when a voltage across a capacitor for holding an output voltage of said DC/DC converters at a ballast voltage of the discharge lamp reaches the ballast voltage;
• and causes the transformers to output voltages when the voltage across the capacitor becomes less than the ballast voltage.

A discharge lamp ballast apparatus comprising:

• a plurality of DC/DC converters, where said converters include transformers that boost a power supply voltage and said transformers are connected in parallel;
• a control unit that controls operation of said DC/DC converters;
• and
• a high voltage generating circuit, said generating circuit including at least a first capacitor and a first diode and a second capacitor and a second diode, and where
• said generating circuit charges said first capacitor to a first voltage with a DC voltage, said DC voltage including an output voltage of one transformer, said output voltage of one transformer being rectified by said first diode at a first timing of AC waveforms output from said one transformer,
• said generating circuit charges said second capacitor to a second voltage, said second voltage being the sum of the first voltage and the DC voltage, where the DC voltage further includes an output voltage of a second transformer, said output voltage of a second transformer being rectified by said second diode at a second timing, said second timing having a different phase than said first timing, thereby making the DC voltage higher than the output voltages of said transformers at terminals of said second capacitor, and
• said control unit controls said DC/DC converters in such manner as to shift operation phases of said transformers.