Patent ID: 6188585
Filing Date: 2001-02-13
Classification: H02M

Abstract:
A DC power supply apparatus comprising:an AC-to-DC converter for converting a commercial AC signal into a first DC signal;a transformer;a DC-to-high-frequency converter for converting said first DC signal into a high frequency signal and applying said high-frequency signal to said transformer, said DC-to-high-frequency converter including at least first and second semiconductor switching devices, said first semiconductor switching device being rendered conductive during a period in which first of at least first and second alternately occurring conduction control signals is applied thereto, to thereby provide said transformer with said first DC signal in a first polarity, said second semiconductor switching device being rendered conductive during a period in which said second conduction control signal is applied thereto, to thereby provide said transformer with said first DC signal in a second polarity opposite to said first polarity;a high-frequency-to-DC converter for converting said high-frequency signal as transformed by said transformer to a second DC signal and applying said second DC signal to a load; anda controller repeatedly generating said first and second conduction control signals with a pause period disposed between the end of said first conduction control signal and the beginning of said second conduction control signal occurring subsequent to the occurrence of said first conduction control signal and between the end of said second conduction control signal and the beginning of said first conduction control signal occurring subsequent to the occurrence of said second conduction control signal;said controller comprising:a pause period control signal generator receiving said commercial AC signal and generating a pause period control signal having a value proportional to a voltage value of said commercial AC signal;a sawtooth generator generating a sawtooth signal having a predetermined period; anda comparator for developing said at least first and second conduction control signals with said pause period, said pause period being a period during which the value of said sawtooth signal changes away from the value of said pause period control signal in one direction and returns to the value of said pause period control signal.