Patent ID: 6157179
Filing Date: 2000-12-05
Classification: H02M,Y02B

Abstract:
A switched-mode power supply circuit comprising:input terminals for receiving an input voltage, and output terminals for supplying a DC output voltage to a load;a capacitance and an inductance;charging means for receiving the input voltage, said charging means being coupled to the capacitance for periodically storing a charge in the capacitance during a first period;rectifier means coupled between the inductance and one of the output terminals for supplying the DC output voltage;a switching element coupled to the inductance; anda control circuit for controlling the switching element in an on or off-state, in which the switching element is periodically in the on-state during a second period,wherein the capacitance, the inductance and the switching element are arranged to form a resonant circuit in the on-state of the switching element for transferring the charge stored in the capacitance to the load via said rectifier means, wherein said first and second periods are disjunct, and wherein transfer of energy from the input terminals to the output terminals is substantially determined by the charge stored in the capacitance, characterized in that the input voltage is an AC line voltage; the charging means comprises a single phase or double phase rectifier circuit for supplying current to the capacitance during the first period; and the control circuit receives the AC line voltage for determining the second period in response to the AC line voltage.