Patent ID: 8686667

Claim:
A lighting power source comprising: a DC power source; a first switching element and a diode coupled in series across output ends of the DC power source; an output circuit comprising an inductor and forming a loop along with the diode; a driving capacitor having a first end coupled to a node between the first switching element and the diode; a charging power source coupled to a second end of the driving capacitor, the charging power source being supplied with power from the DC power source and charging the driving capacitor; a second switching element coupled across the diode; and a control circuit effective to turn on/off the first and second switching elements using the driving capacitor as a power source, wherein during a charging operation, the control circuit charges the driving capacitor by turning on the second switching element while maintaining the first switching element in an OFF state, and during a normal operation which follows the charging operation, the control circuit repeatedly turns on/off the first switching element while maintaining the second switching element in an OFF state.