| 摘要 |
PROBLEM TO BE SOLVED: To ensure zero voltage switching of a switch element of a converter in both a continuous current mode and a discontinuous current mode, while performing PWM control thereon.SOLUTION: The power supply device includes: an LC resonant converter 2 that has a switch element 16, a second inductor 15 connected in series with the switch element 16, and a parallel capacitor 17 connected in parallel with the switch element 16, and that turns on/off the switch element 16 to supply power; a signal generation circuit 4 for generating a pulse width modulation signal S2 of a constant frequency on the basis of a DC output voltage Vout of the converter 2; a zero voltage detection circuit 5 for comparing a voltage V1 between both ends of the switch element 16 with a zero voltage detection threshold and outputting a pulse signal S3 when the end voltage V1 is equal to or lower than the threshold; and a driving signal generation circuit 6 for generating a driving signal S4 to turn on/off the switch element 16 on the basis of a logical product of the pulse width modulation signal S2 and the pulse signal S3. |
