| 摘要 |
PROBLEM TO BE SOLVED: To prevent production of the shortage of driving of switching elements Q1 and Q2, even if characteristics changes take place on a driven transformer T by increased circumference temperature changes in the power supply. SOLUTION: The power supply is equipped with the driven transformer T, the inductance of each windings of which has a positive temperature coefficient, while having secondary windings n21 and n22, a primary winding n1, and a magnetic core, which are connected to the control terminal of the switching elements Q1 and Q2, and the drive circuit 9, which drives the above switching elements Q1 and Q2 by impressing a high-frequency voltage to the primary winding n1 of the driven transformer T. Resonance means containing the driven transformer T is set, so that a driving voltage VGS becomes close to the maximum value, and the characteristic resonance frequency f0 of the above resonance means is switched to high/low, according to increase/decrease of circumference temperature. For example, capacity of a capacitor connected in parallel with the primary winding n1 of the drive transformer T is changed. |
