| 摘要 |
PURPOSE:To reduce a current loss at the time of switching ON of a transistor(TR) by employing the TR drive circuit having a power supply to supply a current to a base of the TR with a collector potential of the TR as a reference. CONSTITUTION:A current loss PCE caused when a collector current IC of a main TR 2 flows from its collector to its emitter is expressed in equation I. Furthermore, a loss PD caused when a current IB is supplied to a base of the TR 2 is expressed in equation II. The overall loss is expressed in equations III, IV. In the equation III, VD is selected to be 0.7V, and VCED=0.1V, VBEM=0.8 V and hfe (current amplification factor of TR)=5 are substituted, then the right term of the equation III as equation IV is 0.38.IC and it indicates that the current loss is considerably reduced in comparison with equation by the Darlington system (PCE+PD=1.08.IC). |
