| 摘要 |
PURPOSE:To reduce the switching distortion at the power stage by using transistors excellent in high frequency performance and reducing the heat dissipation when a great deal of idling current is flowed to the driver stage, in the push pull power amplifier of class B operation. CONSTITUTION:The first transistor pair Tr 27,28 are provided, which constitute the common collector complementary push pull circuit driving a load connected to the output terminl 33, and the middle point of the positive and negative power supplies 36,37 having floating neutral point is connected to the emitter of Tr 27 and 28. Further, to the bases of Tr 27,28,the emitters of second Tr 24,25 constitut- ing the complementary push pull circuit connecting the collector at the both ends of the positive and negative power supplies 36 and 37 are respectively connected. One or the both of the pairs of Tr 27,28 and Tr 24,25 with this constitution are constituted with FET, the voltage of the power supplies 36,37 is set to required minimum voltage for the operation of Tr 24,25, and sufficient idling current is flowed to Tr 24,25,to suppress the heat dissipation. |
