| 摘要 |
PURPOSE:To reduce the power consumption to ensure a higher efficiency, by providing a capacitor which is charged for a certain period and when the absolute value of voltage between both ends of the conductive channel of an amplifying element becomes less than a prescribed value and supplying the power to the amplifying element by the charging voltage of the capacitor. CONSTITUTION:An input signal IN is amplified by a voltage amplifying stage 2 and applied to the bases of transistors (TR) Q1 and Q2' that perform the B-class working of an output stage to receive an amplification of electric power. The power supplying capacitors C and C' are provided to the collectors of TRs Q1 and Q2', respectively, and at the same time switching circuits 3 and 3' are installed between the collectors and circuit power source +VCC and -VCC. The voltage between both ends of a conductive channel between the collector and the emitter of the TRs Q1 and Q2' is detected by comparators 4 and 4'. When this detection output becomes less than a prescribed value, the control signal generating circuits 5 and 5' generate the switch control signals for a certain period. The circuits 3 and 3' are controlled by the circuits 5 and 5'. |
