| 摘要 |
The invention relates to an analog power amplifier (PA), particularly for a closed loop signal amplification requiring high output power, high efficiency, extremely high speed, wide operating temperature range and a low number of components. No thermal compensation, no transistor matching and no adjustments are necessary. Any power transistor switching is eliminated including a high efficiency operation with a multiple level power supply. The input signal of the PA is initially amplified in an input amplifier means which provides a pair of output signals. These signals are separately applied to the bases of a first and third transistors of even conductivity types. The emitter of the first transistor is coupled to the emitter of a second transistor of an opposite conductivity type. The collector, base and emitter respectively of the first, second and third transistors are separately coupled to voltage sources. A fourth transistor coupled in series with the emitter of the third transistor can be employed. The collectors of the second and third transistors have collectors coupled to the output of the PA for providing an output signal thereof.
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