| 摘要 |
PURPOSE:To realize a high-efficiency A-class amplifier in which the 1st step of the 2nd amplifier by using the 2nd amplifier which supplies the power for signal amplification as the vltage follower of gain 1 and then driving the voltage follower by the output difference of the 1st amplifier. CONSTITUTION:The 1st amplifier 1, which amplifies the input signal sent from terminal 5 and delivers it to terminal 40, receives the supply of the power at its output transistors 26 and 27 from power source 2 the middle point of which is floated with a comparatively low level of the voltage. Amplifier 1 features the conventional constitution excepting the fact that bias circuits 82 and 83 are incorporated to current sources 55 and 56 of 2nd amplifier 3. The power is supplied to amplifier 3 from power source 4 the middle point of which is earthed with a high level of voltage. Differential amplifiers 79 and 80 receive the output of amplifier 1 and drive output transistors 62 and 63 of amplifier 3 to vary the intermediate potential of source 2 of amplifier 1 in accordance with the output of amplifier 1. |
