摘要 |
A push pull amplifier is disclosed having upper and lower output devices operating in a mode in which the devices drive a load alternately. The amplifier includes bias means for providing a bias current to the output devices at all times. The bias means is incorporated in a feedback loop and is arranged such that transitions from load current to minimum bias current in the upper and lower output devices are sufficiently gradual so that harmonic frequencies generated by the transitions are within the capability of the amplifier under all signal conditions. The feedback loop includes a non-linear transform circuit for each upper and lower output device to prevent the bias current reducing to zero. The feedback loop also includes a linearity control circuit for controlling the harmonic frequencies in the upper and lower output devices.
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