Doherty amplifier using adaptive bias control
First Claim
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1. A Doherty amplifier comprising:
- a coupler for splitting an input signal;
an envelope detector for detecting an envelop voltage from one part of the input signal;
a plurality of envelope shaping circuits for transforming the envelope voltage of the input signal; and
a plurality of amplifiers for amplifying the other part of the input signal under control of the transformed envelope voltage provided from the envelope shaping circuits.
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Abstract
An amplifier circuit using an adaptive bias control comprises an envelope detector for detecting an envelope of an input signal from a coupler, envelope shaping circuits for transforming of the envelope voltage from the envelope detector. The one transformed envelope voltage is applied to a drain bias for the peaking amplifier and the other is add by VDC to be applied to a gate bias for the carrier amplifier. In the Doherty amplifier, the gate voltage of the peaking amplifier and the drain voltage of the peaking amplifier are controlled in accordance with the input signal envelope to maximize efficiency with a desired linearity.
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Citations
10 Claims
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1. A Doherty amplifier comprising:
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a coupler for splitting an input signal;
an envelope detector for detecting an envelop voltage from one part of the input signal;
a plurality of envelope shaping circuits for transforming the envelope voltage of the input signal; and
a plurality of amplifiers for amplifying the other part of the input signal under control of the transformed envelope voltage provided from the envelope shaping circuits. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A Doherty amplifier using an adaptive bias control, comprising:
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a coupler for splitting an input signal;
a delay line for transferring one part of the input signal;
an envelope detector for detecting envelope voltage as an envelope signal from the other part of the input signal;
a first envelope shaping circuit for transforming the envelope signal from the envelope detector and applying the transformed envelope signal as a gate control bias voltage to a corresponding amplifier;
a second envelope shaping circuit for transforming of the envelope signal from the envelope detector and applying a drain control bias voltage to corresponding amplifier, the drain control bias voltage is the transformed envelope signal and VDC;
a carrier amplifier for amplifying the other part of the input signal, the carrier amplifier being controlled by the drain bias voltage from the second envelope shaping circuit;
a peaking amplifier for amplifying the other part of the input signal, the peaking amplifier being controlled by the gate bias voltage from the first envelope shaping circuit;
an input matching network disposed between the delay line and the carrier and peaking amplifiers for input impedance matching; and
an output matching network coupled to the outputs of the carrier and peaking amplifiers so as to combine the outputs of the amplifiers.
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Specification