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US 2015/0145596 A1Published application
Adaptive biasing scheme for an amplifier
AssigneeNujira Limited
InventorRussell Fagg
Life of this patent
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Abstract
There is provided a bias arrangement for an amplifier adapted to amplify a varying input signal, the arrangement comprising a control circuit arranged to adaptively vary a bias current to the amplifier in dependence on an envelope of the varying input signal.
Claims13
A bias arrangement for an amplifier adapted to amplify a varying input signal, the arrangement comprising:
- a current source configured to generate a bias current;
- and
- a control circuit configured to adaptively vary the bias current to the amplifier in dependence on an envelope of the varying input signal, the control circuit including a peak detection circuit configured to track the envelope of the varying input signal and to provide an output, which is proportional to the instantaneous magnitude of the varying input signal, for controlling the variation of the bias current.
A bias arrangement for a transconductance amplifier arranged to amplify a varying input signal, the arrangement comprising:
- a peak detection circuit configured to track the envelope of an input signal for the transconductance amplifier and to provide an output which is proportional to the instantaneous magnitude of the input signal;
- and
- a bias modulation circuit responsive to the peak detection circuit and arranged to modulate a bias current to the transconductance amplifier in accordance with the envelope of the input signal.
A method of providing a bias current to an amplifier arranged to amplify a varying input signal, the method comprising:
- (a) varying the bias current in dependence on the envelope of the varying input signal by tracking the envelope of the varying input signal;
- and
- (b) providing an output which is proportional to the instantaneous magnitude of the varying input signal for controlling the variation of the bias current.
Dependencies are inferred from the claim text.