Low bias current/temperature compensation current mirror for linear power amplifier
AssigneeAnadigics, Inc.
InventorsOsvaldo Jorge Lopez, Robert Bayruns, Mahendra Singh
Life of this patent
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Abstract
A power amplifier circuit whose performance is optimized by operating its stages in substantially close to a Class B mode by reducing quiescent current during low driver signal levels. As the driver signal amplitude increases, the operation of the amplifier is configured to dynamically adjust to be in a Class AB mode, thereby increasing the power efficiency of the overall circuit at kiw drive levels. A further enhancement to the power amplifier circuit includes a temperature compensation circuit to adjust the bias of the amplifier so as to stabilize the performance in a wide temperature range.
Claims16
A dynamic bias adjustor, comprising:
- a signal detector for determining the drive level of an amplifying device, and
- a bias output circuit connected to said signal detector and configured to operate the amplifying device in a Class B mode or substantially close to a Class B mode during low drive level conditions, and in a Class AB mode during high drive level conditions.
A method of designing an efficiently biased amplifying circuit comprising a pre-amplifier stage, a driver stage and an output stage, the method comprising the steps of:
- providing a dynamic bias adjuster for detecting an alternating current voltage and generating a direct current output voltage having a value proportional to the alternating current voltage peak level;
- connecting the dynamic bias adjuster to the driver output voltage;
- and
- connecting the output voltage of the dynamic bias adjustor to bias the stages of the amplifying circuit whereby at least one of the stages of the amplifying circuit operates in a Class B mode or substantially close to a Class B when the driver output is at or below a predetermined level.
A method of implementing a biasing scheme for an amplifying device, comprising the steps of:
- monitoring a signal level at an output of the amplifying device;
- producing a first signal proportional to the signal level;
- and
- dynamically biasing, as a function of the first signal, the amplifying device to operate in a Class B mode or substantially close to a Class B mode when the signal level is low, and in a Class AB mode when the signal is high.
Dependencies are inferred from the claim text.