RF amplifier with current mirror bias-boosting
AssigneeKoninklijke Philips Electronics N.V.
InventorsSifen Luo, Tirdad Sowlati
Life of this patent
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Abstract
An amplifier circuit comprises an input stage and an output stage. The input stage is biased by means of a circuit, such as a current mirror, that senses the input signal level. As the input signal increases the average current of the sensing circuit also increases. This current is fed forward to the output stage to boost its bias. The bias boosting is thus proportional to the input signal. One of the advantages of the bias scheme presented is that it allows amplifiers to be biased with a lower quiescent current without being pushed into saturation at higher output power levels.
Claims20
A method for improving the performance of an amplifier circuit comprising:
- sensing the current in the input stage;
- feeding said current to the output stage bias circuit to boost the output bias.
A transistor circuit, comprising:
- an input stage;
- an output stage with a biasing circuit;
- and
- a current mirror, which senses the input signal current and
- feeds it to the output stage biasing circuit.
A method of adaptively boosting the bias of an amplifier circuit, comprising:
- sensing the input signal;
- and
- boosting the output stage bias with a current equal or proportional to the input signal.
A subcircuit, to be used in an amplification circuit, comprising:
- an input sensor, arranged to sense the input signal to the circuit;
- and
- an output stage booster, arranged to boost the bias of an output stage of the circuit in proportion to said input signal.
Dependencies are inferred from the claim text.