Power level controlling of first amplification stage for an integrated RF power amplifier
First Claim
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1. A power amplifier circuit comprising:
- an input port for receiving a RF input signal;
an output port for providing therefrom a RF output signal, the RF output signal being an amplified version of the RF input signal;
a supply voltage input port for receiving a supply voltage;
a controllable current source having an input port for receiving a control signal and an output port for providing of a variable bias current therefrom, the variable bias current based upon the control signal;
a first amplification stage having a first variable gain and for receiving the RF input signal and for providing a first amplified RF signal, the first amplification stage coupled to the controllable current source for receiving the variable bias current therefrom and for having the first variable gain thereof varied in proportion to the variable bias current;
a second amplification stage having a second gain and coupled to the first amplification stage for receiving the first amplified RF signal and coupled to the output port for providing the output signal thereto; and
, a control circuit for generating the control signal for provision to the controllable current source, the control signal for being generated in dependence upon the supply voltage, where for the supply voltage having a first potential the variable bias current provided to the first amplification stage is smaller than for the supply voltage having a second potential that is lower than the first potential.
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Abstract
A power amplifier circuit is disclosed having a first amplification stage and a second amplification stage. The first amplification stage is biased using a controllable current source that provides a variable bias current thereto. A control circuit is provided for controlling the variable bias current in dependence upon the supply voltage and temperature of the power amplifier circuit. The control signal varies the variable bias current in dependence upon the supply voltage varying between first and second potential, where each potential supplies sufficient potential for operation of the power amplifier circuit.
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Citations
32 Claims
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1. A power amplifier circuit comprising:
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an input port for receiving a RF input signal;
an output port for providing therefrom a RF output signal, the RF output signal being an amplified version of the RF input signal;
a supply voltage input port for receiving a supply voltage;
a controllable current source having an input port for receiving a control signal and an output port for providing of a variable bias current therefrom, the variable bias current based upon the control signal;
a first amplification stage having a first variable gain and for receiving the RF input signal and for providing a first amplified RF signal, the first amplification stage coupled to the controllable current source for receiving the variable bias current therefrom and for having the first variable gain thereof varied in proportion to the variable bias current;
a second amplification stage having a second gain and coupled to the first amplification stage for receiving the first amplified RF signal and coupled to the output port for providing the output signal thereto; and
,a control circuit for generating the control signal for provision to the controllable current source, the control signal for being generated in dependence upon the supply voltage, where for the supply voltage having a first potential the variable bias current provided to the first amplification stage is smaller than for the supply voltage having a second potential that is lower than the first potential. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A circuit for biasing a power amplifier circuit comprising a first amplification stage and a second amplification stage, the circuit comprising:
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a current source comprising;
a current source input port for receiving a control signal, and an output port for providing a variable bias current in dependence upon the control signal; and
,a current source control circuit comprising;
a supply voltage input port for receiving of a supply voltage, a control signal output port coupled to the current source input port for providing of the control signal to the current source, and current control circuitry for sensing a potential of the supply voltage at the supply voltage input port and for generating the control signal, where the control signal is for resulting in an increasing variable bias current with a decreasing supply voltage sensed on the supply voltage input port which results in the second amplification stage to transition from a linear mode of operation to a saturation mode of operation. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of amplifying a RF input signal to form a RF output signal comprising the steps of:
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sensing of a supply voltage potential;
determining whether the sensed supply voltage potential is one of higher than a first predetermined potential, in between the first predetermined potential and a second predetermined potential and below the second predetermined potential;
amplifying the RF input signal with a first amplification stage having a first variable gain to form a first amplified signal, the first variable gain dependent upon the sensed supply voltage potential;
amplifying the first amplified signal with a second amplification stage having a second gain to form the RF output signal;
adjusting a bias current provided to the first amplification stage for varying the first variable gain in such a manner that at the first predetermined potential a lower bias current is provided to the first amplification stage than is provided to the first amplification stage at the second predetermined potential, the lower bias current for operating of the second amplification stage in a linear mode of operation and a higher bias current for operating of the second amplification stage in a saturation mode of operation. - View Dependent Claims (27, 28, 29, 30, 31, 32)
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Specification