Power distribution and biasing in RF switch-mode power amplifiers
View Patent ↗Methods of and apparatus for distributing power and biasing RF PAs. A power distribution network includes a pre-final amplifier stage power distribution network and a final amplifier stage power distribution network. The pre-final amplifier stage power distribution network includes one or more pre-final amplifier stage power distribution branches, which may be configured to distribute power from one or more pre-final amplifier power supplies to one or more pre-final amplifier stages. Each pre-final amplifier stage power distribution branch comprises a π C-R-C network coupled to an inductive load. A final amplifier stage power distribution network is configured to distribute power from a final amplifier stage power supply to a final stage of the amplifier circuit.
1. A power distribution network for an RF power amplifier, comprising:
a first power distribution branch for distributing a power supply voltage to an input stage of a multistage amplifier circuit of an RF power amplifier; and
a second power distribution branch for distributing said power supply voltage to an output stage of said amplifier circuit,
wherein said first power distribution branch comprises:
a first resistor having a first end configured to receive said power supply voltage,
a first inductor having a first end coupled to said first amplifier stage and a second end coupled to a second end of said first resistor,
a first capacitor having a first end configured to receive said power supply voltage and a second end coupled to ground, and
a second capacitor having a first end coupled to the second end of said first resistor and a second end coupled to ground, and
wherein said second power distribution branch comprises:
a second resistor having a first end configured to receive said power supply voltage,
a second inductor having a first end coupled to said second amplifier stage and a second end coupled to a second end of said second resistor,
a third capacitor having a first end configured to receive said power supply voltage and a second end coupled to ground, and
a fourth capacitor having a first end coupled to the second end of said second resistor and a second end coupled to ground.
2. The power distribution network of claim 1 , further comprising an intermediate stage power distribution branch for distributing the first power supply voltage to an intermediate amplifier stage of said amplifier circuit, said intermediate amplifier stage coupled between the input and output stages of said multistage amplifier circuit.
3. A method of distributing power to a multi-stage amplifier, comprising:
through a first power distribution branch, distributing a first power supply voltage to a first amplifier stage of a multi-stage amplifier circuit; and
through a second power distribution branch, distributing a second power supply voltage to a second amplifier stage of said multi-stage amplifier circuit,
wherein said first power distribution branch includes a π C-R-C circuit that is unique to the first power distribution branch.
4. The method of claim 3 , further comprising receiving a phase modulated RF signal at an input of the first amplifier stage.
5. The method of claim 4 wherein the phase modulated RF signal has a constant magnitude.
6. The method of claim 3 wherein said first or second power supply voltages has a variable magnitude.
7. The method of claim 4 wherein said first or second power supply voltages has a variable magnitude.