Matching network for load line change
AssigneeMedia Tek Inc.
InventorsKENG LEONG FONG, WEI-KAI HONG, MING CHUNG LIU
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Abstract
An amplifier circuit that includes a first power amplifier configured to drive a load and a second power amplifier configured to drive the load through an impedance step-up network. The impedance step-up network is connected to an output of the second power amplifier. The impedance step-up network is configured to switch into a first mode to present an increased impedance to the first power amplifier, and switch into a second mode in which the impedance step-up network steps-up an impedance seen by the second power amplifier looking into the impedance step-up network.
Claims25
An amplifier circuit, comprising:
- a first power amplifier configured to drive a load;
- a second power amplifier configured to drive the load through an impedance step-up network;
- and
- the impedance step-up network, wherein the impedance step-up network is connected to an output of the second power amplifier, the impedance step-up network being configured to:
- i) switch into a first mode to present an increased impedance to the first power amplifier;
- and
- ii) switch into a second mode in which the impedance step-up network steps up an impedance seen by the second power amplifier looking into the impedance step-up network.
An impedance step-up network for a power amplifier, comprising:
- an inductor and a first capacitor that step up the impedance seen at an output of the power amplifier looking into the impedance step-up network;
- a second capacitor configured to be selectively connected in parallel with the inductor;
- and
- a switch in series with the second capacitor, wherein the switch is turned off when the power amplifier drives a load and turned on when the power amplifier does not drive the load.
A method of operating an amplifier circuit that includes a first power amplifier configured to drive a load and a second power amplifier configured to drive the load through an impedance step-up network connected to an output of the second power amplifier, the method comprising:
- switching the impedance step-up network into a first mode to present an increased impedance to the first power amplifier;
- and
- switching the impedance step-up network into a second mode in which the impedance step-up network steps -up an impedance seen by the second power amplifier looking into the impedance step-up network.
Dependencies are inferred from the claim text.