Radio frequency envelope apparatus and method
First Claim
1. Envelope tracking apparatus for use in an RF transmitter and/or receiver circuit, comprising:
- an input node;
a first transistor device having a control terminal in electrical communication with said input node;
a resistor disposed electrically between said input node and said control terminal of said first transistor;
a second transistor device in electrical communication with said first device, the first and second transistor devices each having a conduction terminal coupled to a conduction terminal of the other of the first and second transistor devices;
a third transistor device in electrical communication with said first device;
a fourth transistor device having a control terminal in electrical communication with said first transistor device and said third transistor device, a conduction terminal of said fourth device being in electrical communication with a control terminal of said second device and an output node;
wherein when a first voltage applied to the input node is lower than a second voltage at said output node, said third and fourth transistor devices cooperate to lower said second voltage, said lowered second voltage substantially tracking said first voltage.
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Abstract
Improved radio frequency (RF) envelope tracking apparatus for use in wireless and wired systems. In one exemplary embodiment, a transmitter upconversion stage receives input digital I and Q values, the output of the upconversion stage being fed to both an envelope tracking circuit and a power amplifier (before or after optional filtering). The envelope tracking circuit controls the operation of a power modulator, which adjusts the power amplifier. The envelope tracking circuit is specifically configured to provide improved linearity and power efficiency. The envelope tracking apparatus and methods of the present invention may be applied to heterodyne/super-heterodyne architectures as well as others.
31 Citations
23 Claims
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1. Envelope tracking apparatus for use in an RF transmitter and/or receiver circuit, comprising:
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an input node; a first transistor device having a control terminal in electrical communication with said input node; a resistor disposed electrically between said input node and said control terminal of said first transistor; a second transistor device in electrical communication with said first device, the first and second transistor devices each having a conduction terminal coupled to a conduction terminal of the other of the first and second transistor devices; a third transistor device in electrical communication with said first device; a fourth transistor device having a control terminal in electrical communication with said first transistor device and said third transistor device, a conduction terminal of said fourth device being in electrical communication with a control terminal of said second device and an output node; wherein when a first voltage applied to the input node is lower than a second voltage at said output node, said third and fourth transistor devices cooperate to lower said second voltage, said lowered second voltage substantially tracking said first voltage. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An envelope tracking circuit for use in an RF circuit, comprising:
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an input node; a first transistor electrically coupled to said input node; an output node; a second transistor electrically coupled to said output node and said first transistor; and first and second current sources, said first current source coupled to said first and second transistors, said second current source coupled to said output node; wherein said first and second current sources substantially control the tracking by an output waveform envelope generated at said output node of an input waveform envelope applied to said input node. - View Dependent Claims (8, 9, 10, 11)
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12. Envelope tracking apparatus for use in at least one of an RF transmitter or receiver circuit, comprising:
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an input node; a first transistor device having a control terminal coupled to said input node; an output node; a second transistor device coupled to said first transistor device, said second transistor device having a control terminal coupled to said output node; and a third transistor device coupled to said output node and said control terminal of said second transistor device; wherein said first, second and third transistor devices cooperate to substantially track the signal at said output node to the signal applied to said input node. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. An envelope tracking circuit for use in an RF circuit, comprising:
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an input node; a first transistor electrically coupled to said input node; an output node; a second transistor electrically coupled to said output node and said first transistor; and first and second current sources, said first current source coupled to said first and second transistors, said second current source coupled to said output node; wherein said first and second current sources are utilized in controlling the tracking by an output waveform envelope generated at said output node of an input waveform envelope applied to said input node; and wherein currents provided by said first and second current sources are controlled substantially according to a plurality of control parameters. - View Dependent Claims (22)
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23. Envelope tracking apparatus for use in an RF communication device, comprising:
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an input node; a first switching means in electrical communication with said input node; an output node; a second switching means in electrical communication with said first device, said second device in electrical communication with said second node; and a third switching means in electrical communication with said output node and said second device; wherein said first, second and third switching means cooperate to substantially match the voltage generated at said output node to the voltage applied to said input node.
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Specification