Method and apparatus for protecting devices in an RF power amplifier
First Claim
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1. A circuit for protecting devices in an RF power amplifier comprising:
- a power detector coupled to the output of the RF power amplifier for detecting the output power of the RF power amplifier;
a peak detector coupled to one or more critical nodes in the RF power amplifier for detecting peak voltages at the one or more critical nodes, wherein the peak detector further comprises a first peak detector having an input coupled to the one or more critical nodes in the RF power amplifier, and a second peak detector having an input coupled to a reference tone;
a divider circuit coupled between the peak detector and the one or more critical nodes; and
power control circuitry coupled to the power detector and to the peak detector for controlling the output power of the power amplifier, wherein the power control circuitry protects devices in the RF power amplifier by decreasing the gain of the power amplifier when the peak detector detects a voltage above a voltage threshold at the one or more critical nodes in the RF power amplifier.
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Abstract
A method and apparatus are provided for use with a power amplifier for protecting active devices on the power amplifier. A peak detector is used by control circuitry to detect the presence of a peak voltage that exceeds a threshold voltage. In response to the detection of a peak voltage, the gain of the power amplifier is reduced.
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Citations
23 Claims
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1. A circuit for protecting devices in an RF power amplifier comprising:
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a power detector coupled to the output of the RF power amplifier for detecting the output power of the RF power amplifier; a peak detector coupled to one or more critical nodes in the RF power amplifier for detecting peak voltages at the one or more critical nodes, wherein the peak detector further comprises a first peak detector having an input coupled to the one or more critical nodes in the RF power amplifier, and a second peak detector having an input coupled to a reference tone; a divider circuit coupled between the peak detector and the one or more critical nodes; and power control circuitry coupled to the power detector and to the peak detector for controlling the output power of the power amplifier, wherein the power control circuitry protects devices in the RF power amplifier by decreasing the gain of the power amplifier when the peak detector detects a voltage above a voltage threshold at the one or more critical nodes in the RF power amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A circuit comprising:
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an RF power amplifier having an input and an output; a power detector coupled to the output of the RF power amplifier for detecting the output power of the RF power amplifier; a peak detector coupled to the power amplifier for detecting a peak voltage at a node of the power amplifier, wherein the node is a node other than the output of the power amplifier, wherein the peak detector is comprised of first and second matched peak detectors; and power control circuitry coupled to the peak detector and to the power amplifier for controlling the gain of the power amplifier, wherein the power control circuitry limits the power at the output of the power amplifier when the peak detector detects a peak voltage greater than a threshold voltage. - View Dependent Claims (14, 15, 16, 17)
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18. A circuit for protecting devices in an RF power amplifier comprising:
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a power detector coupled to the output of the RF power amplifier for detecting the output power of the RF power amplifier; a peak detector coupled to one or more critical nodes in the RF power amplifier for detecting peak voltages at the one or more critical nodes, wherein the peak detector further comprises a first peak detector having an input coupled to the one or more critical nodes in the RF power amplifier, and a second peak detector having an input coupled to a reference tone; and power control circuitry coupled to the power detector and to the peak detector for controlling the output power of the power amplifier, wherein the power control circuitry protects devices in the RF power amplifier by decreasing the gain of the power amplifier when the peak detector detects a voltage above a voltage threshold at the one or more critical nodes in the RF power amplifier. - View Dependent Claims (19, 20, 21, 22, 23)
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Specification