Power amplifier saturation detection
First Claim
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1. A saturation detection circuit comprising:
- a first averaging filter configured to receive a negative voltage excursion from a power amplifier;
a comparator in electrical communication with the first averaging filter and configured to generate a saturation detection signal based at least in part on an output of the first averaging filter;
a first switch configured to electrically connect the output of the first averaging filter to a first input of the comparator; and
a second switch configured to electrically connect an output of a second averaging filter to a second input of the comparator when a first band-select signal is received, the output of the second averaging filter serving as a comparator reference voltage when the first band-select signal is received.
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Abstract
In a portable radio transceiver, a power amplifier system includes a saturation detector that detects power amplifier saturation in response to duty cycle of the amplifier transistor collector voltage waveform. The saturation detection output signal can be used by a power control circuit to back off or reduce the amplification level of the power amplifier to avoid power amplifier control loop saturation.
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Citations
20 Claims
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1. A saturation detection circuit comprising:
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a first averaging filter configured to receive a negative voltage excursion from a power amplifier; a comparator in electrical communication with the first averaging filter and configured to generate a saturation detection signal based at least in part on an output of the first averaging filter; a first switch configured to electrically connect the output of the first averaging filter to a first input of the comparator; and a second switch configured to electrically connect an output of a second averaging filter to a second input of the comparator when a first band-select signal is received, the output of the second averaging filter serving as a comparator reference voltage when the first band-select signal is received. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A saturation detection system comprising:
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a first integrated circuit chip including a power amplifier; and a second integrated circuit chip including a saturation detection circuit, the saturation detection circuit including a first averaging filter configured to receive a negative voltage excursion from a power amplifier, a comparator in electrical communication with the first averaging filter and configured to generate a saturation detection signal based at least in part on an output of the first averaging filter, a first switch configured to electrically connect the output of the first averaging filter to a first input of the comparator, and a second switch configured to electrically connect an output of a second averaging filter to a second input of the comparator when a first band-select signal is received, the output of the second averaging filter serving as a comparator reference voltage when the first band-select signal is received. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A wireless device comprising:
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a baseband subsystem configured to generate a band-select signal; and a saturation detection system including a first integrated circuit chip and a second integrated circuit chip, the first integrated circuit chip including a power amplifier that is configured based on the band-select signal, and the second integrated circuit chip including a saturation detection circuit, the saturation detection circuit including a first averaging filter configured to receive a negative voltage excursion from a power amplifier, a comparator in electrical communication with the first averaging filter and configured to generate a saturation detection signal based at least in part on an output of the first averaging filter, a first switch configured to electrically connect the output of the first averaging filter to a first input of the comparator, and a second switch configured to electrically connect an output of a second averaging filter to a second input of the comparator when a first band-select signal is received, the output of the second averaging filter serving as a comparator reference voltage when the first band-select signal is received. - View Dependent Claims (19, 20)
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Specification