Protection circuit for power amplifier
First Claim
1. An apparatus comprising:
- a power amplifier (PA) module to receive an input radio frequency (RFin) signal and provide an output RF (RFout) signal; and
a protection circuit coupled to the PA module and to control a transmitter gain to protect the PA module against high peak voltage of the RFout signal, the protection circuit comprises a plurality of comparators to receive an analog input signal obtained based on the RFout signal, to quantize the analog input signal, and to provide a plurality of digital comparator output signals used to adjust the transmitter gain, the protection circuit further comprises a control circuit to generate at least one control signal with hysteresis based on the plurality of comparator output signals, the at least one control signal is used to adjust the transmitter gain and the protection circuit has faster response to rising amplitude than falling amplitude of the RFout signal based on combinations of a plurality of comparator output signals resulting from a plurality of reference signals compared to the RFout signal.
1 Assignment
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Accused Products
Abstract
Techniques for protecting a power amplifier (PA) are described. In an exemplary design, an apparatus includes (i) a PA module to amplify an input RF signal and provide an output RF signal and (ii) a protection circuit to control a transmitter gain to protect the PA module against high peak voltage. In an exemplary design, the protection circuit includes a set of comparators to quantize an analog input signal and provide digital comparator output signals used to adjust the transmitter gain. In another exemplary design, the protection circuit reduces and increases the transmitter gain with hysteresis. In yet another exemplary design, the protection circuit has faster response to rising amplitude than falling amplitude of the output RF signal. The hysteresis and/or the different rise and fall responses may allow the protection circuit to avoid toggling the transmitter gain under severe load mismatch and to handle time-varying envelope due to amplitude modulation.
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Citations
27 Claims
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1. An apparatus comprising:
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a power amplifier (PA) module to receive an input radio frequency (RFin) signal and provide an output RF (RFout) signal; and a protection circuit coupled to the PA module and to control a transmitter gain to protect the PA module against high peak voltage of the RFout signal, the protection circuit comprises a plurality of comparators to receive an analog input signal obtained based on the RFout signal, to quantize the analog input signal, and to provide a plurality of digital comparator output signals used to adjust the transmitter gain, the protection circuit further comprises a control circuit to generate at least one control signal with hysteresis based on the plurality of comparator output signals, the at least one control signal is used to adjust the transmitter gain and the protection circuit has faster response to rising amplitude than falling amplitude of the RFout signal based on combinations of a plurality of comparator output signals resulting from a plurality of reference signals compared to the RFout signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus comprising:
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a power amplifier (PA) module to receive an input radio frequency (RFin) signal and provide an output RF (RFout) signal; and a protection circuit coupled to the PA module and to control a transmitter gain to protect the PA module against high peak voltage of the RFout signal, the protection circuit configured to reduce the transmitter gain when amplitude of the RFout signal exceeds a high threshold and increase the transmitter gain when the amplitude of the RFout signal falls below a low threshold, the low threshold is below the high threshold to provide hysteresis and the protection circuit has faster response to rising amplitude than falling amplitude of the RFout signal based on combinations of a plurality of comparator output signals resulting from a plurality of reference signals compared to the RFout signal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. An apparatus comprising:
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a power amplifier (PA) module to receive an input radio frequency (RFin) signal and provide an output RF (RFout) signal; and a protection circuit coupled to the PA module and to control a transmitter gain to protect the PA module against high peak voltage of the RFout signal, the protection circuit has faster response to rising amplitude than falling amplitude of the RFout signal based on combinations of a plurality of comparator output signals resulting from a plurality of reference signals compared to the RFout signal. - View Dependent Claims (18, 19, 20, 21)
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22. A method of protecting a power amplifier (PA) module, comprising:
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amplifying an input radio frequency (RFin) signal with the PA module to obtain an output RF (RFout) signal; and controlling a transmitter gain to protect the PA module against high peak voltage of the RFout signal, the transmitter gain is decreased and increased with hysteresis, and is adjusted based on faster response to rising amplitude than falling amplitude of the RFout signal based on combinations of a plurality of comparator output signals resulting from a plurality of reference signals compared to the RFout signal. - View Dependent Claims (23, 24, 25, 26)
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27. An apparatus comprising:
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means for amplifying an input radio frequency (RFin) signal to obtain an output RF (RFout) signal; and means for controlling a transmitter gain to protect the means for amplifying against high peak voltage of the RFout signal, the transmitter gain is decreased and increased with hysteresis and is adjusted based on faster response to rising amplitude than falling amplitude of the RFout signal based on combinations of a plurality of comparator output signals resulting from a plurality of reference signals compared to the RFout signal.
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Specification