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US 8,787,850 B2Granted
Compensating for non-linear capacitance effects in a power amplifier
AssigneeAvago Technologies General IP (Singapore) Pte. Ltd.
InventorsDavid E. Bockelman, Vishnu Srinivasan
Life of this patent
Estimating the term…
Abstract
In one implementation, a power amplifier may include a gain device to receive an input signal and to output an amplified signal, and a compensation device coupled to the gain device to compensate for a change in a capacitance of the gain device occurring due to a change in the input signal. The power amplifier may be formed using a complementary metal oxide semiconductor (CMOS) process.
Claims7
An apparatus comprising:
- a gain device to receive an input signal and to output an amplified signal;
- a compensation device coupled to the gain device to compensate for a change in a capacitance of the gain device occurring due to a change in the input signal;
- and
- a bias source coupled to the compensation device to cause a capacitance of the compensation device to change in an opposite direction to the capacitance change of the gain device, wherein the bias source is configured to align predetermined transition regions of the compensation device and the gain device.
1 more element
A wireless device comprising:
- a transceiver to receive baseband signal information from a baseband processor and to output a radio frequency (RF) signal;
- a power amplifier coupled to the transceiver to receive and amplify the RF signal, the power amplifier comprising a complementary metal oxide semiconductor (CMOS) gain stage having a non-linear phase response to the RE signal when a voltage of the RE signal is in a predetermined range, and a compensation circuit comprising:
- a variable capacitance element coupled to the CMOS gain stage to compensate for the non-linear phase response;
- and a bias generator to provide a bias voltage to the capacitance-coupled transistor to cause the capacitance-coupled transistor to have a first capacitance value when the RE signal causes the CMOS gain stage to have a second capacitance that is substantially equal and opposite to the first capacitance when the RF signal is substantially around a threshold voltage of at least one device of the CMOS gain stage, wherein the variable capacitance element comprises a capacitance-coupled transistor coupled to a transistor of the CMOS gain stage of opposite polarity;
- and
- an antenna coupled to the power amplifier to radiate the amplified RF signal.
3 more elements
Dependencies are inferred from the claim text.