POWER TRACKER FOR MULTIPLE TRANSMIT SIGNALS SENT SIMULTANEOUSLY
Techniques for generating a power tracking supply voltage for a circuit (e.g., a power amplifier) are disclosed. The circuit may process multiple transmit signals being sent simultaneously on multiple carriers at different frequencies. In one exemplary design, an apparatus includes a power tracker and a power supply generator. The power tracker determines a power tracking signal based on inphase (I) and quadrature (Q) components of a plurality of transmit signals being sent simultaneously. The power supply generator generates a power supply voltage based on the power tracking signal. The apparatus may further include a power amplifier (PA) that amplifies a modulated radio frequency (RF) signal based on the power supply voltage and provides an output RF signal.
1 . An apparatus comprising:
a power tracker configured to determine a power tracking signal based on inphase (I) and quadrature (Q) components of a plurality of transmit signals being sent simultaneously; and
a power supply generator configured to generate a power supply voltage based on the power tracking signal.
2 . The apparatus of claim 1 , wherein the power tracker is configured to:
determine an overall power of the plurality of transmit signals based on the I and Q components of the plurality of transmit signals, and
determine the power tracking signal based on the overall power of the plurality of transmit signals.
3 . The apparatus of claim 1 , wherein the power tracker is configured to:
determine a power of each transmit signal in the plurality of transmit signals based on I and Q components of the transmit signal, and
determine the power tracking signal based on powers of the plurality of transmit signals.
4 . The apparatus of claim 1 , wherein the power tracker is configured to:
determine a power of each transmit signal in the plurality of transmit signals based on I and Q components of the transmit signal,
determine a voltage of each transmit signal based on the power of the transmit signal, and
determine the power tracking signal based on voltages of the plurality of transmit signals.
5 . The apparatus of claim 1 , further comprising:
a power amplifier (PA) configured to amplify a modulated radio frequency (RF) signal based on the power supply voltage and provide an output RF signal.
6 . The apparatus of claim 5 , further comprising:
a plurality of transmit circuits configured to receive the I and Q components of the plurality of transmit signals and provide a plurality of upconverted RF signals, each transmit circuit configured to upconvert I and Q components of one of the plurality of transmit signals and provide a corresponding upconverted RF signal, and
a summer configured to sum the plurality of upconverted RF signals and provide the modulated RF signal.
7 . The apparatus of claim 5 , further comprising:
a transmit circuit configured to receive a modulated intermediate frequency (IF) signal for the plurality of transmit signals and provide the modulated RF signal, the modulated IF signal being generated based on the I and Q components of the plurality of transmit signals.
8 . The apparatus of claim 1 , the power supply generator comprising:
a power tracking amplifier configured to receive the power tracking signal and generate the power supply voltage.
9 . The apparatus of claim 8 , the power supply generator further comprising:
a switcher configured to sense a first current from the power tracking amplifier and provide a second current for the power supply voltage based on the sensed first current.
10 . The apparatus of claim 8 , the power supply generator further comprising:
a boost converter configured to receive a battery voltage and provide a boosted voltage for the power tracking amplifier.
11 . The apparatus of claim 10 , wherein the power tracking amplifier operates based on the boosted voltage or the battery voltage.
12 . The apparatus of claim 1 , wherein the plurality of transmit signals are sent on a plurality of carriers at different frequencies.
13 . The apparatus of claim 12 , wherein the power tracking signal has a bandwidth that is smaller than an overall bandwidth of the plurality of carriers.
14 . A method comprising:
determining a power tracking signal based on inphase (I) and quadrature (Q) components of a plurality of transmit signals being sent simultaneously; and
generating a power supply voltage based on the power tracking signal.
15 . The method of claim 14 , wherein the determining the power tracking signal comprises
determining an overall power of the plurality of transmit signals based on the I and Q components of the plurality of transmit signals, and
determining the power tracking signal based on the overall power of the plurality of transmit signals.
16 . The method of claim 14 , wherein the determining the power tracking signal comprises
determining a power of each transmit signal in the plurality of transmit signals based on I and Q components of the transmit signal, and
determining the power tracking signal based on powers of the plurality of transmit signals.
17 . The method of claim 14 , further comprising:
generating a modulated radio frequency (RF) signal based on the I and Q components of the plurality of transmit signals; and
amplifying the modulated RF signal with a power amplifier (PA) operating based on the power supply voltage to obtain an output RF signal.
18 . The method of claim 17 , wherein the generating the modulated RF signal comprises
upconverting I and Q components of each of the plurality of transmit signals to obtain a corresponding upconverted RF signal, and
summing a plurality of upconverted RF signals for the plurality of transmit signals to obtain the modulated RF signal.
19 . An apparatus comprising:
means for determining a power tracking signal based on inphase (I) and quadrature (Q) components of a plurality of transmit signals being sent simultaneously; and
means for generating a power supply voltage based on the power tracking signal.
20 . The apparatus of claim 19 , wherein the means for determining the power tracking signal comprises
means for determining an overall power of the plurality of transmit signals based on the I and Q components of the plurality of transmit signals, and
means for determining the power tracking signal based on the overall power of the plurality of transmit signals.
21 . The apparatus of claim 19 , wherein the means for determining the power tracking signal comprises
means for determining a power of each transmit signal in the plurality of transmit signals based on I and Q components of the transmit signal, and
means for determining the power tracking signal based on powers of the plurality of transmit signals.
22 . The apparatus of claim 19 , further comprising:
means for generating a modulated radio frequency (RF) signal based on the I and Q components of the plurality of transmit signals; and
means for amplifying the modulated RF signal using the power supply voltage to obtain an output RF signal.
23 . The apparatus of claim 22 , wherein the means for generating the modulated RF signal comprises
means for upconverting I and Q components of each of the plurality of transmit signals to obtain a corresponding upconverted RF signal, and
means for summing a plurality of upconverted RF signals for the plurality of transmit signals to obtain the modulated RF signal.
24 . A computer program product, comprising:
a non-transitory computer-readable medium comprising:
code for causing at least one computer to direct determination of a power tracking signal based on inphase (I) and quadrature (Q) components of a plurality of transmit signals being sent simultaneously; and
code for causing the at least one computer to direct generation of a power supply voltage based on the power tracking signal.