Fast envelope system calibration
AssigneeRF Micro Devices, Inc.
InventorJean-Frederic Chiron
Life of this patent
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Abstract
Disclosed is a transceiver for an envelope following system that includes a power amplifier (PA) having a signal input, a signal output, and a power input that receives power from a power management system that modulates a supply voltage provided to the PA in response to an envelope signal. The transceiver includes a calibration subsystem that is adapted to provide a first test signal to the signal input of the PA and to provide a second test signal to the power management system in place of the envelope signal. The calibration subsystem is programmed with calibration methods that sweep the first test signal through a first range and to sweep the second test signal through a second range in order to derive values that make up a pseudo-envelope look-up table (LUT) that is usable by the transceiver.
Claims22
A transceiver for an envelope following system that includes a power amplifier (PA) having a signal input, a signal output, and a power input that receives power from a power management system that modulates a supply voltage provided to the PA in response to an envelope signal, the transceiver comprising:
- calibration circuitry adapted to provide a first test signal to the signal input of the PA and to provide a second test signal to the power management system in place of the envelope signal;
- and
- a calibration subsystem adapted to control the calibration circuitry to sweep the first test signal through a first range and to sweep the second test signal through a second range.
A method of calibrating a pseudo-envelope system having a transceiver with an in-phase/quadrature (I/Q) digital modulator and calibration circuitry that includes an I/Q multiplexer coupled to an in-phase (I) digital-to-analog converter (DAC) and a quadrature (Q) DAC, an envelope multiplexer coupled to an envelope DAC, and a calibration subsystem that is adapted to switch the I/Q multiplexer between a normal mode in which I/Q signals pass from the I/Q digital modulator to the I DAC and the Q DAC and an envelope signal passes from an envelope calculator and a calibration mode in which calibration signals pass from the calibration subsystem to the I DAC, the Q DAC and the envelope DAC in place of the I/Q signals and the envelope signal, comprising:
- switching the I/Q multiplexers and envelope multiplexer from the normal mode to the calibration mode;
- sweeping the calibration signals through predetermined ranges while measuring average power amplifier (PA) power and storing average PA power measurements in a data buffer;
- and
- switching the I/Q multiplexers and the envelope multiplexer from the normal mode to the calibration mode.
Dependencies are inferred from the claim text.