Abstract: The present disclosure generally relates to techniques and apparatus for implementing an envelope-tracking power supply for a radio frequency (RF) power amplifier. One aspect includes an amplification system. The amplification system may include a first amplifier configured to generate an amplifier output voltage, a second amplifier having an output coupled to a supply node for the first amplifier, a voltage regulator having an output coupled to a supply node for the second amplifier, and control circuitry configured to control the voltage regulator to generate a supply voltage at the supply node for the second amplifier based on an indication associated with the amplifier output voltage. In some aspects, the control circuitry may be configured to control the voltage regulator through at least providing an updated control setting for the voltage regulator with a periodicity associated with a power control period.

Abstract: There is disclosed an envelope tracking amplification stage comprising an input path and an envelope path and a delay stage in one of the input path and the envelope path, the delay of the delay stage being determined in dependence on the slope polarity of a signal representing the input and whether the signal in the input path leads or lags the signal in the envelope path.

Abstract: The invention relates to a technique for controlling in an envelope tracking amplification stage, comprising: determining a representation of the output signal of the amplifier; determining a representation of the input signal of the amplifier; adjusting the determined representation of the input signal according to a target characteristic of the amplifier; comparing the adjusted input and determined representation of the output; and generating a control signal in dependence on the comparison.

Abstract: Embodiments related to the setting of an operating point of an amplifier are described and depicted.

Abstract: The invention relates to a technique for controlling in an envelope tracking amplification stage, comprising: determining a representation of the output signal of the amplifier; determining a representation of the input signal of the amplifier; adjusting the determined representation of the input signal according to a target characteristic of the amplifier; comparing the adjusted input and determined representation of the output; and generating a control signal in dependence on the comparison.

Abstract: There is disclosed an envelope tracking amplification stage comprising an input path and an envelope path and a delay stage in one of the input path and the envelope path, the delay of the delay stage being determined in dependence on the slope polarity of a signal representing the input and whether the signal in the input path leads or lags the signal in the envelope path.

Abstract: A method of calibrating a polar amplification stage including a main signal path and a magnitude signal path, the method comprising: generating signals (108, 142) for the main signal path and the magnitude signal path for operating an amplifier (102) between a linear mode of operation and a saturated mode of operation; detecting (114) first and second peaks in a signal at the output of the amplifier (102) representing transitions between the linear and saturated modes of operation; and adjusting (124) the timing in one of the main signal path and the amplitude signal path in dependence on a relative difference between the size of the detected first and second peaks.

Abstract: A method of calibrating a polar amplification stage including a main signal path and a magnitude signal path, the method comprising: generating signals (108, 142) for the main signal path and the magnitude signal path for operating an amplifier (102) between a linear mode of operation and a saturated mode of operation; detecting (114) first and second peaks in a signal at the output of the amplifier (102) representing transitions between the linear and saturated modes of operation; and adjusting (124) the timing in one of the main signal path and the amplitude signal path in dependence on a relative difference between the size of the detected first and second peaks.