278results about "Supply voltage varying control" patented technology

An envelope tracking radio frequency (RF) power amplifier having an adaptive envelope signal processing circuit is disclosed. An RF input voltage is sampled by the adaptive envelope signal processing circuit which provides control signals to the power supply which supplies voltages to RF power devices in order to simultaneously satisfy two operating conditions: a) provide best possible efficiency of the power amplifier stages depending on the input signal characteristics and b) provide compensation for RF transistor AM-AM and AM-PM distortion compensation across the power range. In particular, the voltage control provides for constant power amplifier gain across the input signal dynamic range, thus minimizing power amplifier amplitude distortions and extending the useful power amplifier linear dynamic range up to saturation point. The power amplifier thus exhibits better linearity and efficiency than offered by conventional techniques and topologies.

The present invention, generally speaking, provides methods and apparatus for producing an amplitude modulated communications signal, in which a constant-envelope carrier signal is modified in response to a power control signal to produce a modified constant-envelope carrier signal. The modified constant-envelope carrier signal is amplified in response to an amplitude modulation signal to produce a communications signal having amplitude modulation and having an average output power proportional to a signal level of the modified constant-envelope carrier signal. This manner of operation allows wide dynamic range of average output power to be achieved. Because amplitude modulation is applied after amplitude varying circuitry used to produce the modified constant-envelope carrier signal, the amplitude modulation is unaffected by possible non-linearities of such circuitry. In accordance with another aspect of the invention, operation in the foregoing manner at comparatively low average output power levels is combined with switch mode operation at comparatively high average output power levels, enabling high overall efficiency to be achieved. Hence, the disclosed modulator and amplifier combination, in addition to supporting very low power signals, also supports high power signals.

A transmit power amplifier of a wireless terminal is controlled by determining a power supply voltage applied to the transmit power amplifier, determining a power supply current provided to the transmit power amplifier, determining a relationship of the determined power supply current and the determined power supply voltage, and controlling the power supply voltage responsive to the determined relationship of the power supply current and the power supply voltage. For example, determining a relationship of the determined power supply current and the determined power supply voltage may include determining whether the power supply current meets a predetermined criterion, e.g., a predetermined current range, associated with the determined power supply voltage. The invention may be embodied as apparatus, methods, and computer program products.

A power source circuit for a high frequency power amplifying circuit, that can be used for a portable telephone of the GSM or WCDMA and a portable telephone capable of performing communications in two or more communication systems such as the GSM and CDMA. The power source circuit is constructed by a first direct current power source circuit such as a series regulator whose power efficiency is not high but which reaches a high level quickly, and a second direct current power source circuit such as a switching regulator, which does not reach the high level quickly but whose power efficiency is high. When the power source voltage has to reach the high level at high speed, both of the series regulator and the switching regulator are simultaneously operated. When the output power source voltage reaches a predetermined level, the operation of the series regulator is stopped.

A fast tracking power supply device, a fast tracking power supply control method, and communication equipment are provided. The fast tracking power supply device includes: a basic voltage output unit, configured to output a basic voltage; a basic current unit, configured to output a basic current; a linear amplifier, configured to output a compensation current and a compensation voltage, the linear amplifier is connected in parallel with the basic current output unit, and then is connected in series with the basic voltage output unit. The device can output signal with high efficiency and bandwidth.

An energy-efficient consumer device audio power output stage provides improved battery life and reduced power dissipation. A power supply having a selectable operating mode supplies the power supply rails to the power amplified output stage. The operating mode is controlled in conformity with the audio signal level, which may be determined from a volume control setting of the device and / or from a signal level detector that determines the amplitude of the signal being amplified. The power supply may be a charge pump in which the operating mode uses a capacitive divider to provide for selection of a power supply output voltage that is a rational fraction of the power supply output voltage in a full-voltage operating mode.