CN206099910U - Circuit Structure of Envelope Tracking RF Power Amplifier - Google Patents

Abstract

The utility model discloses a circuit structure of an envelope tracking radio frequency power amplifier. The circuit structure includes a power supply modulator, a low-frequency amplifier module and a high-frequency amplifier module. The power supply modulator is connected with the low-frequency amplifier module, and the high-frequency and low-frequency amplifier modules. They are all composed of low power and high power amplifiers connected in parallel, and all power amplifiers are connected together to share a reconfigurable output matching network. This structure realizes a high-efficiency radio frequency power amplifier suitable for multi-mode and multi-frequency. The utility model combines digital signal processing technology, switching technology and reconfigurable technology to improve the overall efficiency, linearity and integration of the power amplifier. Spend. The utility model adopts the digital pre-distortion calibration signal processing technology and the differential stacked power amplifier structure to improve the linearity, so as to meet the high linearity requirement of 3G/4G and keep the efficiency at a relatively high level.

Description

Circuit Structure of Envelope Tracking RF Power Amplifier

technical field

The utility model relates to an amplifier circuit, in particular to a circuit of a radio frequency power amplifier.

Background technique

RF power amplifier is an indispensable and important part of various wireless communication equipment, which can amplify the weak signal without distortion and radiate it through the antenna. With the development of wireless communication technology, smart mobile phones have been rapidly developed, and need to satisfy the user experience of high-speed data streams for the majority of users. Therefore, most modern mobile communication systems use high-spectrum-efficient modulation methods, such as QPSK and OFDM, which are typically represented by 3G and 4G mobile communication technologies, and such signals have a high peak-to-average ratio. Therefore, when RF power amplifiers When working in the power back-off area, the efficiency is low. With the continuous evolution of globalization, in order to meet the needs of users in different regions, smart phones must meet the requirements of multi-mode and multi-frequency. For example, a mobile phone can be used in two working environments with different network standards at the same time. The design of power amplifiers raises serious challenges. In Chinese patent 201510219484.3, an automatically aligned envelope tracking power amplifier structure is proposed, which uses a single-stage envelope modulator, detector and delay circuit, so the circuit structure is relatively complex and bulky. In addition, this structure cannot well realize the compensation and calibration of the feedback signal.

Utility model content

In Chinese patent 201510219484.3, an automatically aligned envelope tracking power amplifier structure is proposed, which uses a single-stage envelope modulator, detector and delay circuit, so the circuit structure is relatively complex and bulky. In addition, this structure cannot well realize the compensation and calibration of the feedback signal. The utility model is based on the fourth-generation wireless communication LTE-FDD-A/TD-LTE-A, and is backward compatible with LTE-FDD/TD-LTE (3.9G), WCDMA/TD-SCDMA (3G), GSM/ EDGE (2G), combined with a unique digital-analog hybrid circuit architecture, provides a high-performance, highly integrated multi-mode and multi-frequency RF power amplifier circuit structure for mobile smart terminals such as smart phones, which adopts the following technical solutions Realization: the circuit structure of the envelope tracking radio frequency power amplifier, the circuit structure includes a power supply modulator, a low frequency band amplifier module and a high frequency band amplifier module, the power supply modulator is connected to the low frequency band amplifier module, the high frequency band and the low frequency band amplifier module The frequency band amplifier modules are composed of low-power and high-power amplifiers connected in parallel. All the power amplifiers are connected together and share a reconfigurable output matching network. The output matching network can automatically adjust the impedance transformation ratio of the load, thereby realizing each frequency band the best output impedance.

Further, the circuit structure also includes a digital baseband connected to the power modulator with a built-in DSP processor, and the DSP processor generates a signal envelope with a slow conversion rate and a radio frequency signal (in-phase and positive cross signal), slowing down the slew rate requirement of the envelope amplifier.

Furthermore, the digital baseband also includes a digital pre-distortion and slow envelope control signal generating circuit to further improve the overall linearity of the power amplifier.

Further, the power modulator includes a parallel linear envelope amplifier and a switch-type envelope amplifier controlled by a switch; when a high slew rate is required, the linear envelope amplifier works, while the switch-type envelope amplifier is turned off to improve the power supply The linearity of the modulator; conversely, when the required slew rate is low, the switching envelope amplifier operates to improve the efficiency of the power supply modulator, thereby improving the overall efficiency.

Furthermore, all the power amplifiers are pseudo-differential structures that realize signal inversion distribution and combination through a hybrid power divider with a 180-degree delay at the output port, reducing the input and output voltage standing wave ratio. Further, all the power amplifiers include a digitally controlled non-linear compensation bias circuit to improve linearity.

The utility model also provides a multi-frequency and multi-mode envelope tracking radio frequency power amplifier circuit structure including the envelope tracking radio frequency power amplifier circuit structure, and the digital baseband is connected to the normal channel through two D/A converters and filters. The AC modulator is further connected to the low-band amplifier module and the high-band amplifier module through a frequency switch, and the digital baseband is connected to the power modulator through a D/A converter and a filter; the digital baseband is connected to the power supply modulator through a D/A converter; The /D converter and the filter are connected to the down-conversion modulator and further to the antenna; the antenna is connected to the output matching network of the envelope tracking radio frequency power amplifier circuit.

The working state of the multi-frequency and multi-mode envelope tracking RF power amplifier circuit structure is divided into two types: transmitting and receiving; when the module is in the transmitting state, the digital baseband part automatically generates digital signals of I and Q signals according to user data on the one hand, After D/A conversion and low-pass filtering, I and Q analog signals are generated, and then converted into high-frequency modulation signals suitable for transmission through a quadrature modulator. Finally, the digital baseband automatically switches between high and low according to the signal frequency and modulation mode. Low frequency switching and power switching. On the other hand, the data baseband part also automatically generates the digital signal of the required envelope signal and switches the switch of the envelope amplifier according to the modulation mode of the signal, and converts it into an analog envelope signal through D/A and low-pass filter. The envelope signal can control the operating voltage of the power amplifier. When the module is in the receiving state, the received signal is coupled to the down-conversion modulator through the antenna, and the converted signal passes through the band-pass filter and D/A conversion to the digital baseband part.

Further, the power supply modulator is provided with a dual-resistor negative feedback ripple elimination circuit with a negative temperature coefficient compensation function. Ripple is an important parameter of the power modulator, the smaller the ripple, the higher the linearity of the circuit, and the lower the conversion speed of DCToDC. Considering the compromise between efficiency and ripple, a dual-resistor negative feedback circuit with negative temperature coefficient is used to smooth the ripple, and the efficiency of the power modulator is designed to be 80%.

Beneficial effects of the utility model: the utility model provides an envelope tracking radio frequency power amplifier circuit structure, which realizes a high-efficiency radio frequency power amplifier suitable for multi-mode and multi-frequency, the utility model combines digital signal processing technology, Switching technology and reconfigurable technology improve the overall efficiency, linearity and integration of the power amplifier. The utility model adopts the digital pre-distortion calibration signal processing technology and the differential stacked power amplifier structure to improve the linearity, so as to meet the high linearity requirements of 3G/4G and keep the efficiency at a high level.

Description of drawings

Fig. 1 is a circuit configuration diagram of the embodiment.

Fig. 2 is a circuit configuration diagram of the linear envelope amplifier of the embodiment.

Fig. 3 is a circuit configuration diagram of the switched envelope amplifier of the embodiment.

Fig. 4 is a circuit structure diagram of the pseudo-differential power amplifier of the embodiment.

Explanation of reference signs: HP in the figure is a high-power amplifier; LP is a low-power amplifier.

detailed description

A preferred embodiment of the present utility model is a multi-frequency and multi-mode envelope tracking radio frequency power amplifier circuit structure comprising the envelope tracking radio frequency power amplifier circuit structure, including a power modulator, a low frequency band amplifier module and a high frequency band The amplifier module is equipped with a digital baseband connected to the power modulator of the DSP processor, and the power modulator is connected to the low-frequency amplifier module, and the high-frequency and low-frequency amplifier modules are composed of low-power and high-power amplifiers All the power amplifiers are connected in parallel to share a reconfigurable output matching network, and the digital baseband also includes a digital pre-distortion and slow envelope control signal generation circuit. The power modulator includes a linear envelope amplifier and a switch-type envelope amplifier connected in parallel controlled by a switch; when a high slew rate is required, the linear-envelope amplifier is operated while the switch-type envelope amplifier is turned off; At lower rates, the switched envelope amplifier operates. All the power amplifiers are pseudo-differential structures in which signals are distributed and combined in reverse phase through a hybrid power divider with an output port delay of 180 degrees. All said power amplifiers include a non-linear compensating bias circuit with digital control. The digital baseband is connected to the quadrature modulator through two D/A converters and filters, and then connected to the low-band amplifier module and the high-band amplifier module through a frequency switch, and the digital baseband is connected through a D/A converter , the filter is connected to the power modulator; the digital baseband is connected to the down-conversion modulator through an A/D converter and the filter and then connected to the antenna; the antenna is matched with the output of the envelope tracking radio frequency power amplifier circuit Internet connection. The working state of the RF power amplifier circuit structure is divided into two types: transmitting and receiving; when the module is in the transmitting state, the digital baseband part automatically generates digital signals of I and Q signals according to user data on the one hand, and undergoes D/A conversion and After low-pass filtering, I and Q analog signals are generated, and then converted into high-frequency modulation signals suitable for transmission through a quadrature modulator. Finally, the digital baseband automatically switches high/low frequency switches and power switches according to the signal frequency and modulation mode . On the other hand, the data baseband part also automatically generates the digital signal of the required envelope signal and switches the switch of the envelope amplifier according to the modulation mode of the signal, and converts it into an analog envelope signal through D/A and low-pass filter. The envelope signal can control the operating voltage of the power amplifier. When the module is in the receiving state, the received signal is coupled to the down-conversion modulator through the antenna, and the converted signal passes through the band-pass filter and D/A conversion to the digital baseband part. The power modulator is equipped with a dual-resistor negative feedback ripple cancellation circuit with negative temperature coefficient compensation function, and the efficiency of the power modulator is designed to be 80%.

The circuit structure of this embodiment combines the unique circuit architecture of the digital-analog hybrid type, the baseband processor of the transceiver, the power supply modulator connected in parallel, the low-frequency dual-power radio frequency power amplifier, the high-frequency dual-power radio frequency power amplifier and a reproducible A structured matching network realizes a high-efficiency radio frequency power amplifier suitable for multi-mode and multi-frequency. The radio frequency power amplifier of the circuit works in the occasion of high peak-to-average ratio modulation signal, and can improve the overall efficiency of the radio frequency power amplifier.

Claims (8)

1. the circuit structure of envelope tracking radio frequency power amplifier, it is characterized in that: described circuit structure comprises power modulator, low frequency band amplifier module and high frequency band amplifier module, described power modulator is connected described low frequency band amplifier module, described Both the high-frequency and low-frequency amplifier modules are composed of low-power and high-power amplifiers connected in parallel, and all the power amplifiers are connected and share a reconfigurable output matching network. 2. The circuit structure of the envelope tracking radio frequency power amplifier according to claim 1, characterized in that: the circuit structure also includes a digital baseband with a built-in DSP processor connected to the power modulator. 3. The circuit structure of the envelope tracking radio frequency power amplifier according to claim 2, wherein the digital baseband further includes a digital predistortion and slow envelope control signal generating circuit. 4. The circuit structure of the envelope tracking radio frequency power amplifier according to claim 3, characterized in that In: the power modulator includes a parallel linear envelope amplifier and a switch envelope amplifier controlled by a switch Great weapon. 5. The circuit structure of the envelope tracking radio frequency power amplifier according to claim 4, characterized in that: all the power amplifiers are realized by a hybrid power splitter whose output port is delayed by 180 degrees to achieve signal inversion distribution and combination Pseudo differential structure. 6. The circuit structure of the envelope tracking radio frequency power amplifier according to claim 5, characterized in that: all said power amplifiers include a nonlinear compensation bias circuit with digital control. 7. A multi-frequency multi-mode envelope tracking radio frequency power amplifier circuit structure comprising the envelope tracking radio frequency power amplifier circuit structure of claim 5, characterized in that: the digital baseband is transmitted through two D/A converters The filter is connected to the quadrature modulator and further connected to the low-band amplifier module and the high-band amplifier module through a frequency switch, and the digital baseband is connected to the power supply modulator through a D/A converter and a filter; The digital baseband is connected to the down-conversion modulator through an A/D converter and a filter, and then connected to the antenna; the antenna is connected to the output matching network of the envelope tracking radio frequency power amplifier circuit. 8. The multi-frequency and multi-mode envelope tracking radio frequency power amplifier circuit structure according to claim 7, characterized in that: the power modulator is provided with a dual-resistor negative feedback ripple elimination circuit with a negative temperature coefficient compensation function .