CN110808718B - High-stability radio frequency power amplifier - Google Patents
High-stability radio frequency power amplifier Download PDFInfo
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- CN110808718B CN110808718B CN201810884011.9A CN201810884011A CN110808718B CN 110808718 B CN110808718 B CN 110808718B CN 201810884011 A CN201810884011 A CN 201810884011A CN 110808718 B CN110808718 B CN 110808718B
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- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
- H03F1/301—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters in MOSFET amplifiers
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- H—ELECTRICITY
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- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/189—High-frequency amplifiers, e.g. radio frequency amplifiers
- H03F3/19—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only
- H03F3/193—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only with field-effect devices
- H03F3/1935—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only with field-effect devices with junction-FET devices
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
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Abstract
The application discloses a high-stability radio frequency power amplifier, which comprises a pre-amplifier, a power output stage, a voltage-current conversion circuit, a power supply voltage compensation circuit and a current stabilizing circuit. The voltage-current conversion circuit comprises an operational amplifier, a low dropout voltage regulator, a loop stabilizing auxiliary circuit and a feedback circuit; the loop stabilizing auxiliary circuit and the feedback circuit are connected in series between the output end and the non-inverting input end of the operational amplifier. The method introduces a loop stabilizing auxiliary circuit and a feedback circuit into the voltage-current conversion circuit, and is used for providing an additional negative feedback branch circuit so as to ensure that a negative feedback current control loop in the whole PVT working range of the radio frequency power amplifier can work stably and reliably. An isolation circuit and a current stabilizing circuit are also introduced, so that the stability of the radio frequency power amplifier is improved.
Description
Technical Field
The present application relates to a radio frequency power amplifier in a mobile terminal, and more particularly, to a radio frequency power amplifier including a power control circuit.
Background
In a mobile terminal, a radio frequency power amplifier is used to amplify radio frequency signals, and then feed the amplified radio frequency signals to an antenna for external transmission. In the communication process between the mobile terminal and the base station, due to different distances between the mobile terminal and the base station or the situation that an antenna of the mobile terminal is blocked, power control is often required to be performed on the transmitting power output by the radio frequency power amplifier in the mobile terminal. For example in radio frequency power amplifiers for 2G (second generation mobile communication technology) comprising a power control circuit by controlling the voltage V ramp The output power of the radio frequency power amplifier is continuously controlled.
In order to realize the control of the output power of the radio frequency power amplifier, the power control circuit firstly needs to detect the output power of the radio frequency power amplifier, and then builds a negative feedback control loop to realize the stable control of the output power of the radio frequency power amplifier. Common high-integration, low-cost power control circuits include voltage detection schemes and current detection schemes.
The power control circuit adopting the voltage detection scheme can only be applied to a radio frequency power amplifier working in a saturation region, and has poor precision at low output power.
The power control circuit adopting the current detection scheme can be applied to a radio frequency power amplifier working in a saturation region and/or a linear region, and has higher efficiency. The power control circuit adopting the current detection scheme is generally characterized in that a small resistor, for example less than 0.1 omega, is connected in series in the final-stage path of the radio-frequency power amplifier; and controlling the output power of the radio frequency power amplifier by detecting the voltage difference between two ends of the small resistor. The scheme needs small resistors with accurate resistance values, is high in cost and poor in integration level, and can generate extra power consumption on the small resistors connected in series, so that the efficiency of the radio frequency power amplifier is reduced.
In addition, the radio frequency power amplifier is controlled by the voltage V under the normal working state ramp Control to periodically turn on and off, thereby creating a switching spectrum (switch spectrum), which presents a significant challenge to the power control curve of the radio frequency power amplifier. The operating current of the rf Power amplifier varies between 0 and 2A throughout the PVT (Power VS Time) interval, presenting a significant challenge to the stability of the control loop. The radio frequency power amplifier works in a radio frequency band, the power supply and the ground of each module are not ideal enough, and positive feedback is easy to generate and oscillate. Particularly, the working temperature range of the radio frequency power amplifier is between-40 ℃ and 125 ℃, the performances of each module of the radio frequency power amplifier can be greatly changed at different temperatures, and the oscillation is easy to occur.
Disclosure of Invention
The technical problem to be solved by the application is to provide a radio frequency power amplifier comprising a power control circuit, wherein the power control circuit adopting a current detection scheme has the characteristics of low cost, high reliability and high stability.
In order to solve the technical problem, the high-stability radio frequency power amplifier comprises a pre-amplifier, a power output stage, a voltage-current conversion circuit, a power supply voltage compensation circuit and a current stabilizing circuit.
The pre-amplifier is used for pre-amplifying the radio frequency input signal.
The power output stage comprises a power amplifying circuit and a current sampling circuit; the power amplifying circuit is used for amplifying the power of the radio frequency signal which is amplified in advance under the control of the control voltage to obtain output power; the current sampling circuit is used for sampling the current flowing through the power transistor in the power output stage to obtain a sampling current.
The voltage-current conversion circuit comprises an operational amplifier, a low dropout voltage regulator, a loop stabilizing auxiliary circuit and a feedback circuit; the voltage-current conversion circuit is used for converting control voltage into reference current, comparing the reference current with sampling current of the power output stage through the operational amplifier, and connecting a comparison result into the low-dropout voltage regulator which provides power supply voltage for the pre-amplifier; the loop stabilizing auxiliary circuit and the feedback circuit are connected in series between the output end and the non-inverting input end of the operational amplifier;
the power supply voltage compensation circuit is used for compensating output power variation caused by power supply voltage variation of the power output stage;
the current stabilizing circuit is used for adjusting the current flowing through the power transistor in the power output stage to the change of temperature.
The technical effect that this application obtained is: a loop stabilizing auxiliary circuit and a feedback circuit are introduced into the voltage-current conversion circuit and are used for providing an additional negative feedback branch circuit so as to ensure that a negative feedback current control loop can stably and reliably work in the whole PVT working range of the radio frequency power amplifier. The voltage-current conversion circuit controls the current of the power output stage of the current working frequency band through negative feedback, so that the higher efficiency of the radio frequency power amplifier is realized. The power supply voltage compensation circuit enables the output power of the radio frequency power amplifier not to change along with the change of the power supply voltage. The current stabilizing circuit improves the stability of the radio frequency power amplifier in the whole working temperature range.
Preferably, the pre-amplifier comprises an inverter and a feedback resistor; the inverter is formed by cascading a PMOS transistor and an NMOS transistor in sequence between the power supply voltage of the pre-amplifier and the ground, the grid electrodes of the two transistors are connected to serve as the input end of the inverter, and the drain electrodes of the two transistors are connected to serve as the output end of the inverter; the feedback resistor is connected between the input and output terminals of the inverter. This is a specific implementation of a pre-amplifier, by way of example only. The negative feedback resistor is used to determine the DC bias point and provide the required input impedance of the RF power amplifier.
Preferably, the power amplifying circuit is formed by cascading an inductor, a common source transistor and a common gate transistor in sequence between the power supply voltage of the power output stage and the ground; the cascode transistor and the cascode transistor form a cascode structure one. The current sampling circuit comprises a second cascode structure, and the second cascode structure and the first cascode structure form a cascode current mirror structure for sampling the current flowing through two power transistors in the power amplifying circuit; the current sampling circuit further comprises a second current mirror structure, and the second current mirror structure further reduces the intermediate sampling current output by the cascode current mirror to obtain the final sampling current output by the current sampling circuit. This is a specific implementation of the power output stage, by way of example only. The power amplifying circuit adopts a cascode structure, namely the voltage swing can be improved, and the two current mirror structures are used for sampling the output current of the power transistor.
Preferably, the voltage-current conversion circuit further comprises a filtering unit and a voltage generating unit; the control voltage is connected to the inverting input end of the operational amplifier through the filtering unit, and the sampling current of the power output stage generates feedback voltage at the non-inverting input end of the operational amplifier through the voltage generating unit; the output end of the operational amplifier is connected with the grid electrode of the adjusting tube of the low-dropout voltage regulator; the drain of the low dropout regulator supplies power to the preamplifier. The filtering unit can reduce signal interference of irrelevant frequency bands. The voltage generation unit may convert the sampling current of the power output stage into a feedback voltage such that the control voltage and the feedback voltage are compared in the operational amplifier.
Preferably, the filter unit comprises a filter resistor and a filter capacitor, the control voltage is connected to the inverting input end of the operational amplifier through the filter resistor, and the inverting input end of the operational amplifier is grounded through the filter capacitor. This is a specific implementation of the filtering unit, by way of example only.
Preferably, the voltage generating unit is a parallel branch of a first resistor and a second resistor, one end of the parallel branch is grounded, and the other end of the parallel branch is connected with the non-inverting input end of the operational amplifier. This is a specific implementation of the voltage generating unit, by way of example only.
Further, the loop stabilization auxiliary circuit comprises an auxiliary low dropout regulator; the grid electrode of the adjusting tube of the auxiliary low-dropout voltage regulator is connected with the output end of the operational amplifier, the source electrode is connected with the power supply voltage, the drain electrode is grounded through a load resistor on one hand, and the drain electrode is connected to the non-inverting input end of the operational amplifier through a feedback circuit on the other hand. The loop stabilization auxiliary circuit implements an additional negative feedback branch.
Further, the voltage-current conversion circuit further comprises a PVT curve adjustment circuit; the PVT curve adjusting circuit is characterized in that an NMOS transistor connected in a diode structure or a PMOS transistor connected in a diode structure is additionally connected in series between the resistor II and the ground or between the non-inverting input end of the operational amplifier and the resistor II. The PVT curve adjustment circuit is beneficial to improving the switching spectrum of the radio frequency power amplifier.
Further, the voltage-current conversion circuit further comprises a miller compensation circuit; each Miller compensation circuit is connected between the grid electrode and the drain electrode of the adjusting tube of one low-dropout voltage regulator and comprises a Miller capacitor connected in series with a zero-setting resistor. The miller compensation circuit helps to improve the stability of the negative feedback current control loop.
Further, the voltage-current conversion circuit further comprises a temperature compensation circuit; the temperature compensation circuit is formed by connecting a resistor with a positive temperature coefficient and a resistor with a negative temperature coefficient in series. The temperature compensation circuit helps to ensure stable output power of the power output stage of the radio frequency power amplifier at different temperatures.
Preferably, the power supply voltage compensation circuit comprises a differential amplifying circuit and a current mirror; the differential amplifying circuit tracks the change of the power supply voltage, and the current mirror generates compensation current with the same change trend of the power supply voltage. This is a specific implementation of the supply voltage compensation circuit, by way of example only.
Preferably, the current stabilizing circuit comprises a positive temperature coefficient current source, a transistor fifteen and a transistor sixteen; the positive temperature coefficient current source and the transistor fifteen are sequentially connected in series between the power supply and the ground of the current stabilizing circuit; the grid electrode and the drain electrode of the transistor fifteen are connected and connected with a positive temperature coefficient current source; the source electrode of the transistor fifteen is connected with the ground of the current stabilizing circuit; the grid electrode of the transistor sixteen is connected with the grid electrode of the transistor fifteen, the drain electrode of the transistor sixteen is connected with the non-inverting input end of the operational amplifier, and the source electrode of the transistor sixteen is connected with the ground of the current stabilizing circuit. This is a specific implementation of the current stabilizing circuit, by way of example only. The transistor sixteen and the transistor fifteen form a current mirror structure, and the positive temperature coefficient current source obtains an adjusting current which is proportional to the temperature through the current mirror structure and is injected into the non-inverting input end of the operational amplifier, so that the voltage of the non-inverting input end of the operational amplifier is pulled down to the ground, and the stability of the radio frequency power amplifier is improved.
Preferably, the current stabilizing circuit comprises a negative temperature coefficient current source, a seventeen transistor and a twenty transistor; the negative temperature coefficient current source and the transistor seventeen are sequentially connected in series between the power supply and the ground of the current stabilizing circuit; the grid electrode and the drain electrode of the transistor seventeen are connected and connected with a negative temperature coefficient current source; the source electrode of the transistor seventeen is connected with the ground of the current stabilizing circuit; a grid electrode of the transistor eighteen is connected with a grid electrode of the transistor seventeen, a drain electrode of the transistor nineteen is connected with a drain electrode of the transistor, and a source electrode of the transistor eighteen is connected with the ground of the current stabilizing circuit; the grid electrode and the drain electrode of the transistor nineteenth are connected, and the source electrode is connected with a power supply of the current stabilizing circuit; the grid electrode of the transistor twenty is connected with the grid electrode of the transistor nineteenth, the source electrode is connected with the power supply of the current stabilizing circuit, and the drain electrode is connected with the non-inverting input end of the operational amplifier. This is another specific implementation of the current stabilizing circuit, by way of example only. The transistor eighteen and the transistor seventeen form a first current mirror structure, the transistor twenty and the transistor nineteen form a second current mirror structure, and the negative temperature coefficient current source obtains an adjusting current inversely proportional to the temperature through the two current mirror structures and extracts the adjusting current from the non-inverting input end of the operational amplifier, so that the power supply of the current stabilizing circuit is pulled down to the non-inverting input end of the operational amplifier, and the stability of the radio frequency power amplifier is improved.
Further, the pre-amplifier, the power output stage, the voltage-current conversion circuit, the power supply voltage compensation circuit and the current stabilizing circuit are provided with isolation circuits in pairs between the power supplies. The method can reduce and avoid interference among the modules and improve the stability of the radio frequency power amplifier.
Further, the pre-amplifier, the power output stage, the voltage-current conversion circuit, the power supply voltage compensation circuit and the current stabilizing circuit are provided with isolation circuits between the grounds respectively. The method can reduce and avoid interference among the modules and improve the stability of the radio frequency power amplifier.
Preferably, the isolation circuit is an isolation resistor, an isolation inductor and an isolation capacitor which are connected in parallel between two objects to be isolated. This is a specific implementation of an isolation circuit, by way of example only.
Preferably, the isolation circuit is an isolation resistor and an isolation inductor which are connected in parallel between two objects to be isolated, and the isolation capacitor is used for connecting one object to be isolated and a single ground. This is another specific implementation of an isolation circuit, by way of example only.
Preferably, the isolation circuit is of an end-to-end diode structure, one isolation diode is reversely connected between two objects to be isolated, and the other isolation diode is positively connected between the two objects to be isolated. This is yet another specific implementation of an isolation circuit, by way of example only.
The high-stability radio frequency power amplifier provided by the application can be widely applied to the control of the voltage V ramp The radio frequency power amplifier for controlling the output power has the characteristics of stable and reliable operation and has the following beneficial effects.
First, the voltage-current conversion circuit controls the voltage V ramp Conversion to reference current I ramp A negative feedback current control loop is constructed to control the current of the power output stage of the radio frequency power amplifier, thereby achieving higher efficiency.
Secondly, a loop stabilizing auxiliary circuit and a feedback circuit are introduced into the voltage-current conversion circuit and used for providing an additional negative feedback branch circuit so as to ensure that a negative feedback current control loop in the whole PVT working interval of the radio frequency power amplifier can work stably and reliably, and oscillation of the negative feedback current control loop is effectively avoided.
And thirdly, a PVT curve adjusting circuit, a Miller compensating circuit and a temperature compensating circuit are further integrated in the voltage-current converting circuit, so that the voltage-current converting circuit has the characteristics of high integration level and reliable and stable operation. The PVT curve adjusting circuit is beneficial to adjusting PVT curve of the radio frequency power amplifier and improving switching spectrum of the radio frequency power amplifier. The miller compensation circuit helps to improve the stability of the negative feedback current control loop. The temperature compensation circuit helps to ensure stable output power of the power output stage of the radio frequency power amplifier at different temperatures.
Fourth, the output power of the radio frequency power amplifier is not changed along with the change of the power supply voltage by the power supply voltage compensation circuit.
Fifthly, the stability of the radio frequency power amplifier in the whole working temperature range is improved through the current stabilizing circuit.
And sixthly, isolation circuits are inserted between the power supplies and between the grounds of all the modules, so that the interference between the modules is reduced, and the stability of the radio frequency power amplifier is improved.
Drawings
Fig. 1 is a schematic circuit diagram of one embodiment of a high stability rf power amplifier of the present application.
Fig. 2 is a circuit configuration diagram of one embodiment of the preamplifier in fig. 1.
Fig. 3 is a schematic circuit configuration of one embodiment of the power output stage of fig. 1.
Fig. 4 is a circuit configuration diagram of a first embodiment of the voltage-to-current conversion circuit in fig. 1.
Fig. 5 is a circuit configuration diagram of a second embodiment of the voltage-to-current conversion circuit in fig. 1.
Fig. 6 is a circuit configuration diagram of an embodiment of the temperature compensation circuit in fig. 4 and 5.
Fig. 7 is a circuit configuration diagram of an embodiment of the power supply voltage compensation circuit in fig. 1.
Fig. 8 is a circuit configuration diagram of a first embodiment of the current stabilizing circuit in fig. 1.
Fig. 9 is a circuit configuration diagram of a second embodiment of the current stabilizing circuit in fig. 1.
Fig. 10 is a schematic diagram of the isolation of power supplies between modules of a high stability rf power amplifier of the present application.
Fig. 11 is a schematic diagram of the isolation between the modules of the high stability rf power amplifier of the present application.
Fig. 12a to 12c are schematic circuit configurations of three embodiments of the isolation circuit.
The reference numerals in the drawings illustrate: v (V) in Is a radio frequency input signal; v (V) pre Is a radio frequency signal which is amplified in advance; v (V) out Is a radio frequency output signal; v (V) ramp Is a control voltage; v (V) ldo A supply voltage for the pre-amplifier; gnd_pre is the ground of the pre-amplifier; v (V) cc 、V cc_ps A supply voltage for the power output stage; gnd_ps is the ground of the power output stage; i ramp Is the reference current; i comp To compensate for the current; i sense Sampling current; m is a MOS transistor; r is R f Is a feedback resistor; l is inductance; v (V) cascode A gate bias voltage for the common gate transistor; FB is a feedback node; v (V) fb Is the feedback voltage; v (V) cc_vi The power supply is used as a voltage-current conversion circuit; gnd_vi is the ground of the voltage-to-current conversion circuit; OP is an operational amplifier; m is M A An adjusting tube of the low dropout regulator/an adjusting tube of the auxiliary low dropout regulator; m is M B Transistors of the circuit are adjusted for PVT curves; r is R p Is positive temperature coefficientA resistor; r is R n A resistor with a negative temperature coefficient; v (V) cc_comp A power supply for the power supply voltage compensation circuit; gnd_comp is the ground of the supply voltage compensation circuit; d is a diode; i ss Is a tail current source; v (V) cc_ptat A power supply for the current stabilizing circuit; gnd_ptat is the ground of the current stabilizing circuit; i pt 、I ct Is a current source; i ptat 、I ctat To adjust the current; c is a capacitor; ISO is an object that needs to be isolated.
Detailed Description
Referring to fig. 1, an embodiment of a high stability rf power amplifier is provided. The high stability radio frequency power amplifier shown in this embodiment includes a pre-amplifier, a power output stage, a voltage to current conversion circuit, a supply voltage compensation circuit, and a current stabilization circuit.
The pre-amplifier is used for inputting a radio frequency input signal V in Pre-amplifying to obtain a larger dynamic range, and outputting a path of pre-amplified radio frequency signal V pre 。
The power output stage includes a power amplifying circuit and a current sampling circuit. The power amplifying circuit is used for controlling the voltage V ramp Under the control of (a), a path of pre-amplified radio frequency signal V pre Power amplification is carried out to obtain output power V out . The output power V out After passing through the matching circuit, the antenna emits the signal. The current sampling circuit is used for sampling the current flowing through the power transistor in the power output stage to obtain a sampling current I sense 。
The voltage-current conversion circuit comprises an operational amplifier, a Low-dropout regulator (LDO), a loop stabilizing auxiliary circuit and a feedback circuit. The voltage-current conversion circuit is used for controlling the voltage V ramp Converted to and controlled by voltage V ramp Proportional reference current I ramp And through the operational amplifier and the sampling current I of the power output stage sense Comparing, and switching the comparison result (i.e. output of operational amplifier) into a low dropout regulator which provides power for the pre-amplifierSource voltage V ldo . The loop stabilizing auxiliary circuit and the feedback circuit are connected in series between the output end of the operational amplifier and the feedback node FB (i.e., the non-inverting input end of the operational amplifier) to provide an additional negative feedback branch circuit so as to ensure that the negative feedback current control loop can stably and reliably operate in the whole PVT operation interval of the radio frequency power amplifier.
The power supply voltage compensation circuit is used for compensating the power supply voltage V of the power output stage cc Output power V caused by variation out The variation being compensated for so that the different supply voltages V cc Output power V of lower power output stage out And remain constant.
The current stabilizing circuit is used for further adjusting the current flowing through the power transistor in the power output stage so as to improve the stability of the radio frequency power amplifier in the whole working temperature range.
At the position of feedback node FB in FIG. 1, there is a reference current I injected by the voltage-to-current conversion circuit ramp With compensation current I drawn by the supply voltage compensation circuit comp Sampling current I drawn by a power output stage having a current operating frequency band sense With regulated current I injected by a current stabilizing circuit ptat And I ramp +I ptat ＝I comp +I sense . When controlling voltage V ramp At rising, reference current I ramp With a consequent rise, assuming a compensation current I comp And regulating the current I ptat All unchanged, then the sampling current I of the power output stage sense With a consequent increase, which also reflects from another angle an increase in the current flowing through the power transistor in the power output stage, so that the output power V of the radio frequency power amplifier out Increasing; and vice versa.
In addition, when the temperature decreases, the current I is adjusted ptat Decreasing, assuming reference current I ramp And compensation current I comp All unchanged, then the sampling current I of the power output stage sense With a consequent reduction, which also reflects from another angle a reduction in the current flowing through the power transistor in the power output stage, so that the output power V of the radio frequency power amplifier out A reduction; and vice versa. This shows that the current stabilizing circuit can improve the stability of the radio frequency power amplifier at different temperatures.
In the high stability rf power amplifier shown in fig. 1, an amplifying path is formed from the pre-amplifier, the power output stage, the matching circuit to the antenna. On the amplifying path, the RF input signal V in Firstly enter a pre-amplifier to obtain a pre-amplified radio frequency signal V pre Then enters a power output stage to carry out power amplification to obtain a radio frequency output signal V out And then the antenna transmits the signal after passing through the matching circuit.
Meanwhile, the power output stage, the voltage-current conversion circuit and the pre-amplifier are sequentially connected to form a negative feedback current control loop of the radio frequency power amplifier. When controlling voltage V ramp When rising, the voltage-current conversion circuit provides the power voltage V to the pre-amplifier ldo Step up, pre-amplifier output voltage V pre The bias voltage of the power output stage is increased, so that the current flowing through the power transistor in the power output stage is increased. At this time, on the one hand, the output power V of the power output stage is made out With a consequent increase, embody the control voltage V ramp Output power V to radio frequency power amplifier out Is a regulating function of (a); on the other hand, the sampling current I of the power output stage sense With a consequent increase in the feedback voltage V of the feedback node FB fb Raised. Feedback voltage V fb Supply voltage V for a pre-amplifier is raised by an operational amplifier in a voltage-to-current conversion circuit ldo The grid voltage of the regulating tube of the low-voltage differential voltage regulator to ensure the power supply voltage V of the pre-amplifier ldo There is a trend towards a decrease. Thus, a complete current control loop is formed through negative feedback, and the closed-loop control of the output power of the radio frequency power amplifier is realized.
Referring to fig. 2, one embodiment of the preamplifier of fig. 1 is shown. The pre-amplifier comprises an inverter and a feedback resistor R f . The inverter is a power supply voltage V of a pre-amplifier ldo And the ground gnd_pre of the pre-amplifier are cascaded with PMOS transistor M in turn 1 And NMOS transistor two M 2 Formed of two transistors M 1 And M 2 The gate of (a) is connected as the input of the inverter, two transistors M 1 And M 2 Is connected as the output of the inverter. Feedback resistor R f Is connected between the input and output of the inverter. The input end of the inverter receives a radio frequency input signal V in The output end of the inverter outputs a path of pre-amplified radio frequency signal V to the outside pre . Feedback resistor R f For determining the dc bias point and providing the required input impedance of the rf power amplifier. The preamplifiers for different frequency bands may employ the same circuit configuration.
Referring to fig. 3, one embodiment of the power output stage of fig. 1 is shown. The power output stage includes a power amplifying circuit and a current sampling circuit.
The power amplifying circuit is a power supply voltage V at a power output stage cc_ps And the ground gnd ps of the power output stage are sequentially cascaded with an inductor L1 and four transistors M 4 And transistor three M 3 . Transistor three M 3 Transistor four M adopting common source connection mode 4 Transistor three M adopting common grid connection mode 3 And transistor four M 4 And forming a first cascode structure. One path of radio frequency signal V amplified in advance pre Three M of access transistor 3 Is formed by transistor three M 3 Drain into transistor four M 4 At transistor four M 4 Is amplified by the drain output power of (a) and (b) out . The power amplifying circuit adopts a cascode structure, so that the swing amplitude of output voltage can be improved. The inductance L1 is preferably a choke inductance, also called choke (choke inductor), and functions as a dc-blocking inductance.
The current sampling circuit is a power supply voltage V at a power output stage cc_ps Transistor seven M is cascaded in sequence between ground gnd_ps of power output stage 7 Six M transistors 6 And transistor five M 5 Also includes a transistor eight M 8 . Transistor five M 5 Adopts a common source electrode connection mode, and the common source electrode is connected with the common source electrode,transistor six M 6 Five M transistors adopting common gate connection mode 5 And transistor six M 6 And forming a second cascode structure. Transistor five M 5 And transistor three M 3 Gate of (2) is connected to, transistor six M 6 And transistor four M 4 The grid electrode of the first common-source common-grid structure is connected with the grid electrode of the second common-source common-grid structure, and the second common-source common-grid structure and the first common-source common-grid structure form M:1 for sampling two power transistors M flowing through a power amplifying circuit 3 、M 4 Is set in the above-described range). The intermediate sampling current output by the cascode current mirror is reduced by M times by the current flowing through the power transistor in the power amplifying circuit. Transistor seven M 7 Is connected with the drain electrode and is connected with the six M transistors 6 Is formed on the drain electrode of the transistor. Transistor seven M 7 And transistor eight M 8 The source electrodes of the power output stage are connected with the power supply voltage V cc_ps Eight M transistors 8 Is connected to the feedback node FB and samples the sampling current I from the feedback node FB sense . Transistor eight M 8 And transistor seven M 7 Is connected with the grid electrode to form N:1, further reducing the intermediate sampling current output by the cascode current mirror by N times to obtain the sampling current I finally output by the current sampling circuit sense . In this way, the power output stage obtains the sampling current I sense Increasing m×n times is the current flowing through the power transistor, and the scaling factor M and/or N can be adjusted by selecting the element parameters, so as to optimize the stability of the negative feedback current control loop and the efficiency of the rf power amplifier.
Wherein the transistor is three M 3 Transistor four M 4 Five M transistors 5 Six M transistors 6 For example, NMOS transistors. Transistor seven M 7 Eight M transistors 8 For example PMOS transistors. Transistor four M of common gate connection mode 4 Six M transistors 6 With gate bias voltage V cascode 。
Referring to fig. 4, a first embodiment of the voltage-to-current conversion circuit in fig. 1 is shown. The voltage-current conversion circuit comprises a filtering unit, a voltage generating unit, an operational amplifier OP, a low voltageThe differential voltage regulator, the loop stabilizing auxiliary circuit and the feedback circuit. Control voltage V ramp Through a filter resistor R 0 Is connected to the inverting input terminal of the operational amplifier OP, which is also connected to the inverting input terminal of the operational amplifier OP through a filter capacitor C 0 And (5) grounding. Filter resistor R 0 And filter capacitor C 0 A filtering unit is formed. Sampling current I of power output stage sense Output is at resistor R 1 And resistance two R 2 In (in this case, it is assumed that the transistor M indicated by the dotted line B Not present), generating a feedback voltage V at the location of the feedback node FB fb Is connected to the non-inverting input of the operational amplifier OP. resistance-R 1 And resistance two R 2 The parallel branches of (a) constitute a voltage generating unit. The output end of the operational amplifier OP is connected to the loop stabilizing auxiliary circuit and the adjusting tube M A Is formed on the substrate. The loop stabilizing auxiliary circuit and the feedback circuit are connected in series between the output end of the operational amplifier OP and the feedback node FB and are used for providing an extra negative feedback branch outside the negative feedback current control loop so as to ensure that the negative feedback current control loop can work stably and reliably in the whole PVT working interval of the radio frequency power amplifier. Adjusting tube M A A low dropout voltage regulator is formed. Adjusting tube M A The source electrode of the (C) is connected with the power supply voltage V of the voltage-current conversion circuit cc_vi The drain electrode is connected with the power end of the pre-amplifier to provide the power voltage V for the pre-amplifier ldo . The voltage-current conversion circuit also has the advantages of simple circuit, perfect function, high integration level and stable and reliable operation.
When controlling voltage V ramp When rising, the output voltage V of the operational amplifier OP g Lowering, this causes the adjustment tube M A The gate voltage of (2) is reduced to thereby adjust the tube M A The drain voltage of (a) is the pre-amplifier-power supply voltage V ldo Step up, pre-amplifier output voltage V pre The gate voltage of the power output stage is increased, resulting in an increase in the current flowing through the power transistor in the power output stage. This causes the sampling current I of the power output stage sense With a consequent increase in the feedback voltage V of the feedback node FB fb Raised. Final negativeThe high gain of the feedback current control loop causes the feedback voltage V of the feedback node FB fb Finally stable at control voltage V ramp 。
Referring to fig. 5, a second embodiment of the voltage-to-current conversion circuit in fig. 1 is shown. The difference of the second embodiment compared to the first embodiment is only to give one specific implementation of the loop stabilization assistance circuit. The loop stabilizing auxiliary circuit is mainly realized by an auxiliary low-dropout voltage regulator. Adjusting tube M of auxiliary low-dropout voltage regulator A2 The grid electrode of the (a) is connected with the output end of the operational amplifier OP, and the source electrode is connected with the power supply voltage V of the voltage-current conversion circuit cc_vi The drain electrode passes through the load resistor R on the one hand L The drain is connected to the ground gnd_vi of the voltage-to-current conversion circuit and on the other hand to the feedback node FB via a feedback circuit to realize an additional negative feedback branch.
Preferably, the feedback circuit in fig. 4, 5 is a resistor, or any combination of resistors in series and/or parallel.
In the same voltage-current conversion circuit shown in fig. 4 and 5, the following structure is also optionally included.
Preferably, the voltage-current conversion circuit further comprises a PVT curve adjustment circuit. The PVT curve adjusting circuit is arranged at the resistor two R 2 An NMOS transistor M is additionally connected in series between the ground B Fig. 4 and 5 are shown by broken lines. The NMOS transistor M B Connected in a diode configuration, i.e. with gate and drain connected to a resistor R 2 The method comprises the steps of carrying out a first treatment on the surface of the The source is grounded. When controlling voltage V ramp Smaller than NMOS transistor M B At the threshold voltage of (2), resistance two R 2 The branch is disconnected and has only a resistor R 1 A branch circuit which causes the feedback voltage V of the feedback node FB to fb Rise, output voltage V of operational amplifier OP g Step up, supply voltage V of preamplifier ldo Reducing the output voltage V of the preamplifier pre Reducing, thereby reducing transistor tri-M in the power output stage 3 To flow through the power transistor M 3 、M 4 Is reduced. When controlling voltageV ramp Greater than or equal to NMOS transistor M B At the threshold voltage of (2), resistance two R 2 The branch circuit is connected to the circuit, which makes the feedback voltage V of the feedback node FB fb Decrease of output voltage V of operational amplifier OP g Reducing the supply voltage V of the preamplifier ldo Step up, pre-amplifier output voltage V pre Rise, thereby raising transistor three M in the power output stage 3 To flow through the power transistor M 3 、M 4 Is increased. This helps to improve the switching spectrum of the radio frequency power amplifier. Based on the same principle as that of fig. 4 and 5, the PVT curve adjustment circuit can also change the NMOS transistor connected to the diode structure into the PMOS transistor connected to the diode structure, or change the NMOS transistor connected to the diode structure into the PMOS transistor connected to the diode structure 2 An NMOS transistor connected in a diode structure or a PMOS transistor connected in a diode structure (not shown) is added between the two transistors.
Preferably, the voltage-current conversion circuit further comprises a miller compensation circuit I. The Miller compensation circuit I is connected with the adjusting tube M A For example, a miller capacitor is connected in series with a zero resistor between the gate and the drain; fig. 4 and 5 are shown by broken lines. In the loop stabilization auxiliary circuit shown in fig. 5, a miller compensation circuit two is optionally further included. The Miller compensation circuit II is connected with an adjusting tube M of the auxiliary low-dropout voltage regulator A2 For example, a miller capacitor is connected in series with a zero resistor between the gate and the drain; indicated in fig. 5 by a dashed line. The miller compensation circuit improves the phase margin of the negative feedback current control loop through pole separation, thereby improving the stability of the negative feedback current control loop.
Preferably, the voltage-current conversion circuit further comprises a temperature compensation circuit. Referring to fig. 6, an embodiment of the temperature compensation circuit of fig. 4 and 5 is shown. The temperature compensation circuit is implemented by using the resistor R in the diagrams of FIG. 4 and FIG. 5 1 Resistance two R 2 Resistors R all adopting positive temperature coefficient p And a negative temperature coefficient resistor R n And the two are connected in series. By adjusting the resistance R of positive temperature coefficient p And a negative temperature coefficient resistor R n The temperature coefficient of the sampling current of the power transistor can be adjusted, and then the temperature coefficient of the output power of the radio frequency power amplifier can be adjusted, so that the output power which does not change along with the temperature can be obtained.
Referring to fig. 7, an embodiment of the supply voltage compensation circuit of fig. 1 is shown. The power supply voltage compensation circuit comprises a differential amplifying circuit and a current mirror. The differential amplifying circuit mainly comprises a transistor nine M 9 To transistor twelve M 12 And tail current source I ss The composition is formed. Transistor nine M 9 Gate pass resistance tri-R 3 Supply voltage V connected to supply voltage compensation circuit cc_comp Also through a plurality of diodes D connected in series 1 To D n Clamped at a minimum operating voltage (e.g., 3.5V). Ten M transistors 10 Gate pass resistance four R 4 Supply voltage V connected to supply voltage compensation circuit cc_comp . Transistor nine M 9 Ten M of source, transistor 10 Is connected with the source of the tail current source I ss Ground gnd_comp of the power supply voltage compensation circuit. Transistor eleven M 11 Source, transistor twelve M 12 Is connected to the power supply voltage V of the power supply voltage compensation circuit cc_comp . Transistor eleven M 11 Gate and drain of (a), transistor twelve M 12 Is connected to the gate of the transistor. Transistor eleven M 11 Is connected with the drain electrode of the transistor nine M 9 Is formed on the drain electrode of the transistor. Transistor twelve M 12 Is connected to the drain of transistor ten M 10 And is connected to the drain of transistor thirteen M 13 Is formed on the drain electrode of the transistor. The current mirror is mainly composed of a transistor thirteen M 13 And transistor fourteen M 14 The composition is formed. Transistor thirteen M 13 Source, transistor fourteen M 14 Is connected to the power supply voltage V of the power supply voltage compensation circuit cc_comp . Transistor thirteen M 13 Gate of (c) and transistor fourteen M 14 Is connected to the gate of the transistor. Transistor fourteen M 14 Is to draw a compensation current I from the feedback node FB comp . When the power supply voltage of the power supply voltage compensation circuit is V cc_comp When the lifting device is lifted up, the lifting device can be lifted up,ten M transistors 10 Is increased by the current of transistor twelve M 12 To reduce the current of transistor thirteen M 13 Is increased by the current mirror circuit to make transistor fourteen M 14 And the current of (2) increases. The compensation current I thus drawn from the feedback node FB comp Increase when the reference current I ramp And regulating the current I ptat All are unchanged, so that the sampling current I sense Reducing the current flowing through the power transistor and thus the output power V of the radio frequency power amplifier out A reduction; and vice versa. The differential amplifying circuit thus tracks the variation of the supply voltage, and the current mirror generates a compensation current having the same trend as the variation of the supply voltage. The power supply voltage compensation circuit can be used for compensating the power supply voltage V of the circuit cc_comp When the power supply voltage changes, the change of the output power of the radio frequency power amplifier caused by the change is compensated, so that the output power of the radio frequency power amplifier is kept constant under different power supply voltages.
It should be specifically noted that in the high-stability rf power amplifier provided in the present application, the power sources of the modules are connected together in the dc portion, and the isolation circuits are added in pairs in the ac portion. Thus, the dc voltage of the power supply of each module is changed synchronously. The power supply voltage compensation circuit compensates the power supply voltage V of the power supply compensation circuit cc_comp Compensating for dc variations in (i) corresponding to the supply voltage V of the power output stage cc_ps And the direct current variation of the power converter is compensated, so that the compensation of output power is realized.
Referring to fig. 8, a first embodiment of the current stabilizing circuit in fig. 1 is shown. The current stabilizing circuit shown in this embodiment includes a positive temperature coefficient current source I pt Fifteen M transistors 15 And transistor sixteen M 16 . Positive temperature coefficient current source I pt For example by a bandgap reference voltage, which is associated with transistor fifteen M 15 Power supply V serially connected in sequence with current stabilizing circuit cc_ptat And ground gnd_ptat of the current stabilizing circuit. Fifteen M transistors 15 Is connected with the grid electrode and the drain electrode of the transistor and is connected with a positive temperature coefficient current source I pt . Fifteen M transistors 15 Is connected to ground gnd _ ptat of the current stabilizing circuit. Sixteen transistors M 16 Fifteen M of the gate connection transistor 15 The drain of which is connected to the feedback node FB and the source of which is connected to the ground gnd_ptat of the current stabilizing circuit. Sixteen transistors M 16 And transistor fifteen M 15 Forms a current mirror structure, and a positive temperature coefficient current source I pt The current mirror structure obtains the regulated current I which is proportional to absolute temperature ptat The regulated current I ptat From feedback node FB to ground.
The current stabilizing circuit shown in FIG. 8 adjusts the current I in proportion to the temperature as the temperature decreases ptat Decreasing, assuming reference current I ramp And compensation current I comp All unchanged, then the sampling current I of the power output stage sense With a consequent reduction, which indicates a reduction in the current flowing through the power transistor in the power output stage, so that the output power V of the radio frequency power amplifier out And (3) reducing. At the same time, the feedback voltage V of the feedback node FB fb Regulator tube M of low dropout regulator in boost, voltage-to-current conversion circuit A Gate voltage V of (2) g (i.e. the output voltage of the operational amplifier OP) increases, reducing the output voltage V of the LDO ld o. This reduces the supply voltage of the pre-amplifier, reduces the gain of the pre-amplifier, and improves the stability of the radio frequency power amplifier.
Referring to fig. 9, a second embodiment of the current stabilizing circuit of fig. 1 is shown. The current stabilizing circuit shown in this embodiment includes a negative temperature coefficient current source I ct Seventeen transistors M 17 To transistor twenty M 20 . Negative temperature coefficient current source I ct For example by a bandgap reference voltage, which is associated with transistor seventeen M 17 Power supply V serially connected in sequence with current stabilizing circuit cc_ptat And ground gnd_ptat of the current stabilizing circuit. Seventeen transistors M 17 Is connected with the grid electrode and the drain electrode of the transistor and is connected with a negative temperature coefficient current source I ct . Seventeen transistors M 17 Is connected to ground gnd _ ptat of the current stabilizing circuit. Transistor eighteen M 18 Gate connected transistor seventeen M 17 Is connected with the drain of the transistor nineteen M 19 The drain and the source of the current stabilizing circuit are connected with the ground gnd_ptat of the current stabilizing circuit. Transistor nineteen M 19 The grid electrode and the drain electrode of the current stabilizing circuit are connected, and the source electrode is connected with a power supply V of the current stabilizing circuit cc_ptat . Transistor twenty M 20 Gate-connected transistor nineteen M 19 The grid and the source of the (C) are connected with the power supply V of the current stabilizing circuit cc_ptat The drain is connected to the feedback node FB. Transistor eighteen M 18 And transistor seventeen M 17 Forms a first current mirror structure, a transistor twenty M 20 And transistor nineteen M 19 Forms a second current mirror structure, and a negative temperature coefficient current source I ct By means of these two current mirror structures, an adjustment current I is obtained which is inversely proportional to the absolute temperature ctat The regulated current I ctat Power supply V of slave current stabilizing circuit cc_ptat Pulled down to the feedback node FB.
The current stabilizing circuit shown in fig. 9 has a current I inversely proportional to the temperature as the temperature decreases ctat Increase, presume reference current I ramp And compensation current I comp All unchanged, then the sampling current I of the power output stage sense With a consequent reduction, which indicates a reduction in the current flowing through the power transistor in the power output stage, so that the output power V of the radio frequency power amplifier out And (3) reducing. At the same time, the feedback voltage V of the feedback node FB fb Regulator tube M of low dropout regulator in boost, voltage-to-current conversion circuit A Gate voltage V of (2) g (i.e. the output voltage of the operational amplifier OP) increases, reducing the output voltage V of the LDO ldo . This reduces the supply voltage of the pre-amplifier, reduces the gain of the pre-amplifier, and improves the stability of the radio frequency power amplifier.
Referring to fig. 10, an isolated schematic diagram of the power supply of each module of the high-stability rf power amplifier provided in the present application is shown. As shown in FIG. 1, the high-stability RF power amplifier of the present application comprises five modules, namely a pre-amplifier, a power output stage, a voltage-to-current conversion circuit, a supply voltage compensation circuit and a current stabilizing circuit The respective power supplies are V ldo 、V cc_ps 、V cc_vi 、V cc_comp And V cc_ptat . The modules have larger high-frequency interference and coupling, positive feedback is easy to generate, and stability is caused. Thus, the present application inserts isolation circuits between the power supplies of the modules, and one isolation circuit is shown in fig. 10 by a dotted line, so as to improve the stability of the rf power amplifier.
Referring to fig. 11, a schematic diagram of the isolation of the modules of the rf power amplifier with high stability is shown. As shown in fig. 1, the high-stability rf power amplifier of the present application includes five modules, which are a pre-amplifier, a power output stage, a voltage-to-current conversion circuit, a power supply voltage compensation circuit, and a current stabilization circuit, respectively, and are gnd_pre, gnd_ps, gnd_vi, gnd_comp, and gnd_ptat, respectively. The modules have larger high-frequency interference and coupling, positive feedback is easy to generate, and stability is caused. Therefore, the isolation circuits are inserted between the grounds of the modules in pairs, and one isolation circuit is shown by a dotted line in fig. 11 to improve the stability of the radio frequency power amplifier.
Please refer to fig. 12a, which is a first embodiment of the isolation circuit of fig. 10 and 11. The isolation circuit of the embodiment is an RLC parallel circuit, and an isolation resistor Ri, an isolation inductor Li and an isolation capacitor Ci are connected in parallel between two objects ISO1 and ISO2 needing to be isolated.
Please refer to fig. 12b, which is a second embodiment of the isolation circuit of fig. 10 and 11. The isolation circuit of this embodiment is an RC and LC filter circuit, and the isolation resistor Ri and the isolation inductor Li are both connected in parallel between two objects ISO1 and ISO2 that need to be isolated. The isolation capacitor Ci connects one object ISO2 to be isolated and a separate ground Clean gnd.
Please refer to fig. 12c, which is a third embodiment of the isolation circuit of fig. 10 and 11. The isolation circuit of the embodiment is of an end-to-end diode structure, the isolation diode I Di1 is reversely connected between two objects ISO1 and ISO2 needing to be isolated, and the isolation diode II Di2 is positively connected between the two objects ISO1 and ISO2 needing to be isolated.
In other embodiments, the isolation circuit may be selected as a form of open circuit (open circuit) or short circuit, as desired.
The foregoing is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and changes may be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims (18)
1. The high-stability radio frequency power amplifier is characterized by comprising a pre-amplifier, a power output stage, a voltage-current conversion circuit, a power supply voltage compensation circuit and a current stabilizing circuit;
The pre-amplifier is used for pre-amplifying the radio frequency input signal;
the power output stage comprises a power amplifying circuit and a current sampling circuit; the power amplifying circuit is used for amplifying the power of the radio frequency signal which is amplified in advance under the control of the control voltage to obtain output power; the current sampling circuit is used for sampling the current flowing through the power transistor in the power output stage to obtain a sampling current;
the voltage-current conversion circuit comprises an operational amplifier, a low dropout voltage regulator, a loop stabilizing auxiliary circuit and a feedback circuit; the voltage-current conversion circuit is used for converting control voltage into reference current, comparing the reference current with sampling current of the power output stage through the operational amplifier, and connecting a comparison result into the low-dropout voltage regulator which provides power supply voltage for the pre-amplifier; the loop stabilizing auxiliary circuit and the feedback circuit are connected in series between the output end and the non-inverting input end of the operational amplifier;
the power supply voltage compensation circuit is used for compensating output power variation caused by power supply voltage variation of the power output stage;
the current stabilizing circuit is used for adjusting the current flowing through the power transistor in the power output stage to the change of temperature.
2. The high stability rf power amplifier of claim 1, wherein the pre-amplifier comprises an inverter and a feedback resistor; the inverter is formed by cascading a PMOS transistor and an NMOS transistor in sequence between the power supply voltage of the pre-amplifier and the ground, the grid electrodes of the two transistors are connected to serve as the input end of the inverter, and the drain electrodes of the two transistors are connected to serve as the output end of the inverter; the feedback resistor is connected between the input and output terminals of the inverter.
3. The high stability rf power amplifier of claim 1 wherein the power amplifying circuit is a cascade of an inductor, a cascode transistor, and a cascode transistor in sequence between a supply voltage of the power output stage and ground; the common source transistor and the common gate transistor form a common source and common gate structure I;
the current sampling circuit comprises a second cascode structure, and the second cascode structure and the first cascode structure form a cascode current mirror structure for sampling the current flowing through two power transistors in the power amplifying circuit; the current sampling circuit further comprises a second current mirror structure, and the second current mirror structure further reduces the intermediate sampling current output by the cascode current mirror to obtain the final sampling current output by the current sampling circuit.
4. The high-stability radio frequency power amplifier according to claim 1, wherein the voltage-to-current conversion circuit further comprises a filtering unit and a voltage generating unit; the control voltage is connected to the inverting input end of the operational amplifier through the filtering unit, and the sampling current of the power output stage generates feedback voltage at the non-inverting input end of the operational amplifier through the voltage generating unit; the output end of the operational amplifier is connected with the grid electrode of the adjusting tube of the low-dropout voltage regulator; the drain of the low dropout regulator supplies power to the preamplifier.
5. The high stability rf power amplifier of claim 4, wherein the filter unit comprises a filter resistor and a filter capacitor, the control voltage is coupled to the inverting input of the operational amplifier through the filter resistor, and the inverting input of the operational amplifier is further coupled to ground through the filter capacitor.
6. The high stability rf power amplifier of claim 4, wherein the voltage generating unit is a parallel branch of a first resistor and a second resistor, one end of the parallel branch being grounded, and the other end being connected to the non-inverting input of the operational amplifier.
7. The high stability rf power amplifier of claim 1 wherein the loop stabilization auxiliary circuit comprises an auxiliary low dropout regulator; the grid electrode of the adjusting tube of the auxiliary low-dropout voltage regulator is connected with the output end of the operational amplifier, the source electrode is connected with the power supply voltage, the drain electrode is grounded through a load resistor on one hand, and the drain electrode is connected to the non-inverting input end of the operational amplifier through a feedback circuit on the other hand.
8. The high stability radio frequency power amplifier of claim 6, wherein the voltage to current conversion circuit further comprises a PVT curve adjustment circuit; the PVT curve adjusting circuit is formed by adding an NMOS transistor or a PMOS transistor which is connected in series and is in a diode structure between the resistor II and the ground or between the non-inverting input end of the operational amplifier and the resistor II.
9. The high stability radio frequency power amplifier of claim 1, wherein the voltage to current conversion circuit further comprises a miller compensation circuit; the miller compensation circuit is connected between the grid electrode and the drain electrode of the adjusting tube of the low dropout voltage regulator and comprises a miller capacitor connected in series with a zero-setting resistor.
10. The high stability rf power amplifier of claim 6, wherein the voltage to current conversion circuit further comprises a temperature compensation circuit; the temperature compensation circuit is formed by connecting a resistor with a positive temperature coefficient and a resistor with a negative temperature coefficient in series.
11. The high stability rf power amplifier of claim 1, wherein the supply voltage compensation circuit comprises a differential amplifier circuit and a current mirror; the differential amplifying circuit tracks the change of the power supply voltage, and the current mirror generates compensation current with the same change trend of the power supply voltage.
12. The high stability rf power amplifier of claim 1 wherein the current stabilizing circuit comprises a positive temperature coefficient current source, transistor fifteen and transistor sixteen; the positive temperature coefficient current source and the transistor fifteen are sequentially connected in series between the power supply and the ground of the current stabilizing circuit; the grid electrode and the drain electrode of the transistor fifteen are connected and connected with a positive temperature coefficient current source; the source electrode of the transistor fifteen is connected with the ground of the current stabilizing circuit; the grid electrode of the transistor sixteen is connected with the grid electrode of the transistor fifteen, the drain electrode of the transistor sixteen is connected with the non-inverting input end of the operational amplifier, and the source electrode of the transistor sixteen is connected with the ground of the current stabilizing circuit.
13. The high stability rf power amplifier of claim 1, wherein the current stabilizing circuit comprises a negative temperature coefficient current source, transistor seventeen through transistor twenty; the negative temperature coefficient current source and the transistor seventeen are sequentially connected in series between the power supply and the ground of the current stabilizing circuit; the grid electrode and the drain electrode of the transistor seventeen are connected and connected with a negative temperature coefficient current source; the source electrode of the transistor seventeen is connected with the ground of the current stabilizing circuit; a grid electrode of the transistor eighteen is connected with a grid electrode of the transistor seventeen, a drain electrode of the transistor nineteen is connected with a drain electrode of the transistor, and a source electrode of the transistor eighteen is connected with the ground of the current stabilizing circuit; the grid electrode and the drain electrode of the transistor nineteenth are connected, and the source electrode is connected with a power supply of the current stabilizing circuit; the grid electrode of the transistor twenty is connected with the grid electrode of the transistor nineteenth, the source electrode is connected with the power supply of the current stabilizing circuit, and the drain electrode is connected with the non-inverting input end of the operational amplifier.
14. The high stability rf power amplifier of claim 1, wherein the pre-amplifier, the power output stage, the voltage to current conversion circuit, the supply voltage compensation circuit, and the current stabilizing circuit each have isolation circuits between their respective power supplies.
15. The high stability rf power amplifier of claim 1, wherein the pre-amplifier, the power output stage, the voltage to current conversion circuit, the supply voltage compensation circuit, and the current stabilizing circuit each have an isolation circuit between their grounds.
16. The high-stability rf power amplifier of claim 14 or 15, wherein the isolation circuit is an isolation resistor, an isolation inductor, and an isolation capacitor connected in parallel between two objects to be isolated.
17. The high stability rf power amplifier of claim 14 or 15, wherein the isolation circuit is an isolation resistor and an isolation inductor connected in parallel between two objects to be isolated, and an isolation capacitor connects one object to be isolated and a separate ground.
18. The high stability rf power amplifier of claim 14 or 15, wherein the isolation circuit is a diode structure connected end to end, one isolation diode being connected in reverse between two objects to be isolated, the other isolation diode being connected in forward between two objects to be isolated.
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