CN110149098B - Protective circuit of radio frequency power amplifier - Google Patents
Protective circuit of radio frequency power amplifier Download PDFInfo
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- CN110149098B CN110149098B CN201910288289.4A CN201910288289A CN110149098B CN 110149098 B CN110149098 B CN 110149098B CN 201910288289 A CN201910288289 A CN 201910288289A CN 110149098 B CN110149098 B CN 110149098B
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- 230000001681 protective effect Effects 0.000 title description 2
- 238000001514 detection method Methods 0.000 claims description 25
- 239000004973 liquid crystal related substance Substances 0.000 claims description 18
- 230000007423 decrease Effects 0.000 description 16
- 238000010586 diagram Methods 0.000 description 13
- 238000000034 method Methods 0.000 description 8
- 229920006395 saturated elastomer Polymers 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000006870 function Effects 0.000 description 2
- 238000010295 mobile communication Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/52—Circuit arrangements for protecting such amplifiers
Abstract
The embodiment of the application discloses a protection circuit of a power amplifier, which is characterized by at least comprising: a power control circuit and a protection circuit; wherein: the protection circuit is connected with the power control circuit and is used for controlling the inverse relation between the change of the power supply voltage and the change of the voltage drop between the power supply voltage and the output voltage of the protection circuit and transmitting the output voltage of the protection circuit to the power control circuit; the power control circuit is used for acquiring the output voltage of the protection circuit and determining a control voltage based on the output voltage of the protection circuit; and is further configured to obtain a base current through the first transistor based on the control voltage; wherein the change in base current is inversely related to the change in supply voltage.
Description
Technical Field
The application relates to the technical field of power amplifier protection, in particular to a protection circuit of a radio frequency power amplifier.
Background
In order to meet the (PVT) requirements of the third generation partnership project (3rd Generation Partnership Project,3GPP) protocol for a power time template of the output power of the global system for mobile communications (Global System For Mobile Communications, GSM) system in the time domain when the power amplifier is in the saturated mode of operation, the output power of the power amplifier is controlled by an external voltage Vramp; in general, it is possible to realize that the output power of the power amplifier varies with the external voltage Vramp by controlling the base current of the power amplifier. The larger the external voltage Vramp, the larger the base current of the power amplifier, and the larger the output power of the power amplifier.
However, in the existing base current control method, when the power amplifier is operated in the saturation mode (the external voltage Vramp is sufficiently large), the output power of the power amplifier increases with the increase of the power supply voltage; when the output power exceeds the limit of the power amplifier transistor, the power amplifier is blown, and the reliability of the power amplifier is affected.
Disclosure of Invention
Therefore, the embodiment of the application provides a protection circuit of a power amplifier, which improves the reliability of the power amplifier.
The technical scheme of the embodiment of the application is realized as follows:
the embodiment of the application provides a protection circuit of a power amplifier, which at least comprises the following components: a power control circuit and a protection circuit; wherein:
the protection circuit is connected with the power control circuit and is used for controlling the inverse relation between the change of the power supply voltage and the change of the voltage drop between the power supply voltage and the output voltage of the protection circuit and transmitting the output voltage of the protection circuit to the power control circuit;
the power control circuit is used for acquiring the output voltage of the protection circuit and determining a control voltage based on the output voltage of the protection circuit; and is further configured to obtain a base current through the first transistor based on the control voltage; wherein the change in base current is inversely related to the change in supply voltage.
The embodiment of the application provides a protection circuit of a power amplifier, which at least comprises the following components: a power control circuit and a protection circuit; wherein: the protection circuit is connected with the power control circuit and is used for controlling the inverse relation between the change of the power supply voltage and the change of the voltage drop between the power supply voltage and the output voltage of the protection circuit and transmitting the output voltage of the protection circuit to the power control circuit; the power control circuit is used for acquiring the output voltage of the protection circuit and determining a control voltage based on the output voltage of the protection circuit; and is further configured to obtain a base current through the first transistor based on the control voltage; wherein the change in base current is inversely related to the change in supply voltage. In this way, the inverse relation between the change of the power supply voltage and the change of the voltage drop between the power supply voltage and the output voltage of the protection circuit is determined through the protection circuit, and then the inverse relation between the change of the base current and the change of the power supply voltage is determined based on the relation between the output voltage of the protection circuit, the control power supply and the control voltage and the base current; therefore, when the power supply voltage is increased, the protection circuit can limit the base current to be in a lower state, so that the power amplifier is always in an unlimited state, and the reliability of the power amplifier is improved.
Drawings
In the drawings (which are not necessarily drawn to scale), like numerals may describe similar components in different views. Like reference numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example and not by way of limitation, various embodiments discussed herein.
FIG. 1 is a schematic diagram of an electric control circuit in the related art;
fig. 2A is a schematic diagram 1 illustrating a composition structure of an amplifier protection circuit according to an embodiment of the present application;
fig. 2B is a schematic diagram of a composition structure of an amplifier protection circuit according to an embodiment of the present application in fig. 2;
fig. 3A is a schematic diagram of a composition structure of an amplifier protection circuit according to an embodiment of the present application in fig. 3;
fig. 3B is a schematic diagram of a composition structure of an amplifier protection circuit according to an embodiment of the present application in fig. 4;
fig. 4 is a schematic diagram 5 of a composition structure of an amplifier protection circuit according to an embodiment of the present application;
fig. 5 is a schematic diagram of a first current versus supply voltage variation curve of an amplifier protection circuit according to an embodiment of the present application;
FIG. 6 is a schematic diagram illustrating a variation of a voltage drop between a first current and a power supply voltage and a first voltage of an amplifier protection circuit according to an embodiment of the present application;
fig. 7 is a schematic diagram of a variation curve of a voltage drop between a power supply voltage and a first voltage of an amplifier protection circuit according to an embodiment of the present application.
Detailed Description
In the prior art, a control circuit for varying the output power of a power amplifier with an external voltage Vramp by means of a base current is shown in fig. 1. The control circuit shown in fig. 1 includes a power controller 11 and a power amplifier 12. The power controller 11 includes a voltage-to-current converter, an error amplifier, a power tube M, a resistor R, and a current detection resistor Rsense; the power controller 11 obtains an external voltage Vramp through a first end of the voltage-to-current converter, and a first end of a resistor R in the power controller 11 is connected with a power supply module (not shown in the figure) to obtain a power supply voltage Vbat; the second end of the voltage-current converter is connected with the second end of the resistor R and is connected with the positive input end of the error amplifier. In addition, a first end of the current detection resistor Rsense is connected to a power supply module (not shown in the figure) to obtain a power supply voltage Vbat, and a second end is connected to an inverting input end of the error amplifier and a collector of the power amplifier 12, respectively; the output end of the error amplifier is connected with the grid electrode of the power tube; the source of the power tube is connected with the power supply module to obtain the power supply voltage Vbat, and the drain of the power tube is connected with the base of the power amplifier 12.
In the control circuit shown in fig. 1, the voltage-to-current converter is capable of converting an external voltage Vramp into a current Ivi proportional to Vramp, the current Ivi is converted into a forward input voltage v+ of the error amplifier by a resistor R, the output voltage of the error amplifier is Vout, the voltage drop of the current detection resistor Rsense is Vsense, and the collector current Icc of the power amplifier 12 is converted into a reverse input voltage V-of the error amplifier by the current detection resistor Rsense. Due to the imaginary short characteristic of the error amplifier (v+=v-), the reverse input voltage varies with the variation of the forward input voltage. When the external voltage Vramp voltage is increased, the output current Ivi of the voltage-current converter is increased, the forward input voltage V+ of the error amplifier is reduced, the reverse input voltage V-following V+ is reduced, and in order to reduce the voltage at the connecting end of the current detection resistor Rsense and the power amplifier to V-, the output voltage Vout of the error amplifier is reduced, the drain output current Ibase of the power tube is increased, and meanwhile, the collector current Icc of the power amplifier is increased, and the output power is increased; conversely, when the external voltage Vramp decreases, the reverse input voltage V-of the error amplifier increases, vsense decreases, vout increases, ibase decreases, icc decreases, and the output power of the power amplifier decreases.
However, when the external voltage Vramp is in the saturated operation state, as the power supply voltage Vbat increases, the output power of the power amplifier also continuously increases; when the output power exceeds the limit of the power amplifier transistor, the power amplifier is blown, and the reliability of the power amplifier is affected.
In order to solve the above-mentioned problems, an embodiment of the present application provides a protection circuit of a power amplifier, fig. 2 is a schematic diagram of a composition structure of the protection circuit of the power amplifier of the present embodiment, and as shown in fig. 2A, the protection circuit 20 at least includes: a power control circuit 21 and a protection circuit 22; wherein:
the protection circuit 22 is connected with the power control circuit 21, and is used for controlling the inverse relation between the change of the power supply voltage and the change of the voltage drop between the power supply voltage and the output voltage of the protection circuit, and transmitting the output voltage of the protection circuit to the power control circuit;
specifically, the input end of the protection circuit 22 can be connected with a power supply module to obtain the power supply voltage Vbat; and obtains the output voltage Vout of the protection circuit based on the power supply voltage Vbat; therefore, the voltage drop between the supply voltage and the protection circuit output voltage in the above scheme is Vbat-Vout. In this embodiment, the protection circuit functions to control the magnitude of Vbat in inverse relationship to the magnitude of Vbat-Vout.
The power control circuit 21 is configured to obtain a protection circuit output voltage, and determine a control voltage based on the protection circuit output voltage; and is further configured to obtain a base current through the first transistor based on the control voltage; wherein the change in base current is inversely related to the change in supply voltage.
Specifically, the power control circuit 21 is connected to the protection circuit 22 through a wire, and the power control circuit 21 can directly acquire the protection circuit output voltage and can determine the control voltage from the received protection circuit output voltage. In the present embodiment, the power control circuit 21 determines the protection circuit output voltage as the control voltage after acquiring the protection circuit output voltage, that is, the protection circuit output voltage is the same as the control voltage in magnitude.
In addition, the power control circuit 21 has a first transistor (not shown) inside, and the power control circuit 21 converts the control voltage into the base current through the first transistor, and realizes a change in the base current inversely proportional to a change in the power supply voltage based on the relationship between the control voltage and the power supply voltage and the characteristics of the first transistor. That is, as the supply voltage increases, the base current decreases.
Further, based on fig. 2A, the protection circuit of the power amplifier provided in this embodiment further includes a power amplifier 23. Specifically, as shown in fig. 2B, a power amplifier 23 is connected to the power control circuit 21, the power amplifier is configured to obtain a base current of the power control circuit, and the power amplifier obtains an output power based on the base current.
In the present embodiment, by the control of the protection circuit output voltage by the protection circuit 22, the variation relationship between the control voltage and the power supply voltage is restricted, so that the inverse relationship between the variation of the base current in the power control circuit 21 and the variation of the power supply voltage is determined. That is, when the power supply voltage Vbat increases, the protection circuit 22 in this embodiment can limit the base current Ibase of the power amplifier to a lower state, so that the power amplifier always operates in a non-limiting operating state, and further, the reliability of the power amplifier is improved.
An exemplary embodiment of the present application provides a protection circuit of a power amplifier, and fig. 3A is a schematic diagram of another composition structure of the protection circuit of the power amplifier according to the embodiment of the present application, as shown in fig. 3A, where the protection circuit at least includes: a power control circuit 31, a protection circuit 32 and a power amplifier 33.
The protection circuit 32 includes at least: a power supply voltage detection circuit 34 and a clamp circuit 35; wherein:
the output end of the power supply voltage detection circuit 34 is connected with the clamping circuit 35; the clamp circuit 35 is connected to the power control circuit 31, and the power control circuit 31 is connected to the power amplifier 33.
In the solution provided in this embodiment, the supply voltage detection circuit 34 is configured to generate a first current, and control a change of the first current to be in inverse relation to a change of the supply voltage, so as to output the first current to the clamp circuit 35.
Specifically, the power supply voltage detection circuit 34 can be connected to a power supply module (not shown in the figure) to acquire the power supply voltage Vbat; and generates a first current Io based on the power supply voltage Vbat; then, the first current Io is outputted and transferred to the clamp circuit 35. Here, the power supply voltage detection circuit 34 may control the variation of the output first current in inverse relation to the variation of the power supply voltage through its own circuit connection structure.
The clamping circuit 35 is configured to control a direct-proportional relationship between a change of the first current and a change of a voltage drop between the power supply voltage and the output voltage of the protection circuit; and the power supply voltage control circuit is further used for determining that the change of the power supply voltage is in inverse proportion to the change of the voltage drop between the power supply voltage and the output voltage of the protection circuit based on the inverse proportion of the change of the first current to the change of the power supply voltage and the change of the voltage drop between the power supply voltage and the output voltage of the protection circuit.
Specifically, the clamp circuit 35 is connected to the power supply voltage detection circuit 34 through a wire, and receives the first current Io transmitted by the power supply detection circuit; and determines the final output protection circuit output voltage Vout based on the first current Io. By the circuit structure of the clamping circuit, the variation of the first current Io is controlled in direct proportion to the variation of the voltage drop (namely Vbat-Vout) between the power supply voltage and the output voltage of the protection circuit. In this way, since the change in the power supply voltage and the change in the first current are in an inverse relationship and the change in the first current is in a direct relationship with the change in the voltage drop between the power supply voltage and the protection circuit output voltage, it is possible to determine that the power supply voltage is in an inverse relationship with the change in the voltage drop between the power supply voltage and the protection circuit output voltage.
Further, the clamping circuit 35 includes at least a second transistor (not shown), and is further configured to obtain a first voltage based on the first current, and control a change in the first current in direct proportion to a change in a voltage drop between the power supply voltage and the first voltage; the protection circuit is also used for obtaining the output voltage of the protection circuit through the second transistor based on the first voltage; and determining, by the second transistor, that the change in the supply voltage is inversely proportional to the change in the voltage drop between the supply voltage and the protection circuit output voltage.
Here, the second transistor is preferably an NMOS type transistor; after the clamp circuit 35 obtains the first current Io, the first current Io is converted into a first voltage Vo, and the proportional relationship between Io and the voltage drop Vbat-Vo between the power supply voltage and the first voltage is controlled through the circuit structure of the clamp circuit. Further, since Io is inversely proportional to Vbat, which in turn is directly proportional to Vbat-Vo, then Vbat is inversely proportional to Vbat-Vo. Further, since the protection circuit output voltage is obtained by the second transistor and the first voltage, it is determined that Vbat and Vbat-Vout are in an inverse relationship based on the source follower effect of the second transistor.
In the solution provided in this embodiment, the power control circuit 31 comprises a first transistor 301, preferably of PMOS type. In addition, as shown in fig. 3A, the power control circuit 31 further includes: a second error amplifier 302, a fourth resistor 303; wherein, the liquid crystal display device comprises a liquid crystal display device,
the second error amplifier 302 obtains the power supply voltage Vbat and a second preset voltage Vramp through a non-inverting input terminal; the inverting input terminal of the second error amplifier 302 obtains the power supply voltage Vbat through the fourth resistor 303; the output end of the second error amplifier 302 is connected with the clamping circuit 35 and the grid electrode of the first transistor 301; the first transistor 301 obtains a power supply voltage Vbat through a source; the drain of the first transistor 301 is connected to the base of the power amplifier 33;
the first transistor 301 is configured to generate a base current corresponding to a drain through a control voltage of a gate and a power voltage of a source, and transmit the base current to the power amplifier.
Specifically, the positive input end of the second error amplifier 302 is connected to the voltage-current converter 304 and the first end of the fifth resistor 305, and the voltage-current converter 304 is connected to the external power supply module to obtain the second preset voltage Vramp. A second terminal of the fifth resistor 305 is connected to the power supply module, and obtains the power supply voltage Vbat. In addition, the inverting input terminal of the second error amplifier 302 obtains the power supply voltage Vbat through the fourth resistor 303, which specifically includes: the first end of the fourth resistor 303 is connected to the power supply module, the power supply voltage Vbat is obtained, the second end is connected to the inverting input of the second error amplifier 302, and the second end of the fourth resistor 303 is also connected to the collector of the power amplifier.
Further, as can be seen from fig. 3A, the output of the clamp 35 is connected to the output of the second error amplifier 302, and to the gate of the first transistor 301; it can be determined that the voltage at the junction is the same everywhere; that is, the control voltage of the power control circuit 31 is the protection circuit output voltage Vout, and the control voltage is also the input voltage of the gate of the first transistor.
In addition, as can be seen from fig. 3A, the source voltage of the first transistor 301 is Vbat, the gate voltage of the first transistor 301 is Vout, and it can be determined that the voltage drop vgs=vbat-Vout between the gate and the source of the first transistor. In the above analysis, it is known that the clamp circuit 35 is capable of controlling the variation of the supply voltage Vbat in inverse relation to the variation of the voltage drop Vbat-Vout between the supply voltage and the output voltage of the protection circuit; it can be seen that as Vbat increases, vbat-Vout decreases; the voltage drop Vgs between the gate and the source of the first transistor is reduced, and when Vgs is reduced according to the characteristics of the PMOS transistor, the current at the drain is reduced, i.e. Ibase is reduced.
As can be seen from fig. 3A, the power control circuit is connected to the base of the power amplifier through the drain of the first transistor 301, and the power control circuit can control the output power of the power amplifier according to the output base current Ibase. In this embodiment, the second preset voltage Vramp is an external voltage, so that the current level of the base Ibase of the power amplifier can be determined, and the output power of the power amplifier is further controlled. In the application, when the power amplifier works in a saturated state, the power supply voltage Vbat is increased, the power supply voltage detection circuit and the clamping circuit can clamp the base current Ibase in a lower state, so that the power amplifier is always clamped in a non-limiting state, and the reliability of the power amplifier is improved.
In other embodiments of the present application, a level shifting circuit may be added to the power control circuit in order to ensure that the first transistor is not blown. As shown in fig. 3B, the power control circuit 31 further includes: a level shift circuit 36; wherein:
an output terminal of the level shift circuit 36 is connected to a gate of the first transistor 301 of the power control circuit 31; an input terminal of the level shift circuit 36 is connected to an output terminal of the protection circuit 32;
the level shift circuit is configured to control a voltage drop between a voltage output to the gate of the first transistor 301 and a source voltage of the first transistor to be less than a maximum operating voltage of the first transistor.
Specifically, the level shift circuit 36 is capable of shifting the voltage at the input terminal to the output terminal, the input terminal being consistent with the voltage variation at the output terminal. Preferably, the level shift circuit directly translates the voltage at the input terminal to the output terminal; it is simply understood that, in fig. 3B, the input voltage of the level shift circuit 36 is the protection circuit output voltage Vout, and the output voltage of the level shift circuit 36 is vout+vth, so that the gate voltage of the first transistor 301 connected to the output of the level shift circuit is vout+vth.
In addition, the level shift circuit can control a voltage drop between the voltage input to the gate of the first transistor and the source voltage of the first transistor to be smaller than the maximum operation voltage of the first transistor by its own circuit configuration when the power supply voltage Vbat increases. That is, vgs of the first transistor is smaller than the maximum operating voltage.
An exemplary embodiment of the present application provides a protection circuit of a power amplifier, and fig. 4 is a schematic diagram of another composition structure of the protection circuit of the power amplifier according to the embodiment of the present application, as shown in fig. 4, where the protection circuit at least includes: a power control circuit 41, a protection circuit 42 and a power amplifier 43.
The protection circuit 42 further includes: a power supply voltage detection circuit 44 and a clamp circuit 45.
Specifically, the power supply voltage detection circuit 44 includes a first error amplifier 441, a third transistor 442, and a fourth transistor 443; wherein:
the positive input terminal of the first error amplifier 441 is connected to the first resistor 444 to obtain the power supply voltage Vbat; the inverting input terminal of the first error amplifier 441 and the drain electrode of the third transistor 442 are respectively connected to the second resistor 445 to obtain a first preset voltage vcc_i; the output terminal of the first error amplifier 441 is connected to the gate of the third transistor 442 and the gate of the fourth transistor 443, respectively; the source of the third transistor 442 and the source of the fourth transistor 443 are both grounded; the drain of the fourth transistor 443 is connected to the clamp circuit 45;
the fourth transistor 443 is configured to transmit the first current Io generated by the drain to the clamp circuit 45.
Here, the first preset voltage vcc_i is a fixed power supply voltage node inside the circuit, and is not changed with Vbat, and the third transistor 442 and the fourth transistor 443 are preferably NMOS type transistors. In the scheme provided by the application, a first end of a first resistor 444 is connected with a power supply module to acquire a power supply voltage Vbat; a second terminal of the first resistor 444 is connected to the positive input terminal of the first error amplifier 441 and a first terminal of the sixth resistor 446; the second terminal of the sixth resistor 446 is grounded. The resistance value of the first resistor 444 is R1, the resistance value of the sixth resistor is R6, and it can be determined that the forward input voltage V1 of the first error amplifier 441 is (R6/(r1+r6)). The scaling factor a=r6/(r1+r6) is set. In addition, the gate of the fourth transistor 443 is connected to the output terminal of the first error amplifier, and the fourth transistor 443 is capable of mirroring the drain current in the third transistor 442 to the drain of the fourth transistor due to the circuit structure and the characteristics of the transistors, resulting in the first current Io. The drain current of the third transistor has a proportional relationship with the drain current of the fourth transistor.
In the above-described power supply voltage detection circuit, when the power supply voltage Vbat increases, the forward input voltage V1 of the first error amplifier 441 increases, and the reverse input voltage V2 of the first error amplifier 441 also increases according to the virtual short characteristic of the error amplifier; since the first preset voltage vcc_i is fixed, the current across the second resistor 445 decreases; i.e., the drain current of the third transistor 442 decreases. Meanwhile, due to the mirror image relationship between the fourth transistor and the third transistor, the first current Io generated by the drain electrode of the fourth transistor is also reduced. Through the analysis, the power supply voltage detection circuit can control the change of the power supply voltage to be in inverse relation with the change of the first current.
In the protection circuit provided in the present embodiment, the clamp circuit 45 specifically includes a second transistor 451, a third resistor 452, and a first constant current source device 453; wherein, the liquid crystal display device comprises a liquid crystal display device,
the third resistor 452 is connected in parallel with the first constant current source device 453; the third resistor 452 and the first constant current source device 453 acquire a power supply voltage through the parallel first terminals;
the second end of the third resistor connected in parallel with the first constant current source device is respectively connected with the grid electrode of the second transistor and the power supply voltage detection circuit 44; the second transistor obtains a power supply voltage through a drain electrode; the source electrode of the second transistor is connected with the power control circuit;
the second transistor is used for generating a protection circuit output voltage corresponding to the source electrode through the first voltage of the gate electrode and transmitting the protection circuit output voltage to the power control circuit.
In the above scheme, the current of the first constant current source is a fixed value Iref, and the voltage at the connection of the third resistor 452 and the second transistor is the first voltage Vo; the current at the junction of the clamp circuit 45 and the power supply voltage detection circuit is the first current Io. In case the supply voltage Vbat increases, io decreases, since the current at the first constant current source device is unchanged, the current across the third resistor decreases; it can be determined that the voltage drop across the third resistor decreases, i.e., vbat-Vo decreases. That is, the change in the power supply voltage Vbat is inversely proportional to the change in Vbat-Vo. Specifically, fig. 5 is a schematic diagram of the relationship between the first current Io and the power supply voltage Vbat in the present embodiment. The power supply voltage Vbat is larger than or equal to vcc_i/a, where a is a proportionality coefficient, and the magnitude is R6/(r1+r6). Fig. 6 is a relationship between the first current Io and the voltage drop Vbat-Vo between the power voltage and the first voltage in the present embodiment.
Further, the clamp circuit 45 may convert the first voltage Vo into the protection circuit output voltage Vout through the second transistor 451; in the case where the power supply voltage increases, io decreases, vbat-Vo decreases, and the difference between Vout and Vbat decreases based on the source follower effect of the second transistor. That is, the change in the supply voltage Vbat is inversely proportional to the change in Vbat-Vout. From fig. 5 and 6, the relationship of the supply voltage Vbat and the voltage drop Vbat-Vout between the supply voltage and the protection circuit output voltage in fig. 7 can be obtained.
In the scheme provided in the present embodiment, the power control circuit 41 includes a first transistor 411, a second error amplifier 412, a fourth resistor 413, and a level shift circuit 46; wherein, the liquid crystal display device comprises a liquid crystal display device,
the second error amplifier 412 obtains the power supply voltage Vbat and a second preset voltage Vramp through a non-inverting input terminal; an inverting input terminal of the second error amplifier 412 obtains a power supply voltage Vbat through a fourth resistor 413; the output end of the second error amplifier 412 is connected with the input ends of the clamping circuit 45 and the level shifting circuit 46; an output terminal of the level shift circuit 46 is connected to the gate of the first transistor 411; and the first transistor 411 acquires the power supply voltage Vbat through the source; the drain of the first transistor 411 is connected to the base of the power amplifier 43.
Specifically, the positive input end of the second error amplifier 412 is connected to the voltage-current converter 414 and the first end of the fifth resistor 415, and the voltage-current converter 414 is connected to the external power supply module to obtain the second preset voltage Vramp. A second terminal of the fifth resistor 415 is connected to the power supply module, and obtains the power supply voltage Vbat. In addition, the inverting input terminal of the second error amplifier 412 obtains the power supply voltage Vbat through the fourth resistor 413, which specifically includes: the first end of the fourth resistor 413 is connected to the power supply module, and obtains the power supply voltage Vbat, the second end is connected to the inverting input terminal of the second error amplifier 412, and the second end of the fourth resistor 413 is also connected to the collector of the power amplifier.
Further, the level shift circuit 46 includes: a second constant current source device 461 and a fifth transistor 462; wherein, the liquid crystal display device comprises a liquid crystal display device,
the second constant current source device 461 obtains the power supply voltage Vbat through the first terminal;
the fifth transistor 462 obtains a third preset voltage through the drain, is connected to the second terminal of the second constant current source device 461 through the source, and is connected to the gate of the first transistor 411, and is connected to the output terminal of the clamp circuit 45 and the output terminal of the second error amplifier 412 through the gate.
Here, the third preset voltage is a difference Vbat-VT between the power supply voltage and the maximum operating voltage of the first transistor. VT is the maximum operating voltage of the first transistor. In the fifth transistor, the drain electrode of the Vbat-VT is powered, so that the voltage drop Vgs between the gate electrode and the source electrode of the first transistor can not exceed VT at maximum, and the first transistor can be controlled to always work in a non-limiting state, thereby improving the reliability of the first transistor.
The level shift circuit 46 is capable of shifting the voltage at the input terminal to the output terminal, specifically, the input voltage of the level shift circuit 36 is the protection circuit output voltage Vout, the output terminal voltage of the level shift circuit 36 is vout+vth, and the output terminal is always one threshold voltage greater than the voltage at the input terminal.
In the above scheme, when the power amplifier works in a saturated state (i.e. the second preset voltage Vramp is large enough), the power supply voltage Vbat is increased, the first current Io is reduced, vbat-Vo is reduced, the source follower effect of the second transistor reduces the gap between Vbat and Vout, and the voltage drop Vgs (vgs=vbat-Vout) between the gate and the source of the first transistor is reduced through the level shift circuit, so that the base current Ibase is reduced, the output power of the power amplifier is controlled to be reduced, the power amplifier always works in a non-limiting working state, and the reliability of the power amplifier is further improved.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
In the several embodiments provided by the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above described device embodiments are only illustrative, e.g. the division of the units is only one logical function division, and there may be other divisions in practice, such as: multiple units or components may be combined or may be integrated into another system, or some features may be omitted, or not performed. In addition, the various components shown or discussed may be coupled or directly coupled or communicatively coupled to each other via some interface, whether indirectly coupled or communicatively coupled to devices or units, whether electrically, mechanically, or otherwise.
The units described above as separate components may or may not be physically separate, and components shown as units may or may not be physical units; can be located in one place or distributed to a plurality of network units; some or all of the units may be selected according to actual needs to achieve the object of the embodiment of the present application.
In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may be separately used as one unit, or two or more units may be integrated in one unit; the integrated units may be implemented in hardware or in hardware plus software functional units.
Those of ordinary skill in the art will appreciate that: all or part of the steps for implementing the above embodiments may be implemented by hardware related to program instructions, and the foregoing program may be stored in a computer readable storage medium, which when executed, performs steps including the above embodiments; and the aforementioned storage medium includes: a mobile storage device, a Read Only Memory (ROM), a magnetic disk or an optical disk, or the like, which can store program codes.
Alternatively, the above-described integrated units of the present application may be stored in a computer-readable storage medium if implemented in the form of software functional modules and sold or used as separate products. Based on such understanding, the technical solution of an exemplary embodiment of the present application may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a terminal to execute all or part of the circuits described in the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a removable storage device, a ROM, a magnetic disk, or an optical disk.
The foregoing is merely an embodiment of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (10)
1. A protection circuit for a power amplifier, the protection circuit being adapted to be connected to the power amplifier and comprising at least: a power control circuit and a protection circuit; wherein:
the protection circuit is connected with the power control circuit and is used for controlling the inverse relation between the change of the power supply voltage and the change of the voltage drop between the power supply voltage and the output voltage of the protection circuit and transmitting the output voltage of the protection circuit to the power control circuit;
the protection circuit includes at least: a power supply voltage detection circuit and a clamp circuit; wherein, the liquid crystal display device comprises a liquid crystal display device,
the output end of the power supply voltage detection circuit is connected with the clamping circuit; the clamping circuit is connected with the power control circuit, the power supply voltage detection circuit is used for acquiring the change of the power supply voltage, and the clamping circuit is used for outputting the output voltage of the protection circuit according to the change of the power supply voltage; the power control circuit includes: the output end of the second error amplifier is connected with the output end of the clamping circuit and the grid electrode or the base electrode of the first transistor, the output end of the first transistor is used for being connected with a power amplifier, the second error amplifier is used for obtaining the output voltage of the protection circuit, and the control voltage is determined based on the output voltage of the protection circuit; the first transistor is used for obtaining a base current for being transmitted to the power amplifier based on the control voltage; wherein the change in base current is inversely related to the change in supply voltage.
2. The protection circuit of claim 1, further comprising a power amplifier; wherein:
the power amplifier is connected with the power control circuit and used for acquiring the base current of the power control circuit and obtaining output power based on the base current.
3. The protection circuit of claim 1, wherein:
the power control circuit is further configured to determine the output voltage of the protection circuit as the control voltage after obtaining the output voltage of the protection circuit.
4. A protection circuit according to any one of claims 1 to 3, wherein,
the power supply voltage detection circuit is used for generating a first current, controlling the change of the first current to be in inverse relation with the change of the power supply voltage and outputting the first current to the clamping circuit;
the clamping circuit is used for controlling the direct proportion relation between the change of the first current and the change of the voltage drop between the power supply voltage and the output voltage of the protection circuit; and the power supply voltage control circuit is further used for determining that the change of the power supply voltage is in inverse proportion to the change of the voltage drop between the power supply voltage and the output voltage of the protection circuit based on the inverse proportion of the change of the first current to the change of the power supply voltage and the change of the voltage drop between the power supply voltage and the output voltage of the protection circuit.
5. The protection circuit of claim 4, wherein the clamp circuit comprises at least a second transistor; wherein, the liquid crystal display device comprises a liquid crystal display device,
the clamping circuit is used for obtaining a first voltage based on the first current and controlling the change of the first current to be in direct proportion to the change of the voltage drop between the power supply voltage and the first voltage; the protection circuit is also used for obtaining the output voltage of the protection circuit through the second transistor based on the first voltage; and determining, by the second transistor, that the change in the supply voltage is inversely proportional to the change in the voltage drop between the supply voltage and the protection circuit output voltage.
6. The protection circuit of claim 5, wherein the supply voltage detection circuit comprises: a first error amplifier, a third transistor and a fourth transistor; wherein:
the positive input end of the first error amplifier is connected with a first resistor to obtain a power supply voltage; the reverse input end of the first error amplifier and the drain electrode of the third transistor are respectively connected with a second resistor to obtain a first preset voltage; the output end of the first error amplifier is respectively connected with the grid electrode of the third transistor and the grid electrode of the fourth transistor; the source of the third transistor and the source of the fourth transistor are both grounded; the drain electrode of the fourth transistor is connected with the clamping circuit;
the fourth transistor is used for transmitting the first current generated by the drain electrode to the clamping circuit.
7. The protection circuit of claim 5, wherein the clamp circuit further comprises a third resistor and a first constant current source device; wherein, the liquid crystal display device comprises a liquid crystal display device,
the third resistor is connected with the first constant current source device in parallel; the third resistor and the first constant current source device acquire power supply voltage through parallel first ends;
the third resistor and the first constant current source device are respectively connected with the grid electrode of the second transistor and the power supply voltage detection circuit through second ends connected in parallel; the second transistor obtains a power supply voltage through a drain electrode; the source electrode of the second transistor is connected with the power control circuit;
the second transistor is used for generating a protection circuit output voltage corresponding to the source electrode through the first voltage of the gate electrode and the power supply voltage of the drain electrode, and transmitting the protection circuit output voltage to the power control circuit.
8. A protection circuit according to any one of claims 1-3, wherein the power control circuit further comprises: a fourth resistor; wherein, the liquid crystal display device comprises a liquid crystal display device,
the second error amplifier obtains a power supply voltage and a second preset voltage through a non-inverting input end; the reverse input end of the second error amplifier obtains a power supply voltage through a fourth resistor; the first transistor is used for generating a base current corresponding to the drain through the control voltage of the grid electrode and the power supply voltage of the source electrode and transmitting the base current to the power amplifier.
9. A protection circuit according to any one of claims 1-3, wherein the power control circuit further comprises: a level shift circuit; wherein:
the output end of the level shift circuit is connected with the grid electrode of the first transistor of the power control circuit; the input end of the level shift circuit is connected with the output end of the protection circuit;
the level shift circuit is used for controlling the voltage drop between the voltage output to the grid electrode of the first transistor and the source voltage of the first transistor to be smaller than the maximum working voltage of the first transistor.
10. The guard circuit of claim 9, wherein the level shift circuit comprises: a second constant current source device and a fifth transistor; wherein, the liquid crystal display device comprises a liquid crystal display device,
the second constant current source device obtains a power supply voltage through the first end;
the fifth transistor obtains a third preset voltage through a drain electrode, is connected with the second end of the second constant current source device through a source electrode and the grid electrode of the first transistor, and is connected with the output end of the protection circuit and the output end of the second error amplifier through the grid electrode; the third preset voltage is a difference value between a power supply voltage and a maximum working voltage of the first transistor.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910288289.4A CN110149098B (en) | 2019-04-11 | 2019-04-11 | Protective circuit of radio frequency power amplifier |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910288289.4A CN110149098B (en) | 2019-04-11 | 2019-04-11 | Protective circuit of radio frequency power amplifier |
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| CN110149098A CN110149098A (en) | 2019-08-20 |
| CN110149098B true CN110149098B (en) | 2023-10-31 |
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2783334Y (en) * | 2005-02-23 | 2006-05-24 | 华为技术有限公司 | Over current detector |
| CN102193018A (en) * | 2010-02-08 | 2011-09-21 | Nxp股份有限公司 | System and method for sensing an amplifier load current |
| CN102439856A (en) * | 2009-05-21 | 2012-05-02 | 高通股份有限公司 | Adaptive parametric power amplifier protection circuit |
| DE102011106234A1 (en) * | 2011-06-27 | 2012-12-27 | Tesat-Spacecom Gmbh & Co.Kg | Method and apparatus for protecting a high frequency power amplifier against mismatch |
| US8432228B1 (en) * | 2011-07-14 | 2013-04-30 | Anadigics, Inc. | Power control circuit for radio frequency power amplifiers |
| CN103973237A (en) * | 2014-04-30 | 2014-08-06 | 广州钧衡微电子科技有限公司 | Staging overvoltage protection circuit of power amplifier |
| CN205142141U (en) * | 2015-11-06 | 2016-04-06 | 深圳市华乾科技有限公司 | Radio frequency microwave power amplifier's standing wave protection device |
| CN107121999A (en) * | 2017-03-09 | 2017-09-01 | 广州慧智微电子有限公司 | A kind of power control circuit and power amplification circuit |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006111186A1 (en) * | 2005-04-18 | 2006-10-26 | Freescale Semiconductor, Inc | An adaptive protection circuit for a power amplifier |
| EP3020129B1 (en) * | 2013-07-09 | 2021-12-08 | Skyworks Solutions, Inc. | Power amplifier with input power protection circuits |
-
2019
- 2019-04-11 CN CN201910288289.4A patent/CN110149098B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2783334Y (en) * | 2005-02-23 | 2006-05-24 | 华为技术有限公司 | Over current detector |
| CN102439856A (en) * | 2009-05-21 | 2012-05-02 | 高通股份有限公司 | Adaptive parametric power amplifier protection circuit |
| CN102193018A (en) * | 2010-02-08 | 2011-09-21 | Nxp股份有限公司 | System and method for sensing an amplifier load current |
| DE102011106234A1 (en) * | 2011-06-27 | 2012-12-27 | Tesat-Spacecom Gmbh & Co.Kg | Method and apparatus for protecting a high frequency power amplifier against mismatch |
| US8432228B1 (en) * | 2011-07-14 | 2013-04-30 | Anadigics, Inc. | Power control circuit for radio frequency power amplifiers |
| CN103973237A (en) * | 2014-04-30 | 2014-08-06 | 广州钧衡微电子科技有限公司 | Staging overvoltage protection circuit of power amplifier |
| CN205142141U (en) * | 2015-11-06 | 2016-04-06 | 深圳市华乾科技有限公司 | Radio frequency microwave power amplifier's standing wave protection device |
| CN107121999A (en) * | 2017-03-09 | 2017-09-01 | 广州慧智微电子有限公司 | A kind of power control circuit and power amplification circuit |
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| CN110149098A (en) | 2019-08-20 |
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