amplification circuit

Abstract

The amplification circuit includes a switch circuit, an amplifier and a control circuit. The first end of the switch circuit is coupled to a radio frequency signal input terminal or a system voltage terminal, the second end of the switch circuit is coupled to the input terminal of the amplifier, and the control terminal of the switch circuit receives a control signal. The amplifier amplifies the radio frequency signal. The control circuit generates the control signal according to the drive current conducted by the amplifier. When the control circuit determines that the amplifier is operating in a high power state, the control circuit controls the control signal according to the size of the drive current to adjust the conduction degree between the first end and the second end of the switch circuit.

Description

Technical Field

[0001] This invention relates to an amplifier circuit, and more particularly to an amplifier circuit with high power protection. Background Technology

[0002] In wireless communication, the operating environment can change constantly. Therefore, to ensure signal transmission quality, amplifiers are often used to amplify the transmitted signal, thereby improving the quality of signal transmission and reception. However, when the input signal power is high, the transistors in the amplifier may be forced to operate at a higher bias voltage, generating a larger drive current. In this case, excessively high bias voltage and excessive drive current can damage the transistors, causing the amplifier to malfunction.

[0003] In existing technologies, diodes are often placed at the input of amplifiers to clamp the potential of the input signal. However, the characteristics of diodes can reduce the linearity of the amplifier, resulting in the amplifier's performance not meeting expectations. Summary of the Invention

[0004] This invention relates to an amplifier circuit, which includes a switching circuit, an amplifier, and a control circuit.

[0005] The switching circuit has a first terminal, a second terminal, and a control terminal. The first terminal of the switching circuit is coupled to the RF signal input terminal or the system voltage terminal, while the control terminal of the switching circuit receives a first control signal. The amplifier has an input terminal and an output terminal. The input terminal of the amplifier is coupled to the second terminal of the first switching circuit and is used to input the RF signal. The output terminal of the amplifier outputs the amplified RF signal. The control circuit is coupled to the amplifier and generates a first control signal based on the drive current turned on by the amplifier.

[0006] When the control circuit determines that the amplifier is operating in a high-power state, the control circuit controls the first control signal according to the magnitude of the drive current to adjust the conduction degree between the first and second terminals of the switching circuit. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of an amplifier circuit according to an embodiment of the present invention.

[0008] Figure 2 yes Figure 1 A schematic diagram of the node voltage and control signal waveforms of the amplifier circuit under different power conditions.

[0009] Figure 3 This is a schematic diagram of an amplifier circuit according to another embodiment of the present invention.

[0010] Figure 4 This is a schematic diagram of an amplifier circuit according to another embodiment of the present invention.

[0011] Figure 5 This is a schematic diagram of an amplifier circuit according to another embodiment of the present invention.

[0012] Figure 6 This is a schematic diagram of an amplifier circuit according to another embodiment of the present invention.

[0013] Figure 7 This is a schematic diagram of an amplifier circuit according to another embodiment of the present invention.

[0014] Figure 8 This is a schematic diagram of an amplifier circuit according to another embodiment of the present invention.

[0015] Symbol Explanation

[0016] 100, 200, 300, 400, 500, 600, 700: Amplifier circuits

[0017] 110, 140, 210, 240, 250, 260, 340, 360: Switching circuits

[0018] 120, 220, 320, 420, 520: Amplifiers

[0019] 130, 230, 330, 430, 530, 630, 730: Control circuit

[0020] 132, 232, 332, 432, 532, 632 Current Sources

[0021] 134, 234, 334, 434, 534, 634, 734: Comparators

[0022] DR1, DR2, DR3: Reference voltage drop resistors

[0023] M1 to M19: Transistors

[0024] R1 to R7: Resistors

[0025] L1 to L12: Inductors

[0026] RN1: Reference Node

[0027] DN1: Detection Node

[0028] VDD, VSS: System voltage terminals

[0029] SIG RF1 SIG RF2 Radio frequency signals

[0030] Id: Drive current

[0031] Iref1, Iref2: Reference currents

[0032] Vref: Reference voltage

[0033] IN: Signal input terminal

[0034] OUT: Output terminal

[0035] SIGctrl1, SIGctrl2, SIGctrl3, SIGctrl4: Control signals

[0036] 142, 238A, 238B, 342: Inverters

[0037] Vbias: Bias terminal

[0038] VR1, VR2: Voltage divider resistors

[0039] T1, T2, T3: Time Periods Detailed Implementation

[0040] Figure 1 This is a schematic diagram of an amplifier circuit 100 according to an embodiment of the present invention. The amplifier circuit 100 includes a switching circuit 110, an amplifier 120, and a control circuit 130.

[0041] The switching circuit 110 has a first terminal, a second terminal, and a control terminal. The first terminal of the switching circuit 110 can be coupled to the radio frequency signal input terminal IN, and the control terminal of the switching circuit 110 can receive the first control signal SIGctrl1.

[0042] Amplifier 120 has an input terminal and an output terminal. The input terminal of amplifier 120 can be coupled to the second terminal of switching circuit 110 and can receive radio frequency signal SIG. RF1 The output terminal OUT of amplifier 120 can output the amplified radio frequency signal SIG. RF2 .

[0043] Control circuit 130 can be coupled to amplifier 120. Control circuit 130 can generate a first control signal SIGctrl1 based on the drive current Id turned on by amplifier 120, wherein the magnitude of drive current Id is related to the radio frequency signal SIG. RF1 It is related to the power. For example, when the radio frequency signal SIG... RF1 The greater the power, the greater the drive current Id that amplifier 120 conducts.

[0044] In some embodiments, when the control circuit 130 determines that the amplifier 120 is operating in a low-power state, it indicates that the radio frequency signal SIG is present. RF1The power is not large enough to damage amplifier 120. At this time, control circuit 130 can control the first control signal SIGctrl1 to turn on switch circuit 110.

[0045] However, when the control circuit 130 determines that the amplifier 120 is operating in the first high-power state, it indicates that the radio frequency signal SIG... RF1 If the power is too high, potentially damaging amplifier 120, control circuit 130 can control the first control signal SIGctrl1 according to the magnitude of the drive current Id to adjust the conduction level between the first and second terminals of switching circuit 110. In other words, in the first high-power state, the conduction level of switching circuit 110 changes with the magnitude of the drive current Id. For example, when the drive current Id is large, it indicates that the RF signal SIGctrl1... RF1 When the power is relatively high, the control circuit 130 can reduce the conduction level between the first and second terminals of the switching circuit 110 to reduce the RF signal SIG received by the amplifier 120. RF1 The power. In this way, in the RF signal SIG RF1 When the power is high, the input voltage of amplifier 120 can be prevented from being excessively boosted, which could damage the internal transistors.

[0046] Furthermore, when the control circuit 130 determines that the amplifier 120 is operating in the second high-power state, that is, when the radio frequency signal SIG... RF1 When the power is too high, the control circuit 130 can control the first control signal SIGctrl1 to cut off the switching circuit 110, so as to prevent the amplifier 120 from being damaged.

[0047] exist Figure 1 In the amplifier 120, the control circuit 130 may include a comparator 134. The control circuit 130 may also include a current source 132 and / or a reference voltage drop resistor DR1. The comparator 134 has a first input, a second input, and an output. The first input of the comparator 134 may be coupled to a detection node DN1, and the second input of the comparator 134 may be coupled to a reference node RN1 to receive a reference voltage Vref. The detection node DN1 may be located within the amplifier 120. The reference voltage drop resistor DR1 has a first terminal and a second terminal. The first terminal of the reference voltage drop resistor DR1 may be coupled to the system voltage terminal VDD, and the second terminal of the reference voltage drop resistor DR1 may be coupled to the reference node RN1 to generate a reference voltage Vref based on a reference current Iref1. The current source 132 may be coupled to the second terminal of the reference voltage drop resistor DR1 and may provide a reference current Iref1 to generate a voltage difference in the reference voltage drop resistor DR1.

[0048] Comparator 134 can output a first control signal SIGctrl1 based on the voltage at the first input terminal and the voltage at the second input terminal. In some embodiments, the voltage of the detection node DN1 is related to the drive current Id. Therefore, if the reference node RN1 is set to an appropriate voltage value, the change in the drive current Id can be known by comparing the voltages of the detection node DN1 and the reference node RN1, and then the corresponding first control signal SIGctrl1 can be output.

[0049] exist Figure 1 In this amplifier, 120 may include a resistor R1 and a transistor M1. Amplifier 120 may also include an inductor L1. Resistor R1 has a first terminal and a second terminal; the first terminal of resistor R1 may be coupled to the system voltage terminal VDD, and the second terminal of resistor R1 may be coupled to a detection node DN1. Transistor M1 has a first terminal, a second terminal, and a control terminal; the first terminal of transistor M1 may be coupled to the detection node DN1, and the control terminal of transistor M1 may be coupled to the input terminal of amplifier 120. Inductor L1 has a first terminal and a second terminal; the first terminal of inductor L1 may be coupled to the second terminal of transistor M1, and the second terminal of inductor L1 may be coupled to the system voltage terminal VSS. In this case, the control terminal of transistor M1 will receive the radio frequency signal SIG. RF1 And when the radio frequency signal SIG RF1 When the power is high, transistor M1 will conduct a large current, at which time resistor R1 will generate a large voltage drop, causing the voltage of the detection node DN1 to drop.

[0050] Furthermore, in some embodiments, amplifier 120 may also include inductor L2, which may be coupled between resistor R1 and transistor M1. The inductors L1 and / or L2 disposed in amplifier 120 can reduce the radio frequency signal SIG. RF1 To prevent unwanted leakage during amplification, in order to maintain the linearity of amplifier 120.

[0051] In the amplifier circuit 100, the switching circuit 110 may include transistors M17 and M18. Transistor M17 has a first terminal, a second terminal, and a control terminal. The first terminal of transistor M17 may be coupled to the first terminal of the switching circuit 110, and the control terminal of transistor M17 may be coupled to the control terminal of the switching circuit 110. Transistor M18 has a first terminal, a second terminal, and a control terminal. The first terminal of transistor M18 may be coupled to the second terminal of transistor M17, and the control terminal of transistor M18 may be coupled to the control terminal of the switching circuit 110.

[0052] Figure 2This is a schematic diagram of the node voltage and control signal waveforms of an amplifier circuit 100 under different power states according to an embodiment of the present invention. In this embodiment, transistors M17 and M18 can be N-type transistors. In this case, the voltage of the reference node RN1 can be set slightly lower than that of the detection node DN1 at the RF signal SIG. RF1 Since the voltage is low power, during time period T1, when amplifier circuit 100 operates in low power state, comparator 134 will output a high-level first control signal SIGctrl1 to turn on transistors M17 and M18 in switching circuit 110. During time period T2, when amplifier circuit 100 operates in the first high-power state, the detection node DN1 will drop slightly. At this time, the first control signal SIGctrl1 output by comparator 134 will dynamically adjust between low and high potentials, thus dynamically adjusting the conduction level of transistors M17 and M18, so that the voltages of detection node DN1 and reference node RN1 can become closer. For example, in the first high-power state, if the RF signal SIG... RF1 If the signal changes from small to large, then the switching circuit 110 will be turned on from large to small. However, during time period T3, when the amplifier circuit 100 operates in the second high-power state, that is, when the RF signal SIG... RF1 When the power ratio is higher than that in the first high power state, the detection node DN1 will drop significantly. At this time, the control circuit 130 is no longer able to effectively adjust the voltage of the detection node DN1 and the reference node RN1 to a similar range. Therefore, the comparator 134 will output a low-level first control signal SIGctrl1 to turn off the transistors M17 and M18 in the switching circuit 110.

[0053] In some embodiments, the switching circuit 110 may further include resistors R4 and R5. Resistor R4 has a first terminal and a second terminal; the first terminal of resistor R4 is coupled to the first terminal of transistor M17, and the second terminal of resistor R4 is coupled to the second terminal of transistor M17. Resistor R5 has a first terminal and a second terminal; the first terminal of resistor R5 is coupled to the first terminal of transistor M18, and the second terminal of resistor R5 is coupled to the second terminal of transistor M18. Resistors R4 and R5 can be used to balance the drain-source voltages of transistors M17 and M18, respectively.

[0054] In addition, Figure 1 In some embodiments, the amplifier circuit 100 may further include a switching circuit 140. The switching circuit 140 has a first terminal, a second terminal, and a control terminal. The first terminal of the switching circuit 140 may be coupled to the second terminal of the switching circuit 110, the second terminal of the switching circuit 140 may be coupled to the system voltage terminal VSS, and the control terminal of the switching circuit 140 may receive a first control signal SIGctrl1. The switching circuit 140 can provide a radio frequency signal SIG in a high-power state.RF1 The shunt path can further protect amplifier 120.

[0055] For example, when control circuit 130 determines that amplifier 120 is operating in a low-power state, control circuit 130 can control switch circuit 140 to turn off. When control circuit 130 determines that amplifier 120 is operating in a first high-power state, control circuit 130 can also adjust the conduction degree between the first and second terminals of switch circuit 140 according to the magnitude of drive current Id, and the trend of this conduction degree change can be opposite to the trend of the conduction degree change between the first and second terminals of switch circuit 110. That is, in the first high-power state, switch circuit 140 may be turned on in a limited manner to avoid high-power radio frequency signal SIG. RF1 This could damage amplifier 120. For example, in the first high-power state, if the RF signal SIG... RF1 As the power level changes from low to high, the switching circuit 140 will be turned on in an increasing manner. Furthermore, when the control circuit 130 determines that the amplifier 120 is operating in the second high-power state, the control circuit 130 can control the switching circuit 140 to turn on. In this case, even with the presence of a radio frequency signal SIG... RF1 The current can flow into the system voltage terminal VSS through the switching circuit 110 and the shunt path provided by the switching circuit 140, so as to avoid damaging the amplifier 120.

[0056] exist Figure 1 In the switching circuit 140, transistors M19 and M20 may be included. Transistor M19 has a first terminal and a second terminal. The first terminal of transistor M19 may be coupled to the first terminal of switching circuit 140, and the control terminal of transistor M19 may be coupled to the control terminal of switching circuit 140. Transistor M20 has a first terminal and a second terminal. The first terminal of transistor M20 may be coupled to the second terminal of transistor M19, and the control terminal of transistor M20 may be coupled to the control terminal of switching circuit 140.

[0057] Furthermore, in some embodiments, the switching circuit 140 may also include an inverter 142. The inverter 142 has an input terminal and an output terminal; the input terminal of the inverter 142 can receive a first control signal SIGctrl1, while the output terminal of the inverter 142 can output a second control signal SIGctrl2. That is, the control signals of the switching circuits 110 and 140 can be inverted. Although in Figure 1In one embodiment, the switching circuit 140 may include an inverter 142 and use the inverter 142 to generate a second control signal SIGctrl2; however, the invention is not limited thereto. In some other embodiments, the control circuit 130 may additionally include circuitry capable of generating the second control signal SIGctrl2. In this case, the switching circuit 140 may not include an inverter 142 and may directly receive the second control signal SIGctrl2 related to the first control signal SIGctrl1. Figure 1 In one embodiment, the switching circuit 140 may include an inverter 142 and transistors M19 and M20 may be N-channel field-effect transistors (n-channel FETs). In some other embodiments, the inverter 142 may be omitted from the switching circuit 140 and transistors M19 and M20 may be P-channel field-effect transistors (p-channel FETs), so that the control terminals of transistors M19 and M20 directly receive the first control signal SIGctrl1.

[0058] Furthermore, the switching circuit 140 may also include resistors R6 and R7. Resistor R6 has a first terminal and a second terminal; the first terminal of resistor R6 can be coupled to the first terminal of transistor M19, and the second terminal of resistor R6 can be coupled to the second terminal of transistor M19. Resistor R7 has a first terminal and a second terminal; the first terminal of resistor R7 can be coupled to the first terminal of transistor M20, and the second terminal of resistor R7 can be coupled to the second terminal of transistor M20. Resistors R6 and R7 can be used to balance the drain-source voltages of transistors M19 and M20, respectively.

[0059] exist Figure 1 In some embodiments, the amplifier circuit 100 may use switching circuits 110 and 140 to protect the amplifier 120. However, the present invention is not limited thereto. In some embodiments of the present invention, the amplifier circuit 100 may omit the switching circuit 140 and use only the switching circuit 110 to protect the amplifier 120, or the switching circuit 110 may omit the switching circuit and use only the switching circuit 140 to protect the amplifier 120. In other embodiments, the switching circuit 110 or the switching circuit 140 may include only one transistor. For example, the switching circuit 110 may include only one transistor M17 or M18, and the switching circuit 140 may include only one transistor M19 or M20.

[0060] In addition, in some embodiments, the amplifier 120 in the amplifier circuit 100 may also include other components depending on the needs of the system. In this case, the control circuit 130 may also need to be adjusted so that the reference node RN1 can provide the corresponding reference voltage. Figure 3 This is a schematic diagram of an amplifier circuit 200 according to an embodiment of the present invention. Amplifier circuit 200 has a similar structure to amplifier circuit 100 and can operate based on similar principles. Figure 3In this amplifier, amplifier 220 may include resistor R2, transistor M2, and transistor M3. Amplifier 220 may also include inductor L3 and inductor L4.

[0061] Resistor R2 has a first terminal and a second terminal. The first terminal of resistor R2 can be coupled to the system voltage terminal VDD, and the second terminal of resistor R2 can be coupled to the detection node DN1. Inductor L3 has a first terminal and a second terminal. The first terminal of inductor L3 can be coupled to the second terminal of resistor R2. Transistor M2 has a first terminal, a second terminal, and a control terminal. The first terminal of transistor M2 can be coupled to the second terminal of inductor L3 and the output terminal of amplifier 220, and the control terminal of transistor M2 can be coupled to the bias terminal Vbias. Transistor M3 has a first terminal, a second terminal, and a control terminal. The first terminal of transistor M3 can be coupled to the second terminal of transistor M2, and the control terminal of transistor M3 can be coupled to the input terminal of amplifier 220. Inductor L4 has a first terminal and a second terminal. The first terminal of inductor L4 can be coupled to the second terminal of transistor M3, and the second terminal of inductor L4 can be coupled to the system voltage terminal VSS.

[0062] Furthermore, the control circuit 230 may include a reference voltage drop resistor DR1, a transistor M4, and a comparator 234. The control circuit 230 may also include a current source 232. The transistor M4 has a first terminal, a second terminal, and a control terminal. The first terminal of the transistor M4 may be coupled to the second terminal of the reference voltage drop resistor DR1, the second terminal of the transistor M4 may be coupled to the current source 232, and the control terminal of the transistor M4 may be coupled to the bias terminal Vbias. In this way, the control circuit 230 can provide a voltage at the reference node RN1 corresponding to the detection node DN1 of the amplifier 220.

[0063] Furthermore, in Figure 3 In the amplifier circuit 200, switching circuits 250 and 260 may also be included. Switching circuit 250 and switching circuit 210 may have similar structures and operate according to the same principle. Switching circuit 210 has a first terminal, a second terminal, and a control terminal. The first terminal of switching circuit 210 may be coupled to the radio frequency signal input terminal IN, and the control terminal of switching circuit 210 may receive a first control signal SIGctrl1. Switching circuit 250 has a first terminal, a second terminal, and a control terminal. The first terminal of switching circuit 250 may be coupled to the second terminal of switching circuit 210, and the second terminal of switching circuit 250 may be coupled to the input terminal of amplifier 220. The control terminal of switching circuit 250 may receive a third control signal SIGctrl3 related to the first control signal SIGctrl1. For example, the first control signal SIGctrl1 may be the same as the third control signal SIGctrl3.

[0064] Switching circuit 240 has a first terminal, a second terminal, and a control terminal. The first terminal of switching circuit 240 can be coupled to the second terminal of switching circuit 210, and the second terminal of switching circuit 240 can be coupled to the system voltage terminal VSS. The control terminal of switching circuit 240 can receive a second control signal SIGctrl2 related to the first control signal SIGctrl1. Switching circuit 260 has a first terminal, a second terminal, and a control terminal. The first terminal of switching circuit 260 can be coupled to the second terminal of switching circuit 250, and the second terminal of switching circuit 260 can be coupled to the system voltage terminal VSS. The control terminal of switching circuit 260 can receive a fourth control signal SIGctrl4 related to the first control signal SIGctrl1.

[0065] exist Figure 3 In this circuit, control circuit 230 can generate a first control signal SIGctrl1 and can use inverter 238A to generate a second control signal SIGctrl2, which is inverted by the first control signal SIGctrl1, and use inverter 238B to generate a fourth control signal SIGctrl4, which is inverted by the first control signal SIGctrl1. Therefore, switching circuits 210 and 250 can operate synchronously, as can switching circuits 240 and 260. That is, when control circuit 230 determines that amplifier 220 is operating in a low-power state, control circuit 230 can turn on switching circuits 210 and 250 and turn off switching circuits 240 and 260. When control circuit 230 determines that amplifier 220 is operating in a first high-power state, control circuit 230 can adjust the conduction level of switching circuits 210, 240, 250 and 260 according to the magnitude of the drive current Id. Switching circuits 210 and 250 may have the same conduction degree change trend, switching circuits 240 and 260 may have the same conduction degree change trend, and switching circuits 210 and 240 may have opposite conduction degree change trends. When the control circuit 230 determines that the amplifier 220 is operating in the second high power state, the control circuit 230 will turn off switching circuits 210 and 250 and turn on switching circuits 240 and 260.

[0066] However, the present invention does not limit the switching circuits 210 and 250 to receiving the same signal. In some embodiments, the switching circuits 210 and 250 may also receive the first control signal SIGctrl1 and a control signal related to the first control signal SIGctrl1, respectively. Similarly, in some embodiments, the switching circuits 240 and 260 may also receive the second control signal SIGctrl2, or after receiving the first control signal SIGctrl1, share the same inverter to generate the second control signal SIGctrl2.

[0067] Figure 4This is a schematic diagram of an amplifier circuit 300 according to another embodiment of the present invention. Amplifier circuit 300 has a similar structure to amplifier circuit 200 and can operate according to similar principles. However, in amplifier circuit 300, amplifier 320 may include transistor M5, resistor R3, and transistor M6. Amplifier 320 may also include inductors L5 and L6. Inductor L5 has a first terminal and a second terminal, the first terminal of which can be coupled to the system voltage terminal VDD. Transistor M5 has a first terminal and a second terminal, the first terminal of which can be coupled to the second terminal of inductor L5, and the control terminal of transistor M5 can be coupled to the bias terminal Vbias. Resistor R3 has a first terminal and a second terminal, the first terminal of which can be coupled to the second terminal of transistor M5, and the second terminal of resistor R3 can be coupled to the detection node DN1. Transistor M6 has a first terminal, a second terminal, and a control terminal, the first terminal of which can be coupled to the second terminal of resistor R3, and the control terminal of transistor M6 can be coupled to the input terminal of amplifier 320. Inductor L6 has a first terminal and a second terminal. The first terminal of inductor L6 can be coupled to the second terminal of transistor M6, and the second terminal of inductor L6 can be coupled to the system voltage terminal VSS.

[0068] In other words, compared to amplifier circuit 200, in amplifier circuit 300, resistor R3 can be positioned between transistors M5 and M6. In this case, control circuit 330 can also adjust the positions of transistor M7 and reference voltage drop resistor DR1, so that reference node RN1 can provide a voltage corresponding to detection node DN1. For example, control circuit 330 may include transistor M7. Transistor M7 has a first terminal, a second terminal, and a control terminal. The first terminal of transistor M7 can be coupled to the system voltage terminal VDD, the second terminal of transistor M7 can be coupled to the first terminal of reference voltage drop resistor DR1, and the control terminal of transistor M7 can be coupled to the bias terminal Vbias. Furthermore, the second terminal of reference voltage drop resistor DR1 can be coupled to reference node RN1 and current source 332.

[0069] Furthermore, in the amplifier circuit 300, the switching circuit 340 may include an inverter 342, which can invert the first control signal SIGctrl1 to generate a second control signal SIGctrl2. Additionally, the switching circuit 360 may also receive the second control signal SIGctrl2 generated by the inverter 342, thereby reducing the required components.

[0070] In amplifier circuits 100, 200, and 300, resistors R1, R2, and R3 are respectively provided in amplifiers 120, 220, and 320 to provide a voltage related to the drive current Id at the detection node DN1. However, in some embodiments, the voltage drop caused by resistors R1, R2, and R3 may reduce the linearity of amplifiers 120, 220, and 320. Therefore, in some embodiments, the detection node can be located outside the amplifier circuit, such as in the control circuit, to avoid affecting the linear performance of the amplifier.

[0071] Figure 5 This is a schematic diagram of an amplifier circuit 400 according to another embodiment of the present invention. Amplifier circuit 400 has a similar structure to amplifier circuit 100 and can operate according to similar principles. For example, amplifier 420 may include transistor M9. Amplifier 420 may also include inductors L7 and L8. Inductor L7 has a first terminal and a second terminal. The first terminal of inductor L7 can be coupled to the system voltage terminal VDD, and the second terminal of inductor L7 can be coupled to the output terminal of amplifier 420. Transistor M9 has a first terminal, a second terminal, and a control terminal. The first terminal of transistor M9 can be coupled to the second terminal of inductor L7 or the output terminal of amplifier 420, and the control terminal of transistor M9 can be coupled to the input terminal of amplifier 420. Inductor L8 has a first terminal and a second terminal. The first terminal of inductor L8 can be coupled to the second terminal of transistor M9, and the second terminal of inductor L8 can be coupled to the system voltage terminal VSS.

[0072] In this case, the control circuit 430 may include a reference voltage drop resistor DR2, a reference voltage drop resistor DR3, a transistor M8, and a comparator 434. The control circuit 430 may also include a current source 432.

[0073] Reference voltage drop resistor DR2 has a first terminal and a second terminal. The first terminal of reference voltage drop resistor DR2 can be coupled to the system voltage terminal VDD, and the second terminal of reference voltage drop resistor DR2 can be coupled to the detection node DN1. Transistor M8 has a first terminal, a second terminal, and a control terminal. The first terminal of transistor M8 can be coupled to the second terminal of reference voltage drop resistor DR2, the second terminal of transistor M8 can be coupled to the system voltage terminal VSS, and the control terminal of transistor M8 can be coupled to the input terminal of amplifier 420. In this way, the current generated by transistor M8 will change synchronously with the current generated by transistor M9 in amplifier 420, so the voltage on detection node DN1 will also be related to the drive current Id.

[0074] The reference voltage drop resistor DR3 has a first terminal and a second terminal. The first terminal of the reference voltage drop resistor DR3 can be coupled to the system voltage terminal VDD, while the second terminal of the reference voltage drop resistor DR3 can be coupled to the reference node RN1 to generate a reference voltage Vref based on the reference current Iref1. The current source 432 can be coupled to the reference voltage drop resistor DR3 and can provide the reference current Iref1 to cause the reference voltage drop resistor DR3 to generate a voltage drop.

[0075] Comparator 434 has a first input terminal, a second input terminal, and an output terminal. The first input terminal of comparator 434 can be coupled to a detection node DN1, and the second input terminal of comparator 434 can be coupled to a reference node RN1 to receive a reference voltage Vref. The output terminal of comparator 434 can output a first control signal SIGctrl1 based on the voltages of the first and second input terminals to control switching circuits 210, 340, 250, and 360.

[0076] In amplifier circuit 400, since control circuit 430 can generate a voltage related to drive current Id at detection node DN1 through transistor M8 and reference voltage drop resistor DR2, the voltage drop resistor can also be omitted in amplifier 420, thus avoiding affecting the linearity of amplifier 420. Furthermore, in some embodiments, since transistor M8 is mainly for synchronous operation with transistor M9 to generate a detection voltage related to drive current Id at reference voltage drop resistor DR2, the size of transistor M8 can be smaller than the size of transistor M9, thereby reducing the circuit area required for control circuit 430. In some embodiments, the channel width-to-length ratio of transistor M9 can be, for example, but not limited to, eight times the channel width-to-length ratio of transistor M8.

[0077] Figure 6 This is a schematic diagram of an amplifier circuit 500 according to another embodiment of the present invention. Amplifier circuit 500 has a similar structure to amplifier circuit 200 and can operate based on similar principles. Figure 6 In this amplifier, amplifier 520 may include transistors M10 and M11. Amplifier 520 may also include inductors L9 and L10. Inductor L9 has a first terminal and a second terminal, the first terminal of which may be coupled to the system voltage terminal VDD. Transistor M10 has a first terminal, a second terminal, and a control terminal, the first terminal of which may be coupled to the second terminal of inductor L9 and the output terminal of amplifier 520, while the control terminal of transistor M10 may be coupled to the bias terminal Vbias. Transistor M11 has a first terminal, a second terminal, and a control terminal, the first terminal of which may be coupled to the second terminal of transistor M10, while the control terminal of transistor M11 may be coupled to the input terminal of amplifier 520. Inductor L10 has a first terminal and a second terminal, the first terminal of which may be coupled to the second terminal of transistor M11, while the second terminal of inductor L10 may be coupled to the system voltage terminal VSS.

[0078] In this configuration, control circuit 530 may include reference voltage drop resistors DR2 and DR3, transistor M8, comparator 534, transistor M12, and transistor M13. Control circuit 530 may also include current source 532. Transistor M12 has a first terminal, a second terminal, and a control terminal. The first terminal of transistor M12 may be coupled to the second terminal of reference voltage drop resistor DR2, the second terminal of transistor M12 may be coupled to the first terminal of transistor M8, and the control terminal of transistor M12 may be coupled to the bias terminal Vbias. In this way, the current generated by transistors M8 and M12 will change synchronously with the current generated by transistors M11 and M10 in amplifier 520, therefore the voltage on detection node DN1 will also be related to the drive current Id.

[0079] Transistor M13 has a first terminal, a second terminal, and a control terminal. The first terminal of transistor M13 can be coupled to the second terminal of reference voltage drop resistor DR3, the second terminal of transistor M13 can be coupled to current source 532, and the control terminal of transistor M13 can be coupled to bias terminal Vbias.

[0080] Since the control circuit 530 can generate a voltage related to the drive current Id at the detection node DN1 through transistors M8, M12 and reference voltage drop resistor DR2 in amplifier circuit 500, the voltage drop resistor can also be omitted in amplifier 520, thus avoiding affecting the linearity of amplifier 520.

[0081] In the control circuit 530, the detection node DN1 is located between transistor M12 and reference voltage drop resistor DR2, while the reference node RN1 is located between transistor M13 and reference voltage drop resistor DR3. However, in some embodiments, the detection node DN1 and the reference node RN1 may be located in other positions.

[0082] Figure 7 This is a schematic diagram of an amplifier circuit 600 according to another embodiment of the present invention. Amplifier circuit 600 has a similar structure to amplifier circuit 500 and can operate based on similar principles. Figure 7 In the control circuit 630, reference voltage drop resistors DR2 and DR3, transistor M8, comparator 634, transistor M14, and transistor M15 may be included. The control circuit 630 may also include a current source 632.

[0083] Transistor M14 has a first terminal, a second terminal, and a control terminal. The first terminal of transistor M14 can be coupled to the system voltage terminal VDD, and the second terminal of transistor M14 can be coupled to the first terminal of the reference voltage drop resistor DR2. The control terminal of transistor M15 can be coupled to the bias terminal Vbias. In this way, the current generated by transistors M8 and M14 will change synchronously with the current generated by transistors M11 and M10 in amplifier 520. Therefore, the voltage on the detection node DN1 will also be related to the drive current Id.

[0084] Transistor M15 has a first terminal, a second terminal, and a control terminal. The first terminal of transistor M15 can be coupled to the system voltage terminal VDD, the second terminal of transistor M14 can be coupled to the first terminal of the reference voltage drop resistor DR3, and the control terminal of transistor M15 can be coupled to the bias terminal Vbias. Furthermore, in Figure 7 In this configuration, the detection node DN1 can be set between the reference voltage drop resistor DR2 and the transistor M8, while the reference node RN1 can be set between the reference voltage drop resistor DR3 and the current source 632.

[0085] In amplifier circuits 100 to 600, control circuits 130 to 630 may use current sources 132 to 632 to generate a voltage drop across reference voltage drop resistors DR1 or DR3 to provide a corresponding reference voltage Vref at reference node RN1. However, in some embodiments, current sources 132 to 632 may also be replaced by voltage divider resistors.

[0086] Figure 8 This is a schematic diagram of an amplifier circuit 700 according to another embodiment of the present invention. The amplifier circuit 700 has a similar structure to the amplifier circuit 100 and can operate based on similar principles. Figure 8 In the circuit, control circuit 730 may include voltage divider resistors VR1 and VR2 and comparator 734. Voltage divider resistor VR1 has a first terminal and a second terminal. The first terminal of voltage divider resistor VR1 can be coupled to the system voltage terminal VDD, and the second terminal of voltage divider resistor VR1 can be coupled to the reference node RN1. Voltage divider resistor VR2 has a first terminal and a second terminal. The first terminal of voltage divider resistor VR2 can be coupled to the reference node RN1 to provide a reference voltage Vref, and the second terminal of voltage divider resistor VR2 can be coupled to the system voltage terminal VSS.

[0087] In this case, by selecting voltage divider resistors VR1 and VR2 with appropriate resistance values, the required reference voltage Vref can be provided on the reference node RN1, so that the comparator 734 can output the first control signal SIGctrl1 accordingly.

[0088] In summary, the amplification circuit provided by the embodiments of the present invention can control the switching circuit set at the input terminal of the amplifier according to the magnitude of the driving current generated by the amplifier, so as to prevent the amplifier from being damaged due to operation under excessively high power conditions.

[0089] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the scope of the claims of the present invention shall be covered by the present invention.

Claims

1. An amplifier circuit, characterized in that, Include: A first switching circuit has a first terminal coupled to a radio frequency signal input terminal or a first system voltage terminal, a second terminal, and a control terminal for receiving a first control signal. An amplifier has an input terminal coupled to the second terminal of the first switching circuit for inputting a radio frequency signal and an output terminal for outputting an amplified radio frequency signal. A control circuit, coupled to the amplifier, is used to generate the first control signal based on a drive current turned on by the amplifier; and A second switching circuit has a first terminal coupled to the second terminal of the first switching circuit, a second terminal coupled to the first system voltage terminal, and a control terminal for receiving the first control signal or a second control signal related to the first control signal. in: When the control circuit determines that the amplifier is operating in a first high-power state, the control circuit controls the first control signal according to the magnitude of the drive current to adjust the conduction degree between the first terminal and the second terminal of the first switching circuit, and adjusts the conduction degree between the first terminal and the second terminal of the second switching circuit according to the magnitude of the drive current. When the control circuit determines that the amplifier is operating in a low-power state, the control circuit controls the second switching circuit to turn off; and When the control circuit determines that the amplifier is operating in a second high-power state, the control circuit controls the second switching circuit to turn on.

2. The amplifier circuit as described in claim 1, characterized in that, The control circuit includes: A first comparator has a first input terminal coupled to a detection node, a second input terminal coupled to a reference node for inputting a reference voltage, and an output terminal, wherein the first comparator is used to output a first control signal based on the voltage at the first input terminal and the voltage at the second input terminal, and the voltage at the first input terminal is related to the drive current.

3. The amplifier circuit as described in claim 2, characterized in that, The control circuit further includes: A first voltage divider resistor has a first terminal coupled to a second system voltage terminal and a second terminal coupled to the reference node; and A second voltage divider resistor has a first terminal coupled to the reference node for providing the reference voltage, and a second terminal coupled to the first system voltage terminal.

4. The amplifier circuit as described in claim 2, characterized in that, The control circuit further includes: A first reference voltage drop resistor has a first terminal coupled to a second system voltage terminal and a second terminal coupled to the reference node; the first reference voltage drop resistor is used to generate the reference voltage based on a reference current.

5. The amplifier circuit as described in claim 4, characterized in that, The amplifier includes: A first resistor having a first terminal coupled to the second system voltage terminal and a second terminal coupled to the detection node; and A first transistor has a first terminal coupled to the output terminal of the amplifier, a second terminal, and a control terminal coupled to the input terminal of the amplifier.

6. The amplifier circuit as described in claim 2, characterized in that, The amplifier includes: A second resistor having a first terminal coupled to a second system voltage terminal and a second terminal coupled to the detection node; A second transistor having a first terminal coupled to the detection node and the output terminal of the amplifier, a second terminal, and a control terminal coupled to a bias terminal; and A third transistor has a first terminal coupled to the second terminal of the second transistor, a second terminal, and a control terminal coupled to the input terminal of the amplifier.

7. The amplifier circuit as described in claim 6, characterized in that, The control circuit further includes: A fourth transistor has a first terminal coupled to the second terminal of a first reference voltage drop resistor, the second terminal coupled to a first current source, and a control terminal coupled to the bias terminal.

8. The amplifier circuit as described in claim 2, characterized in that, The amplifier includes: A fifth transistor has a first terminal coupled to the output terminal of the amplifier, a second terminal, and a control terminal coupled to a bias terminal. A third resistor having a first terminal coupled to the second terminal of the fifth transistor, and a second terminal coupled to the detection node; and A sixth transistor has a first terminal coupled to the second terminal of the third resistor, a second terminal, and a control terminal coupled to the input terminal of the amplifier.

9. The amplifier circuit as described in claim 8, characterized in that, The control circuit further includes: A seventh transistor has a first terminal coupled to a second system voltage terminal, a second terminal coupled to the reference node, and a control terminal coupled to the bias terminal.

10. The amplifier circuit as described in claim 1, characterized in that, The control circuit includes: A second reference voltage drop resistor has a first terminal coupled to a second system voltage terminal and a second terminal coupled to a detection node; An eighth transistor has a first terminal coupled to the second terminal of the second reference voltage drop resistor, a second terminal coupled to the first system voltage terminal, and a control terminal coupled to the input terminal of the amplifier. and A second comparator has a first input terminal coupled to a detection node, a second input terminal coupled to a reference node for inputting a reference voltage, and an output terminal, wherein the second comparator is used to output the first control signal based on the voltage at the first input terminal and the reference voltage at the second input terminal, and the voltage at the first input terminal is related to the drive current.

11. The amplifier circuit as described in claim 10, characterized in that, The control circuit further includes: A third reference voltage drop resistor has a first terminal coupled to the second system voltage terminal and a second terminal coupled to the reference node; the third reference voltage drop resistor is used to generate the reference voltage based on a reference current.

12. The amplifier circuit as described in claim 11, characterized in that, The amplifier includes: A ninth transistor has a first terminal coupled to the output terminal of the amplifier, a second terminal, and a control terminal coupled to the input terminal of the amplifier.

13. The amplifier circuit as described in claim 11, characterized in that, The amplifier includes: A tenth transistor has a first terminal coupled to the output terminal of the amplifier, a second terminal, and a control terminal coupled to a bias terminal; and An eleventh transistor has a first terminal coupled to the second terminal of the tenth transistor, a second terminal, and a control terminal coupled to the input terminal of the amplifier.

14. The amplifier circuit as described in claim 13, characterized in that, The control circuit further includes: A twelfth transistor has a first terminal coupled to the second terminal of the second reference voltage drop resistor, a second terminal coupled to the first terminal of the eighth transistor, and a control terminal coupled to the bias terminal; and A thirteenth transistor has a first terminal coupled to the second terminal of the third reference voltage drop resistor, a second terminal, and a control terminal coupled to the bias terminal.

15. The amplifier circuit as described in claim 11, characterized in that, The control circuit further includes: A fourteenth transistor has a first terminal coupled to the second system voltage terminal, a second terminal coupled to the first terminal of the second reference voltage drop resistor, and a control terminal coupled to a bias terminal. and A fifteenth transistor has a first terminal coupled to the second system voltage terminal, a second terminal coupled to the first terminal of the third reference voltage drop resistor, and a control terminal coupled to the bias terminal.

16. The amplifier circuit as described in claim 1, characterized in that, in: The first terminal of the first switching circuit is coupled to the radio frequency signal input terminal; When the control circuit determines that the amplifier is operating in the low-power state, the control circuit controls the first control signal to turn on the first switching circuit; and When the control circuit determines that the amplifier is operating in the second high-power state, the control circuit controls the first control signal to turn off the first switching circuit.

17. The amplifier circuit as described in claim 1, characterized in that, The second switching circuit further includes: An inverter has an input terminal for receiving the first control signal and an output terminal for outputting the second control signal.

18. The amplifier circuit as described in claim 1, characterized in that, Also includes: A third switching circuit, wherein the third switching circuit has a first terminal coupled to the second terminal of the first switching circuit, a second terminal coupled to the input terminal of the amplifier, and a control terminal for receiving the first control signal or a third control signal related to the first control signal; as well as A fourth switching circuit has a first terminal coupled to the second terminal of the third switching circuit, a second terminal coupled to the first system voltage terminal, and a control terminal for receiving a fourth control signal related to the first control signal. in: When the control circuit determines that the amplifier is operating in the first high-power state, the control circuit adjusts the conduction degree between the first terminal and the second terminal of the third switching circuit and the conduction degree between the first terminal and the second terminal of the fourth switching circuit according to the magnitude of the drive current. When the control circuit determines that the amplifier is operating in the low-power state, the control circuit controls the third switching circuit to turn on and the fourth switching circuit to turn off; and When the control circuit determines that the amplifier is operating in the second high-power state, the control circuit controls the third switch circuit to turn off and the fourth switch circuit to turn on.

19. The amplifier circuit as described in claim 1, characterized in that, The first terminal of the first switching circuit is coupled to the first system voltage terminal, wherein: When the control circuit determines that the amplifier is operating in a low-power state, the control circuit controls the first control signal to turn off the first switching circuit; and When the control circuit determines that the amplifier is operating in a second high-power state, the control circuit controls the first control signal to turn on the first switching circuit.

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