An amplifier gain temperature drift compensation circuit

Abstract

The application discloses an amplifier gain temperature drift compensation circuit, which comprises a PTAT circuit, an LDO voltage stabilizing circuit and an amplifying circuit; the PTAT circuit is used for generating a PTAT voltage Vt proportional to absolute temperature; the LDO voltage stabilizing circuit is connected with the PTAT circuit, and is used for generating a power supply voltage VB proportional to absolute temperature according to the PTAT voltage; the amplifying circuit is connected with the LDO voltage stabilizing circuit, and is powered by the power supply voltage VB; the temperature characteristic of the gain of the amplifying circuit is opposite to the temperature characteristic of the power supply voltage VB. The PTAT circuit and the LDO voltage stabilizing circuit can realize gain temperature drift compensation of the amplifying circuit, without changing the original topology of the amplifying circuit, without increasing the design complexity, and with low cost, high reliability, better noise and linearity, and being suitable for various signal amplification scenes requiring stable gain.

Description

Technical Field

[0001] This invention relates to the field of amplifiers, and in particular to an amplifier gain temperature drift compensation circuit. Background Technology

[0002] In existing RF and analog integrated circuits, the gain of amplifiers will drift significantly with temperature (i.e., gain will drift due to temperature). The main reason is that the transistor threshold voltage, carrier mobility, current gain and other parameters of the amplifier will change with temperature, which will eventually manifest as the gain changing with temperature, causing the gain to deviate from the design value.

[0003] Currently, the main methods for compensating for gain drift in amplifiers are as follows: 1. Add a temperature compensation bias circuit inside the amplifier to adjust the gate bias voltage of the amplifier to counteract the effect of temperature on gain. The drawbacks of this method are: it increases the design complexity of the amplifier and destroys the original topology; moreover, the temperature compensation bias circuit is coupled with the main circuit of the amplifier, affecting performance such as noise and linearity. 2. Using digital calibration technology, temperature information is collected by a temperature sensor, and the digital circuit adjusts the gain resistor or bias current of the amplifier accordingly based on the temperature information to achieve gain calibration; this method requires the addition of an extra temperature sensor and digital control circuit, which is costly.

[0004] In view of the above problems, it is necessary to study an amplifier gain temperature drift compensation circuit to overcome the shortcomings of the existing technology. Summary of the Invention

[0005] The purpose of this invention is to provide an amplifier gain temperature drift compensation circuit to overcome the shortcomings of the prior art.

[0006] To achieve the above objectives, the solution of the present invention is: An amplifier gain temperature drift compensation circuit includes a PTAT circuit, an LDO voltage regulator circuit, and an amplifier circuit. The PTAT circuit generates a PTAT voltage Vt proportional to the absolute temperature. The LDO voltage regulator circuit is connected to the PTAT circuit and generates a power supply voltage VB proportional to the absolute temperature based on the PTAT voltage. The amplifier circuit is connected to the LDO voltage regulator circuit and is powered by the power supply voltage VB. The temperature characteristic of the amplifier circuit's gain is opposite to the temperature characteristic of the power supply voltage VB.

[0007] The LDO voltage regulator circuit includes an error amplifier EA, a MOSFET M21, and a feedback network. The non-inverting input of the error amplifier EA is connected to the reference terminal of the LDO voltage regulator circuit. The output of the error amplifier EA is connected to the gate of the MOSFET M21, and the source of the MOSFET M21 is connected to the driving power supply VDD. The drain of the MOSFET M21 is connected to the output of the LDO voltage regulator circuit. The feedback network is connected to the output of the LDO voltage regulator circuit and the inverting input of the error amplifier EA. The reference terminal of the LDO voltage regulator circuit is connected to the output of the PTAT circuit and is used to input the PTAT voltage Vt. The output of the LDO voltage regulator circuit is used to output the power supply voltage VB.

[0008] The feedback network includes resistors R21 and R22. The first end of resistor R21 is connected to the output of the LDO voltage regulator circuit, the second end of resistor R21 and the first end of resistor R22 are connected to the inverting input of error amplifier EA, and the second end of resistor R22 is grounded.

[0009] The amplifier circuit uses a radio frequency amplifier circuit.

[0010] The amplifier circuit includes MOSFETs M31, M32, M33, and M34; resistors R31, R32, R33, R34, R35, R36, R37, R38, and R39; capacitors C31 and C32; and a current source I31. The first terminals of capacitors C31 and C32 are connected to the first and second input terminals of the amplifier circuit, respectively. The second terminal of capacitor C31 is connected to the gate of MOSFET M32 and the first terminal of resistor R37. The second terminal of capacitor C32 is connected to the gate of MOSFET M31 and the first terminal of resistor R36. The sources of MOSFETs M31 and M32 are connected to the first terminal of current source I31. The second terminal of current source I31 and the first terminal of resistor R39 are grounded. The second terminal of resistor R39 is connected to the second terminal of resistor R36. The second terminal of resistor R37 and the first terminal of resistor R38 are connected. The drain of MOSFET M31 is connected to the source of MOSFET M33, and the drain of MOSFET M32 is connected to the source of MOSFET M34. The gates of MOSFET M33 and M34 are connected to the first terminal of resistor R35. The second terminal of resistor R35 is connected to the first terminals of resistors R33 and R34. The drain of MOSFET M34, the second terminal of resistor R34, and the first terminal of resistor R32 are connected to the first output terminal of the amplifier circuit. The drain of MOSFET M33, the second terminal of resistor R33, and the first terminal of resistor R31 are connected to the second output terminal of the amplifier circuit. The second terminals of resistors R31, R32, and R38 are connected to the power supply terminal of the amplifier circuit. The power supply terminal of the amplifier circuit is connected to the output terminal of the LDO voltage regulator circuit and is used to connect to the power supply voltage VB.

[0011] By adopting the above scheme, the present invention can achieve gain temperature drift compensation of the amplifier circuit through the PTAT circuit and LDO voltage regulator circuit. The setting of the PTAT circuit and LDO voltage regulator circuit does not require modification of the original topology of the amplifier circuit, and does not add extra design complexity. Furthermore, the PTAT circuit and LDO voltage regulator circuit are fully analog circuits, which do not require a digital control unit, resulting in low cost, high reliability, and better noise and linearity. They are suitable for various signal amplification scenarios that require stable gain. Attached Figure Description

[0012] Figure 1 This is the circuit schematic diagram of the present invention.

[0013] Figure 2 This is a circuit diagram of the PTAT circuit of the present invention. Detailed Implementation

[0014] To further explain the technical solution of the present invention, the present invention will be described in detail below through specific embodiments.

[0015] like Figure 1 As shown, this invention discloses an amplifier gain temperature drift compensation circuit, which includes a PTAT (Proportional To Absolute Temperature) circuit, an LDO (Low Dropout Linear Regulator) voltage regulator circuit, and an amplifier circuit. The PTAT circuit generates a PTAT voltage Vt proportional to the absolute temperature. The LDO voltage regulator circuit is connected to the PTAT circuit and generates a power supply voltage VB proportional to the absolute temperature based on the PTAT voltage. The amplifier circuit is connected to the LDO voltage regulator circuit and is powered by the power supply voltage VB. The temperature characteristic of the amplifier circuit's gain is opposite to the temperature characteristic of the power supply voltage VB.

[0016] The working principle of this invention is as follows: the PTAT circuit generates a PTAT voltage Vt that is proportional to the absolute temperature in real time. This PTAT voltage Vt is used as a reference voltage for the LDO voltage regulator circuit, so that the LDO voltage regulator circuit generates a power supply voltage VB that is proportional to the absolute temperature to power the amplifier circuit. The gain compensation brought to the amplifier circuit by the change of the power supply voltage VB with temperature can offset the gain shift of the amplifier circuit itself caused by the change of temperature, thereby realizing that the overall gain of the amplifier circuit does not change with temperature, thus compensating for the gain temperature drift of the amplifier. To facilitate understanding, the following scenario illustrates the problem: "The gain of the amplifier circuit decreases with increasing temperature, while the power supply voltage VB increases with increasing temperature." When the ambient temperature rises, the threshold voltage (Vth) of each MOSFET in the amplifier circuit decreases, and the carrier mobility decreases, leading to a decrease in the gain of the amplifier circuit. At this time, the PTAT circuit senses the increase in ambient temperature, and its output PTAT voltage Vt also increases synchronously, causing the power supply voltage VB output by the LDO regulator circuit to also increase synchronously. As the supply voltage for the amplifier circuit, the increase in the power supply voltage VB directly increases the gain of the amplifier circuit (i.e., the increase in the power supply voltage VB increases the bias voltage of each MOSFET in the amplifier circuit), thus precisely offsetting the gain decrease caused by the increase in ambient temperature.

[0017] In embodiments of the present invention, in conjunction with Figure 2 As shown, the PTAT circuit may include transistors Q11 and Q12, MOSFETs M11, M12, and M13, resistors R11 and R12, and an operational amplifier OP. The gate and collector of transistor Q11 are grounded, and the emitter of transistor Q11 is connected to the inverting input terminal of the transport amplifier OP and the drain of MOSFET M11. The gate and collector of transistor Q12 are grounded, and the emitter of transistor Q12 is connected to the first terminal of resistor R11. The second terminal of resistor R11 is connected to the transport amplifier OP. The non-inverting input of the transport amplifier OP is connected to the drain of MOSFET M12. The output of the transport amplifier OP is connected to the gates of MOSFETs M11, M12, and M13. The sources of MOSFETs M11, M12, and M13 are connected to the control power supply VCC. The drain of MOSFET M13 and the first terminal of resistor R12 are connected to the output of the PTAT circuit. The output of the PTAT circuit is used to output the PTAT voltage Vt, while the second terminal of resistor R12 is grounded. This PTAT circuit utilizes the characteristic that the base-emitter voltage of bipolar transistors (i.e., transistors Q11 and Q12) changes with temperature to generate a PTAT voltage Vt that is proportional to the absolute temperature.

[0018] In an embodiment of the present invention, the LDO voltage regulator circuit may include an error amplifier EA, a MOSFET M21, and a feedback network; the non-inverting input of the error amplifier EA is connected to the reference terminal of the LDO voltage regulator circuit; the output of the error amplifier EA is connected to the gate of the MOSFET M21, and the source of the MOSFET M21 is connected to the driving power supply VDD; the drain of the MOSFET M21 is connected to the output of the LDO voltage regulator circuit; the feedback network is connected to the output of the LDO voltage regulator circuit and the inverting input of the error amplifier EA; the feedback network may include resistors R21 and R22; the first end of resistor R21 is connected to the output of the LDO voltage regulator circuit; the second end of resistor R21 and the first end of resistor R22 are connected to the inverting input of the error amplifier EA; the second end of resistor R22 is grounded; the reference terminal of the LDO voltage regulator circuit is connected to the output of the PTAT circuit and used to input the PTAT voltage Vt; the output of the LDO voltage regulator circuit is used to output the power supply voltage VB. The feedback network generates a feedback voltage VF based on the power supply voltage VB output by the LDO regulator circuit and sends it to the inverting input of the error amplifier EA. The error amplifier EA compares the feedback voltage VF with the PTAT voltage Vt and adjusts the conduction level of the MOSFET M21, thereby regulating the power supply voltage VB output by the entire LDO regulator circuit. When the PTAT voltage Vt changes, the power supply voltage VB output by the LDO regulator circuit also changes synchronously.

[0019] In embodiments of the present invention, the amplification circuit may be a radio frequency amplifier circuit (such as a low-noise amplifier circuit, a driver amplifier circuit, or a power amplifier circuit); the following provides a specific structure of the amplification circuit. Figure 1As shown, the amplifier circuit may include MOSFETs M31, M32, M33, and M34, resistors R31, R32, R33, R34, R35, R36, R37, R38, and R39, capacitors C31 and C32, and a current source I31. The first terminals of capacitors C31 and C32 are connected to the first and second input terminals of the amplifier circuit, respectively. The second terminal of capacitor C31 is connected to the gate of MOSFET M32 and the first terminal of resistor R37. The second terminal of capacitor C32 is connected to the gate of MOSFET M31 and the first terminal of resistor R36. The sources of MOSFETs M31 and M32 are connected to the first terminal of current source I31. The second terminal of current source I31 and the first terminal of resistor R39 are grounded. The second terminal of resistor R39 is connected to the second terminal of resistor R36. The second terminal of resistor R37 and the first terminal of resistor R38 are connected. The drain of MOSFET M31 is connected to the source of MOSFET M33, and the drain of MOSFET M32 is connected to the source of MOSFET M34. The gates of MOSFET M33 and M34 are connected to the first terminal of resistor R35. The second terminal of resistor R35 is connected to the first terminals of resistors R33 and R34. The drain of MOSFET M34, the second terminal of resistor R34, and the first terminal of resistor R32 are connected to the first output terminal of the amplifier circuit. The drain of MOSFET M33, the second terminal of resistor R33, and the first terminal of resistor R31 are connected to the second output terminal of the amplifier circuit. The second terminals of resistors R31, R32, and R38 are connected to the power supply terminal of the amplifier circuit. The power supply terminal of the amplifier circuit is connected to the output terminal of the LDO voltage regulator circuit and is used to connect to the power supply voltage VB.

[0020] In summary, this invention can achieve gain temperature drift compensation for amplifier circuits through PTAT circuits and LDO voltage regulator circuits. The setup of PTAT circuits and LDO voltage regulator circuits does not require modification of the original topology of the amplifier circuit, and does not increase the design complexity. Furthermore, PTAT circuits and LDO voltage regulator circuits are all analog circuits, requiring no digital control unit, resulting in low cost, high reliability, and better noise and linearity. They are suitable for various signal amplification scenarios that require stable gain.

[0021] The above embodiments and figures are not intended to limit the product form and style of the present invention. Any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the patent scope of the present invention.

Claims

1. An amplifier gain temperature drift compensation circuit, characterized in that: This includes PTAT circuits, LDO voltage regulator circuits, and amplifier circuits; The PTAT circuit is used to generate a PTAT voltage Vt that is proportional to the absolute temperature. The LDO voltage regulator circuit is connected to the PTAT circuit. The LDO voltage regulator circuit is used to generate a power supply voltage VB that is proportional to the absolute temperature based on the PTAT voltage. The amplifier circuit is connected to the LDO voltage regulator circuit, and the amplifier circuit is powered by the power supply voltage VB; the temperature characteristic of the amplifier circuit's gain is opposite to the temperature characteristic of the power supply voltage VB.

2. The amplifier gain temperature drift compensation circuit as described in claim 1, characterized in that: The LDO voltage regulator circuit includes an error amplifier EA, a MOSFET M21, and a feedback network; the non-inverting input of the error amplifier EA is connected to the reference terminal of the LDO voltage regulator circuit; the output of the error amplifier EA is connected to the gate of the MOSFET M21, and the source of the MOSFET M21 is connected to the driving power supply VDD. The drain of MOSFET M21 is connected to the output of the LDO regulator circuit, and the feedback network is connected to the output of the LDO regulator circuit and the inverting input of the error amplifier EA. The reference terminal of the LDO voltage regulator circuit is connected to the output terminal of the PTAT circuit and is used to input the PTAT voltage Vt. The output terminal of the LDO voltage regulator circuit is used to output the power supply voltage VB.

3. The amplifier gain temperature drift compensation circuit as described in claim 2, characterized in that: The feedback network includes resistors R21 and R22. The first end of resistor R21 is connected to the output of the LDO voltage regulator circuit, the second end of resistor R21 and the first end of resistor R22 are connected to the inverting input of error amplifier EA, and the second end of resistor R22 is grounded.

4. The amplifier gain temperature drift compensation circuit as described in claim 1, characterized in that: The amplifier circuit uses a radio frequency amplifier circuit.

5. The amplifier gain temperature drift compensation circuit as described in claim 4, characterized in that: The amplifier circuit includes MOSFETs M31, M32, M33, and M34, resistors R31, R32, R33, R34, R35, R36, R37, R38, and R39, capacitors C31 and C32, and current source I31. The first terminals of capacitors C31 and C32 are connected to the first and second input terminals of the amplifier circuit, respectively. The second terminal of capacitor C31 is connected to the gate of MOSFET M32 and the first terminal of resistor R37. The second terminal of capacitor C32 is connected to the gate of MOSFET M31 and the first terminal of resistor R36. The sources of MOSFETs M31 and M32 are connected to the first terminal of current source I31. The second terminal of current source I31 and the first terminal of resistor R39 are grounded. The second terminal of resistor R39 is connected to the second terminals of resistors R36, R37, and R38. The drain of MOSFET M31 is connected to the source of MOSFET M33, and the drain of MOSFET M32 is connected to the source of MOSFET M34. The source of S-channel MOSFET M34, the gate of MOSFET M33, and the gate of MOSFET M34 are connected to the first terminal of resistor R35. The second terminal of resistor R35 is connected to the first terminals of resistors R33 and R34. The drain of MOSFET M34, the second terminal of resistor R34, and the first terminal of resistor R32 are connected to the first output terminal of the amplifier circuit. The drain of MOSFET M33, the second terminal of resistor R33, and the first terminal of resistor R31 are connected to the second output terminal of the amplifier circuit. The second terminals of resistors R31, R32, and R38 are connected to the power supply terminal of the amplifier circuit. The power supply terminal of the amplifier circuit is connected to the output terminal of the LDO voltage regulator circuit and is used to connect to the power supply voltage VB.

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