Active phase shifter with temperature compensation

Abstract

The invention discloses an active phase shifter with temperature compensation. The active phase shifter comprises an input transformer balun, a multi-phase filter, a vector modulation module based on a Gilbert unit, an output transformer balun and a positive temperature coefficient current source, the input transformer Balun is used for converting a single-ended signal of an input end into a differential signal; the multi-phase filter is used for converting the differential signal into an orthogonal signal; the vector modulation module based on the Gilbert unit is used for carrying out polarity selection on the orthogonal signals and carrying out vector synthesis; the output transformer Balun is used for converting the output end differential signal into a single-end signal; the positive temperature coefficient current source is used for controlling the gain of the Gilbert unit. By designing the positive temperature coefficient current source changing along with the temperature, the change of the gain of the vector modulation module along with the temperature is slowed down, and the stability of the key performance of the active phase shifter within the temperature range of-55 DEG C to 85 DEG C is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of radio frequency integrated circuit design, and in particular relates to an active phase shifter with temperature compensation. Background Art

[0002] The phase shifter is one of the most critical circuit modules in the phased array transceiver. It can control the signal in the channel to obtain phase shift and generate relative delay, so that the phased array can receive or transmit electromagnetic beams with specific pointing angles. Key indicators of phased array radar, such as beam width and beam scanning resolution, are directly related to parameters such as the phase shift number and phase shift accuracy of the phase shifter.

[0003] Depending on whether the phase shifter uses a variable gain amplifier for vector modulation, it can be divided into active phase shifters and passive phase shifters. Passive phase shifters exhibit wider bandwidth and higher linearity, while active phase shifters have higher precision, smaller area, and higher gain. At present, the common industrial-grade chip temperature application standard is -40 to 85°C, and the military-grade is -55 to 125°C. The application scenarios of phased array radars have strict requirements on the reliability of phase shifters at different temperatures. The variable gain amplifier in the active phase shifter is severely affected by temperature changes, which seriously affects its stable operation in high and low temperature environments.

[0004] Therefore, in the engineering application of active phase shifters, it is imperative to design a temperature compensation scheme for active phase shifters and improve the temperature robustness of active phase shifters. Summary of the invention

[0005] The object of the present invention is to provide an active phase shifter with temperature compensation, which can improve the stability of key performance of the active phase shifter within a temperature range of -55 to 85°C.

[0006] To achieve the above-mentioned object of the invention, one aspect of the present invention provides an active phase shifter with temperature compensation, comprising an input transformer balun, a polyphase filter, a vector modulation module based on a Gilbert cell, an output transformer balun and a positive temperature coefficient current source;

[0007] The input transformer balun is used to convert the single-ended signal at the input end into a differential signal; the multi-phase filter is used to convert the differential signal into an orthogonal signal; the vector modulation module based on the Gilbert unit is used to select the polarity of the orthogonal signal and perform vector synthesis; the output transformer balun is used to convert the differential signal at the output end into a single-ended signal; the positive temperature coefficient current source is used to control the gain of the Gilbert unit.

[0008] Preferably, the input transformer balun has the same structure as the output transformer balun, including first to fourth inductors; the first inductor is coupled to the third inductor, and the second inductor is coupled to the fourth inductor; one end of the first inductor is a single-ended input port, and the other end is connected to one end of the second inductor; the other end of the second inductor is grounded; one end of the third inductor is a first differential output port, and the other end is grounded; one end of the fourth inductor is a second differential output port, and the other end is grounded.

[0009] Preferably, the multi-phase filter comprises four first resistors, four second resistors, four first capacitors and four second capacitors; the first resistors and the first capacitors are cross-connected in series to form a first-order multi-phase filter, and the second resistors and the second capacitors are cross-connected in series to form a second-order multi-phase filter; the first-order multi-phase filter and the second-order multi-phase filter are cascaded to form a second-order multi-phase filter.

[0010] Preferably, the vector modulation module based on the Gilbert unit includes an I-way Gilbert unit, a Q-way Gilbert unit, a first load inductor, and a second load inductor;

[0011] The I-way Gilbert unit has the same structure as the Q-way Gilbert unit, and includes first to fourth bipolar transistors, a first field effect transistor, a second field effect transistor, and a digital-to-analog converter; the bases of the first bipolar transistor and the fourth bipolar transistor are connected to the first orthogonal signal, and the bases of the second bipolar transistor and the third bipolar transistor are connected to the second orthogonal signal; the emitters of the first bipolar transistor and the second bipolar transistor are connected and connected to the source of the first field effect transistor, and the emitters of the third bipolar transistor and the fourth bipolar transistor are connected and connected to the source of the second field effect transistor; the first bipolar transistor and the third bipolar transistor are connected and connected to the source of the second field effect transistor. The collector of the transistor is connected to one end of the first load inductor and is connected to the first output signal, and the other end of the first load inductor is connected to the power supply; the collectors of the second bipolar transistor and the fourth bipolar transistor are connected to one end of the second load inductor and are connected to the second output signal, and the other end of the second load inductor is connected to the power supply; the gate of the first field effect transistor is connected to the first control signal, the gate of the second field effect transistor is connected to the second control signal, and the first control signal and the second control signal are inverted; the sources of the first field effect transistor and the second field effect transistor are connected and connected to the digital-to-analog converter, and the output current of the positive temperature coefficient current source is input to the digital-to-analog converter.

[0012] Preferably, the positive temperature coefficient current source includes third to eleventh field effect transistors and a third resistor; the gates of the third to fifth field effect transistors are connected and connected to ground; the source of the third field effect transistor is connected to the power supply, the drain of the third field effect transistor is connected to the source of the fourth field effect transistor, and the drain of the fourth field effect transistor is connected to the source of the fifth field effect transistor; the drain of the fifth field effect transistor is connected to the drain of the eighth field effect transistor and connected to the gate of the ninth field effect transistor, and the source of the ninth field effect transistor is connected to ground; the sources of the sixth and seventh field effect transistors are connected and connected to the power supply, the gates of the sixth and seventh field effect transistors are connected and connected to the drain of the seventh field effect transistor, the drain of the ninth field effect transistor and the drain of the eleventh field effect transistor; the gates of the eighth, tenth and eleventh field effect transistors are connected and connected to the drain of the tenth field effect transistor and the drain of the sixth field effect transistor, the source of the tenth field effect transistor is connected to ground, the source of the eleventh field effect transistor is connected to one end of the third resistor, and the other end of the third resistor is connected to ground.

[0013] According to the active phase shifter with temperature compensation of the above aspect of the present invention, by designing a positive temperature coefficient current source that changes with temperature, the change of the vector modulation module gain with temperature is slowed down, thereby improving the stability of the key performance of the active phase shifter in the temperature range of -55 to 85°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work:

[0015] Figure 1 The overall structure diagram of an active phase shifter with temperature compensation according to an embodiment of the present invention;

[0016] Figure 2 A circuit diagram of an input and output transformer balun according to an embodiment of the present invention;

[0017] Figure 3 A circuit diagram of a polyphase filter according to an embodiment of the present invention;

[0018] Figure 4 A circuit diagram of a vector modulation module based on a Gilbert unit according to an embodiment of the present invention;

[0019] Figure 5 A circuit diagram of a positive temperature coefficient current source according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] An embodiment of the present invention provides an active phase shifter with temperature compensation, such as Figure 1 As shown, the active phase shifter with temperature compensation of the embodiment of the present invention includes an input transformer balun, a polyphase filter, a vector modulation module based on a Gilbert unit, an output transformer balun and a positive temperature coefficient current source. The input transformer balun is used to convert the single-ended signal at the input end into a differential signal; the polyphase filter is used to convert the differential signal into an orthogonal signal; the vector modulation module based on the Gilbert unit is used to select the polarity of the orthogonal signal and perform vector synthesis; the output transformer balun is used to convert the differential signal at the output end into a single-ended signal; and the positive temperature coefficient current source is used to control the gain of the Gilbert unit.

[0022] The input transformer balun has the same structure as the output transformer balun. Figure 2 As shown, the input and output transformer baluns include first to fourth inductors L1, L2, L3, and L4; the first inductor L1 is coupled to the third inductor L3, and the second inductor L2 is coupled to the fourth inductor L4; one end of the first inductor L1 is a single-ended input port V1, and the other end is connected to one end of the second inductor L2; the other end of the second inductor L2 is grounded; one end of the third inductor L3 is a first differential output port V2+, and the other end is grounded; one end of the fourth inductor L4 is a second differential output port V2-, and the other end is grounded.

[0023] like Figure 3 As shown, the multi-phase filter includes four first resistors R1, four second resistors R2, four first capacitors C1 and four second capacitors C2; the first resistor R1 and the first capacitor C1 are cross-connected in series to form a first-order multi-phase filter, and the second resistor R2 and the second capacitor C2 are cross-connected in series to form a second-order multi-phase filter; the first-order multi-phase filter and the second-order multi-phase filter are cascaded to form a second-order multi-phase filter; the input port of the multi-phase filter is connected to the first and second differential output ports V2+ and V2- of the input transformer balun, and the multi-phase filter outputs the first and second orthogonal signals VI+, VQ+, VI-, VQ-, which are connected to the vector modulation module based on the Gilbert unit.

[0024] like Figure 4As shown, the vector modulation module based on the Gilbert unit includes an I-way Gilbert unit, a Q-way Gilbert unit, and a first load inductor ZL1 and a second load inductor ZL2. The I-way Gilbert unit includes first to fourth bipolar transistors Q1, Q2, Q3, Q4, a first field effect transistor M1, a second field effect transistor M2, and a digital-to-analog converter DAC1; the bases of the first bipolar transistor Q1 and the fourth bipolar transistor Q4 are connected to the first orthogonal signal VI+, and the bases of the second bipolar transistor Q2 and the third bipolar transistor Q3 are connected to the second orthogonal signal VI-; the emitters of the first bipolar transistor Q1 and the second bipolar transistor Q2 are connected and connected to the source of the first field effect transistor M1, and the emitters of the third bipolar transistor Q3 and the fourth bipolar transistor Q4 are connected and connected to the source of the second field effect transistor M2; the collectors of the first bipolar transistor Q1 and the third bipolar transistor Q3 are connected and connected to the source of the second field effect transistor M2. The electrode is connected to one end of the first load inductor ZL1 and connected to the first output signal OUT+, and the other end of the first load inductor ZL1 is connected to the power supply; the collectors of the second bipolar transistor Q2 and the fourth bipolar transistor Q4 are connected to one end of the second load inductor ZL2 and connected to the second output signal OUT-, and the other end of the second load inductor ZL2 is connected to the power supply; the gate of the first field effect transistor M1 is connected to the first control signal VI1, and the gate of the second field effect transistor M2 is connected to the second control signal VI2. The first control signal VI1 and the second control signal VI2 are inverted and used to control the polarity of the first output signal OUT+; the source of the first field effect transistor M1 and the second field effect transistor M2 are connected and connected to the digital-to-analog converter DAC1. The control signal S1 and the output current IP of the positive temperature coefficient current source are input to the digital-to-analog converter DAC1. By inputting different control signals S1 to the digital-to-analog converter DAC1, the digital-to-analog converter DAC1 can output 1, 2, 3, ..., 64 times the IP. The gain of the I-channel Gilbert cell is proportional to the tail current I1 and inversely proportional to the temperature; the tail current I1 of the I-channel Gilbert cell is provided by the digital-to-analog converter DAC1. The structure and working principle of the Q-channel Gilbert cell are the same as those of the I-channel Gilbert cell.

[0025] like Figure 5As shown, the positive temperature coefficient current source includes the third to eleventh field effect transistors MP1, MP2, MP3, MP4, MP5, MN1, MN2, MN3, MN4 and a third resistor R3; the gates of the third to fifth field effect transistors MP1, MP2, MP3 are connected and connected to the ground; the source of the third field effect transistor MP1 is connected to the power supply, the drain of the third field effect transistor MP1 is connected to the source of the fourth field effect transistor MP2, and the drain of the fourth field effect transistor MP2 is connected to the source of the fifth field effect transistor MP3; the drain of the fifth field effect transistor MP3 is connected to the drain of the eighth field effect transistor MN1 and connected to the gate of the ninth field effect transistor MN2, and the ninth field effect transistor The source of the sixth field effect transistor MP4 and the seventh field effect transistor MP5 are connected to each other and are connected to the power supply, the gates of the sixth and the seventh field effect transistors MP4 and MP5 are connected to each other and are connected to the drain of the seventh field effect transistor MP5, the drain of the ninth field effect transistor MN2 and the drain of the eleventh field effect transistor MN4; the gates of the eighth, tenth and eleventh field effect transistors MN1, MN3 and MN4 are connected to each other and are connected to the drain of the tenth field effect transistor MN3 and the drain of the sixth field effect transistor MP4, the source of the tenth field effect transistor MN3 is connected to the ground, the source of the eleventh field effect transistor MN4 is connected to one end of the third resistor R3, and the other end of the third resistor R3 is connected to the ground.

[0026] The third to fifth field effect transistors MP1 to MP3 and the eighth to eleventh field effect transistors MN1 to MN3 are the start-up circuit of the current source, and the sixth, seventh, tenth and eleventh field effect transistors MP4, MP5, MN3, MN4 and the third resistor R3 generate a current with a positive temperature coefficient; the sixth and seventh field effect transistors MP4 and MP5 have the same size and work in the saturation region; the size of the eleventh field effect transistor MN4 is K times that of the tenth field effect transistor MN3, and the tenth and eleventh field effect transistors MN3 and MN4 work in the subthreshold region; the output current IP of the positive temperature coefficient current source is proportional to the temperature; the slope of the output current can be adjusted by changing the multiple K of the size of the eleventh field effect transistor MN4 and the tenth field effect transistor MN3 and the third resistor value R3; in the positive temperature coefficient current source circuit, in addition to the normal working state, there is also a zero degenerate working state; when the circuit just starts to add the power supply voltage, the sixth and seventh field effect transistors MP4 and MP5 are not turned on, and their gate voltages are always kept at a high level , which is also a stable working state of the circuit; in order to make the temperature compensation circuit enter a normal working state, a startup circuit is added outside the circuit; the third to fifth field effect transistors MP1~MP3 are inverse ratio transistors, and the channel length is greater than the channel width, which acts as a resistor; when the circuit is in a zero degenerate working state, the tenth and eleventh field effect transistors MN3 and MN4 are cut off, and their gate voltages are 0; the eighth field effect transistor MN1 in the start-up circuit is cut off, so the source-drain voltage of the eighth field effect transistor MN1 is divided into a high level, thereby causing the eleventh field effect transistor MN4 to be turned on; after the eleventh field effect transistor MN4 is turned on, the gate voltages of the sixth and seventh field effect transistors MP4 and MP5 are pulled down, so that the circuit enters a normal working state; and then the eighth field effect transistor MN1 is turned on accordingly; compared with the resistance of the third to fifth field effect transistors MP1~MP3, the voltage across the source-drain of the eighth field effect transistor MN1 is very small at this time, and the ninth field effect transistor MN2 cannot be turned on, so the startup circuit is closed, which does not affect the normal operation of the circuit.

[0027] The active phase shifter with temperature compensation of the above embodiment of the present invention is tested. In the temperature range of -55 to 85°C, the gain change is less than 0.34 dB, the root mean square phase error change is less than 0.73°, and the root mean square amplitude error change is less than 0.15 dB. It can be seen that the active phase shifter with temperature compensation in the embodiment of the present invention, by designing a positive temperature coefficient current source that changes with temperature, slows down the change of the gain of the vector modulation module with temperature, and effectively improves the stability of the key performance of the active phase shifter in the temperature range of -55 to 85°C.

[0028] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. An active phase shifter with temperature compensation, characterized in that: Includes input transformer balun, polyphase filter, Gilbert cell-based vector modulation module, output transformer balun and positive temperature coefficient current source; The input transformer balun is used to convert the single-ended signal at the input end into a differential signal; the multi-phase filter is used to convert the differential signal into an orthogonal signal; the vector modulation module based on the Gilbert unit is used to select the polarity of the orthogonal signal and perform vector synthesis; the output transformer balun is used to convert the differential signal at the output end into a single-ended signal; the positive temperature coefficient current source is used to control the gain of the Gilbert unit.

2. The active phase shifter with temperature compensation as claimed in claim 1, characterized in that: The input transformer balun has the same structure as the output transformer balun, including the first to fourth inductors; the first inductor is coupled to the third inductor, and the second inductor is coupled to the fourth inductor; one end of the first inductor is a single-ended input port, and the other end is connected to one end of the second inductor; the other end of the second inductor is grounded; one end of the third inductor is a first differential output port, and the other end is grounded; one end of the fourth inductor is a second differential output port, and the other end is grounded.

3. The active phase shifter with temperature compensation according to claim 1 or 2, characterized in that: The multi-phase filter comprises four first resistors, four second resistors, four first capacitors and four second capacitors; the first resistors and the first capacitors are cross-connected in series to form a first-order multi-phase filter, and the second resistors and the second capacitors are cross-connected in series to form a second-order multi-phase filter; the first-order multi-phase filter and the second-order multi-phase filter are cascaded to form a second-order multi-phase filter; the input port of the multi-phase filter is connected to the first and second differential output ports of the input transformer balun, and the multi-phase filter outputs the first and second orthogonal signals, which are connected to the vector modulation module based on the Gilbert unit.

4. The active phase shifter with temperature compensation as claimed in claim 3, characterized in that: The vector modulation module based on the Gilbert unit includes an I-way Gilbert unit, a Q-way Gilbert unit, a first load inductor and a second load inductor; The I-way Gilbert unit has the same structure as the Q-way Gilbert unit, and includes first to fourth bipolar transistors, a first field effect transistor, a second field effect transistor, and a digital-to-analog converter; the bases of the first bipolar transistor and the fourth bipolar transistor are connected to the first orthogonal signal, and the bases of the second bipolar transistor and the third bipolar transistor are connected to the second orthogonal signal; the emitters of the first bipolar transistor and the second bipolar transistor are connected and connected to the source of the first field effect transistor, and the emitters of the third bipolar transistor and the fourth bipolar transistor are connected and connected to the source of the second field effect transistor; the first bipolar transistor and the third bipolar transistor are connected and connected to the source of the second field effect transistor. The collector of the transistor is connected to one end of the first load inductor and is connected to the first output signal, and the other end of the first load inductor is connected to the power supply; the collectors of the second bipolar transistor and the fourth bipolar transistor are connected to one end of the second load inductor and are connected to the second output signal, and the other end of the second load inductor is connected to the power supply; the gate of the first field effect transistor is connected to the first control signal, the gate of the second field effect transistor is connected to the second control signal, and the first control signal and the second control signal are inverted; the sources of the first field effect transistor and the second field effect transistor are connected and connected to the digital-to-analog converter, and the output current of the positive temperature coefficient current source is input to the digital-to-analog converter.

5. The active phase shifter with temperature compensation according to claim 1 or 2, characterized in that: The positive temperature coefficient current source includes third to eleventh field effect transistors and a third resistor; the gates of the third to fifth field effect transistors are connected and connected to the ground; the source of the third field effect transistor is connected to the power supply, the drain of the third field effect transistor is connected to the source of the fourth field effect transistor, and the drain of the fourth field effect transistor is connected to the source of the fifth field effect transistor; The drain of the fifth field effect transistor is connected to the drain of the eighth field effect transistor and is connected to the gate of the ninth field effect transistor, and the source of the ninth field effect transistor is connected to the ground; The sources of the sixth and seventh field effect transistors are connected to each other and to a power supply, and the gates of the sixth and seventh field effect transistors are connected to each other and to the drain of the seventh field effect transistor, the drain of the ninth field effect transistor, and the drain of the eleventh field effect transistor; The gates of the eighth, tenth, and eleventh field effect transistors are connected and connected to the drain of the tenth field effect transistor and the drain of the sixth field effect transistor, the source of the tenth field effect transistor is connected to ground, the source of the eleventh field effect transistor is connected to one end of the third resistor, and the other end of the third resistor is connected to ground.

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