CN111566937A - Automatic amplitude control device and method - Google Patents

Automatic amplitude control device and method Download PDF

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Publication number
CN111566937A
CN111566937A CN201880085040.7A CN201880085040A CN111566937A CN 111566937 A CN111566937 A CN 111566937A CN 201880085040 A CN201880085040 A CN 201880085040A CN 111566937 A CN111566937 A CN 111566937A
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China
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oscillator
coupled
amplitude
current
current source
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Inventor
周涵超
王明贵
陈永权
戴惜时
秦鹏
叶刘晓
宋翔
张�成
何钰娟
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Huawei Technologies Co Ltd
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Huawei Technologies Co Ltd
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00—Automatic control of frequency or phase; Synchronisation
    • H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
    • H03L7/08—Details of the phase-locked loop
    • H03L7/099—Details of the phase-locked loop concerning mainly the controlled oscillator of the loop

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Abstract

The embodiment of the invention provides an automatic amplitude control device and method. The device includes: the device comprises an oscillator and a current source array, wherein one end of the current source array is coupled to a source end of a cross-coupled tube in the oscillator, and the other ends of the current source array are respectively coupled to the ground; the device further comprises: the comparator is used for comparing the amplitude detection signal of the oscillator with a reference voltage signal to obtain a comparison result; and the controller is used for controlling the current coupled to the source end by the current source array according to the comparison result. The embodiment of the invention has the advantages of simple design, small area overhead and low power consumption.

Description

Automatic amplitude control device and method Technical Field
The present disclosure relates to the field of circuits, and more particularly, to an automatic amplitude control apparatus and method.
Background
Under the current process conditions, the variation (variation) of the Process Voltage Temperature (PVT) greatly affects the amplitude of a Voltage Controlled Oscillator (VCO), for the same configuration condition, the Fast NMOS Fast PMOS (FF) corner (corner) swing may be large enough to affect the reliability of the circuit, but under the Slow NMOS Slow PMOS (SS) corner (corner) swing, the VCO may not start oscillating, and at high temperature, due to the reduced value of the quality factor (Q) of the resonance (tan), the oscillation starting capability may be much worse than the low temperature, and if it needs to be configured separately for each scene, the following problems may exist: the configuration obtained according to the simulation depends on the model (model) condition during the simulation, and cannot be completely matched with the actual situation; extra circuits are needed to be added for monitoring the working environment and the process corner, so that the redundancy of the chip, the test time and the test cost are increased.
Fig. 1 is a circuit diagram of a circuit for regulating and controlling the amplitude of a resonant signal of a VCO by using an analog feedback scheme, where the whole control process is a negative feedback process.
In the analog feedback scheme, on one hand, because the system is not an ideal linear system, the actual phase margin of Opamp is difficult to design to ensure the stability of the negative feedback of the system; on the other hand, the reference voltage Vref, the amplitude Vpeak of the VCO and the noise of the operational amplifier Opamp are mostly low-frequency flicker noise (flicker noise), and a large RC filter is needed to eliminate the noise, so that the area overhead is large and is not easy to solve; on the other hand, the loop is in a real-time working state, and certain power consumption waste exists.
Disclosure of Invention
The embodiment of the invention provides an automatic amplitude control device and method, which are simple in design, small in area overhead and small in power consumption.
In a first aspect, there is provided an automatic amplitude control apparatus, the apparatus comprising: the device comprises an oscillator and a current source array, wherein one end of the current source array is coupled to a source end of a cross-coupled tube in the oscillator, and the other ends of the current source array are respectively coupled to the ground; the device further comprises: the comparator is used for comparing the amplitude detection signal of the oscillator with a reference voltage signal to obtain a comparison result; and the controller is used for controlling the current coupled to the source end by the current source array according to the comparison result.
In the embodiment of the invention, a digital feedback calibration process is introduced, an amplitude detection signal of an oscillator is compared with a reference voltage signal through a comparator to obtain a comparison result, and then the current of the source end of a cross coupling tube coupled to the oscillator through a current source array is controlled through a controller according to the comparison result. The digital domain design is adopted, so that the circuit design is simplified, the design is simple, filtering is not needed, the area overhead is small, and the circuit is in a silent state after the calibration is finished, so that the power consumption and the noise are not contributed, and the power consumption is small.
In one possible embodiment, the current source array includes N parallel branches, each branch includes a switch and a current source connected in series, where N is an integer greater than 2; and the controller is used for respectively controlling the on-off of the switch in each branch according to the comparison result so as to control the current coupled to the source end by the current source array. According to the embodiment, the controller controls the on-off of the switch, so that the current of the current source array coupled to the source end is controlled, and the design is simple.
In a possible embodiment, the values of the current sources in the N branches of the current source array form an equal ratio sequence, and the controller is configured to generate an N-bit control signal by using a binary search method to control the on/off of the switches in the N branches, respectively. According to this embodiment, by adopting the binary search method, the efficiency of the amplitude control is high.
In a possible implementation, the oscillator further includes a resonant cavity, the cross-coupled transistor is an NMOS transistor, and the apparatus further includes: a peak detection circuit for detecting a minimum value of the amplitude of the resonance signal generated by the oscillator; two input ends of the peak detection circuit are respectively coupled to two differential output ends of the resonant cavity; an output of the peak detection circuit is coupled to an input of the comparator. According to this embodiment, a way of obtaining an amplitude detection signal of an oscillator is provided.
In a possible implementation, the oscillator further includes a resonant cavity, the cross-coupled transistor is a PMOS transistor, and the apparatus further includes: a peak detection circuit for detecting a maximum value of an amplitude of a resonance signal generated by the oscillator; two input ends of the peak detection circuit are respectively coupled to two differential output ends of the resonant cavity; an output of the peak detection circuit is coupled to an input of the comparator. According to this embodiment, another way of acquiring the amplitude detection signal of the oscillator is provided.
In a possible embodiment, the input of the comparator is coupled to the source of the oscillator. According to this embodiment, since the amplitude of the signal at the source terminal of the oscillator is related to the amplitude of the resonance signal generated by the oscillator, another way of obtaining the amplitude detection signal of the oscillator is provided.
In a possible embodiment, the apparatus further comprises: an Auto Band Select (ABS) circuit, configured to Select a working frequency point of the oscillator before the controller controls the current source array to be coupled to the current of the source according to the comparison result; and after the controller controls the current coupled to the source end by the current source array according to the comparison result, the working frequency point of the oscillator is selected again. According to the embodiment, the current of the source end of the cross coupling tube coupled to the oscillator by the current source array is changed in the amplitude calibration process of the oscillator, and slight influence is generated on the frequency, so that the amplitude calibration is combined with an ABS algorithm, and the amplitude calibration is added in two times of ABS, so that accurate frequency and ideal amplitude can be obtained after frequency point configuration.
In a second aspect, an automatic amplitude control apparatus is provided, which is used to control the amplitude of a resonant signal generated by an oscillator, one end of a current source array is coupled to the source ends of cross-coupled transistors in the oscillator, and the other ends of the current source array are respectively coupled to ground, and the apparatus includes: the comparison module is used for comparing the amplitude detection signal of the oscillator with a reference voltage signal to obtain a comparison result; and the control module is used for controlling the current coupled to the source end by the current source array according to the comparison result obtained by the comparison module.
In one possible embodiment, the current source array includes N parallel branches, each branch includes a switch and a current source connected in series, where N is an integer greater than 2; the controlling the current coupled to the source end by the current source array according to the comparison result comprises: and respectively controlling the on-off of the switch in each branch according to the comparison result so as to control the current coupled to the source end by the current source array.
In one possible embodiment, the values of the current sources in the N branches of the current source array form an equal ratio sequence; the control module is specifically configured to generate N-bit control signals by using a binary search method to control on/off of the switches in the N branches respectively.
In a possible implementation, the oscillator further includes a resonant cavity, the cross-coupled transistor is an NMOS transistor, and the apparatus further includes: and the detection module is used for detecting the minimum value of the amplitude of the resonance signal generated by the oscillator and taking the minimum value of the amplitude of the resonance signal as the amplitude detection signal of the oscillator.
In a possible implementation, the oscillator further includes a resonant cavity, the cross-coupled transistor is a PMOS transistor, and the apparatus further includes: and the detection module is used for detecting the maximum value of the amplitude of the resonance signal generated by the oscillator and taking the maximum value of the amplitude of the resonance signal as the amplitude detection signal of the oscillator.
In a possible embodiment, the apparatus further comprises: and the detection module is used for taking a signal of the source end of the oscillator as an amplitude detection signal of the oscillator.
In a possible embodiment, the apparatus further comprises: the frequency point selection module is used for selecting a working frequency point of the oscillator before the comparison module controls the current coupled to the source end by the current source array according to the comparison result; and after the comparison module controls the current coupled to the source end by the current source array according to the comparison result, selecting the working frequency point of the oscillator again.
In a third aspect, an automatic amplitude control method is provided, the method comprising: comparing the amplitude detection signal of the oscillator with a reference voltage signal to obtain a comparison result; and controlling the current of a current source array coupled to the source end of the cross coupling tube of the oscillator according to the comparison result.
In a possible embodiment, the controlling the current of the current source array coupled to the source terminals of the cross-coupled transistors of the oscillator according to the comparison result includes: and according to the comparison result, controlling the on-off of a switch in each branch of a current source array coupled to the source end of the cross-coupled tube of the oscillator so as to control the current coupled to the source end by the current source array.
In one possible embodiment, the controlling the on/off of the switch in each branch of the current source array coupled to the source terminal of the cross-coupled tube of the oscillator includes: and generating N-bit control signals by adopting a binary search method to control the on-off of switches in N branches of a current source array coupled to the source end of a cross-coupled tube of the oscillator, wherein N is an integer greater than 2.
In one possible embodiment, the method further comprises: and detecting the minimum value of the amplitude of the resonance signal generated by the oscillator, and taking the minimum value of the amplitude of the resonance signal as the amplitude detection signal of the oscillator.
In one possible embodiment, the method further comprises: and detecting the maximum value of the amplitude of the resonance signal generated by the oscillator, and taking the maximum value of the amplitude of the resonance signal as the amplitude detection signal of the oscillator.
In one possible embodiment, the method further comprises: and taking a signal of a source end of the oscillator as an amplitude detection signal of the oscillator.
In one possible embodiment, the method further comprises: selecting a working frequency point of the oscillator before controlling the current coupled to the source end by the current source array according to the comparison result; and selecting the working frequency point of the oscillator again after controlling the current coupled to the source end by the current source array according to the comparison result.
In a fourth aspect, an embodiment of the present invention provides a chip, which may be disposed in a terminal, and includes a processor and an interface. The processor is configured to support the chip to perform the corresponding functions in the method of the third aspect. The interface is used to support communication between the chip and other chips or other network elements. The chip may also include a memory for coupling with the processor that holds the necessary program instructions and data for the chip.
In a fifth aspect, an embodiment of the present invention provides a computer storage medium for storing computer software instructions for the terminal, which includes a program designed to execute the third aspect.
In a sixth aspect, an embodiment of the present invention provides a computer program product, which contains instructions, and when the program is executed by a computer, the instructions cause the computer to execute the functions performed by the terminal in the method design of the third aspect.
Drawings
Fig. 1 is a circuit diagram of a prior art circuit for regulating the amplitude of a resonant signal of a VCO using an analog feedback scheme;
fig. 2A is a schematic structural diagram of an automatic amplitude control apparatus according to an embodiment of the present invention;
fig. 2B is a schematic structural diagram of another automatic amplitude control apparatus according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another automatic amplitude control apparatus according to an embodiment of the present invention;
FIG. 4 is a diagram illustrating an automatic frequency band selection and automatic amplitude calibration relationship according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of another automatic amplitude control apparatus provided in the embodiment of the present invention;
fig. 6 is a schematic structural diagram of another automatic amplitude control apparatus according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of another automatic amplitude control apparatus according to an embodiment of the present invention;
fig. 8 is a flowchart of an automatic amplitude control method according to an embodiment of the present invention.
Detailed Description
The embodiment of the invention provides an automatic amplitude control device and method, which are simple in design, small in area overhead and small in power consumption.
Fig. 2A is a schematic structural diagram of an automatic amplitude control apparatus according to an embodiment of the present invention, where the apparatus includes: an oscillator 201 (such as a VCO) and a current source array 202, one end of the current source array 202 is coupled to a source end (also referred to as a common mode end) of a cross-coupled tube in the oscillator 201, and the other ends of the current source array 202 are respectively coupled to a ground; the device further comprises: a comparator 203, configured to compare the amplitude detection signal of the oscillator 201 with a reference voltage signal, so as to obtain a comparison result; and a controller 204, configured to control the current coupled to the source terminal by the current source array according to the comparison result.
It will be appreciated that the cross-coupled tube, i.e. the negative resistance generator of the VCO, can change the negative resistance of the VCO by adjusting the current coupled to the source end of the cross-coupled tube, thereby adjusting the amplitude of the VCO.
In the embodiment of the invention, a digital feedback calibration process is introduced, an amplitude detection signal of an oscillator is compared with a reference voltage signal through a comparator to obtain a comparison result, and then the current of the source end of a cross coupling tube coupled to the oscillator through a current source array is controlled through a controller according to the comparison result. The digital domain design is adopted, so that the circuit design is simplified, the design is simple, filtering is not needed, the area overhead is small, and the circuit is in a silent state after the calibration is finished, so that the power consumption and the noise are not contributed, and the power consumption is small.
In one possible embodiment, the current source array includes N parallel branches, each branch includes a switch and a current source connected in series, where N is an integer greater than 2; and the controller is used for respectively controlling the on-off of the switch in each branch according to the comparison result so as to control the current coupled to the source end by the current source array. According to the embodiment, the controller controls the on-off of the switch, so that the current of the current source array coupled to the source end is controlled, and the design is simple.
In a possible embodiment, the values of the current sources in the N branches of the current source array form an equal ratio sequence, and the controller is configured to generate an N-bit control signal by using a binary search method to control the on/off of the switches in the N branches, respectively. According to this embodiment, by adopting the binary search method, the efficiency of the amplitude control is high.
It is understood that the values of the current sources in the N branches of the current source array may be the same or different. The values of the current sources in the N branches of the current source array form an equal ratio sequence, which is not necessary, but is an alternative embodiment, and the values of the current sources in the N branches of the current source array may also form an equal difference sequence, or other types of sequences. It should be noted that, when the values of the current sources in the N branches of the current source array are in an arithmetic series, or in other forms of arithmetic series, the algorithm used by the controller in generating the N-bit control signal may refer to the prior art, and is not described herein again.
In one example, the values of the current sources in the N branches of the current source array form an equal ratio sequence, the ratio is 2, the controller is a Successive Approximation Register (SAR), and the SAR is configured to generate an N-bit control signal by using a binary search method to respectively control the on/off of the switches in the N branches.
In a possible implementation, the oscillator further includes a resonant cavity, the cross-coupled transistor is an NMOS transistor, and the apparatus further includes: a peak detection circuit for detecting a minimum value of the amplitude of the resonance signal generated by the oscillator; two input ends of the peak detection circuit are respectively coupled to two differential output ends of the resonant cavity; an output of the peak detection circuit is coupled to an input of the comparator. According to this embodiment, a way of obtaining an amplitude detection signal of an oscillator is provided.
In a possible implementation, the oscillator further includes a resonant cavity, the cross-coupled transistor is a PMOS transistor, and the apparatus further includes: a peak detection circuit for detecting a maximum value of an amplitude of a resonance signal generated by the oscillator; two input ends of the peak detection circuit are respectively coupled to two differential output ends of the resonant cavity; an output of the peak detection circuit is coupled to an input of the comparator. According to this embodiment, another way of acquiring the amplitude detection signal of the oscillator is provided.
In a possible embodiment, the input of the comparator is coupled to the source of the oscillator. According to this embodiment, since the amplitude of the signal at the source terminal of the oscillator is related to the amplitude of the resonance signal generated by the oscillator, another way of obtaining the amplitude detection signal of the oscillator is provided.
In a possible embodiment, the apparatus further comprises: an Auto Band Select (ABS) circuit, configured to Select a working frequency point of the oscillator before the controller controls the current source array to be coupled to the current of the source according to the comparison result; and after the controller controls the current coupled to the source end by the current source array according to the comparison result, the working frequency point of the oscillator is selected again. According to the embodiment, the current of the source end of the cross coupling tube coupled to the oscillator by the current source array is changed in the amplitude calibration process of the oscillator, and slight influence is generated on the frequency, so that the amplitude calibration is combined with an ABS algorithm, and the amplitude calibration is added in two times of ABS, so that accurate frequency and ideal amplitude can be obtained after frequency point configuration.
Fig. 2B is a schematic structural diagram of another automatic amplitude control apparatus according to an embodiment of the present invention, where the apparatus includes: a comparator 211 for comparing the magnitude of an amplitude detection signal with a reference voltage signal, wherein the amplitude detection signal may be a resonance signal of the VCO or a signal related to the resonance signal of the VCO; a SAR212 for generating an N-bit control signal according to an output result of the comparator 211; a current source array 213 comprising N current sources, wherein N is greater than two; the N current sources included in the current source array 204 are connected to the source terminal of the VCO through N switches; each of the N control signals is used to control one of the N switches to be on or off.
In the embodiment of the invention, a digital feedback calibration process is introduced, a current source accessed from a source end of the VCO is continuously adjusted through a dichotomy of the SAR, the amplitude error of the VCO can be controlled in the resolution range of 1 Least Significant Bit (LSB) through a successive approximation mode, and the design of a digital domain is adopted, so that the circuit design is simplified, the design is simple, filtering is not needed, the area overhead is small, and the circuit is in a silent state after the calibration is finished, and power consumption and noise are not contributed, so that the power consumption is small.
It is understood that the currents provided by the N current sources included in the current source array 204 may be in phaseLikewise, they may be different. The number N of the current sources may be any integer greater than or equal to 2, and may be determined according to the accuracy of the amplitude of the resonant signal generated by the VCO that needs to be controlled in practical design. In one example, N is 6, the ratio of the currents provided by any two of the N current sources is a multiple of 2, for example, the 6 current sources provide currents of 1unit, 2 units, and 2 units respectively2unit、23unit、24unit、25The unit can be regarded as a unit of current magnitude, the amplitude control precision of the VCO can reach the precision of the current source control with the current of 1unit, and the ratio of the currents provided by the 6 current sources is 1:22:23:24:25. According to this embodiment, the amplitude of the resonance signal generated by the VCO can be accurately controlled.
The SAR algorithm is a binary search method, and compared with other algorithms, the SAR algorithm has higher efficiency. SAR uses "binary search method" to generate digital quantity, taking 8-bit digital quantity as an example, SAR first generates half of 8-bit digital quantity, namely 10000000B, tests the size of analog quantity Vi (reference voltage), uses Vo to represent the first voltage, if Vo > Vi, clears the most significant bit, if Vo < Vi, retains the most significant bit. After the most significant bit is determined, SAR determines the size of the analog quantity Vi again by a binary search method, i.e. by y1000000B (y is the determined bit) which is half of the lower 7 bits. After bit6 is determined, SAR determines bit5 bits in a binary search, i.e., the analog magnitude is probed with yy100000B (y is the determined bit) which is half of the lower 6 bits. This process is repeated until the least significant bit0 is determined and the automatic amplitude control ends.
Assuming that the amplitude detection signal Vpeak is 0.4V, the reference voltage signal Vref is 0.312V, and the voltage resolution corresponding to one current bit is 0.005V, the operation process is substantially as follows:
the first step is as follows: i [5:0] (100000), (Vpeak ═ 0.4V) > (Vref ═ 0.312V), comparator output 1;
the second step is that: i [5:0] (110000), (Vpeak ═ 0.32V) > (Vref ═ 0.312V), comparator output 1;
the third step: i [5:0] ═ 111000, (Vpeak ═ 0.28V < (Vref ═ 0.312V), comparator output 0;
the fourth step: i [5:0] ═ 110100, (Vpeak ═ 0.32V) > (Vref ═ 0.312V), comparator output 1;
the fifth step: i [5:0] (110110), (Vpeak ═ 0.315V) > (Vref ═ 0.312V), comparator output 1;
and a sixth step: i [5:0] -110111, (Vpeak ═ 0.31V) < (Vref ═ 0.312V), and the comparator outputs 0.
So far, the comparison process is completed, the obtained deviation between Vpeak and Vref is smaller than the voltage resolution corresponding to one current bit, if a comparison result with higher precision is needed, bit bits can be increased, and the resolution is improved.
Fig. 3 is a schematic structural diagram of another automatic amplitude control apparatus provided in an embodiment of the present invention, where the apparatus includes: a comparator 301, configured to compare a magnitude of an amplitude detection signal with a reference voltage signal, where the amplitude detection signal is a resonance signal of the VCO; a controller 302, configured to generate an N-bit control signal according to an output result of the comparator 301, where the controller 302 is an SAR in this embodiment; a current source array 303 comprising N current sources, wherein N is greater than two; the N current sources included in the current source array 303 are connected with the source end of the VCO through N switches; one bit of the N bit control signals is used for controlling one switch in the N switches to be in an opening or closing state.
It is understood that the embodiment of the present invention does not limit the composition of the VCO. The composition of the VCO shown in fig. 3 is merely an example. Referring to fig. 3, the VCO includes a resonant cavity 304 and a cross-coupled tube 305, and the cross-coupled tube 305 is an NMOS tube. The device further comprises: a peak detection circuit 306 for detecting a minimum value of the amplitude of the resonance signal generated by the VCO (also referred to as the amplitude of the VCO); two input ends of the peak detection circuit 306 are respectively connected to two differential output ends of the resonant cavity 304; an output terminal of the peak detection circuit 306 is connected to an input terminal of the comparator 301. According to this embodiment, one possible implementation of obtaining the amplitude of the VCO is provided.
In a possible embodiment, the apparatus further comprises: an Auto Band Select (ABS) circuit 307, configured to Select a working frequency point of the VCO; the ABS circuit 307 has a status output terminal, the status output terminal of the ABS circuit 307 is used for indicating the number of times of completing the selection of the working frequency point of the VCO, and the status output terminal of the ABS circuit 307 is connected to the enable terminal of the controller 302; the controller 302 has a status output terminal, the status output terminal of the controller 302 is used for indicating whether the automatic amplitude control of the VCO is completed, and the status output terminal of the controller 302 is connected to the enable terminal of the ABS circuit 307; when the number of times that the status output end of the ABS circuit 307 indicates that the selection of the working frequency point of the VCO is completed is one, the enable end of the controller 302 takes effect; the enable terminal of the ABS circuit 307 is enabled when the status output of the controller 302 indicates that automatic amplitude control of the VCO is complete. According to the embodiment, the amplitude calibration of the VCO changes the tail current to slightly influence the frequency, so that the amplitude calibration is combined with the ABS algorithm, and the amplitude calibration is added in two ABS processes, so that the accurate frequency and the ideal amplitude can be obtained after the frequency point configuration.
It can be understood that, after the ABS circuit determines the working frequency point of the VCO, the working frequency point of the VCO may be adjusted, for example, by controlling the on or off state of a switch serially connected to a capacitor in the VCO, the capacitor connected to the VCO is controlled, and accordingly the purpose of adjusting the working frequency point of the VCO is achieved.
Fig. 4 is a schematic diagram illustrating a relationship between automatic band selection and automatic amplitude calibration according to an embodiment of the present invention. Referring to fig. 4, the overall calibration process is described as follows:
when the system selects the working frequency point of the VCO, an ABS process needs to be performed first, after the first ABS is completed, the state machine enters into Automatic Amplitude Calibration (AAC), after AAC is completed, the state machine returns to the initial state, the second ABS is performed, and until the ABS process is completed, the state machine exits. In order to ensure that an optimal frequency band (band) is selected in system application, an algorithm adopts an ABS process (ABS _ ST1 is effective) firstly, amplitude calibration (AAC _ END is effective) is carried out after the process is finished, and ABS (ABS _ ST2 is effective) is carried out again after the calibration is finished.
Brief description of AAC procedure: the peak detection circuit detects the lowest level of the resonance (tank) voltage, 0/1 output is obtained by comparing with the reference voltage Vref, the controller of the SAR generates a 6bit control word according to a 0/1 signal to control the switch of a current source at the tail of the VCO, the tail current source array adopts a binary proportion, namely 1-2-4-8-16-32, and the binary successive comparison process is completed after 6 times. The magnitude of Vpeak and Vref is compared by the comparator, and the result 0/1 is output. If the output is equal to 0, the SAR changes Bit <5:0> downwards by adopting a bisection method, otherwise, the bisection method is upwards, the switch of the corresponding current source is switched on or off along with the Bit <5:0>, the swing of the VCO is increased or reduced, and the difference between the Vpeak and the Vref is smaller than 1LSB finally through the process of successive comparison.
Because the amplitude calibration changes the tail current of the VCO and slightly influences the resonant frequency of the VCO, the amplitude calibration is combined with the ABS algorithm, and the amplitude calibration is added in the two ABS processes, so that accurate frequency and ideal amplitude can be obtained after frequency point configuration.
Fig. 5 is a schematic structural diagram of another automatic amplitude control apparatus provided in an embodiment of the present invention, where the apparatus includes: a comparator 501, configured to compare an amplitude detection signal with a reference voltage signal, where the amplitude detection signal is a resonance signal of the VCO; a controller 502, configured to generate an N-bit control signal according to an output result of the comparator 501, where the controller 302 is an SAR in this embodiment; a current source array 503 comprising N current sources, wherein N is greater than two; the N current sources included in the current source array 503 are connected to the source terminal of the VCO through N switches; one bit of the N bit control signals is used for controlling one switch in the N switches to be in an opening or closing state.
It is understood that the embodiment of the present invention does not limit the composition of the VCO. The composition of the VCO shown in fig. 5 is merely an example. Referring to fig. 5, the VCO includes a resonant cavity 504 and a cross-coupled tube 505, the cross-coupled tube 505 is a PMOS tube, and the apparatus further includes: a peak detection circuit 506 for detecting a maximum value of the resonance signal generated by the VCO; two input ends of the peak detection circuit 506 are respectively connected with two differential output ends of the resonant cavity 504; the output terminal of the peak detection circuit 506 is connected to the input terminal of the comparator 501. According to this embodiment, another possible implementation of obtaining the amplitude of the VCO is provided.
In a possible embodiment, the apparatus further comprises: the ABS circuit 507 is used for selecting the working frequency point of the VCO; the ABS circuit 507 has a status output terminal, the status output terminal of the ABS circuit 507 is used for indicating the number of times of completing the selection of the working frequency point of the VCO, and the status output terminal of the ABS circuit 507 is connected to the enable terminal of the controller 502; the controller 502 has a status output terminal, the status output terminal of the controller 502 is used for indicating whether the automatic amplitude control of the VCO is completed, and the status output terminal of the controller 502 is connected to the enable terminal of the ABS circuit 507; when the number of times that the state output end of the ABS circuit 507 indicates that the selection of the working frequency point of the VCO is completed is one, the enable end of the controller 502 takes effect; the enable of the ABS circuit 507 is enabled when the status output of the controller 502 indicates that automatic amplitude control of the VCO is complete. According to the embodiment, the amplitude calibration of the VCO changes the tail current to slightly influence the frequency, so that the amplitude calibration is combined with the ABS algorithm, and the amplitude calibration is added in two ABS processes, so that the accurate frequency and the ideal amplitude can be obtained after the frequency point configuration.
The relationship between the automatic band selection and the automatic amplitude calibration may refer to fig. 4 and corresponding text descriptions, which are not described herein again.
Fig. 6 is a schematic structural diagram of another automatic amplitude control apparatus provided in an embodiment of the present invention, where the apparatus includes: a comparator 601, configured to compare an amplitude detection signal with a reference voltage signal, where the amplitude detection signal is a signal at a source end of the VCO, and the signal at the source end is a signal related to the resonant signal; a controller 602, configured to generate an N-bit control signal according to an output result of the comparator 601, where the controller 602 is a SAR in this embodiment; a current source array 603 comprising N current sources, wherein N is greater than two; the current source array 603 comprises N current sources connected to the source terminal of the VCO through N switches; one bit of the N bit control signals is used for controlling one switch in the N switches to be in an opening or closing state.
It is understood that the embodiment of the present invention does not limit the composition of the VCO. The composition of the VCO shown in fig. 6 is merely an example. In a possible implementation, the input terminal of the comparator 601 is connected to the source terminal of the VCO. According to this embodiment, since the voltage of the source terminal of the VCO is related to the amplitude of the VCO, yet another possible implementation of obtaining the amplitude of the VCO is provided. Since this mode omits a peak detection circuit, the occupied area can be further reduced.
In a possible embodiment, the apparatus further comprises: the ABS circuit 604 is configured to select a working frequency point of the VCO; the ABS circuit 604 has a status output end, the status output end of the ABS circuit 604 is used for indicating the number of times of completing the selection of the working frequency point of the VCO, and the status output end of the ABS circuit 604 is connected to the enable end of the controller 602; the controller 602 has a status output terminal, the status output terminal of the controller 602 is used for indicating whether the automatic amplitude control of the VCO is completed, and the status output terminal of the controller 602 is connected to the enable terminal of the ABS circuit 604; when the number of times that the state output end of the ABS circuit 604 indicates that the selection of the working frequency point of the VCO is completed is one, the enable end of the controller 602 takes effect; the enable terminal of the ABS circuit 604 is enabled when the status output of the controller 602 indicates that automatic amplitude control of the VCO is complete. According to the embodiment, the amplitude calibration of the VCO changes the tail current to slightly influence the frequency, so that the amplitude calibration is combined with the ABS algorithm, and the amplitude calibration is added in two ABS processes, so that the accurate frequency and the ideal amplitude can be obtained after the frequency point configuration.
The relationship between the automatic band selection and the automatic amplitude calibration may refer to fig. 4 and corresponding text descriptions, which are not described herein again.
The embodiment of the invention completes the automatic amplitude calibration of the VCO by the feedback mode of the digital domain, has simple realization mode and good expansibility, can continuously evolve according to process nodes, does not introduce extra noise into a calibration circuit, does not need large device area and RC filtering, and does not consume extra power after the calibration process is finished.
Fig. 7 is a schematic structural diagram of another automatic amplitude control apparatus for controlling the amplitude of a resonant signal generated by an oscillator, where one end of a current source array is coupled to source ends of cross-coupled transistors in the oscillator, and the other ends of the current source array are respectively coupled to ground, the apparatus including:
a comparing module 701, configured to compare the amplitude detection signal of the oscillator with a reference voltage signal to obtain a comparison result;
a control module 702, configured to control the current coupled to the source end by the current source array according to the comparison result obtained by the comparison module 701.
In one example, the current source array comprises N parallel branches, each branch comprising a switch and a current source connected in series, where N is an integer greater than 2;
the control module 702 is specifically configured to respectively control on/off of switches in each branch according to a comparison result obtained by the comparison module 701, so as to control a current coupled to the source end by the current source array.
In one possible embodiment, the values of the current sources in the N branches of the current source array form an equal ratio sequence; the control module 702 is specifically configured to generate N-bit control signals by using a binary search method to respectively control on/off of the switches in the N branches.
In a possible implementation, the oscillator further includes a resonant cavity, the cross-coupled transistor is an NMOS transistor, and the apparatus further includes: and the detection module is used for detecting the minimum value of the amplitude of the resonance signal generated by the oscillator and taking the minimum value of the amplitude of the resonance signal as the amplitude detection signal of the oscillator.
In a possible implementation, the oscillator further includes a resonant cavity, the cross-coupled transistor is a PMOS transistor, and the apparatus further includes: and the detection module is used for detecting the maximum value of the amplitude of the resonance signal generated by the oscillator and taking the maximum value of the amplitude of the resonance signal as the amplitude detection signal of the oscillator.
In a possible embodiment, the apparatus further comprises: and the detection module is used for taking a signal of the source end of the oscillator as an amplitude detection signal of the oscillator.
In a possible embodiment, the apparatus further comprises: a frequency point selection module, configured to select a working frequency point of the oscillator before the comparison module 701 controls the current, coupled to the source end, of the current source array according to the comparison result; and after the comparison module controls the current coupled to the source end by the current source array according to the comparison result, selecting the working frequency point of the oscillator again.
Fig. 8 is a flowchart of an automatic amplitude control method according to an embodiment of the present invention, where the method is used to control an amplitude of a resonant signal generated by an oscillator, one end of a current source array is coupled to source ends of cross-coupled transistors in the oscillator, and the other ends of the current source array are respectively coupled to ground, where the method includes:
step 801, comparing the amplitude detection signal of the oscillator with a reference voltage signal to obtain a comparison result.
And step 802, controlling the current coupled to the source end by the current source array according to the comparison result.
In one possible embodiment, the current source array includes N parallel branches, each branch includes a switch and a current source connected in series, where N is an integer greater than 2; the controlling the current coupled to the source end by the current source array according to the comparison result comprises: and respectively controlling the on-off of the switch in each branch according to the comparison result so as to control the current coupled to the source end by the current source array.
In one possible embodiment, the values of the current sources in the N branches of the current source array form an equal ratio sequence; the switching on and off of the switch in each branch circuit is controlled respectively, and the method comprises the following steps: and generating N-bit control signals by adopting a binary search method so as to respectively control the on-off of the switches in the N branches.
In a possible implementation, the oscillator further includes a resonant cavity, the cross-coupled transistor is an NMOS transistor, and the method further includes: and detecting the minimum value of the amplitude of the resonance signal generated by the oscillator, and taking the minimum value of the amplitude of the resonance signal as the amplitude detection signal of the oscillator.
In a possible embodiment, the oscillator further includes a resonant cavity, the cross-coupled transistor is a PMOS transistor, and the method further includes: and detecting the maximum value of the amplitude of the resonance signal generated by the oscillator, and taking the maximum value of the amplitude of the resonance signal as the amplitude detection signal of the oscillator.
In one possible embodiment, the signal of the source terminal of the oscillator is used as the amplitude detection signal of the oscillator.
In one possible embodiment, the method further comprises: selecting a working frequency point of the oscillator before controlling the current coupled to the source end by the current source array according to the comparison result; and selecting the working frequency point of the oscillator again after controlling the current coupled to the source end by the current source array according to the comparison result.
An embodiment of the present invention further provides a chip apparatus, where the chip includes a processing unit, and is configured to execute the method shown in fig. 8.
The embodiment of the invention also provides a chip device which comprises a processor and a memory. The memory includes instructions that the processor executes to perform the method of fig. 8 described above.
In the various embodiments of the invention described above, implementation may be in whole or in part via software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions can be stored on a computer readable storage medium or transmitted from one computer readable medium to another, for example, from one website, computer, server, or data center to another website, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)), or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.
The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made on the basis of the technical solutions of the present invention should be included in the scope of the present invention.

Claims (14)

  1. An automatic amplitude control device, characterized in that the device comprises:
    the device comprises an oscillator and a current source array, wherein one end of the current source array is coupled to a source end of a cross-coupled tube in the oscillator, and the other ends of the current source array are respectively coupled to the ground; the device further comprises:
    the comparator is used for comparing the amplitude detection signal of the oscillator with a reference voltage signal to obtain a comparison result;
    and the controller is used for controlling the current coupled to the source end by the current source array according to the comparison result.
  2. The apparatus of claim 1, wherein the current source array comprises N parallel branches, each branch comprising a switch and a current source in series, wherein N is an integer greater than 2; and the controller is used for respectively controlling the on-off of the switch in each branch according to the comparison result so as to control the current coupled to the source end by the current source array.
  3. The apparatus of claim 2, wherein values of the current sources in the N branches of the current source array form an equal ratio sequence, and the controller is configured to generate an N-bit control signal using a binary search method to control on and off of the switches in the N branches, respectively.
  4. The apparatus of any one of claims 1 to 3, wherein the oscillator further comprises a resonant cavity, the cross-coupled tube is an NMOS tube, and the apparatus further comprises:
    a peak detection circuit for detecting a minimum value of the amplitude of the resonance signal generated by the oscillator;
    two input ends of the peak detection circuit are respectively coupled to two differential output ends of the resonant cavity;
    an output of the peak detection circuit is coupled to an input of the comparator.
  5. The apparatus of any of claims 1-3, wherein the oscillator further comprises a resonant cavity, the cross-coupled transistors are PMOS transistors, and the apparatus further comprises:
    a peak detection circuit for detecting a maximum value of an amplitude of a resonance signal generated by the oscillator;
    two input ends of the peak detection circuit are respectively coupled to two differential output ends of the resonant cavity;
    an output of the peak detection circuit is coupled to an input of the comparator.
  6. The apparatus of any of claims 1-3, wherein an input of the comparator is coupled to a source terminal of the oscillator.
  7. The apparatus of any of claims 1 to 6, further comprising:
    the automatic frequency band selection ABS circuit is used for selecting a working frequency point of the oscillator before the controller controls the current coupled to the source end by the current source array according to the comparison result; and the number of the first and second groups,
    and after the controller controls the current coupled to the source end by the current source array according to the comparison result, selecting the working frequency point of the oscillator again.
  8. A method of automatic amplitude control, the method comprising:
    comparing the amplitude detection signal of the oscillator with a reference voltage signal to obtain a comparison result;
    and controlling the current of a current source array coupled to the source end of the cross coupling tube of the oscillator according to the comparison result.
  9. The method of claim 8,
    the controlling the current of the current source array coupled to the source end of the cross-coupled tube of the oscillator according to the comparison result comprises:
    and according to the comparison result, controlling the on-off of a switch in each branch of a current source array coupled to the source end of the cross-coupled tube of the oscillator so as to control the current coupled to the source end by the current source array.
  10. The method of claim 9, wherein controlling the switching of the switches in the respective branches of the current source array coupled to the source terminals of the cross-coupled tubes of the oscillator comprises:
    and generating N-bit control signals by adopting a binary search method to control the on-off of switches in N branches of a current source array coupled to the source end of a cross-coupled tube of the oscillator, wherein N is an integer greater than 2.
  11. The method of any of claims 8 to 10, further comprising:
    and detecting the minimum value of the amplitude of the resonance signal generated by the oscillator, and taking the minimum value of the amplitude of the resonance signal as the amplitude detection signal of the oscillator.
  12. The method of any of claims 8 to 10, further comprising:
    and detecting the maximum value of the amplitude of the resonance signal generated by the oscillator, and taking the maximum value of the amplitude of the resonance signal as the amplitude detection signal of the oscillator.
  13. The method of any of claims 8 to 10, further comprising: and taking a signal of a source end of the oscillator as an amplitude detection signal of the oscillator.
  14. The method of any of claims 8 to 13, further comprising:
    selecting a working frequency point of the oscillator before controlling the current coupled to the source end by the current source array according to the comparison result; and selecting the working frequency point of the oscillator again after controlling the current coupled to the source end by the current source array according to the comparison result.
CN201880085040.7A 2018-03-30 2018-03-30 Automatic amplitude control device and method Pending CN111566937A (en)

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