CN112882529B - Swing detection circuit with DC offset elimination function - Google Patents
Swing detection circuit with DC offset elimination function Download PDFInfo
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- 230000008030 elimination Effects 0.000 title abstract description 10
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- 238000013139 quantization Methods 0.000 claims abstract description 28
- 239000003990 capacitor Substances 0.000 claims description 38
- 230000000903 blocking effect Effects 0.000 claims description 6
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F3/00—Non-retroactive systems for regulating electric variables by using an uncontrolled element, or an uncontrolled combination of elements, such element or such combination having self-regulating properties
- G05F3/02—Regulating voltage or current
- G05F3/08—Regulating voltage or current wherein the variable is DC
- G05F3/10—Regulating voltage or current wherein the variable is DC using uncontrolled devices with non-linear characteristics
- G05F3/16—Regulating voltage or current wherein the variable is DC using uncontrolled devices with non-linear characteristics being semiconductor devices
- G05F3/20—Regulating voltage or current wherein the variable is DC using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations
- G05F3/26—Current mirrors
- G05F3/262—Current mirrors using field-effect transistors only
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Abstract
The invention provides a swing detection circuit with direct current offset elimination, wherein a first input end of a detection voltage generation circuit is connected with a positive end of a voltage-controlled oscillator, a second input end of the detection voltage generation circuit is connected with a negative end of the voltage-controlled oscillator, a third input end and a fourth input end of the detection voltage generation circuit are connected with bias voltages, a first input end and a second input end of a reference voltage generation circuit are connected with the bias voltages, an output end of the detection voltage generation circuit is connected with a first input end of a quantization encoder, an output end of the reference voltage generation circuit is connected with a second input end of the quantization encoder, and the quantization encoder is provided with a plurality of bit output ends. The invention eliminates the direct current component in the detection signal and codes by comparing the reference voltage with the direct current signal with the detection signal, thereby realizing the effect of eliminating the direct current offset and having the advantages of simple structure, small layout area and low power consumption.
Description
Technical Field
The present invention relates to the field of voltage-controlled oscillator swing detection technology, and in particular, to a swing detection circuit with dc offset cancellation.
Background
As chip integration becomes higher and the operating frequency becomes faster, wireless communication systems, high-speed digital circuits, etc. provide a clean, stable clock signal by integrating an on-chip clock source. Phase locked loops are conventional clock generation circuits that are stable closed loop systems, excellent tamper resistance, and a broad output frequency range, and are widely used in the marketplace. The phase noise characteristic of the phase-locked loop is improved, the clock jitter is reduced, the application requirement of a high-performance system can be met, the requirement of low power consumption is met while the performance is improved, and the phase-noise characteristic of the phase-locked loop is an important index of high-integration electronic equipment. Therefore, a high performance, low power phase locked loop is a very important feature.
A common phase-locked loop circuit generally consists of a reference clock, a phase frequency detector, a charge pump, a loop filter, a voltage controlled oscillator, and a digital divider. The voltage-controlled oscillator is an important component module of the phase-locked loop, and is also a constraint factor of the design of the high-performance low-power-consumption phase-locked loop. A degraded VCO (voltage controlled oscillator) signal tends to cause near-end signals to be mixed and drowned in a communication system, and a highly perturbed clock signal can cause instability of high-speed digital circuits. The LC oscillator is widely applied to a phase-locked loop system at present, consists of an inductance-capacitance array and a starting tube, and has the advantages of high frequency, low phase noise and small jitter. Conventional free-running LC oscillators or current mirror controlled LC oscillators have device characteristics changed due to process, voltage, temperature (PVT) effects, resulting in excessively high or low output voltage swings, which may lead to performance degradation of the voltage controlled oscillator. Meanwhile, in order to ensure that the LC oscillator can start vibrating normally under PVT, more power consumption needs to be increased to meet the requirement, and the power consumption is redundant under the condition of overhigh output swing. In order to make LC oscillators operate in a normal swing interval and to increase efficient use of power consumption, voltage controlled oscillators are typically swing controlled.
The digital swing control can avoid the stability problem of the analog control loop, and the traditional swing detection circuit has larger direct current drift under the influence of PVT, and has larger direct current deviation if the detected analog signal is directly subjected to digital code conversion. And the reference circuit is adopted to generate the reference voltage and convert the reference voltage into the reference digital code, and the direct current deviation is eliminated by a digital technology, so that larger area and power consumption are required.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a swing amplitude detection circuit with direct current offset elimination, which is suitable for a swing amplitude digital detection system of a voltage-controlled oscillator, and a group of reference circuits symmetrical to the swing amplitude detection circuit are used for generating reference voltages with direct current signals, and the reference voltages with the direct current signals are compared and converted into digital codes, so that the direct current elimination is realized.
The invention provides a swing detection circuit with direct current offset elimination, which comprises a detection voltage generation circuit, a reference voltage generation circuit and a quantization encoder; the detection voltage generation circuit is used for converting the swing amplitude of the voltage-controlled oscillator into linear voltage; the first input end of the detection voltage generation circuit is connected with the positive end of the voltage-controlled oscillator, the second input end of the detection voltage generation circuit is connected with the negative end of the voltage-controlled oscillator, the third input end and the fourth input end of the detection voltage generation circuit are connected with the bias voltage, the first input end and the second input end of the reference voltage generation circuit are connected with the bias voltage, the output end of the detection voltage generation circuit is connected with the first input end of the quantization encoder, the output end of the reference voltage generation circuit is connected with the second input end of the quantization encoder, and the quantization encoder is provided with a plurality of bit output ends.
Further, the detection voltage generating circuit comprises a blocking capacitor, a first input pair tube, a first current mirror, a first filter capacitor and a matching resistor array, signals of a first input end and a second input end of the detection voltage generating circuit are connected to a grid electrode of the first input pair tube through the blocking capacitor, a third input end and a fourth input end of the detection voltage generating circuit provide direct current working points for the grid electrode of the first input pair tube, a drain electrode of the first current mirror, the first filter capacitor are connected with a source electrode of the first input pair tube, the matching resistor array is connected with a drain electrode of the first input pair tube and the first filter capacitor, and the first filter capacitor is connected with the first input end of the quantization encoder; the first input pair tube converts swing voltage change of the voltage-controlled oscillator into linear output detection voltage with ripple waves, the first current mirror controls gain of the first input pair tube, direct current is generated at the output voltage, and the output voltage passes through the first filter capacitor to filter ripple wave components to obtain detection voltage with direct current signals.
Further, the reference voltage generating circuit comprises a second input pair tube, a second current mirror, a second filter capacitor and a divider resistor array, wherein a third input end and a fourth input end of the detection voltage generating circuit, and a first input end and a second input end of the reference voltage generating circuit are direct current working points provided for grid electrodes of the second input pair tube, a drain electrode of the second current mirror and a source electrode of the second input pair tube are connected with each other, the divider resistor array is connected with the drain electrode of the second input pair tube and the second filter capacitor, and each divider resistor in the divider resistor array is connected with the second input end of the quantization encoder; the second current mirror controls the gain of the second input pair of tubes and generates the same direct current as the detection voltage generation circuit at the output voltage.
Further, the output end of the quantization encoder has k bits, the voltage dividing resistor array generates 2-k level reference voltages between the generated direct current and the input power or ground, each level voltage is < V ref1:Vref2^k>+VDC containing direct current signals, wherein V ref1:Vref2^k is the reference voltage corresponding to 1-2-k level, and V DC is the direct current which is the same as the detection voltage generating circuit and generated by the second current mirror at the output voltage.
Further, the quantization encoder compares the detection voltage at the first input terminal with the reference voltage at the second input terminal, eliminates the direct current signal, and generates a digital code D out < k-1:0> of the detection voltage.
Further, the first input pair of tubes is identical to the second input pair of tubes.
Further, the first current mirror is identical to the second current mirror.
Further, the first filter capacitor is the same as the second filter capacitor.
Further, the matching resistor array is identical to the voltage dividing resistor array.
Compared with the prior art, the invention has the beneficial effects that:
The invention provides a swing detection circuit with DC offset elimination, which eliminates the DC component in the detection signal and codes the DC component by comparing the reference voltage with the DC signal with the detection signal, thereby realizing the effect of DC offset elimination and having the advantages of simple architecture, small layout area and low power consumption. More specifically, the reference voltage generating circuit can generate a reference voltage with a direct current signal, and the reference voltage generating circuit and the detection voltage generating circuit are symmetrical in circuit design, so that the direct current signal and the direct current signal of the detection voltage generating circuit synchronously change under the influence of the changes of the process, the voltage and the temperature, and therefore the digital code generated by the comparison of the quantization encoder is calculated by a zero voltage point and is not influenced by the changes of the process, the voltage and the temperature, and the stability of the circuit is improved.
The foregoing description is only an overview of the present invention, and is intended to provide a better understanding of the present invention, as it is embodied in the following description, with reference to the preferred embodiments of the present invention and the accompanying drawings. Specific embodiments of the present invention are given in detail by the following examples and the accompanying drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute a limitation on the application. In the drawings:
Fig. 1 is a schematic diagram of a voltage controlled oscillator control system employing a swing detection circuit according to the present invention;
FIG. 2 is a schematic diagram of a swing detection circuit with DC offset cancellation according to the present invention;
FIG. 3 is a diagram of a swing detection circuit with DC offset cancellation according to the present invention;
fig. 4 is a diagram of a swing detection circuit with dc offset cancellation according to the present invention.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and detailed description, wherein it is to be understood that, on the premise of no conflict, the following embodiments or technical features may be arbitrarily combined to form new embodiments.
A swing detection circuit with DC offset cancellation, as shown in FIG. 1 and FIG. 2, comprises a detection voltage generation circuit, a reference voltage generation circuit and a quantization encoder; the detection voltage generation circuit is used for converting the swing amplitude of the voltage-controlled oscillator into linear voltage; the first input end of the detection voltage generation circuit is connected with the positive end Vvcop (t) of the voltage-controlled oscillator, the second input end of the detection voltage generation circuit is connected with the negative end Vvcon (t) of the voltage-controlled oscillator, the third input end and the fourth input end of the detection voltage generation circuit are connected with bias voltages, the first input end and the second input end of the reference voltage generation circuit are connected with bias voltages, the output end of the detection voltage generation circuit is connected with the first input end of the quantization encoder, the output end of the reference voltage generation circuit is connected with the second input end of the quantization encoder, and the quantization encoder is provided with k bit output ends.
As shown in fig. 3 and 4, the detection voltage generating circuit includes a blocking capacitor C 11、C12, a first input pair transistor M 11、M12, a first current mirror M 13, a first filter capacitor C 13 and a matching resistor array, The signals of the first input end and the second input end of the detection voltage generating circuit are connected to the grid electrodes of the first input pair of tubes M 11 and M 12 through a blocking capacitor C 11、C12, the third input end and the fourth input end of the detection voltage generating circuit are direct current working points provided for the grid electrodes of the first input pair of tubes M 11 and M 12, The drain electrode of the first current mirror M 13, the first filter capacitor C 13 are connected with the source electrode of the first input pair tube M 11、M12, the matching resistor array is connected with the drain electrode of the first input pair tube M 11、M12 and the first filter capacitor C 13, the first filter capacitor C 13 is connected with the first input end of the quantization coder; The first input pair of tubes M 11、M12 converts the swing voltage variation of the voltage controlled oscillator into a linear output detection voltage V PD with ripple, the first current mirror M 13 controls the gain of the first input pair of tubes M 11、M12, And generating direct current V DC at the output voltage, and filtering ripple components of the output voltage through a first filter capacitor C 13 to obtain detection voltage V PD+VDC with direct current signals. as shown in fig. 3, when the first input pair of transistors M 11、M12 and the first current mirror M 13 are NMOS transistors, the drain of the first input pair of transistors M 11、M12 is connected to the power supply Vdd, the source of the first current mirror M 13 is grounded, One end of the first filter capacitor C 13 is grounded. As shown in fig. 4, when the first input pair of transistors M 11、M12 and the first current mirror M 13 are PMOS transistors, the drain of the first input pair of transistors M 11、M12 is grounded, the source of the first current mirror M 13 is connected to the power supply Vdd, one end of the first filter capacitor C 13 is connected to the power supply Vdd.
The reference voltage generating circuit comprises a second input pair tube M 21、M22, a second current mirror M 23, a second filter capacitor C 23 and voltage dividing resistor arrays R 1 to R 2^k. The first input pair of tubes M 11、M12 is identical to the second input pair of tubes M 21、M22, the first current mirror M 13 is identical to the second current mirror M 23, The first filter capacitor C 13 is identical to the second filter capacitor C 23, the matching resistor array is identical to the divider resistor arrays R 1 to R 2^k, To ensure consistent circuit conditions. The third input end and the fourth input end of the detection voltage generating circuit, the first input end and the second input end of the reference voltage generating circuit are direct current working points provided by the grid electrode of the second input pair tube M 21、M22, the drain electrode of the second current mirror M 23 and the second filter capacitor C 23 are connected with the source electrode of the second input pair tube M 21、M22, the divider resistor arrays R 1 to R 2^k connect the drain of the second input pair of tubes M 21、M22 and the second filter capacitor C 23, Each of the voltage dividing resistors of the voltage dividing resistor arrays R 1 to R 2^k is connected with a second input terminal of the quantization encoder; the second current mirror M 23 controls the gain of the second input to the tube M 21、M22, and generates the same direct current V DC at the output voltage as the detection voltage generation circuit, The voltage dividing resistor arrays R 1 to R 2^k generate a reference voltage of 2-k stages between the generated direct current V DC and the input power V dd or ground, Each stage voltage is < V ref1:Vref2^k>+VDC containing a dc signal. As shown in fig. 3, when the second input pair of transistors M 21、M22 and the second current mirror M 23 are NMOS transistors, the drain of the second input pair of transistors M 21、M22 is connected to the power supply Vdd, the source of the second current mirror M 23 is grounded, One end of the second filter capacitor C 23 is grounded. As shown in fig. 4, when the second input pair of transistors M 21、M22 and the second current mirror M 23 are PMOS transistors, the drain of the second input pair of transistors M 21、M22 is grounded, the source of the second current mirror M 23 is connected to the power supply Vdd, one end of the second filter capacitor C 23 is connected to the power supply Vdd.
The quantization encoder compares the detection voltage V PD+VDC at its first input with the reference voltage < V ref1:Vref2^k>+VDC at its second input, eliminates the DC signal, and generates the digital code D out < k-1:0> -of the detection voltage.
The invention provides a swing detection circuit with DC offset elimination, which eliminates the DC component in the detection signal and codes the DC component by comparing the reference voltage with the DC signal with the detection signal, thereby realizing the effect of DC offset elimination and having the advantages of simple architecture, small layout area and low power consumption. More specifically, the reference voltage generating circuit can generate a reference voltage with a direct current signal, and the reference voltage generating circuit and the detection voltage generating circuit are symmetrical in circuit design, so that the direct current signal and the direct current signal of the detection voltage generating circuit synchronously change under the influence of the changes of the process, the voltage and the temperature, and therefore the digital code generated by the comparison of the quantization encoder is calculated by a zero voltage point and is not influenced by the changes of the process, the voltage and the temperature, and the stability of the circuit is improved.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way; those skilled in the art can smoothly practice the invention as shown in the drawings and described above; however, those skilled in the art will appreciate that many modifications, adaptations, and variations of the present invention are possible in light of the above teachings without departing from the scope of the invention; meanwhile, any equivalent changes, modifications and evolution of the above embodiments according to the essential technology of the present invention still fall within the scope of the present invention.
Claims (8)
1. A swing detection circuit with dc offset cancellation, characterized by: comprises a detection voltage generating circuit, a reference voltage generating circuit and a quantization encoder; the detection voltage generation circuit is used for converting the swing amplitude of the voltage-controlled oscillator into linear voltage; the first input end of the detection voltage generation circuit is connected with the positive end of the voltage-controlled oscillator, the second input end of the detection voltage generation circuit is connected with the negative end of the voltage-controlled oscillator, the third input end and the fourth input end of the detection voltage generation circuit are connected with the bias voltage, the first input end and the second input end of the reference voltage generation circuit are connected with the bias voltage, the output end of the detection voltage generation circuit is connected with the first input end of the quantization encoder, the output end of the reference voltage generation circuit is connected with the second input end of the quantization encoder, and the quantization encoder is provided with a plurality of bit output ends;
The detection voltage generation circuit comprises a blocking capacitor, a first input pair tube, a first current mirror, a first filter capacitor and a matching resistor array, wherein signals of a first input end and a second input end of the detection voltage generation circuit are connected to a grid electrode of the first input pair tube through the blocking capacitor, a third input end and a fourth input end of the detection voltage generation circuit provide direct current working points for the grid electrode of the first input pair tube, a drain electrode of the first current mirror, the first filter capacitor are connected with a source electrode of the first input pair tube, the matching resistor array is connected with the drain electrode of the first input pair tube and the first filter capacitor, and the first filter capacitor is connected with the first input end of the quantization encoder; the first input pair tube converts swing voltage change of the voltage-controlled oscillator into linear output detection voltage with ripple waves, the first current mirror controls gain of the first input pair tube, direct current is generated at the output voltage, and the output voltage passes through the first filter capacitor to filter ripple wave components to obtain detection voltage with direct current signals.
2. The swing detection circuit with dc offset cancellation of claim 1, wherein: the reference voltage generation circuit comprises a second input pair tube, a second current mirror, a second filter capacitor and a divider resistor array, wherein a third input end and a fourth input end of the detection voltage generation circuit and a first input end and a second input end of the reference voltage generation circuit are direct current working points provided for grid electrodes of the second input pair tube, a drain electrode of the second current mirror and a source electrode of the second input pair tube are connected with each other, the divider resistor array is connected with the drain electrode of the second input pair tube and the second filter capacitor, and each divider resistor in the divider resistor array is connected with the second input end of the quantization encoder; the second current mirror controls the gain of the second input pair of tubes and generates the same direct current as the detection voltage generation circuit at the output voltage.
3. A swing detection circuit with dc offset cancellation as claimed in claim 2, wherein: the output end of the quantization encoder is provided with k bits, the voltage dividing resistor array generates 2-k-level reference voltages between the generated direct current and an input power supply or ground, each level of voltage is < V ref1:Vref2^k>+VDC containing direct current signals, V ref1:Vref2^k is reference voltage corresponding to 1-2-k-level, and V DC is direct current which is the same as that generated by the detection voltage generating circuit at the output voltage of the second current mirror.
4. A swing detection circuit with dc offset cancellation as claimed in claim 3, wherein: the quantization encoder compares the detection voltage of the first input end with the reference voltage of the second input end, eliminates the direct current signal, and generates a digital code D out < k-1:0> of the detection voltage.
5. A swing detection circuit with dc offset cancellation as claimed in claim 2, wherein: the first input pair of tubes is identical to the second input pair of tubes.
6. A swing detection circuit with dc offset cancellation as claimed in claim 2, wherein: the first current mirror is identical to the second current mirror.
7. A swing detection circuit with dc offset cancellation as claimed in claim 2, wherein: the first filter capacitor is the same as the second filter capacitor.
8. A swing detection circuit with dc offset cancellation as claimed in claim 2, wherein: the matching resistor array is identical to the voltage dividing resistor array.
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| CN202011634876.3A CN112882529B (en) | 2020-12-31 | 2020-12-31 | Swing detection circuit with DC offset elimination function |
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| CN112882529B true CN112882529B (en) | 2024-10-11 |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1671050A (en) * | 2004-09-30 | 2005-09-21 | 东南大学 | Fixed amplitude circuit for voltage controlled oscillator |
| CN204517791U (en) * | 2015-04-03 | 2015-07-29 | 南京能瑞自动化设备股份有限公司 | A kind of automatic amplitude of oscillation calibration circuit of voltage controlled oscillator |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103944514B (en) * | 2014-04-28 | 2017-06-16 | 无锡中感微电子股份有限公司 | Amplitude detection controls circuit and digitally controlled crystal oscillator system |
| CN104796138B (en) * | 2015-04-22 | 2017-12-26 | 西安电子科技大学 | A kind of output voltage swing corrects LC voltage controlled oscillators automatically |
| CN111917396A (en) * | 2019-05-09 | 2020-11-10 | 复旦大学 | Broadband low-power-consumption oscillator device with self-adaptive voltage bias |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1671050A (en) * | 2004-09-30 | 2005-09-21 | 东南大学 | Fixed amplitude circuit for voltage controlled oscillator |
| CN204517791U (en) * | 2015-04-03 | 2015-07-29 | 南京能瑞自动化设备股份有限公司 | A kind of automatic amplitude of oscillation calibration circuit of voltage controlled oscillator |
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