CN100468968C - Transduction tuned circuit and associated method - Google Patents
Transduction tuned circuit and associated method Download PDFInfo
- Publication number
- CN100468968C CN100468968C CNB2005101193144A CN200510119314A CN100468968C CN 100468968 C CN100468968 C CN 100468968C CN B2005101193144 A CNB2005101193144 A CN B2005101193144A CN 200510119314 A CN200510119314 A CN 200510119314A CN 100468968 C CN100468968 C CN 100468968C
- Authority
- CN
- China
- Prior art keywords
- transduction
- control signal
- amplitude
- signal
- output signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
Abstract
The invention provides a transduction tuning circuit and the relative method to adjust the transduction factor in transduction-capacity filter system. The tuning circuit uses the constant amplitude and the periodic inputting signal to trigger the transduction unit to charge and discharge the capacity unit to establish the output signal, uses the amplitude testing feedback circuit to adjust the transduction factor of the transduction unit by the amplitude of the output signal and uses the amplitude of the output signal to lock the prearranging amplitude range.
Description
Technical field
The invention provides a kind of transduction tuned circuit and correlation technique, refer to a kind of transduction tuned circuit and correlation technique that comes tuning transduction coefficient via the amplitude locked loop especially.
Background technology
In modern information-intensive society, various files, data, data and audio and video information can both exchange in the mode of electronic signal, handle, transmit.Therefore, be used for handling the various signal processing circuits of electronic signal, also just become one of most important hardware foundation of advanced information society.
Signal processing circuit forms with various filter combinations mostly.As is known to the person skilled in the art, one of technology that realizes filter is exactly the filter transfer function (transfer function) that is combined into institute's desire realization with trnasducing element (transconductor cell, or be commonly referred to as Gm cell).Trnasducing element is a kind of circuit that can input voltage be converted to output current according to transduction coefficient, because it can be an output current with the voltage transitions of input, so have the function of transduction, and the transformational relation between output current/input voltage (ratio) is just decided by the transduction coefficient of trnasducing element itself.Electric capacity of a trnasducing element collocation just can be realized out an integrator (integrator), and suitably make up a plurality of integrators, just can realize out various filter transfer functions.For instance, make up two trnasducing elements and two electric capacity, just can realize out the transfer function of single order (first order).Make up four trnasducing elements and electric capacity, then can further realize out the transfer function of second order, by that analogy.And, just can be described as transduction-electric capacity (Gm-C) filter with the filter that trnasducing element collocation electric capacity is realized out.Transduction-capacitive filter can be used to realize high frequency, the filter function of continuous time (continuous time), so also become the research and development emphasis of present information manufacturer.
In transduction-capacitive filter of being realized with trnasducing element collocation electric capacity, the characteristic of its filter is also just decided by the transduction coefficient of each trnasducing element and the capacitance of each electric capacity.For example, the frequency range of filter, the limit of filter transfer function (pole), zero point (zero) position and gain or the like all can be relevant with transduction coefficient, capacitance.Wherein, ratio (the Gm/C of transduction coefficient and capacitance; to call transduction-capacity ratio in the following text) be one of most important parameter, because this ratio is understood the frequency domain characteristic (similarly being limit, dead-center position of filter transfer function or the like) of master control (dominate) filter usually.Yet; because undesirable factors such as process variation and operating temperature; the capacitance regular meeting of the transduction coefficient of trnasducing element and electric capacity drifts about to some extent and departs from the original design load of setting of circuit designers; related also make transduction-capacity ratio also can with drift, therefore also make the actual characteristic of filter depart from the filter characteristic that circuit designers was originally expected.
In order to resist undesirable factors such as processing procedure, temperature, in general transduction-capacitive filter, can adopt the adjustable trnasducing element of transduction, and the transduction tuned circuit of arranging in pairs or groups adjusts the transduction coefficient of each trnasducing element, to compensate the characteristic drift that undesirable factor is caused.In the adjustable trnasducing element of transduction, its transduction coefficient can controlled adjustment, and the function of transduction tuned circuit is exactly suitably to adjust its transduction coefficient for each trnasducing element in the transduction-capacitive filter, make filter characteristic (especially transduction-capacity ratio) can resist undesirable factor, be difficult for drifting about because of factors such as processing procedure, temperature.For instance, when reality realizes transduction-capacitive filter, increased by 5% as if the capacitance that causes each electric capacity in the filter that makes a variation to some extent because of manufacture of semiconductor than original design load, then when this transduction tuned circuit operation, just can suitably adjust the transduction value of each trnasducing element in the filter, make the transduction value also than the rough increase by 5% of original design load.So, transduction-capacity ratio will suitably be compensated, and makes transduction-capacity ratio level off to original design load, keeps the due characteristic of filter.
But, in known various transduction tuned circuits and technology, known transduction tuned circuit often takies more layout area because of circuit is too complicated, consumes more power, make time, cost, layout area and the power drain of the manufacturing of transduction-capacitor filtering art designs all can increase, be unfavorable for transduction-capacitor filtering The Application of Technology.
Summary of the invention
The present invention will provide a kind of preferable transduction tuned circuit and correlation technique, it can realize the tuning function of transduceing with the circuit of simplifying, layout area is less, power consumption is less, overcoming the shortcoming of prior art, and make transduction-capacitor filtering technology can be easier, realize more accurately.
The invention provides a kind of transduction tuned circuit, it includes: trnasducing element, but its receiving inputted signal also provides corresponding drive signal, so that the value of this drive signal is corresponding to the level and the transduction coefficient of this input signal, and this trnasducing element can be adjusted this transduction coefficient according to the value of control signal; Capacitance module is used for receiving this drive signal and discharges and recharges so that corresponding output signal to be provided; And the amplitude detecting feedback circuit, it can adjust the value of this control signal according to this output signal level, and utilizes this control signal of feedback that this output signal level amplitude is locked to default amplitude range; Wherein this amplitude detecting feedback circuit includes: peak detector is used for detecting this output signal level amplitude, and provides corresponding pre-control signal according to testing result; And low pass filter, it can provide this control signal according to this pre-control signal, and this control signal is fed back to this trnasducing element; It is characterized in that: this peak detector includes: comparison module, and being used for relatively, whether this output signal level surpasses default target zone; And charge pump and at least one second capacitance module, this charge pump can be according to the comparative result of this comparison module and this second capacitance module is discharged and recharged, make this second capacitance module that this pre-control signal can be provided according to the comparative result of this comparison module, wherein this input signal is a periodic signal with constant amplitude, and this trnasducing element is to make the product of the current value of this drive signal corresponding to this transduction coefficient and this incoming signal level, to be the value that makes this transduction coefficient have positively related relation with the value of this control signal to this trnasducing element, makes this transduction coefficient can the synchronously increase/minimizing with the value increase/minimizing of control signal.
In an embodiment of the present invention, wherein when this output signal level surpassed default target zone, this amplitude detecting feedback circuit can be adjusted the value of this control signal and feed back the value that makes this trnasducing element reduce this drive signal; When this output signal level was in this default target zone, this amplitude detecting feedback circuit can be adjusted the value of this control signal and feed back the value that makes this trnasducing element increase this drive signal.
In an embodiment of the present invention, wherein this amplitude detecting feedback circuit includes: peak detector is used for detecting this output signal level amplitude, and provides corresponding pre-control signal according to testing result; And low pass filter, it can provide this control signal according to this pre-control signal, and this control signal is fed back to this trnasducing element.
In an embodiment of the present invention, wherein this peak detector includes: comparison module, and being used for relatively, whether this output signal level surpasses default target zone; Charge pump and at least one second capacitance module, this charge pump can discharge and recharge this second capacitance module according to the comparative result of this comparison module, makes this second capacitance module that this pre-control signal can be provided according to the comparative result of this comparison module.
In an embodiment of the present invention, transduction tuned circuit is to be applied to a filter system, include at least one filter in this filter system, also be provided with the trnasducing element of at least one correspondence in each filter, and this transduction tuned circuit can utilize this control signal to adjust the transduction coefficient of the trnasducing element of each filter.
The invention provides a kind of method of adjusting transduction coefficient, include: input signal is provided and produces corresponding drive signal with input signal, so that the value of this drive signal is corresponding to level and this transduction coefficient of this input signal according to transduction coefficient; Discharge and recharge to capacitance module with this drive signal, and provide corresponding output signal according to the situation that discharges and recharges; Relatively whether this output signal level surpasses default target zone, and provides a pre-control signal according to comparative result; Utilize this pre-control signal of feedback that this output signal level amplitude is locked to default amplitude range; And carry out those steps repeatedly, so that this output signal level amplitude is locked to default amplitude range, lock this transduction coefficient by this; Wherein the value of this drive signal is synchronously increase and decrease with the increase and decrease of this transduction coefficient.
In an embodiment of the present invention, this method also comprises: carry out those steps repeatedly, so that this output signal level amplitude is locked to default amplitude range, lock this transduction coefficient by this.
In an embodiment of the present invention, when wherein adjusting this transduction coefficient,, this transduction coefficient is reduced if this output signal level surpasses default target zone according to this output signal level; Otherwise, this transduction coefficient is increased.
In one embodiment of this invention, this method is to apply to filter system, include at least one filter in this filter system, be that other realizes filter function according to the transduction coefficient of the trnasducing element of correspondence in each filter, and this method also includes: when adjusting this transduction coefficient, adjust the transduction coefficient of the trnasducing element in each filter simultaneously.
In transduction tuned circuit of the present invention, owing to only need use trnasducing element, so can significantly reduce the overall power consumption and the layout area of transduction tuned circuit, can assist transduction-capacitive filter with circuit structure more economical, that more simplify, make transduction-capacitive filter can accurately realize its filtering characteristic.
Description of drawings
The 1st figure is a kind of function block schematic diagram of traditional transduction tuned circuit.
The 2nd figure is arranged at function block schematic diagram in the filter system for transduction tuned circuit of the present invention.
What the 3rd figure illustrated is the operating principle of transduction tuned circuit among the 2nd figure.
The 4th figure has illustrated a kind of embodiment of amplitude detecting feedback circuit among the 2nd figure.
The 5th figure has further illustrated a kind of embodiment of transduction tuned circuit among the 4th figure.
What the 6th figure illustrated is the operating principle of transduction tuned circuit among the 5th figure.
The 7th figure is the application scenarios of transduction tuned circuit collocation second order transduction-capacitive filter of the present invention.
[main element symbol description]
10,30 tuning circuits
12 frequency/phase detectors
14,52 charge pumps
16 low pass filters
18 voltage controlled oscillators
20,24,32,42 trnasducing elements
22,38 transduction-capacitive filters
34,54 capacitance modules
36 amplitude detecting feedback circuits
40 filter systems
46 peak detectors
48 low pass filters
50 comparison modules
The 56A-56B comparator
58 or the door
The 60A-60B current source
62 reference source circuits
The T cycle
Vo_M, Vi_M amplitude
Vpc controls signal in advance
Gm, Gm (1)-Gm (N), Gm1-Gm5 transduction coefficient
Io, Ia, Id electric current
C, C2, Ca, Cb, Cx electric capacity
The Wr reference clock
Wo, CK clock
Vc0, Vc control signal
The Vi input signal
The Vo output signal
Vtar+, Vtar-, Vi+, Vi-voltage
Vcmp, Vsi, Vso signal
Sa, Sd slope
T1-t7, ta-td time
Ta, Td period
K0-k2, Q parameter
Embodiment
Please refer to the 1st figure, what it was illustrated is the circuit diagram that traditional transduction tuned circuit 10 (being designated hereinafter simply as tuning circuit 10) collocation transduction-capacitive filter 22 forms filter system.Be provided with a plurality of trnasducing elements 24 (and a plurality of electric capacity of arranging in pairs or groups in the transduction-capacitive filter 22, icon not) realizes out specific filter transfer function with combination, and tuning circuit 10 is a transduction tuned circuit, it is a transduction coefficient of adjusting each trnasducing element 24 correspondence with the principle of phase-locked loop, makes the filter characteristic of transduction-capacitive filter 22 can resist the characteristic drifts that variation caused such as processing procedure, temperature.
Shown in the 1st figure, tuning circuit 10 is to form the phase-locked loop with frequency/phase detector 12, charge pump 14, low pass filter 16 and voltage controlled oscillator 18.Wherein, the voltage controlled oscillator 18 clock Wo that can vibrate, 12 of frequency/phase detectors can compare clock Wo and another has the reference clock Wr of fixed frequency, to detect frequency and/or the phase difference between these two clock Wo, Wr.The testing result of frequency/phase detector 12 can form control signal Vc0 via the processing of charge pump 14, low pass filter 16.This control signal Vc0 can feed back to voltage controlled oscillator 18, makes voltage controlled oscillator 18 suitably change the frequency of clock Wo.The purpose of this phase-locked loop will make the frequency of the frequency lock of clock Wo to reference clock Wr exactly.
In order to reflect transduction coefficient and the capacitance variation in transduction-capacitive filter 22, voltage controlled oscillator 18 equally also is to realize out with a plurality of trnasducing elements 20 (and arrange in pairs or groups a plurality of electric capacity, not icon) combination.Just as discussed earlier, trnasducing element (collocation electric capacity) just can realize out various transfer functions, so also can be used to realize out the oscillation functions of voltage controlled oscillator 18.Therefore, the characteristic of voltage controlled oscillator 18 similarly is a frequency of oscillation, also just is controlled by the transduction-capacity ratio of each trnasducing element 20 and corresponding electric capacity.And control signal Vc0 is exactly the transduction coefficient that is used for adjusting each trnasducing element 20, makes the frequency (frequency of clock Wo just) that voltage controlled oscillator 18 vibrates out can be controlled by control signal Vc0.Since the frequency of clock Wo depends on transduction-capacity ratio, when the phase-locked loop is stably reached phase-locked and is made the frequency lock of clock Wo be default value (frequency of reference clock Wr just), transduction-capacity ratio should also just be locked to default design load, reaches the tuning purpose of transduction.And this control signal Vc0 also just can be used to adjust the transduction coefficient in transduction-capacitive filter 22, makes filter characteristic in transduction-capacitive filter 22 can resist processing procedure, drift that temperature caused.
For instance, when supposing the filter system in realizing the 1st figure, process variation makes the capacitance of each electric capacity greater than former design load.If at the beginning of the phase-locked loop brings into operation, the transduction coefficient of each trnasducing element 20 also is maintained at former design load, and then the frequency of clock Wo may be lower and can not meet the frequency of reference clock Wr.When the phase-locked loop feed back repeatedly stably reach to adjust transduction coefficient phase-locked after, the frequency of clock Wo can be locked to the frequency of reference clock Wr, on behalf of the transduction coefficient of each trnasducing element 20, this also just suitably increased, with the increase of building-out capacitor value.Adjust transduction coefficient in transduction-capacitive filter 22 according to identical adjustment degree, also just can make the filtering characteristic of transduction-capacitive filter 22 level off to former design load, resist the characteristic drift that undesirable factor causes.
But, the tuning circuit 10 among the 1st figure also has shortcoming.Because need realize out the transfer function of second order during the transfer function that will realize having oscillation functions with trnasducing element at least, so in voltage controlled oscillator 18, at least need to use four trnasducing elements 20 (and corresponding electric capacity), will increase tuning circuit 10 shared layout area and power consumption like this.In addition, in order to avoid the operation of reference clock Wr coupled interference transduction-capacitive filter 22, the frequency of reference clock Wr preferably will be higher than the frequency range of transduction-capacitive filter 22 operations, and the reference clock Wr of high frequency can relatedly make whole tuning circuit 10 also need run on high frequency, and the power demand of tuning circuit 10 is more increased.Because the essence of voltage controlled oscillator 18 is to produce vibration, and concerning circuit, vibration is exactly a kind of instability, so when realizing tuning circuit 10, many details of also need worrying, similarly be starting of oscillation opportunity of voltage controlled oscillator 18 or the like, and this can increase the circuit complexity of tuning circuit 10 and design, the time of manufacturing, cost.
In order to overcome the shortcoming of traditional tuning circuit and correlation technique, the present invention proposes a kind of transduction tuned circuit and correlation technique based on the amplitude locked loop.Please refer to the 2nd figure, it is that transduction tuned circuit 30 of the present invention (being designated hereinafter simply as tuning circuit 30) is arranged at the function block schematic diagram in the filter system 40.One or more transduction-capacitive filters (among the 2nd figure with transduction-capacitive filter 38 as representative) can be provided with in the filter system 40, one or more trnasducing elements 42 (and the electric capacity of correspondence, not shown) can be provided with in each transduction-capacitive filter.And tuning circuit 30 is transduction tuned circuit, and its each transduction-capacitive filter that can be in the filter system 40 is adjusted transduction coefficient, makes the filter characteristic of each transduction-capacitive filter can resist the drift that undesirable factor causes.
In order to realize the transduction tunable technology of amplitude locked loop of the present invention, be provided with trnasducing element 32, capacitance module 34 and amplitude detecting feedback circuit 36 in the tuning circuit 30 of the present invention.Trnasducing element 32 can be the adjustable trnasducing element of transduction, but the corresponding output current Io of its receiving inputted signal Vi and transduction output is as drive signal, so that the value of this drive signal (size of current of electric current I o just) is corresponding to the transduction coefficient Gm (and level of input signal Vi) of trnasducing element 32 itself.The transduction coefficient Gm size of trnasducing element 32 then is controlled by control signal Vc.Can be provided with at least one electric capacity (among the 2nd figure with capacitor C as representative) in the capacitance module 34, be used for accepting discharging and recharging of electric current I o, on capacitor C, to set up voltage, as output signal Vo.36 values that can adjust control signal Vc according to the level (similarly being voltage level) of output signal Vo of amplitude detecting feedback circuit are locked to default amplitude range to utilize this level amplitude that feeds back output signal Vo.For example, when the level of output signal Vo surpassed default target zone, amplitude detecting feedback circuit 36 can be adjusted the value that makes control signal Vc made trnasducing element 32 adjust transduction coefficient Gm to reduce the value of output current Io with feedback; When the level of output signal Vo was in default target zone, 36 of amplitude detecting feedback circuits can be adjusted the value of control signal Vc and feed back and make trnasducing element 32 adjust transduction coefficient Gm to increase the value of output current Io.
In order to reflect the transduction coefficient and the capacitance variation of the trnasducing element 42 in transduction-capacitive filter 38, the characteristic electron of trnasducing element 32 be with transduce-each trnasducing element 42 in the capacitive filter 38 intercouples.For example, each trnasducing element 32 and 42 can be implemented in the same chip with layout, the processing procedure of mutual collocation, makes trnasducing element 32 can reflect the characteristic of each trnasducing element 42.In like manner, concerning the electric capacity of capacitance module 34, the characteristic of its electric capacity also be with transduction-capacitive filter 38 in each electric capacity (for example being to be implemented in the same chip) that intercouple with the layout of collocation mutually, identical processing procedure and material behavior, make the characteristic of these electric capacity can present the variation of same trend.
In order to further specify the operation situation of tuning circuit 30 of the present invention, please continue with reference to the 3rd figure (and in the lump with reference to the 2nd figure) operating principle that is tuning circuit 30 of the 3rd figure signal.When tuning circuit 30 operations, trnasducing element 32 can be by input signal Vi triggering for generating output current Io.In the present invention, this input signal Vi can be a square wave voltage signal with constant frequency, constant amplitude.Shown in the 3rd figure, the voltage amplitude of input signal Vi can be Vi_M, and its cycle is constant T then, make input signal Vi voltage level can+Vi_M and-be the cycle square-wave waveform between Vi_M to change.Be subjected to the triggering of this input signal Vi, trnasducing element 32 can be according to the relation transduction output current Io of Io (t)=Gm*Vi (t), thus the size of current of electric current I o also will Gm*Vi_M and-present the variation of square-wave waveform between the Gm*Vi_M, as shown in the figure 3.
When electric current I o exports capacitance module 34 to, electric current I o will discharge and recharge capacitor C, sets up voltage-sawtooth on capacitor C, just output signal Vo.Shown in the 3rd figure, when electric current I o when the preceding half period is maintained at Gm*Vi_M, can and make the voltage level of output signal Vo be linear to capacitor C charging and rise.According to electric current to the formula of electric capacity charging as can be known, the voltage ascensional range Vo_M of output signal Vo just equals Gm*Vi_M* (T/2)/C.In like manner, in the later half cycle, electric current I o changes into-during Gm*Vi_M, and capacitor C will and make the voltage level of output signal Vo be linear to electric current I o discharge to descend, and its voltage fall also is Gm*Vi_M* (T/2)/C.
By above-mentioned discussion as can be known, when period T and input signal amplitude Vi_M were fixed as constant, the voltage amplitude Vo_M of output signal Vo will depend on transduction-capacity ratio Gm/C.The equation of voltage amplitude Vo_M is put in order slightly, just can be obtained equation: Gm/C=(Vo_M/V i_M) * (T/2).That is to say that when transduction-capacity ratio was drifted about because of undesirable factor, the voltage amplitude Vo_M of output signal Vo also will drift about thereupon.If can voltage amplitude Vo_M be locked to a certain default design load via the amplitude locked loop, so, transduction-capacity ratio Gm/C also can be locked to default design load, and this present invention just tuning principle of transduceing.
In other words, amplitude detecting feedback circuit 36 of the present invention can utilize control signal Vc to adjust the transduction coefficient Gm of trnasducing element 32 repeatedly, so that make the change in voltage scope of output signal Vo be locked to default amplitude range (just voltage amplitude Vo_M being locked to default design load).Finish when locking, transduction-capacity ratio will level off to default design load naturally, can resist the characteristic drift that non-ideal factor causes.And the control signal Vc that trnasducing element 32 is adjusted transduction coefficient Gm just be can be used to adjust other trnasducing element 42 (shown in the 2nd figure) in transduction-capacitive filter 38, reach the tuning purpose of transduceing.In the equivalence, as long as this ratio of voltage amplitude (Vo_M/Vi_M) is locked to a certain design load, just representative transduction-capacity ratio has been locked to default design load.
For instance, suppose that the filter system 40 among the 2nd figure makes capacitance in each circuit all than former design load height because of process variation, and at the beginning of the operation of amplitude locked loop, the transduction coefficient of each trnasducing element 42 also is maintained at former design load.So, when the amplitude locked loop brought into operation, transduction-capacity ratio will depart from former design load, and the amplitude of output signal Vo also can depart from its design load and become smaller.But, the amplitude locked loop can begin to revise repeatedly the value of transduction coefficient Gm, makes the amplitude of output signal Vo stably be leveled off to default amplitude range and reach the amplitude locking.And after amplitude locking was finished, transduction coefficient Gm certainly will also suitably be transferred big and be enough to compensating offset and become big capacitance, made each transduction-capacity ratio in the filter system 40 can both level off to former design load, resisted the influence that process variation is brought.
Please continue to continue the example among the 2nd figure with reference to the 4th figure, the 4th figure has further illustrated a kind of embodiment of amplitude detecting feedback circuit 36 among the present invention.Shown in the 4th figure, in this embodiment, can be provided with peak detector 46 and low pass filter 48 in the amplitude detecting feedback circuit 36.Peak detector 46 is used for detecting the voltage level amplitude of output signal Vo, and provides corresponding pre-control signal Vpc according to testing result.48 of low pass filters can provide control signal Vc (for example being to carry out low-pass filtering to produce control signal Vc with controlling signal Vpc in advance) according to pre-control signal Vpc, and control signal Vc is fed back to trnasducing element 32, form the amplitude locked loop.
Please refer to the 5th figure, it has further shown a kind of embodiment of tuning circuit 30 among the 4th figure.Just shown in the 5th figure, in one embodiment of this invention, can be provided with comparison module 50, charge pump 52 and another capacitance module 54 in the peak detector 46.In addition, tuning circuit 30 of the present invention another reference source circuit 62 of also can arranging in pairs or groups moves.
General, the circuit unit comparison of differential-type can be resisted noise, so in the embodiment of the 5th figure, also the trnasducing element 32 with differential-type is that example illustrates the present invention.The trnasducing element 32 of differential-type has two outputs, can export respectively two anti-phase output current Io ,-Io, discharge and recharge with the capacitor C in capacitance module 34, set up output signal Vo.50 of comparison modules can comparison output signal Vo voltage level whether surpass default target zone, and comparative result is output as signal Vcmp.And charge pump 52 just can discharge and recharge the capacitor C in the capacitance module 54 2 according to the signal Vcmp of comparison module 50, makes capacitance module 54 can set up voltage according to the comparative result of comparison module 50 with as pre-control signal Vpc on capacitor C 2.
In general, in adjustable trnasducing element 32 (and other trnasducing element), the level of control signal Vc (similarly being voltage level) can become positively related relation with transduction coefficient Gm, makes the transduction coefficient Gm can the synchronously increase/minimizing with the value increase/minimizing of control signal Vc.That is to say that the voltage level of control signal Vc is high more, the value of transduction coefficient Gm is also high more.In this case, the operational scenario of peak detector 46 can be described below: when the level of output signal Vo surpasses this default target zone, comparison module 50 can make capacitor C 2 discharges in 52 pairs of capacitance modules 54 of charge pump, the voltage level of pre-control signal Vpc is reduced, to reduce the value of control signal Vc jointly; Otherwise when the voltage level of output signal Vo was in this default target zone, 50 of comparison modules can make 54 chargings of 52 pairs of these capacitance modules of charge pump, and the voltage level of pre-control signal Vpc is raise, and increased with the value that makes control signal Vc jointly.In principle, when the level of output signal Vo surpasses this default target zone, represent the transduction coefficient Gm may be excessive,, feed back transduction coefficient Gm is slightly subtracted so comparison module 50 can be via charge pump 52, capacitance module 54 and the value of reduction control signal Vc.Otherwise when the level of output signal Vo was in this default target zone, transduction coefficient Gm may be too small, so comparison module 50 will be via charge pump 52, capacitance module 54 and the level of increase control signal Vc slightly increases transduction coefficient Gm with feedback.
In order to realize above-mentioned functions, in comparison module 50, can be provided with two comparator 56A, 56B, the trnasducing element 32 of the ejector half of working poor, this two comparator 56A, 56B also can be the comparators of differential-type.Wherein, comparator 56A can compare output signal Vo, and whether (voltage Vtar just equals (Vtar+)-(Vtar-) greater than fixed value voltage Vtar, voltage Vtar+, Vtar-are two definite value direct voltages), whether comparator 56B then can compare output signal Vo less than negative fixed value voltage Vtar.Therefore, voltage+Vtar ,-Vtar also just is defined as the default target zone of comparison module 50; The comparative result of two comparator 56A, 56B then can via or door 58 and be integrated into signal Vcmp.Then can be provided with two current source 60A and 60B in the charge pump 52, can carry out charge and discharge to capacitor C 2 respectively via the control of signal Vcmp.When signal Vcmp be high level (just when output signal Vo surpass default target zone and greater than voltage Vtar or less than-Vtar) time, current source 60B available current Id (it can be the definite value direct current) is capacitor C 2 discharges; Otherwise, when signal Vcmp is low level, change then that to be come with electric current I a (also can be the definite value direct current) by current source 60A be capacitor C 2 charging.Wherein, can have fixing proportionate relationship between the size of current of electric current I a and Id, Ia:Id=1:K just, wherein K is a constant.
As for the reference source circuit among the 5th figure 62, then be to be used for providing each definite value direct voltage for tuning circuit 30.Wherein, as described in the previous paragraph, definite value direct voltage Vtar+, Vtar-promptly are used for being defined as the default target zone of comparison module 50.Definite value direct voltage Vi+, Vi-then can produce periodically, have the input signal Vi of definite value amplitude via the Switch Control of fixed clock CK frequently.Shown in the 5th figure, when clock CK was maintained the phase place of a certain level (when for example being high level), the level of input signal Vi just equaled voltage (Vi+)-(Vi-); When clock CK was the phase place of another level (when for example being low level), the level of input signal Vi just equaled voltage (Vi-)-(Vi+).In addition, control common mode (common-mode) bias voltage of differential-type trnasducing element 32 (and other each differential-type circuit unit) if necessary, also reference source circuit 62 provides the direct current common mode bias of definite value thus.
For further specifying the operational scenario of each circuit among the 5th figure, please continue with reference to the 6th figure (and in the lump with reference to the 5th figure).The 6th figure illustrates the operating principle of tuning circuit 30 among the 5th figure with the waveform of each coherent signal among the 5th figure, and the transverse axis of the 6th figure is the time, and the longitudinal axis of each signal waveform then is a voltage swing.Shown in the 6th figure, periodic triggers along with input signal Vi, the voltage level of output signal Vo also can present the variation of sawtooth waveform, and will detecting the level of output signal Vo, comparison module 50 (the 5th figure) whether surmounts default target zone (in the present embodiment, just by fixed value voltage Vtar ,-scope that Vtar defined out), and provide corresponding signal Vcmp to reflect comparative result.For example, between time t1 to t2, the voltage level of output signal Vo is in default target zone, so signal Vcmp is a low level, and current source 60A (the 5th figure) will be capacitor C 2 chargings, make the voltage of pre-control signal Vpc present the linear trend that rises in the section at this moment, the slope that its voltage rises can show to be Sa.To between the time t2 to t3, the level of output signal Vo begins the overshoot scope, so signal Vcmp transfers high level to, changes current source 60B is come capacitor C 2 discharge, make the voltage of pre-control signal Vpc be linear downward trend in the section at this moment, its descending slope can show to be Sd.Since electric current I a:Id=1:K, so slope | and Sa|:|Sd| also can equal 1:K.
By the 3rd figure and relevant discussion as can be known, time rate of change meeting and the transduction-capacity ratio Gm/C of output signal Vo are directly proportional.Therefore, when transduction-capacity ratio during greater than default design load, the output signal Vo of sawtooth waveform can rise apace/descend, in this case, the amplitude of output signal Vo voltage level overshoot scope is bigger, level is maintained at the outer time of target zone also can be long, and current source 60B is that the time that capacitor C 2 is discharged also can be long, makes the voltage level of pre-control signal Vpc present overall downward trend.Picture is in the 6th figure, when at time t1, output signal Vo rises apace, its peak value between time t2, t3 will be with bigger amplitude overshoot scope, being maintained at the outer time (period between time t2-t3 just) of target zone also can be longer, make current source 60B can have the more time to be capacitor C 2 discharges, this also makes pre-control signal Vpc can present total system downward trend, jointly, control signal Vc (being represented by dotted lines in the 6th figure) also can descend, so that feed back to trnasducing element 32 transduction coefficient Gm is turned down.So, the trend of output signal Vo variation will ease up a little.Relatively, if transduction-capacity ratio is less, the time rate of change of output signal Vo can be comparatively slow, and the time that output signal Vo is maintained in the target zone increases, and also makes current source 60A can have the longer time to be capacitor C 2 chargings.Therefore, control signal Vpc in advance and can present the trend that totally raises up, control signal Vc is increased, feed back to trnasducing element 32 again transduction coefficient Gm is increased.
Finish the phase-locked back (for example after time ta) of stable state Deng the phase-locked loop, the time (similarly be period Td) of output signal Vo outside target zone and the time (period Ta) of output signal Vo in target zone should be able to present the ratio of Ta:Td=K:1, the ratio Ia:Id=1:K that cooperates charge pump 52 charging and discharging currents just just can make pre-control signal Vpc present overall stable (just being maintained at constant).Jointly, control signal Vc also just presents stable definite value, and Gm is maintained at fixed value with transduction coefficient, and this fixed value also just can make transduction-capacity ratio be maintained at default design load.
In other words, as long as in the ratio 1:K of current source 60A, 60B, set the value of constant K, the amplitude of output signal Vo when going out condition (period Ta:Td=K:1 just) that amplitude locking finishes and locking with regard to definable (by among the 6th figure as can be known, when amplitude locks, the amplitude DV1+DV2 that output signal Vo exceeds target zone will can be the ratio of 1:K with target zone DV, can learn the amplitude range of output signal Vo after amplitude locking thus), and defined the lock value of transduction-capacity ratio jointly.That is to say, when the designer when carrying out circuit design, just can be, and in charge pump 52, realize this constant K by the anti-size that pushes away the constant K value of required transduction-capacity ratio, just can will transduce by the amplitude locking during operation of amplitude locked loop-capacity ratio is locked to the required design load of designer.
Please once again with reference to the 5th figure, in the reference source circuit 62 of the 5th figure, available same resitstance voltage dividers such as each definite value direct voltage Vi+, Vi-, Vtar+, Vtar-generate.Though the resistance value of resitstance voltage divider may be drifted about to some extent because of processing procedure, the temperature related value of these direct voltages that makes of drifting about to some extent, ratio regular meeting mutual between each direct voltage is kept fixing.Just shown in the 3rd figure and correlation formula,, just transduction-capacity ratio can be locked to design load as long as amplitude ratio (Vo_M/Vi_M) can be locked to design load.Wherein, amplitude Vo_M during locking can depend on voltage Vtar+, Vtar-, amplitude voltage Vi_M is then determined by voltage Vi+, Vi-, therefore, even the value of voltage Vi+, Vi-, Vtar+, Vtar-is drifted about to some extent, as long as the proportionate relationship between each voltage is kept unanimity, the present invention still can be locked to default design load with transduction-capacity ratio with the amplitude locked loop.
Be stressed that at this, that discuss among the 5th figure, the 6th figure only is a kind of embodiment of the present invention, one of main spirit of the present invention, reach the purpose of adjusting transduction coefficient with the amplitude phase-locked loop exactly, as long as can realize the various equivalent electric circuits of this technical spirit, all should be covering scope of the present invention.For example, in the embodiment of the 5th figure, also can be provided with the electric capacity of two couplings in the capacitance module 34, each electric capacity is connected between two current output terminals and ground end of trnasducing element 32 of differential-type, and is used as output signal Vo with the cross-pressure difference of two electric capacity.
Please refer to the 7th figure, continue the example of the 2nd figure, the 7th figure is the application that transduction tuned circuit 30 of the present invention is described with the example of second order transduction-capacitive filter.Shown in the 7th figure, be to combine with five trnasducing elements (transduction coefficient of each trnasducing element is respectively Gm1 to Gm5) and each capacitor C a, Cb and Cx in the transduction-capacitive filter 38, it can be at the transfer function (for example being the transfer function under Laplce changes) of realizing a second order between input signal Vsi and the output signal Vso.By each equation among the 7th figure as can be known, every significant coefficient of this transfer function is as k1, k0, resonant angular frequency w0 all can be relevant with transduction-capacity ratio with filter characteristic parameters such as qualitative factor (quality factor) Q.And tuning circuit 30 of the present invention just can utilize the principle of amplitude locked loop that transduction-capacity ratio is locked as default design load, guarantees to transduce-the accurate operation of capacitive filter 38.
In summary, compared to known and conventional art, it is that transduction-capacitive filter is realized the function that transduction is tuning that the present invention only need can come according to the principle of amplitude locked loop with the electric capacity of single trnasducing element and collocation, dying, the shared layout area of transduction tuned circuit of the present invention is less, power consumption is also less, time and the cost also can the economization circuit design made, make transduction-capacitor filtering technology energy more convenient, accurately be employed.
The above only is preferred embodiment of the present invention, and all equalizations of being done according to claim scope of the present invention change and modify, and all should belong to covering scope of the present invention.
Claims (7)
1. transduction tuned circuit, it includes:
Trnasducing element, its receiving inputted signal also provide corresponding drive signal, so that the value of this drive signal is corresponding to the level and the transduction coefficient of this input signal, and this trnasducing element is adjusted this transduction coefficient according to the value of control signal;
Capacitance module is used for receiving this drive signal and discharges and recharges so that corresponding output signal to be provided; And
The amplitude detecting feedback circuit, it adjusts the value of this control signal according to this output signal level, and utilize this control signal of feedback that this output signal level amplitude is locked to default amplitude range, wherein this amplitude detecting feedback circuit includes: peak detector, be used for detecting this output signal level amplitude, and provide corresponding pre-control signal according to testing result; And low pass filter, it provide this control signal according to controlling signal in advance, and this control signal is fed back to this trnasducing element;
It is characterized in that:
This peak detector includes:
Comparison module, being used for relatively, whether this output signal level surpasses default target zone; And
Charge pump and at least one second capacitance module, this charge pump discharges and recharges this second capacitance module according to the comparative result of this comparison module, makes this second capacitance module provide this pre-control signal according to the comparative result of this comparison module,
Wherein this input signal is a periodic signal with constant amplitude, and this trnasducing element system makes the product of the current value of this drive signal corresponding to this transduction coefficient and this incoming signal level, the value that this trnasducing element system makes this transduction coefficient has positively related relation with the value of this control signal, makes this transduction coefficient can the synchronously increase/minimizing with the value increase/minimizing of control signal.
2. transduction tuned circuit according to claim 1, wherein when this output signal level surpassed default target zone, this amplitude detecting feedback circuit can be adjusted the value of this control signal and feed back the value that makes this trnasducing element reduce this drive signal; When this output signal level was in this default target zone, this amplitude detecting feedback circuit can be adjusted the value of this control signal and feed back the value that makes this trnasducing element increase this drive signal.
3. transduction tuned circuit according to claim 1, wherein when this output signal level surpasses this goal-selling scope, this comparison module makes this charge pump to this second capacitance module discharge, the level of this pre-control signal is reduced, to reduce the value of this control signal jointly; When this output signal level was in this target zone, this comparison module made this charge pump to this second capacitance module charging, and the level of this pre-control signal is raise, and increases with the value that makes this control signal jointly.
4. transduction tuned circuit according to claim 1, it is to be applied to filter system, include at least one filter in this filter system, be provided with the trnasducing element of at least one correspondence in each filter in addition, and this transduction tuned circuit utilizes this control signal to adjust the transduction coefficient of the trnasducing element of each filter.
5. method of adjusting transduction coefficient includes:
Input signal is provided and produces corresponding drive signal with input signal, so that the value of this drive signal is corresponding to level and this transduction coefficient of this input signal according to transduction coefficient;
Discharge and recharge to capacitance module with this drive signal, and provide corresponding output signal according to the situation that discharges and recharges;
Relatively whether this output signal level surpasses default target zone, and provides a pre-control signal according to comparative result;
Utilize this pre-control signal of feedback that this output signal level amplitude is locked to default amplitude range; And
Carry out those steps repeatedly,, lock this transduction coefficient by this so that this output signal level amplitude is locked to default amplitude range,
Wherein the value of this drive signal is synchronously increase and decrease with the increase and decrease of this transduction coefficient.
6. method according to claim 5 when wherein adjusting this transduction coefficient according to this output signal level, if this output signal level surpasses default target zone, then makes this transduction coefficient reduce; Otherwise, this transduction coefficient is increased.
7. method according to claim 5, it is to apply to filter system, include at least one filter in this filter system, be in addition to realize filter function according to the transduction coefficient of the trnasducing element of correspondence in each filter, this method is used for adjusting the transduction coefficient of the trnasducing element of each filter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005101193144A CN100468968C (en) | 2005-11-03 | 2005-11-03 | Transduction tuned circuit and associated method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005101193144A CN100468968C (en) | 2005-11-03 | 2005-11-03 | Transduction tuned circuit and associated method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1767381A CN1767381A (en) | 2006-05-03 |
| CN100468968C true CN100468968C (en) | 2009-03-11 |
Family
ID=36743028
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005101193144A Active CN100468968C (en) | 2005-11-03 | 2005-11-03 | Transduction tuned circuit and associated method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100468968C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101414821B (en) * | 2007-10-16 | 2012-07-04 | 联发科技股份有限公司 | Error protection method |
| US9602079B2 (en) | 2009-06-23 | 2017-03-21 | Qualcomm Incorporated | Tunable adaptive filter with variable gain trans-conductance stage |
-
2005
- 2005-11-03 CN CNB2005101193144A patent/CN100468968C/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN1767381A (en) | 2006-05-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8085098B2 (en) | PLL circuit | |
| CN102522984B (en) | Phase-locked loop and voltage-controlled oscillating circuit thereof | |
| CN101877589A (en) | Phase-locked loop circuit | |
| TWI412234B (en) | Phase locked loop and voltage controlled oscillator thereof | |
| CN103259533A (en) | Phase-locked loop circuit of LC oscillator and temperature compensating method thereof | |
| US7468629B2 (en) | Tuning circuit for transconductors and related method | |
| CN101425795B (en) | Accurate saw-tooth wave generating circuit | |
| CN116232318B (en) | Phase-locked loop, chip and electronic equipment | |
| CN116232319B (en) | Phase-locked loop, chip and electronic equipment | |
| US20170310328A1 (en) | Signal generation circuit and signal generation method | |
| JP5097235B2 (en) | Semiconductor device | |
| CN114785340A (en) | Frequency band phase-locked loop based on programmable capacitor array | |
| CN101783680A (en) | Frequency synthesizer and calibration method thereof | |
| US20080191760A1 (en) | PLLS covering wide operating frequency ranges | |
| US8274317B2 (en) | Phase-locked loop circuit comprising voltage-controlled oscillator having variable gain | |
| CN100468968C (en) | Transduction tuned circuit and associated method | |
| US8373511B2 (en) | Oscillator circuit and method for gain and phase noise control | |
| CN105610436A (en) | Charge pump phase-locked loop with adaptive acceleration locking structure | |
| US7023249B1 (en) | Phase locked loop with low phase noise and fast tune time | |
| US7649408B2 (en) | Loop filters | |
| JP2007142791A (en) | Frequency synthesizer | |
| US20110260760A1 (en) | Voltage control oscillator and control method thereof | |
| US5621349A (en) | Device for controlling an output level of an FM detecting circuit using phase locked loop | |
| CN101123433A (en) | Phase locked loop | |
| KR101344893B1 (en) | Phase locked loop circuit comprising voltage controlled oscillator having variable gain |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |