CN101325408A - Circuit for generating triangular wave - Google Patents
Circuit for generating triangular wave Download PDFInfo
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- CN101325408A CN101325408A CNA2007100419068A CN200710041906A CN101325408A CN 101325408 A CN101325408 A CN 101325408A CN A2007100419068 A CNA2007100419068 A CN A2007100419068A CN 200710041906 A CN200710041906 A CN 200710041906A CN 101325408 A CN101325408 A CN 101325408A
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Abstract
A triangular wave generating circuit comprises a clock pulse signal input end; an integrating circuit composed of an inverted input end and an output end, wherein a capacitance is connected to a first operational amplifier; a charging circuit composed of a first constant circuit, a first switch device, a second switch service, a second constant circuit connected in series; a first comparing circuit composed of a divider resistance R1, a divider resistance R2, a first comparator; a second comparing circuit composed of a divider resistance R3, a divider resistance R4, a second comparator; an RS trigger composed of a first gate circuit and a second gate circuit; a current setting circuit composed of a phase comparator, a first filter, a second operational amplifier, a field effect tube and a load circuit, wherein the load circuit is in the mirror relation with the first constant current and the second current circuit. The output of the triangular wave is controlled by the constant circuit, which keeps the period synchronism with the pulse signal without peak voltage change and offset drift triangular wave form, and the linearity reaches 0.1%.
Description
[technical field]
The invention provides a kind of circuit for generating triangular wave of the D genus audio power amplifier that is used for the PWM modulation.
[background technology]
In the D genus audio power amplifier with the PWM modulation, the triangular wave of circuit for generating triangular wave output is used to converting analogue signals to pulse signal.Because how much the contained harmonic wave of triangular wave output waveform is the basic sign of weighing PWM control method quality, the bad triangular wave of the linearity can produce huge distorted signals.Thereby it is very crucial how to obtain the good triangular wave of high carrier frequency and the linearity.
A kind of circuit that produces triangular wave shown in Figure 1 is made up of clock pulse input terminal 1, amplifier 2, resistance 3, operational amplifier 4, electric capacity 5, output 6, and wherein operational amplifier 4, electric capacity 5 constitute integrating circuit.When the pulse signal of input alternately uprised step-down, electric capacity 5 charged and discharge, output voltage V in this circuit the inside
OutProduce triangular wave.
In this circuit, output voltage can be used following formulate:
Q=CV Q is the electric weight of electric capacity 5, and C is the capacitance size of electric capacity 5, and V is the voltage of electric capacity 5,
It=CV
OutThe electric current of i electric capacity 5, t are the time, and C is the capacitance size of electric capacity 5,
V
Out=it/C=(RV
In)/C R is the resistance of resistance 3, V
InIt is input voltage.
From these formula output voltage V as can be seen
OutThe resistance value that depends on resistance 3, the capacitance of electric capacity 5 and the frequency of input clock and amplitude.Because the variation of the resistance of resistance 3 and the capacitance of electric capacity 5 can cause the variation of output voltage, thereby has influenced the linearity of triangular wave.
Fig. 2 is another circuit that produces triangular wave, and the circuit of Fig. 1 has been done improvement.The implication of input 1, amplifier 2, operational amplifier 4, electric capacity 5, output 6 and circuit shown in Figure 1 is the same among Fig. 2, has increased control and has amplified the switching device 11,12 and the constant- current circuit 13,14 of output.When switch switching device 11 closures, switching device 12 disconnected, electric capacity 5 was charged by electric current I 1 in this circuit; When switching device 11 disconnects, switching device 12 closures the time, electric capacity 5 is by electric current I 2 chargings opposite with electric current I 1.Repeat this process and produced triangular waveform at output 6.In this circuit, because the small drift of electric current in the constant-current circuit and the minor variations of input clock duty ratio can cause output voltage V
OutVariation, thereby also influenced the linearity of triangular waveform.
[summary of the invention]
The present invention seeks to above-mentioned existing circuit for generating triangular wave is made improvements again, array output feedback control signal control constant-current circuit switch with comparator circuit and rest-set flip-flop circuit, form the current value that electric current is provided with circuit decision constant-current circuit with phase comparator, filter, operational amplifier, field effect transistor and load circuit, obtain the triangular wave of high linearity and consistent therefrom with the clock pulse signal cycle.
In order to achieve the above object, the circuit for generating triangular wave of the present invention's proposition comprises:
(1) clock pulse signal input, the triangular wave output;
(2) first operational amplifiers, an electric capacity connects the counter-rotating input and the output formation integrating circuit of this operational amplifier, the non-counter-rotating input end grounding of this operational amplifier, the output of this operational amplifier connects the triangular wave output;
(3) charging circuit that is in series successively by first constant-current circuit, first switching device, second switch device, second constant-current circuit, first constant-current circuit connects positive supply, second constant-current circuit connects negative supply, and the junction of first switching device, second switch device connects the counter-rotating input of first operational amplifier;
It is characterized in that: also comprise
(4) first comparison circuit of forming by divider resistance R1, divider resistance R2, first comparator, divider resistance R1 connects with divider resistance R2, divider resistance R1 meets the positive voltage+V of setting, divider resistance R2 ground connection, the junction of divider resistance R1 and divider resistance R2 connects the non-counter-rotating input of first comparator, and the counter-rotating input of first comparator connects the output of first operational amplifier;
(5) second comparison circuit of forming by divider resistance R3, divider resistance R4, second comparator, divider resistance R3 connects with divider resistance R4, divider resistance R3 ground connection, divider resistance R4 meets the negative voltage-V of setting, the junction of divider resistance R3 and divider resistance R4 connects the non-counter-rotating input of second comparator, and the counter-rotating input of second comparator connects the output of first operational amplifier;
(6) rest-set flip-flop of forming by first gate circuit and second gate circuit, an input of first gate circuit connects the output of first comparator, an input of second gate circuit connects the output of second comparator by an inverter, and the signal N1 of rest-set flip-flop output receives first switching device and second switch device;
(7) by phase comparator, first filter, second operational amplifier, field effect transistor, the electric current of forming with load circuit is provided with circuit, the input IN of phase comparator connects the clock pulse signal input, the input REF of phase comparator connects the output signal of rest-set flip-flop, the output UP of phase comparator and output UP with DW corresponding be connected of DW with first filter, the analog signal XC of first filter output connects the non-counter-rotating input of second operational amplifier, the counter-rotating input of second operational amplifier connects the source electrode of field effect transistor, the grid of field effect transistor is linked in the output of second operational amplifier, the source electrode of field effect transistor is by a grounding through resistance, the drain electrode of field effect transistor is connected to negative supply by a load circuit, and this load circuit is the mirror image annexation with first constant-current circuit and second constant-current circuit.
Circuit of the present invention is a phase-locked loop, and the output of triangular wave is by constant-current circuit control, is not subjected to the influence of resistance and capacitance variations; The triangular wave of this circuit does not have the crest voltage variation simultaneously, and is synchronous with the clock pulse signal hold period, so the linearity of the waveform of this triangular waveform generation circuit is very high.
[description of drawings]
Fig. 1 is a kind of existing circuit for generating triangular wave figure
Fig. 2 is another existing circuit for generating triangular wave figure.
Fig. 3 is circuit for generating triangular wave figure of the present invention.
[embodiment]
Below in conjunction with accompanying drawing embodiments of the present invention are specified.
See the present invention shown in Figure 3, the circuit that a kind of triangular waveform produces.
The pulse signal that reference clock CLK sends is input to the IN input of digital phase comparator 22 by input 20 through second filter 21, and the REF input of phase comparator 22 connects the signal N1 from rest-set flip-flop.The noise signals that second filter 21 is eliminated in the clock pulse signal.The phase place of phase comparator 22 comparison clock CLK pulse signals and from the phase place of the signal N1 of rest-set flip-flop, export high level to the first filter 23 according to result relatively at output UP and DW, first filter 23 is removed the HFS of phase comparator 22 outputs, and the output of phase comparator 22 is converted to analog signal XC.
The analog signal XC of first filter, 23 outputs is connected to the non-counter-rotating input of second operational amplifier 30, and the counter-rotating input of second operational amplifier 30 connects the source electrode of field effect transistor 32, and the grid of field effect transistor 32 is linked in the output of second operational amplifier 30.The source electrode of field effect transistor 32 is connected to ground by a resistance 31, and the drain electrode of field effect transistor 32 is connected to negative supply-5V by a load circuit 33, and load circuit 33 is as the load of field effect transistor 32.Second operational amplifier 30, field effect transistor 32 and resistance 31 are formed the circuit of a control load circuit 33 electric currents, just decide the size of load 33 electric currents according to filter 23 output XC.
First constant-current circuit 34, first switching device 36, second switch device 37, second constant-current circuit 35 charging circuit that is in series successively.First constant-current circuit 34 meets positive supply 5V, and second constant-current circuit 35 meets negative supply-5V.The current value of first constant-current circuit 34, second constant-current circuit 35 and the load circuit 33 current values annexation that establishes mirror image, this mirror image annexation belongs to technique known, and multiple realization means are arranged, and does not enumerate diagram for this reason one by one.Be subjected to the Current Control of load circuit 33, flow through first constant-current circuit 34, second constant-current circuit 35 with the equally big electric current of load circuit 33 electric currents.First switching device 36, second switch device 37 are subjected to control from the signal N1 of rest-set flip-flop, and first switching device 36 is closed when signal N1 is low, second switch device 37 disconnects; 36 disconnections of first switching device, second switch device 37 are closed when N1 is high; The junction of first switching device 36, second switch device 37 connects the counter-rotating input of first operational amplifier 39.First operational amplifier, 39 non-counter-rotating input end groundings, its output connects triangular wave output 46.Electric capacity 40 connects the counter-rotating input and the output of first operational amplifier 39, constitutes an integrating circuit.The switch that first switching device, 36 controls, first constant-current circuit, 34 electric currents flow through, first constant-current circuit 36 makes the output voltage of the operational amplifier 39 of winning approach first predetermined value for electric capacity 40 chargings.The switch that second switch device 37 controls second constant-current circuit 35 electric currents flow through, second constant-current circuit 35 makes the output voltage of the operational amplifier 39 of winning approach second predetermined value for electric capacity 40 chargings.
Form first comparison circuit by divider resistance R1, divider resistance R2, first comparator 41, compare the output and the first predetermined magnitude of voltage of first operational amplifier 39, when consistent with first magnitude of voltage of being scheduled to, first comparator, 41 output signals.Divider resistance R1 connects with divider resistance R2, divider resistance R1 meets the positive voltage+V of setting, divider resistance R2 ground connection, the junction of divider resistance R1 and divider resistance R2 connects the non-counter-rotating input of first comparator 41, and the counter-rotating input of first comparator 41 connects the output of first operational amplifier 39.
Form second comparison circuit by divider resistance R3, divider resistance R4, second comparator 42, compare the output and the second predetermined magnitude of voltage of first operational amplifier 39, when consistent with second magnitude of voltage of being scheduled to, second comparator, 42 output signals.Divider resistance R3 connects with divider resistance R4, divider resistance R3 ground connection, divider resistance R4 meets the negative voltage-V of setting, the junction of divider resistance R3 and divider resistance R4 connects the non-counter-rotating input of second comparator 42, and the counter-rotating input of second comparator 42 connects the output of first operational amplifier 39.
Form rest-set flip-flop by first gate circuit 44 and second gate circuit 45, control the open and close of first switching device 36, second switch device 37, the output signal of rest-set flip-flop depends on the output of first comparator 41 and second comparator 42.An input of first gate circuit 44 connects the output of first comparator 41, and an input of second gate circuit 45 connects the output of second comparator 42 by an inverter 43.The signal N1 of rest-set flip-flop output receives first switching device 36 and second switch device 37 and phase comparator 22.
It is as follows that triangular waveform of the present invention produces the circuit working principle.
Behind the circuit start, along with the output of rest-set flip-flop is high or low, first switching device 36 or second switch device 37 are closed.Putative signal N1 is an electronegative potential, switching device 36 is closed, electric capacity 40 is charged by constant-current circuit 34, the linear decline of the output voltage of first amplifier 39, when the output of first operational amplifier 39 reach-during V, the output signal LO of comparator 42 becomes high potential, and the output N of inversion device 43 becomes electronegative potential, and the output N1 of second gate circuit 45 becomes high potential.
When signal N1 became high potential, switching device 36 disconnected 37 closures, and electric capacity 40 is charged by constant-current circuit 35 opposite directions, and the output voltage of first operational amplifier 39 begins to raise gradually.When first operational amplifier, 39 output voltages be higher than-during V, it is high that signal LO step-down, signal N1 keep, the output of first operational amplifier 39 little by little raises.
When the output of first operational amplifier 39 reaches+V, the output signal HI of first comparator 41 becomes electronegative potential, and second gate circuit, 45 output N1 are inverted and become low signal.When signal N1 becomes low signal, switching device 37 disconnects, switching device 36 is closed, the output voltage of first operational amplifier 39 begins to descend, and when the output voltage of first operational amplifier 39 began to descend, the output signal HI of first comparator 41 became high potential.Above operation repeats, and the result has obtained triangular wave at output 46.The speed that is appreciated that the triangular wave rising from above and descends is decided by the current value of constant- current circuit 34,35, and waveform is steeper when current value is big, and is more smooth when current value is little.
When the input voltage of comparator 41,42 be+/-V the time, other predetermined voltage also may be its input.The circuit of decision constant- current circuit 34,35 current values comprises phase comparator 22, filter 23, the second operational amplifiers 30, resistance 31, field effect transistor 32 and load circuit 33.The operation principle of this part circuit is as follows: the IN input that is input to digital phase comparator 22 when reference clock CLK signal by input 20 through second filter 21, the phase place of the phase place of phase comparator 22 comparison signal N1 and clock CLK signal 20, export a signal according to result relatively and give filter 23, filter 23 is exported analog signal XC according to the result of phase comparator 22.30 outputs of second operational amplifier raise when signal XC is big, this has reduced the biasing between field effect transistor 32 source electrodes and the grid, thereby reduced the electric current of load circuit 33, when signal XC diminishes, 30 outputs of second operational amplifier reduce, this has increased the biasing between field effect transistor 32 source electrodes and the grid, thereby has increased the electric current of load circuit 33.
When flowing through the variation of load circuit 33 electric currents, constant- current circuit 34,35 also changes, this has changed the forward position and the edge, back of the output waveform of first operational amplifier 39, so cycle of movable signal N1, the work of this phase-locked loop makes signal N1 and the same phase shift of clock signal, this causes the cycle of signal N1 consistent with the cycle of clock CLK, that is to say that cycle of triangular waveform of output 46 is consistent with the cycle of the CLK of reference clock.
Like this, the circuit that this triangular waveform produces obtains a triangular waveform with the same cycle of reference clock CLK at output 46, the crest voltage of triangular waveform be compared the output voltage of device 41,42+/-V accurately specifies, and therefore do not have the crest voltage variation.Further charging and discharging currents is decided by constant- current circuit 34,35, and has kept this state, and this is avoided the drift that compensates.This circuit produces the triangular waveform of the high linearity of no peak change or offset drift, and the linearity of triangular waveform can reach 0.1%.
Claims (2)
1. a circuit for generating triangular wave comprises
(1) clock pulse signal input, the triangular wave output;
(2) first operational amplifiers, an electric capacity connects the counter-rotating input and the output formation integrating circuit of this operational amplifier, the non-counter-rotating input end grounding of this operational amplifier, the output of this operational amplifier connects the triangular wave output;
(3) charging circuit that is in series successively by first constant-current circuit, first switching device, second switch device, second constant-current circuit, first constant-current circuit connects positive supply, second constant-current circuit connects negative supply, and the junction of first switching device, second switch device connects the counter-rotating input of first operational amplifier;
It is characterized in that: also comprise
(4) first comparison circuit of forming by divider resistance R1, divider resistance R2, first comparator, divider resistance R1 connects with divider resistance R2, divider resistance R1 meets the positive voltage+V of setting, divider resistance R2 ground connection, the junction of divider resistance R1 and divider resistance R2 connects the non-counter-rotating input of first comparator, and the counter-rotating input of first comparator connects the output of first operational amplifier;
(5) second comparison circuit of forming by divider resistance R3, divider resistance R4, second comparator, divider resistance R3 connects with divider resistance R4, divider resistance R3 ground connection, divider resistance R4 meets the negative voltage-V of setting, the junction of divider resistance R3 and divider resistance R4 connects the non-counter-rotating input of second comparator, and the counter-rotating input of second comparator connects the output of first operational amplifier;
(6) rest-set flip-flop of forming by first gate circuit and second gate circuit, an input of first gate circuit connects the output of first comparator, an input of second gate circuit connects the output of second comparator by an inverter, and the signal N1 of rest-set flip-flop output receives first switching device and second switch device;
(7) by phase comparator, first filter, second operational amplifier, field effect transistor, the electric current of forming with load circuit is provided with circuit, the input IN of phase comparator connects the clock pulse signal input, the input REF of phase comparator connects the output signal of rest-set flip-flop, the output UP of phase comparator and output UP with DW corresponding be connected of DW with first filter, the analog signal XC of first filter output connects the non-counter-rotating input of second operational amplifier, the counter-rotating input of second operational amplifier connects the source electrode of field effect transistor, the grid of field effect transistor is linked in the output of second operational amplifier, the source electrode of field effect transistor is by a grounding through resistance, the drain electrode of field effect transistor is connected to negative supply by a load circuit, and this load circuit is the mirror image annexation with first constant-current circuit and second constant-current circuit.
2. be connected in series one second filter between the circuit for generating triangular wave according to claim 1, the input IN that it is characterized in that phase comparator and clock pulse signal input.
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CNA2007100419068A CN101325408A (en) | 2007-06-12 | 2007-06-12 | Circuit for generating triangular wave |
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CNA2007100419068A CN101325408A (en) | 2007-06-12 | 2007-06-12 | Circuit for generating triangular wave |
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Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101557210B (en) * | 2009-03-05 | 2011-01-05 | 西安民展微电子有限公司 | Sawtooth waves and clock signals generating circuit |
CN101847982B (en) * | 2009-01-22 | 2012-05-30 | 三洋电机株式会社 | Triangle wave generating circuit |
CN103001608A (en) * | 2005-10-17 | 2013-03-27 | 哈曼国际工业有限公司 | Precision triangle waveform generator |
CN103001607A (en) * | 2011-09-08 | 2013-03-27 | 英特尔移动通信有限责任公司 | Triangular waveform generator having differential output synchronized with external clock signal |
CN104811164A (en) * | 2014-01-28 | 2015-07-29 | 晶豪科技股份有限公司 | Triangular wave generating circuit with clock signal synchronization |
CN109194323A (en) * | 2018-11-08 | 2019-01-11 | 常州朗奇威电器有限公司 | Optical coupling isolation circuit and its working method for motor control |
CN110289780A (en) * | 2019-06-26 | 2019-09-27 | 西南交通大学 | The gradation Synchronos method of sub-controller triangular carrier in MMC dcs |
-
2007
- 2007-06-12 CN CNA2007100419068A patent/CN101325408A/en active Pending
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103001608A (en) * | 2005-10-17 | 2013-03-27 | 哈曼国际工业有限公司 | Precision triangle waveform generator |
CN103001608B (en) * | 2005-10-17 | 2016-06-22 | 哈曼国际工业有限公司 | Precision triangular wave generator |
CN101847982B (en) * | 2009-01-22 | 2012-05-30 | 三洋电机株式会社 | Triangle wave generating circuit |
CN101557210B (en) * | 2009-03-05 | 2011-01-05 | 西安民展微电子有限公司 | Sawtooth waves and clock signals generating circuit |
CN103001607A (en) * | 2011-09-08 | 2013-03-27 | 英特尔移动通信有限责任公司 | Triangular waveform generator having differential output synchronized with external clock signal |
CN103001607B (en) * | 2011-09-08 | 2016-02-17 | 英特尔移动通信有限责任公司 | There is the triangular wave generator of the difference output synchronous with external timing signal |
CN104811164A (en) * | 2014-01-28 | 2015-07-29 | 晶豪科技股份有限公司 | Triangular wave generating circuit with clock signal synchronization |
CN104811164B (en) * | 2014-01-28 | 2017-10-24 | 晶豪科技股份有限公司 | Circuit for generating triangular wave with clock signal synchronization |
CN109194323A (en) * | 2018-11-08 | 2019-01-11 | 常州朗奇威电器有限公司 | Optical coupling isolation circuit and its working method for motor control |
CN110289780A (en) * | 2019-06-26 | 2019-09-27 | 西南交通大学 | The gradation Synchronos method of sub-controller triangular carrier in MMC dcs |
CN110289780B (en) * | 2019-06-26 | 2023-08-08 | 西南交通大学 | Sub-controller triangular carrier wave fractional synchronization method in MMC distributed control system |
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