Utility model content
The utility model solves the problems, such as to be to provide a kind of precision synchronous function generating circuit, exports the same of AC signal
When, driving zero cross detection comparison circuit generates synchronous square-wave signal output.
The utility model is to be achieved through the following technical solutions:
A kind of precision synchronous function generating circuit, comprising:
Oscillator generates sine wave signal by accurate oscillating integrated circuit;
Coupler, the sine wave signal that oscillator generates are sent to push-pull amplifier through coupler;
Push-pull amplifier receives the signal that coupler is sent and amplifies, promotes output electric current and output power;
Zero cross detection comparison circuit receives the signal that push-pull amplifier is sent, it is defeated to generate synchronous square-wave signal
Out.
The oscillator is the 12 feet warp that the sine wave distortion factor is adjusted using ICL8038 precision oscillating integrated circuit
Function adjustment resistance Rw1 is connected with power supply Vee, is grounded through resistance R1;4 feet that its sine wave is symmetrically adjusted, 5 feet are respectively through electricity
Resistance R3*, resistance R2* are connected with power supply Vee;Its 10 foot is grounded by capacitor Ct;Its 2 foot for exporting sine wave is connected to coupling
The coupled capacitor C2 of clutch.
The output frequency of the oscillator is determined by R3*, R2* and Ct, as R2*=R3*=R, frequency of oscillation fo=
0.3/RCt。
It is defeated that the push-pull amplifier is made of two symmetrical emitter-base bandgap gradings NPN type triode Q1, PNP type triode Q2
Device docks out;Triode Q1, triode Q2 base stage be separately connected input signal, collector is separately connected positive-negative power,
Output end is connected with zero cross detection comparison circuit respectively;
Resistance R7, the diode D1 for overcoming intermodulation distortion are equipped in the collector of triode Q1;In the current collection of triode Q2
Pole is equipped with resistance R8, the diode D2 for overcoming intermodulation distortion;
Current-limiting resistance R9, compensating electric capacity C3 are scurried into the collector of triode Q1;Current limliting is scurried into triode Q2 collector
Resistance R10, compensating electric capacity C4.
When the described push-pull amplifier static state: two pipe emitter junction current potential of triode Q1, Q2 is respectively diode D1, D2
Forward conduction voltage drop, cause two pipes to be in faint on state;
When dynamic: sinusoidal signal, positive half cycle triode Q2 cut-off is added in input signal, and triode Q1 base potential improves,
On state;Negative half period triode Q1 cut-off, triode Q2 base potential improve, on state.
Amplification quantity feed circuit is also connected between coupler and push-pull amplifier;Including comparator U1B, just
Phase input terminal is connected with coupler, is also grounded through resistance R4;Its inverting input terminal is grounded through resistance R6, through resistance R5, external
Resistance Rw2 is connected with the first output end vo 1;Its output end is connected with push-pull amplifier.
The peak power output and efficiency of push-pull amplifier are as follows:
The maximum power obtained in load are as follows: Pomax=Vcc2/2RL
Electric current in each power supply is half of sine wave, average value are as follows:
Iav1=Vcc/ π RL;
Iav2=Vcc/ π RL;
The general power that two power supplys provide are as follows: PE=PE1+PE2=2Vcc2/πRL;
Pomax=Vcc2/2RL;
PE=PE1+PE2=2Vcc2/πRL;
Efficiency are as follows: η=Pomax/PE=π/4=78.5%;
The output of push-pull amplifier is Vo1=(1+ (R5+Rw2)/R6) * IaV1.
Zero cross detection comparison circuit includes comparator U1A, and normal phase input end is put with Push-Pull power respectively through resistance R12
Big device output end, the first output end vo 1 are connected, and inverting input terminal is grounded through resistance R11, output end and second output terminal
Vo2 is connected.
Compared with prior art, the utility model has technical effect beneficial below:
The utility model product uses precision oscillator, coupler, power amplifier and zero cross detection comparison circuit,
Make output waveform positive half cycle and negative half period very symmetrical by way of function tune, promotes output power with amplification is recommended, pass through
External potentiometer (Rw2) realizes adjustable gain section, and while exporting AC signal, driving zero cross detection comparison circuit generates same
The square-wave signal of step exports;The utility model improves circuit level, and it is few to make it have factor small in size, low in energy consumption, parasitic
And the advantages of strong anti-interference performance, it is used by product test and user's high-volume, demonstrates the feasibility and reliability of circuit.
The utility model can also be used for other field, such as all kinds of lathes, heavy-duty machinery, mechanical test are set with position
And the place of detection.It therefore, will be right to machining equipment operational safety with the technology transplant of this project and popularization and application
The working strength of the person is operated, raises labour productivity and brings good social and economic benefit.
Specific embodiment
The utility model is described in further detail below with reference to specific embodiment, described is to the utility model
Explanation rather than limit.
Referring to Fig. 1, Fig. 2, precision synchronous function generating circuit characterized by comprising
Oscillator generates sine wave signal by accurate oscillating integrated circuit;
Coupler, the sine wave signal that oscillator generates are sent to push-pull amplifier through coupler;
Push-pull amplifier receives the signal that coupler is sent and amplifies, promotes output electric current and output power;
Zero cross detection comparison circuit receives the signal that push-pull amplifier is sent, it is defeated to generate synchronous square-wave signal
Out.
Referring to Fig. 3, the oscillator is using ICL8038 precision oscillating integrated circuit, and the sine wave distortion factor is adjusted
12 feet be connected through function adjustment resistance Rw1 with power supply Vee, be grounded through resistance R1;4 feet that its sine wave is symmetrically adjusted, 5 feet
It is connected respectively through resistance R3*, resistance R2* with power supply Vee;Its 10 foot is grounded by capacitor Ct;Its 2 foot for exporting sine wave connects
Meet the coupled capacitor C2 as coupler.
- Fig. 8 referring to fig. 4, the push-pull amplifier constitute two by NPN type triode Q1, PNP type triode Q2
Symmetrical emitter-follower docks;Triode Q1, triode Q2 base stage be separately connected input signal, collector connects respectively
Positive-negative power is connect, output end is connected with zero cross detection comparison circuit respectively;
Resistance R7, the diode D1 for overcoming intermodulation distortion are equipped in the collector of triode Q1;In the current collection of triode Q2
Pole is equipped with resistance R8, the diode D2 for overcoming intermodulation distortion;
Current-limiting resistance R9, compensating electric capacity C3 are scurried into the collector of triode Q1;Current limliting is scurried into triode Q2 collector
Resistance R10, compensating electric capacity C4.
Referring to fig. 2, amplification quantity feed circuit is also connected between coupler and push-pull amplifier;Including comparator
U1B, normal phase input end are connected with coupler, are also grounded through resistance R4;Its inverting input terminal is grounded through resistance R6, through resistance
R5, outer connecting resistance Rw2 are connected with the first output end vo 1;Its output end is connected with push-pull amplifier.
Referring to Fig. 9, zero cross detection comparison circuit includes comparator U1A, normal phase input end through resistance R12 respectively with push away
Draw power amplifier output, the first output end vo 1 is connected, inverting input terminal is grounded through resistance R11, output end and
Two output end vos 2 are connected.
Below with reference to examples and drawings, the present invention will be further described.
Referring to Fig. 1, Fig. 2, precision synchronous function generating circuit mainly by precision oscillator, coupler, power amplifier and
Double-limit comparator composition forms as follows substantially:
(1) accurate oscillating circuit
The basic application circuit of the chip (ICL8038 precision oscillating integrated circuit) as shown in Fig. 3 figure, output frequency by
R2*, R3* and Ct are determined.As R2*=R3*=R, frequency of oscillation fo=0.3/RCt;
It is proposed in connection claimed below:
1., select resistance R2*, R3* and Ct temperature characterisitic to get well.
2., external power supply should stablize.
3., should select precision resister, R2*=R3*=10K, capacitor should select small, the high-quality non-polarized capacitors that leak electricity
Device, Ct=3300pF.
Fo=0.3/RCt
=0.3/ (10 × 103×3300×1012)
=9.0909Hz
4., function adjust resistance Rw1, the symmetry of the positive negative wave of output can be changed.
(2) blocking coupling circuit
Since oscillation source is single supply power supply, output waveform has flip-flop, it is therefore desirable to which coupled capacitor carries out isolation coupling
It closes, can be only achieved expected effect.C2=0.033u/50V
(3) push-pull amplifier circuit
A, working principle (setting ui as sine wave)
Referring to fig. 4, two symmetrical emitter-followers are made of NPN type, PNP type triode to dock, dual power supply supplies
Capacitance (referring to fig. 4) is not added in electricity, input/output terminal.
For input signal ui before and after zero passage, the distortion that output signal occurs becomes intermodulation distortion (referring to Fig. 5).
B, intermodulation distortion Producing reason: being transistor characteristic there are non-linear, transistor cutoff when ui <uT.
Overcome the measure of intermodulation distortion: increasing R1, D1, D2, R2 branch in circuit (referring to Fig. 6).
When static: two pipe emitter junction current potential of Q1, Q2 is respectively the forward conduction voltage drop of diode D1, D2, causes two Guan Jun
In faint on state;
When dynamic: setting ui and sinusoidal signal is added.Positive half cycle Q2 cut-off, Q1 base potential further increase, and entrance is good
On state;Negative half period Q1 cut-off, Q2 base potential further increases, into good on state.
C, the calculating of peak power output and efficiency
Assuming that ui is sine wave and amplitude is sufficiently large, Q1, Q2 can be saturated when being connected, and output reaches maximum value at this time.Vcc
=︱ Vee ︱
If ignoring the saturation voltage drop of transistor, the maximum amplitude for loading the voltage and current on (RL) is respectively as follows:
ULmax=Vcc ILmax=Vcc/RL
The maximum power obtained in load are as follows:
Pomax=Vcc2/2RL
The direct current mean power that power supply provides calculates:
Electric current in each power supply is half of sine wave, average value are as follows:
Iav1=Vcc/ π RL
Iav2=Vcc/ π RL
The general power that two power supplys provide is (referring to Fig. 7):
PE=PE1+PE2=2Vcc2/πRL
Pomax=Vcc2/2RL
PE=PE1+PE2=2Vcc2/πRL
Efficiency are as follows:
η=Pomax/PE=π/4=78.5%
Referring to Fig. 8 in order to ensure power amplification trouble free service, current-limiting resistance R9, R10, C3, C4 are scurried into Q1, Q2 collector
For compensating electric capacity, output sine wave is made to meet technical requirements.Output voltage is as follows
Vo1=(1+ (R5+Rw2)/R6) * IaV1
(4) zero cross detection comparison circuit
Zero cross detection comparison circuit receives the signal that push-pull amplifier is sent, it is defeated to generate synchronous square-wave signal
Out.It is required that sine wave input voltage peak value Vo1 >=0.4V
Referring to Figure 10, upper figure is the sine wave signal that zero cross detection comparison circuit receives that push-pull amplifier is sent
(while being the output signal of the first output end vo 1), the following figure is that synchronous square-wave signal is generated through zero cross detection comparison circuit,
The as output signal of second output terminal Vo2.
The utility model makes output waveform positive half cycle and negative half period very symmetrical by way of function tune, is amplified with recommending
Output power is promoted, adjustable gain section is realized by external potentiometer Rw2, while exporting AC signal, driving zero crossing inspection
Surveying comparison circuit and generating synchronous square-wave signal output example given above is to realize the utility model preferably example, this
Utility model is not limited to the above embodiments.Those skilled in the art is done according to the technical characteristic of technical solutions of the utility model
Any nonessential addition, replacement out, belong to the protection scope of the utility model.