CN204633623U - A kind of precise rectification circuit - Google Patents

Abstract

Be a kind of precise rectification circuit disclosed in the utility model, comprise ac signal U _ipositive half-cycle signal be sent to the first branch road of output and be sent to output second branch road and at output, two positive half-cycle signal be combined into the combiner circuit of unipolarity positive signal after anti-phase for the negative half-cycle signal of ac signal; Here two branch roads all do not have diode, overcome current rectification circuit as input signal U _iwhen there is sudden change, the signal U that signal rectifier circuit exports _o2there will be the rising spike of sudden change or the deficiency of decline spike.

Description

A kind of precise rectification circuit

Technical field

The utility model relates to a kind of precise rectification circuit.

Background technology

The main feature of rectification circuit converts ambipolar AC signal to unipolar signal.In signal rectifier circuit, include two branch roads, article one, the positive half-cycle signal of ac signal is sent to output by branch road, another branch road is sent to output after anti-phase for the negative half-cycle signal of ac signal, at output, the signal node of positive-negative half-cycle is synthesized into unipolarity positive signal, the general one-way conduction character that all can utilize diode, but in order to compensate the pressure drop that diode produces, usual employing diode and amplifier combine and are rectified into positive signal to ambipolar AC signal, the single-chip microcomputer of A/D function is had (as ARM to facilitate, DSP) or A/D chip sampling.

As shown in Figure 1, Figure 2, Figure 3 shows, these traditional signal rectifier circuits have a common ground to be exactly containing diode to now widely used signal rectifier circuit, adopt diode and amplifier to combine and are rectified into positive signal to ambipolar AC signal.Because the rectification circuit shown in Fig. 1 has the high advantage of input impedance, be commonly use rectification circuit the most at present, the parameter in figure designs by gain 1, and the relation of its constrained input is as follows:

$U_{o1}=U_i+(U_i-U_2)\×\frac{R4}{R3}---(1-1)$

As input signal U _iat positive half cycle (U _i>=0), time, operational amplifier IC1A the 1st pin exports positive voltage signal and feeds back to the 2nd pin through D1, and D1 is in forward conduction state, and D2 is in reverse blocking state, i.e. U ₂=U ₁.According to the empty short concept of amplifier, the 2nd pin of operational amplifier IC1A is equal with the voltage of the 3rd pin, i.e. U ₁=U _i, so U ₂=U ₁=U _i, therefore when positive half cycle, (1-1) formula is:

$U_{o1}=U_i+(U_i-U_2)\×\frac{R4}{R3}=U_i+(U_i-U_i)\×\frac{2\mathrm{K\Ω}}{1\mathrm{K\Ω}}=U_i---(1-2)$

As input signal U _iat negative half period (U _i≤ 0), time, operational amplifier IC1A the 1st pin exports negative voltage signal and feeds back to the 2nd pin through D2, R2, and D1 is in reverse blocking state, and D2 is in forward conduction state, according to the empty short concept of amplifier, the 2nd pin of operational amplifier IC1A is equal with the voltage of the 3rd pin, i.e. U ₁=U _i, so:

$I_{R1}=\frac{U_1}{R1}=\frac{U_i}{R1}$

So:

$U_2=I_{R1}\×(R1+R2)=\frac{U_i}{R1}\×(R1+R2)=\frac{U_i}{1\mathrm{K\Ω}}\×(1\mathrm{K\Ω}+1\mathrm{K\Ω})=2U_i---(1-3)$

Therefore when negative half period, (1-1) formula is:

$U_{o1}=U_i+(U_i-U_2)\×\frac{R4}{R3}=U_i+(U_i-2U_i)\×\frac{2\mathrm{K\Ω}}{1\mathrm{K\Ω}}=-U_i---(1-4)$

From upper surface analysis, no matter U _iat positive half cycle or negative half period, always have diode to be in conducting state in rectification circuit, see Fig. 6,7,8,9 to the test waveform of Fig. 1 circuit, the 1st passage is U _iwaveform, the 3rd passage is U _o1waveform.From oscillogram, as input signal U _iwhen there is sudden change (climbing speed or fall off rate too fast), the reverse recovery characteristic of diode will cause output signal U _o1there is rising spike or the decline spike of sudden change; this error in data not only making A/D circuit sampling arrive; also the overvoltage of moment can be caused to impact to A/D pin, the peak voltage more disadvantageously suddenlyd change produces interference to the circuit around it, causes misoperation etc. to protective circuit.

Utility model content

In order to overcome above-mentioned the deficiencies in the prior art, the utility model provides a kind of not containing the precise rectification circuit of diode, in this precise rectification circuit, as input signal U _iwhen there is sudden change, the signal U that signal rectifier circuit exports _o2there will not be rising spike or the decline spike of sudden change.

The technical scheme that the utility model adopts is: a kind of precise rectification circuit, comprises ac signal U _ipositive half-cycle signal be sent to output the first branch road and by be sent to after anti-phase for the negative half-cycle signal of ac signal output second branch road and output by positive half-cycle signal and negative half-cycle signal anti-phase after be combined into the combiner circuit of unipolarity positive signal;

The first described branch road comprises operational amplifier B, triode Q1, triode Q3; The out-phase termination input AC signal of telecommunication U of described operational amplifier B _i, in-phase end ground connection, output is connected with the base stage of described triode Q1, triode Q3 respectively; Described triode Q1 is PNP type triode, and described triode Q3 is NPN type triode; Described triode Q1 collector electrode connects negative level, described triode Q3 grounded collector, and described triode Q1 forms output after being connected with the emitter of described triode Q3 and is connected with the out-phase end of described operational amplifier B;

The second described branch road comprises operation amplifier C, triode Q2 and triode Q4; The homophase termination input AC signal of telecommunication U of described operational amplifier C _i, output is connected with the base stage of described triode Q2, triode Q4 respectively; Described triode Q2 is PNP type triode, and described triode Q4 is NPN type triode; Described triode Q2 collector electrode connects negative level, described triode Q4 grounded collector, and described triode Q2 forms output after being connected with the emitter of described triode Q4 and is connected with the out-phase end of described operational amplifier C.

Here two branch roads all do not have diode, overcome current rectification circuit as input signal U _iwhen there is sudden change, the signal U that signal rectifier circuit exports _o2there will be the rising spike of sudden change or the deficiency of decline spike.

In this technical scheme, also there is following optimal way:

Described output by positive half-cycle signal and negative half-cycle signal anti-phase after be combined into unipolarity positive signal combiner circuit be anti-phase proportional amplifier circuit; Described anti-phase proportional amplifier circuit comprises operational amplifier IC1D; The in-phase end ground connection of described operational amplifier IC1D, the emitter connecting place that out-phase end meets described triode Q1 and described triode Q3 respectively and described triode Q2 are connected with the emitter of described triode Q4 connecting place.

Input AC signal of telecommunication U _ibefore the first branch road described in input and the second branch road, also comprise input follower, described input follower comprises operational amplifier A, input AC signal of telecommunication U _iwith the in-phase end of operational amplifier A, the out-phase end of operational amplifier A and output are connected to form the input signal end of a described branch road and the second branch road.

Below with reference to accompanying drawing and example, the utility model is described in detail.

Accompanying drawing explanation

Fig. 1, be rectification circuit schematic diagram () of the prior art.

Fig. 2, be rectification circuit schematic diagram (two) of the prior art.

Fig. 3, be rectification circuit schematic diagram (three) of the prior art.

Fig. 4, be precise rectification circuit schematic diagram of the present utility model.

Fig. 5, be to resolution chart while of prior art and utility model circuit.

Fig. 6, be under Fig. 5 circuit condition, manually SW1 opened and pass records U _iwith U _o1, U _o2positive half cycle oscillogram ().

Fig. 7, be under Fig. 5 circuit condition, manually SW1 opened and pass records U _iwith U _o1, U _o2negative half period oscillogram ().

Fig. 8, be under Fig. 5 circuit condition, manually SW1 opened and pass records U _iwith U _o1, U _o2positive half cycle oscillogram (two).

Fig. 9, be under Fig. 5 circuit condition, manually SW1 opened and pass records U _iwith U _o1, U _o2negative half period oscillogram ().

Embodiment

Embodiment 1, as shown in Figure 4, signal rectifier circuit in the present embodiment is made up of follower, amplifier and comparator, anti-phase adder three part, whole circuit is not containing diode, adopt four-way amplifier OPA4727AIPW (A, B, C, D), and in conjunction with triode to input AC signal of telecommunication U _irectification.This circuit comprises three parts, and Part I is conventional input follower, is made up of operational amplifier A, and object is to improve input impedance, reduces output impedance.Input AC signal of telecommunication U _ifrom the in-phase end pin input of the 3rd of four-way amplifier OPA4727AIPW namely operational amplifier A, export U by the 1st pin of the output of operational amplifier A i.e. the integrated circuit OPA4727AIPW of four-way amplifier _a, that is: at input AC signal of telecommunication U _iwhen entering into the in-phase end of operational amplifier A, be connected with the resistance R1 of a 1K, in addition, the power supply that this operational amplifier adopts be+5V with-5V power supply signal and AC earth, therefore, to connect respectively the electric capacity C1 of 100nF and C2 ground connection at power input.

U _a＝U _i(2-1)

Part II is the core of signal rectifier circuit, comprises two-way respectively by input exchange signal U _irotary head is to output respectively for the signal of positive half cycle and negative half period, and wherein the signal of negative half period exports after oppositely, and the first branch road comprises the out-phase termination input AC signal of telecommunication U of operational amplifier B, PNP triode Q1, NPN triode Q3, operational amplifier B _ioutput the 1st pin after input follower exports U _a, in-phase end ground connection, output is connected with the base stage of PNP triode Q1, NPN triode Q3 respectively; PNP triode Q1 collector electrode connects-5V negative level, NPN triode Q3 grounded collector, and PNP triode Q1 forms output after being connected with the emitter of NPN triode Q3 and is connected with the out-phase end of operational amplifier B.

Second branch road comprises the homophase termination input AC signal of telecommunication U of operational amplifier C, PNP triode Q2, NPN triode Q4, operational amplifier C _ioutput the 1st pin after input follower exports U _a, output is connected with the base stage of PNP triode Q2, NPN triode Q4 respectively; PNP triode Q2 collector electrode connects-5V negative level, NPN triode Q4 grounded collector, and PNP triode Q2 forms output after being connected with the emitter of NPN triode Q4 and is connected with the out-phase end of operational amplifier C.

First branch road is responsible for taking out ac signal U _ipositive half-cycle signal, filtering ac signal U _inegative half-cycle signal, its operation principle is: at ac signal U _ipositive half cycle (U _i>=0) time, ac signal U _aafter operational amplifier B is anti-phase, export negative voltage signal by the 7th pin of integrated circuit, triode Q3 is in cut-off state, and negative voltage signal is through the base stage of resistance R11 to triode Q1, makes triode Q1 be in conducting state, then exports U by emitter _bfeed back to operational amplifier B out-phase end through resistance R3, namely the 6th pin of integrated circuit (IC) OPA4727AIPW, make operational amplifier B be operated in anti-phase proportional amplifier state, U _bwith U _arelational expression as follows:

$U_b=-U_a\×\frac{R3}{R2}=-U_a\×\frac{1\mathrm{K\Ω}}{1\mathrm{K\Ω}}=-U_a---(2-2)$

Because of U _a=U _i, so at positive half cycle (U _i>=0) time:

U _b＝-U _a＝-U _i(2-3)

At U _inegative half period (U _i≤ 0) time, U _apositive voltage signal is exported by OPA4727AIPW the 7th pin after operational amplifier B is anti-phase, triode Q1 is in cut-off state, so OPA4727AIPW the 6th pin does not just have negative-feedback signal, operational amplifier B is made to be operated in anti-phase comparator state, so OPA4727AIPW the 7th pin exports positive voltage pulse signals, through the base stage of resistance R4 to triode Q3, triode Q3 saturation conduction, makes U _bbe shorted to GND, i.e. U _b=0V.

Filtering U is responsible for by second branch road _ipositive half-cycle signal, take out U _inegative half-cycle signal, its operation principle is: at U _ipositive half cycle (U _i>=0), time, the output of operational amplifier C also exports positive voltage signal with regard to OPA4727AIPW the 8th pin, and triode Q2 is in cut-off state, so U _c=0V, the out-phase end of operational amplifier C i.e. OPA4727AIPW the 9th pin just do not have negative-feedback signal, operational amplifier C is made to be operated in positive phase comparator state, so when the in-phase end of operational amplifier C i.e. the 8th pin of OPA4727AIPW export positive voltage pulse signals, through the base stage of resistance R6 to triode Q4, triode Q4 saturation conduction, makes U _cbe shorted to GND.At U _inegative half period (U _i≤ 0) time, U _aexport after operational amplifier C positive, export negative voltage signal by OPA4727AIPW the 8th pin, triode Q4 is in cut-off state, and negative voltage signal is through the base stage of resistance R12 to triode Q2, makes triode Q2 be in conducting state, then exports U by emitter _cand feed back to out-phase end i.e. OPA4727AIPW the 9th pin of operational amplifier C, make operational amplifier C be operated in follower state, U _cwith U _arelational expression as follows:

U _c＝U _a(2-4)

Because of U _a=U _i, so at negative half period (U _i≤ 0) time:

U _c＝U _a＝U _i(2-5)

Part III is the circuit output signal of the first branch road and the second branch road being combined into unipolar signal, what this circuit was conventional is anti-phase proportional amplifier circuit, this anti-phase proportional amplifier circuit is formed primarily of operational amplifier D, and object is the U that Part II circuit is exported _band U _csignal carries out anti-phase and is added, and finally obtains the positive signal U of all-wave _o2.U _o2with U _b, U _crelational expression as follows:

U _o2＝-(U _b+U _c) (2-6)

From the analysis to Part II circuit, at U _ipositive half cycle (U _i>=0) time, U _b=-U _i, at U _inegative half period (U _i≤ 0) time, U _c=U _i, so obtained by (2-6) formula:

$U_{o2}=-(U_b+U_c)=-(-U_i{|}_{U_i\≥0}+U_i{|}_{U_i\≤0})=U_i{|}_{U_i\≥0}-U_i{|}_{U_i\≤0}---(2-7)$

Fig. 5 is that see Fig. 6,7,8,9 to the test waveform of Fig. 5 circuit, the 1st passage is U by unified for the rectification circuit of the present embodiment shown in the circuit with diode shown in Fig. 1 and Fig. 4 circuit carrying out testing _iwaveform, the 2nd passage is U _o2waveform.From oscillogram, when manually opening SW1 and closing, no matter at U _ipositive half cycle or negative half period occur sudden change time, U _o2all do not occur the rising spike that suddenlys change or decline spike, therefore the utility model signal rectifier circuit is specially adapted to sample to the alternating voltage of the photovoltaic combining inverter containing mechanical switch (as relay, air switch) or current signal.

Claims (3)

1. a kind of precise rectification circuit, comprises ac signal U _ipositive half-cycle signal be sent to output the first branch road and the negative half-cycle signal of ac signal is sent to output second branch road and output by positive half-cycle signal and negative half-cycle signal anti-phase after be combined into the combiner circuit of unipolarity positive signal; It is characterized in that:

The first described branch road comprises operational amplifier B, triode Q1, triode Q3; The out-phase termination input AC signal of telecommunication U of described operational amplifier B _i, in-phase end ground connection, output is connected with the base stage of described triode Q1, triode Q3 respectively; Described triode Q1 is PNP type triode, and described triode Q3 is NPN type triode; Described triode Q1 collector electrode connects negative level, described triode Q3 grounded collector, and described triode Q1 forms output after being connected with the emitter of described triode Q3 and is connected with the out-phase end of described operational amplifier B;

The second described branch road comprises operational amplifier C, triode Q2 and triode Q4; The homophase termination input AC signal of telecommunication U of described operational amplifier C _i, output is connected with the base stage of described triode Q2, triode Q4 respectively; Described triode Q2 is PNP type triode, and described triode Q4 is NPN type triode; Described triode Q2 collector electrode connects negative level, described triode Q4 grounded collector, and described triode Q2 forms output after being connected with the emitter of described triode Q4 and is connected with the out-phase end of described operational amplifier C.

2. precise rectification circuit according to claim 1, is characterized in that: described output by positive half-cycle signal and negative half-cycle signal anti-phase after be combined into unipolarity positive signal combiner circuit be anti-phase proportional amplifier circuit; Described anti-phase proportional amplifier circuit comprises operational amplifier IC1D; The in-phase end ground connection of described operational amplifier IC1D, out-phase end connects the emitter connecting place of described triode Q1 and described triode Q3 and the emitter connecting place of described triode Q2 and described triode Q4 respectively.

3. precise rectification circuit according to claim 1 and 2, is characterized in that: input AC signal of telecommunication U _ibefore the first branch road described in input and the second branch road, also comprise input follower, described input follower comprises operational amplifier A, input AC signal of telecommunication U _iwith the in-phase end of operational amplifier A, the out-phase end of operational amplifier A and output are connected to form the input signal end of a described branch road and the second branch road.