CN1030334A - Battery feed circuit - Google Patents

Battery feed circuit Download PDF

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Publication number
CN1030334A
CN1030334A CN 88103656 CN88103656A CN1030334A CN 1030334 A CN1030334 A CN 1030334A CN 88103656 CN88103656 CN 88103656 CN 88103656 A CN88103656 A CN 88103656A CN 1030334 A CN1030334 A CN 1030334A
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current
circuit
battery
electric current
voltage
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CN 88103656
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CN1011653B (en
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高远健司
东条敏郎
木下和美
山本雄三
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Fujitsu Ltd
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Fujitsu Ltd
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Priority claimed from JP62149266A external-priority patent/JPS63314060A/en
Priority claimed from JP62149264A external-priority patent/JPS63314471A/en
Priority claimed from JP62149268A external-priority patent/JPH0638625B2/en
Priority claimed from JP62149265A external-priority patent/JPH0638624B2/en
Application filed by Fujitsu Ltd filed Critical Fujitsu Ltd
Publication of CN1030334A publication Critical patent/CN1030334A/en
Publication of CN1011653B publication Critical patent/CN1011653B/en
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Abstract

A kind of powered battery comprises the peripheral circuit in the line circuit of main battery power pack and switching system thereof along separate routes.This peripheral circuit comprises: be low-impedance device for in-phase signal 1.; 2. bias circuit; buffer unit and AC shunt capacitance; 3. powered battery current control circuit; 4. powered battery current monitoring circuit and voltage/current transfer resistance; 5. with the circuit of High Accuracy Control bidirectional battery supply current, 6. current foldback circuit.

Description

Battery feed circuit
What the present invention relates to is a kind of battery feed circuit, more properly says, is a kind of battery feed circuit that is provided in the switching system circuit.
Usually, battery feed circuit places switching system on one side, and its main purpose is to provide direct current by subscribers feeder (line A and line B) to telephone terminal equipment, and makes it work.These battery feed circuits are connected on the end points of the line A that forms above-mentioned subscribers feeder and line B.Therefore they must design like this; Input impedance for the AC signal of looking from line A and line B is a predetermined value.This input impedance is divided into two kinds of (Z DT, Z CT) and will satisfy following condition:
(1) differential wave (voice signal) is interchange high impedance Z DT;
(2) be AC impedance Z for in-phase signal (exchanging induction reactance and other undesirable AC signal) CT;
(3) value of dc-battery supplying resistance is provided by the direct current that provides telephone set required, for example is hundreds of ohm.
Interchange terminal impedance Z with respect to differential wave DTPreferably be high impedance, so that prevent its decay.On the other hand, with respect to the interchange terminal impedance Z of above-mentioned same-phase signal CTPreferably be Low ESR, decay significantly to cause it.Furtherly, in recent years, it is very severe that the condition of same-phase signal has become; Even, also wish to prevent the deterioration of voice signal when same-phase electric current during greater than the dc-battery supply current.
As for correlation technique, what can mention is No. 42263, unexamined Japanese Patent Application Publication 57-.Above-mentioned condition (1) and (2) are satisfied in this patent application, but can not handle above-mentioned recent trend, promptly when same-phase signal electric current during greater than the dc-battery supply current, prevent the requirement of the deterioration of voice signal.Its reason is that the battery feed circuit shown in above-mentioned the disclosing is made up of with the NPN transistor that line A is connected with a collector electrode the PNP transistor that a collector electrode is connected with line B, aforementioned PNP transistor is only sent direct current from its collector electrode, and direct current flows into promptly this direct current from the collector electrode of latter's NPN transistor and can't circulate in direction in contrast to this.
Therefore, can not only handle line A, and can handle the battery feed circuit of reverse dc to line B DC Forward Current, i.e. bidirectional battery power supply circuits, it is very necessary just to seem in practice.This bidirectional power supply circuit can become more and more necessary in the market from now on.
It is contemplated that out the method for various realization battery feed circuits.Take a single example, have the people once to propose to adopt the bidirectional battery power supply circuits of trsanscondutance amplifier, be shown in international electric electronic engineering (IEEE) solid-state circuit periodical SC-16 volume, No. 4, among the Fig. 2 on the 262nd page of publishing in August, 1981 (the details back will provide).But, because this battery feed circuit depends on peripheral circuit (for example, biasing circuit) and function in the circuit; Even if therefore bidirectional power supply circuit itself can realize that it does not have practical significance yet.
Therefore, handle of the present invention combines the criterion of also significant bidirectional battery power supply circuits as its purpose with actual track.
In order to achieve the above object; the present invention proposes a kind of bidirectional battery power supply circuits; it has compatible peripheral circuit; for example Low ESR (with respect to same-phase signal) forms circuit; biasing circuit, powered battery current control circuit, powered battery current monitoring circuit; powered battery current detection circuit, and the protective circuit when the powered battery current overload.
Above-mentioned purpose of the present invention and feature can further be understood from following description of preferred embodiments with reference to accompanying drawing.
Fig. 1 is the circuit diagram of the bidirectional battery power supply circuits introduced in the said prior art open file.
Fig. 2 is that expression is equipped with Low ESR to form the schematic diagram of basic structure of the battery feed circuit of circuit according to the present invention.
Fig. 3 is that expression is equipped with Low ESR to form the diagrammatic sketch of an embodiment of the battery feed circuit of circuit according to the present invention.
Fig. 4 is the pc equivalent circuit of battery feed circuit shown in Figure 2.
Fig. 5 is the differential wave equivalent electric circuit of battery feed circuit shown in Figure 2.
Fig. 6 is the same-phase signal equivalent electric circuit of battery feed circuit shown in Figure 2.
Fig. 7 is the example diagrammatic sketch of the traditional total biasing circuit of expression.
Fig. 8 is the block diagram of expression biasing circuit principle of the present invention.
Fig. 9 is the line map of an embodiment of expression biasing circuit of the present invention.
Figure 10 is the circuit diagram more specifically of presentation graphs 9 circuit.
Figure 11 is the more specifically circuit diagram of presentation graphs 9 circuit.
Figure 12 is the diagrammatic sketch of the notion of expression common batteries power supply circuits.
Figure 13 is the diagrammatic sketch of an example of expression common batteries power supply circuits.
Figure 14 is expression load resistance R 1Diagram with the relation of powered battery electric current I.
Figure 15 is the theory diagram of expression powered battery current control circuit of the present invention and the diagrammatic sketch of peripheral circuit.
Figure 16 is a diagram of explaining the work of powered battery current control circuit of the present invention.
Figure 17 is the schematic diagram of powered battery current control circuit of the present invention and peripheral circuit.
Figure 18 is a chart of explaining non-equilibrium state.
Figure 19 is the diagrammatic sketch of the total switching system of expression.
Figure 20 is the circuit diagram of an example of the traditional supervisory circuit of expression.
Figure 21 is the diagrammatic sketch according to the major part of powered battery current monitoring circuit of the present invention.
Figure 22 is the diagrammatic sketch according to the embodiment of powered battery current monitoring circuit of the present invention.
Figure 23 (1), (2), (3), (4) and (5) are that expression detects electric current and it is attended by the diagrammatic sketch of the continuous wave of same-phase signal.
Figure 24 (1), (2), (3), (4) and (5) are that expression detects electric current and it is attended by the diagrammatic sketch of the continuous wave of ground connection error.
Figure 25 is an example of expression current mirror circuit (interior flow pattern).
Figure 26 is an example of expression current mirror circuit (outer flow pattern).
Figure 27 is that expression is than Figure 26 example diagrammatic sketch of multiple terminals more.
Figure 28 is the schematic diagram of the many systems of the total exchange of expression.
Figure 29 is an instance graph of representing not adopt the powered battery current detection circuit of operational amplifier.
Figure 30 is the equivalent circuit diagram when being illustrated in inverse detection.
Figure 31 is the diagrammatic sketch of expression according to the principle and the structure of powered battery current detection circuit of the present invention.
Figure 32 is the embodiment of expression according to powered battery current detection circuit of the present invention.
Figure 33 is the diagrammatic sketch of the key component of expression cells known power supply circuits.
Figure 34 is principle and the structural representation of expression according to current overload protection circuit of the present invention.
Figure 35 is principle and the structure that expression is equipped with online B current overload protection circuit on one side.
Figure 36 is a diagrammatic sketch of explaining operating principle of the present invention.
Figure 37 is the embodiment of battery feed circuit of the present invention and current overload protection circuit.
Figure 38 A and Figure 38 B are the diagrammatic sketch of expression according to the example of battery feed circuit of the present invention system.
As previously shown, the present invention has proposed special suggestion with regard to the shared peripheral circuit of bidirectional battery power supply circuits.In this case, bidirectional battery power supply circuits itself can be thought and can be realized by multiple device; But it is, can arbitrarily design this body structure of bidirectional battery power supply circuits, and in fact unrestricted with the peripheral circuit that relates among the present invention.The bidirectional battery power supply circuits that disclose in aforementioned application is open only draw does an example.
Fig. 1 is the circuit diagram by the open middle bidirectional battery power supply circuits of introducing of aforementioned application.In the figure, battery feed circuit is by first trsanscondutance amplifier 10 and second trsanscondutance amplifier 20, and feedback control circuit 50 forms, and direct current is offered so-called line A41 and the line B42 that is connected on the subsets TEL by battery feed terminal OUT1 and OUT2.First has identical structure with trsanscondutance amplifier 10 and 20; Form by operational amplifier 16 and the various resistance of 26A.And they have all disposed bias input end B1 and B2, control input end CNT1 and CNT2 and above-mentioned powered battery end OUT1 and OUT2.Please note that above-mentioned resistance comprises first to the 5th resistance (11 to 15) of dispensing first trsanscondutance amplifier 10 and to first to the 5th resistance (21 to 25) of the second logical amplifier (20).
Battery feed circuit shown in Figure 1 sees international electric electronic engineering (IEEE) the solid-state circuit periodical of publishing in August, 1981, the SC-16 volume, among Fig. 2 on the 262nd page of No. 4, and be provided with an a pair of trsanscondutance amplifier (10 and 20) and a feedback control circuit (50), as elementary cell.In Fig. 3 of same one page of this publication, trsanscondutance amplifier has been shown, has been equivalent to constant-current source on its function.Therefore, they satisfy aforesaid condition (1) (for the high impedance of differential amplifier) and condition (3) (predetermined dc-battery supplying resistance).But above-mentioned condition (2) (with respect to the Low ESR of same-phase signal) can not be satisfied separately by trsanscondutance amplifier.So for obtaining the Low ESR with respect to same-phase signal, actual practice is to introduce feedback control circuit 50 and place above-mentioned control input end CNT1 and CNT2(to see Fig. 1 its output).
The conventional example of having mentioned (Japanese unexamined patent discloses 57-42263 number, the PNP transistor can only send direct current and NPN transistor can only input dc power stream, that is, this circuit is not the bidirectional battery power supply circuits.But operational amplifier (16 and 26) itself can be sent electric current from its output, also can input current, so if same-phase signal also has no relation greater than the dc-battery supply current.
In the battery feed circuit of Fig. 1, introduced feedback control circuit 50, at first come mid-point voltage between detection line A41 and the B42 by resistance 51 and 52.Differential wave is rendered as waveform d1 and d2 in Fig. 1, institute's shape differential wave component is not used as mid-point voltage and detects.Yet same-phase signal is rendered as C1 and C2 waveform in the figure, is m so detect the waveform of mid-point voltage.Mid-point voltage m is added in and gets V BB/ 2(V BBBe the supply voltage of amplifier 16 and 26) be the positive terminal of the positive amplifier 53 of its paraphase input.Its output is added in control input end CNT1 and CNT2.Thus, same-phase signal electric current (this is the external communication induction) can alternately flow into trsanscondutance amplifier 16 and 26.
As mentioned above, battery feed circuit (Fig. 1) requires larger-size feedback control circuit 50, comprises that mid-point voltage detects resistance 51 and 52, positive amplifier 53, and this has just had such problem, and promptly the circuit size that becomes is very big also complicated.
Make after these problems have been considered in invention, the bidirectional battery power supply circuits that it proposes have not required feedback control circuit basically.That is, it has proposed an extremely simple circuit that forms device as Low ESR (with respect to same-phase signal).
Fig. 2 is that expression the present invention is equipped with Low ESR to form the basic structure of the battery feed circuit of circuit.In the figure, there is not above-mentioned feedback control circuit (50 among Fig. 1).Be provided with the electric capacity 30 that is coupled with control input end CNT1 and CNT2 in this position.
In operation, simply say, see this situation and do not have the equivalence that has electric capacity 30 to exist from same-phase signal.Therefore realized desired Low ESR with respect to same-phase signal.And then, the dc-battery supply current be it seems that its state also is the same.On the other hand, as if with respect to differential wave, electric capacity 30 can be divided into two, and its mid point can equivalence be a virtual earth, so obtained high impedance for differential wave.
Therefore, a single electric capacity only is set, then makes above-mentioned complex feedback control circuit 50 of cancellation and V BB/ 2 power supplys become possible (it will be described in detail operations principle back).
Fig. 3 is that the expression present device has Low ESR to form an embodiment of the battery feed circuit of device.Basically, it has the structure identical with Fig. 2.But output 19 and 29 places in operational amplifier 16 and 26 are provided with the buffer circuit 60 and 65 that comprises emitter follower.Notice that corresponding buffer circuit has been disclosed in No. the 4387273rd, the United States Patent (USP).By this, even same-phase signal substantially exceeds the powered battery current interference, and they also can fully be carried out.Further, bias input end B1 and B2 have been added with by three divider resistances 71,72 and 73 predetermined voltages that distribute.Notice that the I/O of voice signal V can suitably be chosen, but the example that the figure shows be shown in the position be provided with transformer 74, as the input and output of voice signal V.
Have a look above-mentioned buffer circuit 60 and 65, the former is by the transistor of PNP transistor 61 and two emitter-coupled of NPN transistor 62() and resistance 63 form; And the latter, buffer circuit 65 is by PNP transistor 66, two emitter-coupled transistors of NPN transistor 67() and resistance 68 compositions.In-phase signal C1 and C2 at a time greater than the dc-battery supply current, are partly represented by hachure in the drawings.C1 flows into PNP transistor 61, and C2 flows into PNP transistor 66.At next constantly, the polarity of in-phase signal C1 and C2 produces and changes.At this, next electric current corresponding to C1 flows into from NPN transistor 62; Electric current corresponding to C2 flows into from NPN transistor 67.Notice that original dc-battery supply current lies prostrate through ground E(0 continuously) arrive e to V to a to b to c to d BB(-48V) (at Figure 48) flowed.
Below, with reference to Fig. 4, Fig. 5 and Fig. 6 the operation principle that Low ESR forms the battery feedback circuit of device that has of Fig. 2 is made an explanation.Fig. 4 is that the direct current of battery feed circuit shown in Figure 2 is handed over and imitated circuit.The claimable dc-battery power supply circuits that its expression obtains.The resistance R that notes resistance gives first setting, satisfies relational expression R to making 15＜＜R 12, R 11(call in the following text 11,12 and 15 the expression resistance 11,12 and 15, below identical).For the dc-battery power supply circuits, electric capacity 30(Fig. 2) do not exist.Capacitor 30 does not exist and means that there be not (Fig. 2) in resistance 14 and 24.Here, have a look first trsanscondutance amplifier 10 more on one side, the direct current I that flows through ABe expressed from the next:
I A＝〔V A×R 12/（R 12+R 11）〕÷R 15（1）
Electric current I is as follows by the reason of formula (1) expression: in Fig. 2, be rendered as infinite-impedance with respect to direct current electric capacity 30, do not have (open circuit) basically, and resistance 14(be connected with an infinite-impedance) at one end also be open-circuit condition.Therefore, resistance 14 is not effect fully in circuit, is essentially not exist.Owing to this reason, have only resistance 13 to be connected between the inverting input and output of operational amplifier.Resistance 13 is sent output signal back to inverting input strictly according to the facts, but the input current of operational amplifier is extremely faint, so the voltage drop of resistance 13 can not be ignored (when electric current is zero, having only the voltage signal feedback in the past).
Therefore, the value of resistance 13 can be zero ohm (short circuit), that is, it can be used as the form of voltage follower.In Fig. 4, as voltage V AWhen being added on the circuit, the voltage V between OUT1 and the normal phase input end XBecome by resistance R 11And R 12The value of dividing potential drop, and
V X＝R 12/（R 11+R 12）×V A
As for the positive input voltage, because V appears in the output of voltage follow strictly according to the facts XBe added in the two ends of resistance 15.Now, because R 15＜＜R 12, R 11,
I A＝（V X/R 15）＝〔R 12/（R 11+R 12）×V〕÷R 15
Here, with above-mentioned formula (1), direct current equivalent resistance R A(=V A/ I A) become:
R A＝V A/I A＝V A/〔V A×R 12/（R 12+R 11）÷R 15〕＝〔（R 11+R 12）×R 15〕/R 12（2）
Can know by formula (2) and to find out, if three resistance 11,12 and 15 suitably are set, just can obtain desired resistance R A(for example, hundreds of ohm) (satisfying aforementioned condition (3)).And then, resistance value R APrecision be improved by the resistance accuracy that improves three resistance.
On the other hand, to the direct current equivalent resistance R of second trsanscondutance amplifier 20 BAlso can set similarly, be expressed from the next:
R B＝〔（R 21+R 22）×R 25〕/R 22（3）
Fig. 5 is the differential wave isoboles of battery feed circuit shown in Figure 2.For differential wave, circuit equivalent in have two serial connection capacitors 30 ' circuit, alternating current component is had virtual earth E.The capacitance of supposing the capacitor 30 among Fig. 2 is C Ab, capacitor 30 ' capacitance be C Ab* 2.The formation of this equivalent electric circuit is because of synchronization fluctuate about the differential wave of figure center line A and line B.Here, if C AbResistance R with respect to resistance 14 and 24 14And R 15Select fully greatly, that is:
R 14，R 24＞＞1/2πfC ab（4）
Here f is the differential wave low-limit frequency.Then be added in capacitor 30 ' on voltage be substantially zero.By this, at first in the drawings by V +The voltage of the point of expression can be expressed from the next:
V +＝V in×R 11/（R 12+R 11） （5）
Here, V InBe the voltage that appears at the OUT1 place.But V +Owing to the so-called imaginary short of operational amplifier 16 equals V_, so the voltage V_ that locates in anti-phase input (-) becomes:
（V O-V_）/R 13＝（V_-O）/R 14（6）
Here, V OBe the voltage of the output of operational amplifier 16.The right side molecule-O represent to be added in electric capacity 30 ' on voltage be zero, as earlier mentioned.By this formula (6), we obtain:
V O＝〔（R 13+R 14）/R 14〕×V_ （7）
From this formula (7) and above-mentioned formula (5) (V +=V_), electric current I A(=(V In-V O)/R 15) can be expressed from the next:
I A＝V in/R 15〔（R 12+R 11）/R 11-（R 13+R 14）/R 14〕 （8）
Here, set, make R if the resistance of resistance 11,12,13 and 14 is given earlier 11=R 14And R 12=R 13, the I of then above-mentioned formula (8) ABecome I A=O.I A=O means the high impedance of having realized with respect to differential wave (satisfying aforementioned condition (1)).
Fig. 6 is the in-phase signal equivalent electric circuit of battery feed circuit shown in Figure 2.When in-phase signal (C1 and C2) when entering, wave form varies shown in the voltage V-of the voltage V+ of the forward of the operational amplifier 16 in first trsanscondutance amplifier 10 input (+) and oppositely input (-) presses.Second trsanscondutance amplifier, 20 1 sides also present same variation.This situation is, and occurs with respect to in-phase signal absolute no-voltage on electric capacity 30.That is, for in-phase signal, electric capacity 30 comes down to non-existent.Consequently, it is identical with the pc equivalent circuit shown in Fig. 4 that the in-phase signal equivalent electric circuit becomes, impedance (for example hundreds of ohm) corresponding to the dc-battery supplying resistance becomes the impedance with respect to in-phase signal, thereby has obtained Low ESR (satisfying above-mentioned condition (2)).
As mentioned above, according to the present invention, can realize having the bidirectional battery power supply circuits that Low ESR forms device, it is simpler than the circuit among Fig. 1.
The explained later biasing circuit provides the biasing circuit of bias voltage in particular for the two-way main battery power pack on the line circuit of switching system.This battery feed circuit comprises an operational amplifier as shown in Figure 1.Must apply predetermined bias at the main battery power pack, so that the operational amplifier operate as normal.Biasing circuit promptly provides this bias voltage.
Fig. 7 illustrates the example of a conventional biasing circuit.Biasing circuit 80 among the figure has three resistance 71,72 and 73(sees Fig. 3), and obtain bias voltage V by so-called electric resistance partial pressure B1And V B2Here, be to being applied to the supply voltage V on the main battery power pack 5 usually BBCarry out dividing potential drop.
Notice that main battery power pack 5 has the bias voltage of reception V B1And V B2Bias input end B1 and B2(see Fig. 3) and provide the powered battery end OUT1 of predetermined direct current and OUT2(to see same figure), and by line A41 and line B42 control subscriber phone TEL.The input-output part (transformer etc.) of voice signal is shown among Fig. 3, and it narrates omission.
For the conventional biasing circuit 80 shown in Fig. 7, power supply (V BB) directly link to each other with B2 with bias input end B1, the noise former state that is produced by power supply enters the main battery power pack like this, thereby causes both poor sound quality.Also have a problem in addition, promptly be not easy freely to be provided with as required bias voltage.And, can not carry out the reverse battery power supply.The reverse battery power supply means under the situation that terminal high-level service such as automatic calling are provided, make electric current along the direction opposite from line B42 to the line A41 (A → B) that flows with common direct current, but by the bidirectional battery power supply circuits of above narration, what make electric current self oppositely becomes possibility.
A second aspect of the present invention is, considering on the basis of these problems, and a biasing circuit that is used for the bidirectional battery power supply circuits is provided, and makes power supply noise can not enter the main battery power pack and accomplish and changes bias voltage at an easy rate.Notice that the operational amplifier in the main battery power pack 5 has the ability of eliminating intrinsic noise, so power supply noise can not enter from this part.
Fig. 8 is the theory diagram of expression according to biasing circuit of the present invention.Biasing circuit 80 of the present invention comprises: the bias voltage generation device 81 with high output impedance; Buffer unit 83 with low output impedance, it is received in the bias voltage V that produces on the output point 82 BAnd this bias voltage offered main battery power pack 5; And be connected output point 82 and the ground interchange shunt capacitance 84 between the E.Notice that biasing circuit shown in the figure is linked the side among line A41 or the line B42, it also can all link to each other with line B42 with line A41.
Narrate its course of work below.Bias voltage generation device 81 has high output impedance, and promptly output point 82 is a high impedance, utilizes the high impedance of output point 82 and is connected in output point 82 and the electric capacity 84 of ground between the E makes alternating component is presented Low ESR.Consequently, from power supply (V BB) noise of coming in suppressed by electric capacity 84.
On the other hand, be provided with buffer unit 83, will appear at the high output impedance bias voltage V of output point 82 with low output impedance BBecome low output impedance, and this bias voltage is offered input B1 and B2.
Fig. 9 is the circuit diagram according to biasing circuit embodiment of the present invention, as shown in the figure, biasing circuit 80 according to this embodiment comprises: have the bias voltage generation device 81 of high output impedance, comprise current source 91 and resistance 92, and form output point 82 on their tie point.And then the buffer unit 83 with low output impedance comprises voltage follower circuit 94.AC bias circuit 84 with shown in the part link to each other.
One end of bias voltage generation device 81 (being an end of current source 91) and power supply (voltage V BB) link to each other with main battery power pack (5 among Fig. 7).Common V BBBe-48V.On the other hand, an end of resistance 92 and reference power source V BRLink to each other.V BR, remain on the steady state value between-2 to-3V to 3V than earth potential (OV) low 2.(V between these power supplys BBTo V BR) mobile electric current I BLittle, with the reduction power loss, thereby resistance 92 will have high value.If 92 resistance value is R 92, bias voltage V then BCompare V BRLow magnitude of voltage I B* R 92, and it is added to B1 or B2 among bias input end B(Fig. 7 by voltage follower circuit 94).
Figure 10 is the more detailed circuit diagram of Fig. 9 circuit, and it illustrates a biasing circuit that is suitable for as the reverse battery power supply.For the reverse battery power supply, the biasing circuit of Fig. 9 is positioned at line A and line B both sides.Give identical reference number corresponding to the part of component part among the line A among the line B and add one worn-out.Note, shown in as the voltage follower circuit 94 and 94 of buffer unit ' constitute by operational amplifier, on the other hand, current source 91(Fig. 9) and 91 ' comprise current mirror circuit (CM1 and CM2) 101 and 101 ' reach reference current generation device 102.Reference current I from reference current generation device 102 BOffer line A side or line B side by current switching device 103.This device is connected to the contact a of line A side usually, only just is connected to contact b during the reverse battery power supply.Current mirror circuit be used to make second end points 105 and 105 ' inflow (or outflow) electric current equal first end points 106 and 106 ' inflow (or outflow) electric current.Utilize their characteristic, produced the resistance 92 and 92 of flowing through ' bias current (equaling above-mentioned reference current I).
During normal battery power supply (promptly not being the reverse battery power supply), electric current I BFlow into contact a from current switching device 103, flow to first end points 106 of current mirror circuit 101 then, bias current I BThe resistance 92(resistance of flowing through R 92).As a result, obtain one than reference voltage source V at output point 82 BR(2 to-3V) low I B* R 92Bias voltage V B1Size according to set bias voltage is provided with reference current I rightly B(because R 92Be a fixed value).In this case, online B side, do not have current direction current mirror circuit 101 ' first end points 106 ', therefore, do not have bias current I yet BFlow to second end points 105 '.Thereby, the voltage V of reference voltage source BR(2 to-3V) as bias voltage V B2
On the contrary, during the reverse battery power supply, current switching device 103 switches to contact b.By this, electric current I BFlow through resistance 92 ', the bias voltage of line B side is V BR-I * R 92', online A side, the no current resistance 92 of flowing through, bias voltage V B1Be elevated to V BRTherefore realized the reverse battery power supply
Figure 11 is the more detailed circuit diagram of Figure 10 circuit.Be given identical reference number corresponding to the part among Figure 10.In Figure 11, represented in more detail current mirror circuit 101 and 101 ', reference current generation device 102 and current switching device 103.Reference current generation device 102 comprises: current mirror circuit 111(wherein electric current flows out from first and second end points), transistor 112 and resistance 113(resistance R r).By this structure, from the electric current I of transistor 112 BFor
I B＝V BB/R r
With electric current I BAn electric current that equates offers the current switch that comprises pair of transistor 114 and 115.On the base stage of transistor 115 and 114, add N/R(respectively normally/oppositely) input and threshold value input V ThDuring the normal battery power supply, N/R=" H " (height), electric current I BFlow to transistor 114.During the reverse battery power supply, N/R=" L " (low), electric current I BFlow to transistor 115.For with bias voltage V B1(V B2) be made as desirable value, suitably select resistance 92(92 ') resistance R 92Resistance R with above-mentioned resistance 113 rRatio.
Usually, supply voltage V BB(-48V) is not completely fixed, and is accompanied by some fluctuations.Therefore, bias voltage preferably also changes along with this fluctuation.In the circuit of Figure 11, electric current I BBe by supply voltage V BB(the V of resistance 113 decision BB/ R r), so V BBFluctuation be exactly I BFluctuation, resistance 92(92 ') on voltage drop also change, thereby make bias voltage follow V automatically BBFluctuation.Supply voltage V BBNot only be subjected to the influence that above-mentioned direct current changes, and because it is the circuit of a usefulness-48V, so also be subjected to the influence of AC noise, the electric current of mirror image circuit 101 and 101 ' output is proportional to the electric current of input, common point V BBNoise be not added on the output current.That is, the mirror image circuit has the high output impedance of constant-current source.On the other hand, the electric current that flows through resistance 113 is vulnerable to by V BBThe The noise that fluctuates and cause.This value is by V BBN/ R provides (V wherein BBNBe V BBNoise voltage).Here the noise current of Chan Shenging is added to mirror image circuit 101(101 ' by mirror image circuit 111 and current switching device 103).This electric current is by exchanging shunt capacitance 84(84 ') switch to ground E, suppressed effectively at a 82(82 ') voltage that produces.Note, with the voltage V of reference voltage source BRBe set to than the low scheduled voltage (2 to 3V) of earth potential, thereby V BRSelf ripple disable.In this case, can utilize the diode of a plurality of coupled in series to produce V BR
According to above-mentioned aspect of the present invention, realized a such biasing circuit, it makes power supply noise can not enter the main battery power pack, makes bias voltage to be set at an easy rate and and then to control the reverse battery power supply at an easy rate.
To explain the powered battery current control circuit below, especially for the powered battery current control circuit of control from the powered battery electric current of bidirectional battery power supply circuits, these bidirectional battery power supply circuits are positioned on the line circuit of switching system.
As previously mentioned, battery feed circuit generally includes an operational amplifier.Predetermined bias voltage must be added on the battery feed circuit so that the operational amplifier operate as normal is provided with biasing circuit this bias voltage is provided.Biasing circuit is than the low several volts of earth potential (OV) usually with line B side, is than supply voltage (48V) high a few volt (or opposite) with line A side.The existence of these a few volt bias voltages makes need control the powered battery electric current to the distance of subscriber phone according to telephone wire (line A and B).
Figure 12 is the schematic diagram of a conventional batteries electric power system of expression.Among the figure, TEL is a subscriber phone, R LBe the resistance of telephone wire and phone TEL, promptly so-called load resistance.Battery feed circuit is with respect to load resistance R LCarry out powered battery.The dc-battery supplying resistance for example is 220 Ω.Notice that 1 is the dc-battery supply current among the figure, V BBBe supply voltage, for example-48V.In Figure 12, do not relate to bias voltage at all.In principle, it is possible not having the powered battery of bias voltage.
But, for battery feed circuit, below saying of will summarizing of some things.Be connected to so design of battery feed circuit, so that seem to obtain a predetermined value with respect to the input impedance of AC signal from line A and line B as the line A and the line B end of above-mentioned telephone wire.This input impedance roughly is divided into two types also must satisfy above-mentioned condition (1), (2) and (3).
And then as mentioned above, in recent years, the condition that influences in-phase signal has increased.Both make the in-phase signal electric current greater than dc-battery supply current I, also required in voice signal, not cause distortion.In-phase signal means that greater than dc-battery supply current I electric current I will flow along the direction opposite with normal direction.In order to make reverse current flows, in practice bias voltage is placed (as 2V) within several volts.
Figure 13 is the schematic diagram of a universal battery electric power system of expression.The above-mentioned bias voltage that is arranged within several volts is shown-2V(line B side in the drawings) and+2V(line A side) battery.What need point out in the drawings a bit is that the dc-battery supplying resistance becomes for example 100 Ω, less than the no bias conditions (220 Ω → 100 Ω) of Figure 12.Its reason is based on such fact, promptly must reduce resistance offers phone TEL with compensation powered battery electric current I.
Figure 14 is expression load resistance R LCurve chart with the relation of powered battery electric current I.Telephone wire is long more, R LBig more, as the R of foreseeable maximum length LFor example be 1900 Ω, then the minimum guarantee value of powered battery electric current is for example 20mA at this moment.This 20mA reduces to 100 Ω by resistance among Figure 13 and guarantees.But user's telephone wire is short more, the R among the figure LMore to moving to left.The powered battery electric current I is proportional to 1/R LRise rapidly (chain-dotted line P).Therefore, too many powered battery current direction short distance user.For eliminating this inconvenience, attempt the characteristic of the powered battery electric current I among the figure is modified to solid line Q always.That is, be suppressed to for example 50mA for short distance user powered battery electric current I.By this to slacken too much powered battery electric current.
In prior art, attempted to make the powered battery resistance (corresponding to 100 Ω among Figure 13) in the main battery power pack variable, thereby according to load resistance R LSize control the size of powered battery electric current I.But, make the internal structure of main battery power pack become very complicated for satisfying above-mentioned condition (1), (2), (3) simultaneously, the technology that changes powered battery resistance simultaneously is very difficult actually.
A third aspect of the present invention is, considering on the basis of the problems referred to above, a powered battery current control circuit is provided, it can easyly inerrably be restricted to electric current about 50mA, can also provide other optional function, for example reverse battery power supply and balance/unbalanced mode.
Figure 15 represents that according to the theory diagram of powered battery current control circuit of the present invention and peripheral circuit shown main battery power pack 5 and biasing circuit 80 are as peripheral circuit.Main battery power pack 5 is provided with: the bias voltage V that receives biasing circuit 80 B1And V B2(Figure 10) bias input end B1 and B2 transmit the powered battery end OUT1 and the OUT2 of powered battery electric current I to phone TEL by line A41 and line B42.And then, reference Figure 15 in the main battery power pack 5 and the above-mentioned powered battery resistance of 25 expressions.Omission is to the explanation (Fig. 3) of voice signal input-output part (transformer etc.).
Powered battery current control circuit 200 according to the present invention comprises: detect the checkout gear 210 of powered battery electric current I, when the powered battery electric current I surpasses predetermined value I ThThe time detect overload current (I-I Th) checkout gear 220, according to overload current (I-I Th) change the bias voltage V of auto bias circuit 80 B1And V B2Bias control device 230.Its operation principle of explained later.
As previously mentioned, in prior art, attempted to change the powered battery electric current I, but in the present invention, be by changing bias voltage V by powered battery resistance 15 among change Figure 15 and 25 resistance B1And V B2Change the powered battery electric current I.This can make circuit realize easily, and further realizes other optional function.
Figure 16 is the curve chart of explaining according to powered battery current control circuit of the present invention work.The first half is corresponding to the curve among Figure 14.The latter half is represented according to controlled bias voltage of the present invention.Earth potential (OV) is represented by chain-dotted line E.Supply voltage V BBAs transverse axis.User distance is near more, load resistance R LMore little, the powered battery electric current I is big more, but in powered battery current control circuit 200, I is in case surpass predetermined value I Th, change the bias voltage V of line B side at least B2Or the bias voltage V of line A side B1, so that they mutually near and reduce powered battery battery I by control.Figure 16 has represented V B1And V B2All mutual close situation.
Figure 17 represents the example according to powered battery current control circuit of the present invention and peripheral circuit.The overall structure of circuit at first with the aid of pictures, main battery power pack 5 only is represented as powered battery resistance 11 and 12, powered battery end OUT1 and OUT2, and bias input end B1 and B2.Part in the biasing circuit 80 provides with the reference number among Figure 11.Part in the powered battery current sensing means 210 provides with reference number 211 to 215.Part in the overload current checkout gear 220 provides with reference number 221 to 224.Part in the bias control device 230 provides with reference number 231 to 237 and 36 to 39.
Powered battery current sensing means 210 can be a device that can detect the size of powered battery electric current I, but in the present embodiment, electric current I changes current value in the voltage drop that detects formation on the resistance 214 and 215 into by converter (VI) 211 and 212, and its result is mixed as detecting current i by electric current blender (CMIX) 213.This i is proportional to the powered battery electric current I.Detection current i upper right portion from current mirror circuit 222(figure) first end 224 flows out.Notice that converter 211 and 212 lays respectively at line A41 side and line B42 side, its result is mixed to eliminate aforesaid in-phase signal by blender 213.
The detection current i is added on first end (224) of the 6th current mirror circuit (CM6) 222 that forms overcurrent detecting device 220 parts.Constant-current source 221 links to each other with second end (223), all exports an above-mentioned predetermined value I who is proportional to the powered battery electric current I in All Time ThConstant current i ThWhen the powered battery electric current I surpasses predetermined value I ThBe △ I(=I-I Th) time, similarly produce overcurrent △ i(=i-i Th).This △ i is the control bias voltage, that is the controlling elements of control powered battery electric current.Note why use current mirror circuit to be and enter biasing circuit because they have high output impedance and can suppress power supply noise effectively.
For the control bias voltage, above-mentioned overcurrent △ i is done following processing.At first, overcurrent △ i enters first end 234 of the 5th current mirror circuit (CM5) that forms bias control device 230 parts.An electric current that equates with △ i is as Control current i cFlow into second end 232 to change the electric current and the voltage status of biasing circuit 80.
Biasing circuit 80 has the 3rd current mirror circuit (CM3) 111 that forms current source in bias control device 230 sides, resistance 112 and 113, and buffer transistor 133; Have the 1st current mirror circuit (CM1) 101 in main battery power pack 5 sides, resistance 92, voltage follower circuit 94(is used for line A entirely), and identical part 101 ', 92 ' and 94 ' (being used for line B entirely).See line A41 side, reference voltage is V BRReference voltage source link to each other with an end of resistance 92.This V BRRemain on a steady state value between-2 to-3V, than earth potential low 2 to 3V.Resistance as resistance 92 is R 92, bias voltage V then B1Compare V BRLow voltage drop I B* R 92The refined plaited straw 4 of ⑼ ü Miao  dirt  is added to bias input end B1.At this moment electric current I BBe the electric current of the 2nd end 105 of inflow current mirror image circuit 101, and equal to flow into the electric current of the 1st end 106.The electric current that flows into first end 106 is an electric current I B, it is closed by transistor 114(transistor 115) and from the 2nd end 116 of the 3rd current mirror circuit 111.This electric current equates with the electric current that the 1st end 117 produces.This is to flow through transistor 112 and the big or small V of being BB/ R 139(R 139Be the resistance of resistance 139) electric current.More than the narration about line A41 side, online B42 side, transistor 115 is closed, no current flow to the 2nd current mirror circuit 101 ' the 1st end 106 ', so also no current flow to the 2nd end 105 ', resistance 92 ' on absence of voltage, voltage V BRBecome bias voltage V B2The state shown in the latter half curve is identical among this state and Figure 16, wherein V B1And V B2Remain the predetermined constant value (when I less than I ThThe time).
This powered battery current detection circuit 600 is represented by the reference number among Figure 21 320, and is realized by a forward and reverse battery supply current testing circuit.But the circuit 320 among Figure 21 has two key elements, operational amplifier 322 and 323.Building-out capacitor in yet in general, operational amplifier needs.Make the increase that electric capacity causes chip area on large scale integrated circuit LSIS, and a lot of triodes and other element are arranged in the operational amplifier, this also makes chip area increase.Therefore, there is not operational amplifier in the best powered battery current detection circuit of assembling.
Figure 29 has represented an example that does not use the powered battery current detection circuit of operational amplifier.Reference number 311,41,5 and 320 among the figure has been represented aforesaid same element.When a forward powered battery electric current I fFlow to when detecting resistance 311 voltage V 0And V 1Appear at this two ends.As shown in the figure, an end of resistance 311 is low-resistance ends, promptly is connected to form main battery feed part 5(Figure 28) the output of operational amplifier.
The NPN triode 33 of diode connection is connected in series with the emitter of PNP triode 32, and receives the constant-current source 36 that bias current is provided.The collector electrode of PNP triode 32 is connected to the lowest electric potential voltage source V BBBy the electric current of PNP triode 32, its base stage can be with the voltage V on the high impedance monitoring detection resistance 311 1The voltage V of resistance 311 1Base stage one emitter voltage V with triode 32 and 33 BEAddition, and deliver to the base stage of NPN triode 34.At this, if think the V of PNP triode 32 and 35 BESubstantially equal, and the V of NPN triode 33 and 34 BESubstantially equal, the voltage V on the resistance 311 then 1Appear at an end (right-hand member among the figure) of monitoring resistor 31 faithfully, and forward detects current i fFlow to resistance 31, its amplitude is:
i f＝（R 311/γ 31）I f
R wherein 311And γ 31It is respectively the value of resistance 311 and 31.
From i fCan detect the powered battery electric current I f
In the circuit of Figure 29, the voltage on the resistance 311 is generally 1V or littler.Therefore, in order accurately to measure the base stage one emitter voltage V of triode BEIn fluctuation can not be ignored.Because the positive-negative-positive triode generally presents consistent V BE, and NPN type triode also presents consistent V BESo, can eliminate the variation in the same conduction type triode (PNP is to PNP, and NPN is to NPN).The triode that is used to eliminate variation is that triode 33(is used to eliminate 34) and triode 35(be used to eliminate 32).Yet eliminating with triode itself is the technology that can learn from Japanese unexamined patent (Kokai) application number 61-62268.
Do not adopt operational amplifier can assemble powered battery current detection circuit shown in Figure 29 yet and reach desirable purpose.But, in sort circuit, can only detect forward powered battery electric current I f, be not suitable for forward and the oppositely detection of the two.
Therefore, the assignee attempted to add among PNP triode 37(Figure 29 of line shown in the dotted line in the past) so that obtain and reverse battery supply current i fCorresponding inverse detection current i rEquivalent electric circuit when Figure 30 has represented inverse detection.This is the same with Figure 29, has just switched up and down.Therefore, the operational amplifier OP of main battery power pack 5 places the top, so that flow through the powered battery electric current I that detects resistance 311 rDirection and the I of Figure 29 fThe direction unanimity.Middle in the case reverse battery supply current I rAmplitude can be by the inverse detection current i rObtain:
i r＝（I r×R 311-2V BE）/γ 31
Yet, used 2V in the above-mentioned formula BE( PNP triode 32 and 37 voltage V BESum) nominal value, owing to lack accuracy, so can not use the circuit of Figure 30.
Calabash shell serving as a dipper gown good fortune Huan is prosperous to be waitd upon fried twisted dough sticks  rose and takes off the powered battery current detection circuit 20 shown in high and steep 9 and only add that a reversal detection systems can not realize desirable powered battery current detection circuit.
The 5th aspect of the present invention provides a kind of powered battery current detection circuit, and it is by eliminating the V of triode BEDifference, for forward with oppositely all obtained the high Precision Detection electric current, and do not use any operational amplifier.
Figure 31 represents the principle and the structure of powered battery current detection circuit of the present invention.First checkout gear, 641 monitoring forward powered battery electric current I fFlow through the voltage at two ends when detecting resistance 311, and its result is added to first monitoring resistor 645.So forward detects current i fOn resistance 645, produce.First checkout gear does not comprise any operational amplifier, but is made up of a PNP triode and a NPN triode.Inner first cancellation element 643 is eliminated the V of triode BE
On the other hand, second checkout gear, 622 monitoring reverse battery supply current Ir flow through the voltage at two ends when detecting resistance 311, and its result is added to second monitoring resistor 646.So, the inverse detection current i rIn resistance 646, produce.Second checkout gear 642 does not comprise any operational amplifier, and just is made up of a PNP triode and a NPN triode.Inner second cancellation element 644 is eliminated the V of triode BE
Always say that a kind of prejudice is arranged, be exactly forward and oppositely want a shared monitoring resistor.As reference Figure 29 and 30 illustrated, can not eliminate the V that detects the triode in the reverse battery supply current Ir system by introducing device BEThe invention provides two other monitoring resistors of branch and handle positive and negative two directions, promptly 645 and 646.The result can specifically, pack in second checkout gear 642 and eliminate triode V easily in checkout gear BEDevice.
Therefore, by the simple combination of NPN and PNP triode, can eliminate the V of triode fully BE, and can detect the powered battery electric current of positive and negative two directions.
Figure 32 has represented an embodiment of powered battery current detection circuit of the present invention.Reference number 641 and 642 is first and second checkout gears shown in Figure 31 among the figure.When forward powered battery electric current I fProduced forward respectively when flowing through detection resistance 311 and detected current i with reverse battery supply current Ir fWith the inverse detection current i rTherefore, 641 monitorings of first checkout gear detect the voltage V on the resistance 311 RAnd it is delivered to first detect resistance 645.This structure comprises PNP triode 411 and NPN triode 412, also comprises eliminating its V BE First cancellation element 643, promptly be connected into the NPN triode 431 and the PNP triode 432 of diode form.Triode 432 is eliminated the V of triode 411 BEAnd triode 431 is eliminated the V of triode 412 BEReference number 361 provides the constant-current source of bias current, and this bias current provides the base current of triode 412, produces the V of triode 431 BE, and make triode 411 in running order.Said structure and Figure 29 structural similarity, but one second checkout gear 642 is provided in the present invention in addition.
In second checkout gear 642, detect the voltage V on the resistance 311 RMonitored and be added to second monitoring resistor 646.This structure comprises PNP and NPN triode 421 and 422 and eliminate its V BE Second cancellation element 644, promptly be connected into the NPN triode 441 and 442 of diode form.Triode 442 is eliminated the V of triode 421 BE, triode 441 is eliminated the V of triode 422 BEReference number 362 is the constant-current sources that are used to provide bias current, and it provides base current and produce the V of triode 441 and 442 for triode 422 BE
In second checkout gear 642, proved and when Ir passes through, detected the voltage V on the resistance 311 RBe created on second monitoring resistor 646.If the voltage on the resistance 646 is V 3And V 4, following formula is then arranged:
V 3＝V 0+V BEP1+V BEN1-V BEN2（11）
V 4＝V 0-V R+V BEP2（12）
At this, V BEP1And V BEP2Be respectively the V of PNP triode 442 and 421 BE, V BEN1And V BEN2Be respectively the V of NPN triode 441 and 422 BE, V BEP1=V BEP2, V BEN1=V BEN2
From formula (11), deduct formula (12) and (have reverse battery supply current Ir and V 3＞V 4), following formula is then arranged:
V 3-V 4＝V BEP1+V BEN1-V BEN2+V R-V BEP2（13）
With V BEN1=V BEN2And V BEP1=V BEP2Substitution formula (13) then has following formula:
V 3-V 4＝V R
Thus, there is not V BEAny intervention, detect the voltage V on the resistance 311 RAppear at (V on second monitoring resistor 646 faithfully 3-V 4).
As mentioned above, according to the present invention, need not any operational amplifier, can accurately detect forward and reverse battery supply current.
What will explain at last is current foldback circuit, particularly the current foldback circuit in the bidirectional battery power supply circuits in the line circuit of switching system.
Battery feed circuit is generally said the overcurrent that must prevent to flow through subscribers feeder A and subscribers feeder B.Therefore, must provide and press down function of current, also satisfy aforesaid condition (1) simultaneously, (2) and (3).At this, overcurrent will take place when being connected the battery mistake when earth fault.Earth fault often takes place in the subscribers feeder A limit that particularly is connected to power supply-48V.
Figure 33 represents a kind of key component of cells known power supply circuits.It has at length represented the main battery power pack 5 of Fig. 7, and its working condition is the same with afore-mentioned basically.But, for the ease of explaining that we will be from Figure 33.This circuit comprises subscribers feeder A limit operational amplifier OP a, triode Q a, resistance R A1And R A2; Subscribers feeder B limit operational amplifier OP b, triode Q b, and resistance R B1And R B2Subscribers feeder A limit is identical with the work on B limit.On the A limit, as Control current i aBy the time, resistance R A2Last generation voltage R A2* i aBy operational amplifier OP a" imaginary short ", this voltage appears at resistance R faithfully A1On.Dc-battery supply current I as a result a(=(R A2* i a)/R A1) flow to subscriber phone TEL.
When detecting overcurrent, make resistance R A1On voltage reduce just can realize overcurrent protection, so resistance R A2On voltage less.For example, in resistance R A2Install shunt resistance additional before, when measuring overcurrent, shunt resistance just with resistance R A2In parallel.Perhaps, Control current i aBe adjusted, so that i aReduce.The circuit of Figure 33 is disclosed by Japanese unexamined patent (KOKai) No.5742263.
Though above-mentioned Japanese unexamined patent publication No. 5742263 disclosed powered battery satisfy aforementioned condition (1), (2) and (3), but can not satisfy the aforesaid new demand that had both made the in-phase signal electrorheological also can prevent the voice signal distortion must be greater than the dc-battery supply current time, reason is that disclosed powered battery has a collector electrode and is connected to the PNP triode of subscribers feeder B and the NPN triode that collector electrode is connected to subscribers feeder A.Previous PNP triode is sent direct current from collector electrode only, and a back NPN triode absorbs direct current at collector electrode only, is impossible so direct current is oppositely powered.
Use bidirectional battery power supply circuits, particularly the bidirectional battery power supply circuits shown in Fig. 2 can head it off.When sort circuit added overcurrent protection in giving Fig. 2, the problem that has the overcurrent protection function explained among a Figure 33 not to be suitable for, reason were type and Figure 33 different fully of battery feed circuit shown in Figure 2.
Last aspect of the present invention provides the overcurrent protection that the bidirectional battery power supply circuits that adopt mutual conductance to amplify are suitable for.
Figure 34 has represented the principle and the structure of current foldback circuit of the present invention.The circuit that is used for overcurrent protection is exactly a battery feed circuit shown in Figure 2.The reference number 700 expression current foldback circuits on subscribers feeder A limit.In order further to increase over-flow protecting effect, can adorn a same current foldback circuit in the similar part on subscribers feeder B limit.But the over-flow protecting effect when theoretically, providing just to be enough to obtain earth fault on subscribers feeder A limit.Figure 35 has represented the principle and the structure of the current foldback circuit that subscribers feeder B limit also provides, and has identical reference number and symbol corresponding to the part of Figure 34.
Current foldback circuit 700 among Figure 34 comprises voltage generation circuit 720 and 730 and switching device 740 and 750.As shown in the figure, 720 and 730,740 and 750 be connected in pairs between the in-phase input end 17 and inverting input 18 of operational amplifier.Voltage generation circuit 720 and 730 produces preset voltage.In addition, switching device 740 and 750 is controlled its open and close state selectively by overcurrent detecting device 220.
As previously mentioned, device for generating voltage 720 and 730 is a bipolarity, so that the situation when handling the in-phase signal electric current greater than dc-battery power supply stream, and can handle the anti-phase powered battery of high function (anti-phase I aAnd I b).
Figure 36 is in order to illustrate operation principle of the present invention.Predetermined constant voltage+the V that applies 1Make dc-battery supply current+I aBe restricted.In addition, the predetermined constant voltage-V that applies LMake dc-battery supply current-I aBe restricted.When+I aWhen restricted, switching device 740 is closed, when-I aWhen being limited, switching device 750 is closed.Overcurrent detecting device 220 decisions which with closure.Expressed overcurrent detecting device 220 among Figure 15.
+ I aOr-I aAmplitude I aDetermine by following formula:
I a＝R 12/R 11×V L/R 15
Resistance be set to R 12=R 13, R 11=R 14R 11, R 12Deng resistance be shown in Figure 2 11,12 or the like.V LValue (aforesaid+V for presetting constant pressure source LWith-V L) amplitude.What trsanscondutance amplifier had the inherence is the function of electric current with voltage transitions.If voltage V LBe suppressed to a steady state value, its corresponding electric current I aAlso will be suppressed to a constant, just obtain overcurrent protection function.
Figure 37 has represented an embodiment of current foldback circuit of the present invention and battery feed circuit.As previously mentioned, not needing all has current foldback circuit on subscribers feeder A limit and subscribers feeder B limit, but subscribers feeder B has also established current foldback circuit 700 ' (Figure 35) in the limit among this embodiment.Circuit 700 and 700 ' the same structurally is so only be illustrated circuit 700.
Form current foldback circuit 700 voltage generation circuit (as Figure 34 and 35 720 and 730) comprise a diode bridge 800.The switching device (740 and 750 in 34 and 35) that forms same circuit 700 is made of single triode switch 900.Diode is equipped with on diode bridge 800 each limit, and its forward drop (and conducting voltage of triode 900) forms the predetermined constant voltage (V of Figure 36 L).Therefore, if V LGreatly, the diode on each limit is then wanted plural serial stage.
Introduce diode bridge 800 and can obtain following two advantages: at first, two switching devices 740 of single triode switch 900 alternative Figure 34 and 750, this is based on the effect of diode full-wave rectification.
No matter second advantage is overcurrent I aDirection just with instead, single diode bridge 800 all can be handled.Diode bridge is changed the sense of current automatically.As a result, switching device can be a triode switch 900, does not promptly need other Direct/Reverse switching device 740 and 750 of the branch shown in Figure 34 and 35.In addition from the viewpoint of overcurrent detecting device 640, no matter the direction of overcurrent how, is enough by detecting electric current I o, so solved the difference that flows to switching device 740 and 750 in Figure 34 and 35 and the problem of output on-off Control current.
If detect electric current I o and overcurrent I aFlow I aMajor part then flow to bias input end B by resistance 12 and 11 1, also flow to operational amplifier 16 by resistance 15, but the electric current by resistance 13,14 and 15 flow through diode 801, triode switch 900(it by i OInstitute's conducting) and diode 802 and reach B 1Diode 801 and 801 forward voltage drop sum 2V FSaturation voltage drop V with triode switch 900 CESatForm aforesaid normal threshold voltage V L
Otherwise, if detect current i OWith overcurrent I aFlow I aMajor part flow to powered battery end OUT1 by resistance 12 and 11 and flow out from operational amplifier 16, but the electric current by resistance 14 and 13 from B1 by diode 804, triode switch 900(it by i 0Open-minded) and diode 803 reach OUT1.Diode 804 and 803 forward voltage drop sum 2V FForm aforesaid constant voltage V with the saturation voltage drop of triode switch LTherefore, V LThe battery supply feed stream I of rectification aOr I aFlow, can protect battery feed circuit not damaged by overcurrent.
As mentioned above, the present invention has realized a kind of current foldback circuit, and it is adapted to the bidirectional battery power supply circuits of capacitive coupling trsanscondutance amplifier to type.
Above-mentioned main battery power pack and its peripheral circuit group be individualism not, but in fact is loaded into a unit, forms a battery feed circuit.
Figure 38 A and 38B have represented an embodiment of battery feed circuit of the present invention system.The same element of narrating with the front has same reference number and symbol.Among Figure 38 A and the 38B; 1-A and 1-B are to tackling battery feed circuit part shown in Figure 2; 2 corresponding to the biasing circuit part among Figure 11; 3-A, 3-B, 3-C and 3D are corresponding to the powered battery flow control circuit among Figure 17; 4-A and 4-B are corresponding to the powered battery current monitoring circuit among Figure 22; 5-A and 5B are corresponding to the powered battery current detection circuit among Figure 31, and 6-A and 6B are corresponding to the current foldback circuit part among Figure 37.In Figure 38 A and 38B, CM represents " current mirror " circuit, SEL presentation selector.3-A, 4-B and 5-B are common grounds in single battery feed circuit, and 3-A, 4-A and 5-A are also like this.
As above describe in detail, a kind of structure that is suitable for practical application according to the present invention has realized the bidirectional battery power supply circuits.
If load resistance R LDiminish, the powered battery electric current I becomes and compares I ThBig Δ I, so above-mentioned Control current i cFlow to bias control device 230.Therefore, the electric current I that flows out from circuit mirror current (CM3) 111 BBe reduced to I E-i cThe electric current I that is reduced B-i cTo circuit mirror current 101, the voltage drop on the resistance 92 is than originally reducing i through transistor 114 c* P 92So, bias voltage V B1Rising i c* R 92(see V among Figure 16 B1The rising situation).
On the other hand, referring to voltage bias VB 2One side, the 3rd end 233 of the 5th circuit mirror current (CM5) 231 flow into that first end 237 from the 4th circuit mirror current (CM4) 235 flows out and the electric current by transistor 139 (Δ i is equivalent to i c).Therefore, i cFlow out from second end 236 of circuit mirror current 235, end through transistor 136(transistor 137), and the circuit mirror current 101 in the inflow biasing circuit 80 '.So resistance 92 ' (resistance is R 92') on pressure drop be i c* R 92', this just makes the curve V among Figure 16 B2One decline place is arranged.
Above-mentioned explanation is to make according to the groundwork situation of powered battery control circuit.The function that reverse battery power supply and balance-non-equilibrium mode can also be arranged in addition.As previously mentioned, reverse battery power supply be meant with from subscribers feeder B42 to subscribers feeder A 41The opposite sense of current of normal flow direction of dc-battery supply current I (A → B), it is used among high-level service facility such as the automatic terminal device.For making electric current I reverse, constitute a current switch by transistor 114 and 115, they by N/R(normal/oppositely) input selects conducting and ends.Under normal (N) powered battery situation, N/R=" L ", transistor 114 conductings (transistor 115 ends).Under reverse (R) powered battery situation, transistor 115 conductings (transistor 114 ends), the curve V among Figure 16 B1And V B2Oppositely.
In order to obtain this reverse battery power supply, in bias control circuit 230, the current switch that is made of transistor 136 and 137 is arranged also.During the reverse battery power supply, the current i of the aforementioned transistor 136 of flowing through cEnd then flow to transistor 137(transistor 136).
And balance-non-equilibrium mode is to instigate bias voltage V B1And V B2Balance or unbalanced mode.More than said all working situation all be balance mode.
Curve interpretation among Figure 18 uneven mode, corresponding with earlier figures 3.In Figure 17, bias voltage V B1And V B2Curve be to change in the same way, but in the non-equilibrium mode of Figure 18, bias voltage V B2Remain unchanged, and bias voltage V B1Raise separately, so that the powered battery electric current I reaches predetermined value I ThBelow will explain to uneven mode according to the battery-powered situation of normal electrical.In order to realize uneven mode, the electric current that flows through transistor 114 only needs the I under the aforementioned balance mode B-i cBecome I B-2i c, just only need pressure drop with resistance 92 from i c* R 92Raise and be 2i c* R 92On the other hand, in subscribers feeder B one side, only need with under balance mode flow to circuit mirror current 105 ' the electric current vanishing, just with the pressure drop vanishing of resistance 92 ' cause.Therefore, constitute the transistor 138 and 139 of current switch by U/B(imbalance/balance) import conducting selectively and end.Under balance mode, U/B is input as " L ", transistor 139 conductings, and transistor 139 ends, and condition is as previously mentioned.On the other hand, when U/B is " H ", and be again under non-equilibrium mode, transistor 138 conductings, transistor 139 ends.After transistor 139 ended, (Δ i, its value equaled i to the above-mentioned electric current that flows out from first end 237 of circuit mirror current (CM4) 235 c) vanishing, and be added to electric current vanishing on the current switch (136 and 137).Satisfied thus make resistance 92 ' on the aforementioned condition of pressure drop vanishing.Because transistor 138 is along with transistor 139 ends and conducting, so become the current i of the 3rd end 233 of original inflow circuit mirror current 231 from the Control current of circuit mirror current 111 cWith the current i that flows into its second end 232 cSum is 2i cTherefore, flow through the electric current (during normal battery power supply) of transistor 133 and transistor 134 from the following I of balance mode B-i cReduce to I B-2i cThe result makes that the aforementioned electric current that makes is I B-2i cCondition be met, realized non-equilibrium mode.Under non-equilibrium mode, may be at the bias voltage V of subscribers feeder A B1With supply voltage V BBBetween produce a sizable voltage gap, and as the situation of Figure 18, reference voltage V BB(-48V) is increased to voltage for example-24V.This makes the electric energy loss in battery feed circuit etc. reduce.Yet, voltage is reduced to-the reducing of 24V(magnitude of voltage from-48V by electric resistance partial pressure), divider resistance produce power loss (producing heat), so this is insignificant.So,, just must use low power consuming transducer, for example so-called DC-to-DC converter for magnitude of voltage is reduced to-24V from-48V.
As mentioned above,, might not have under the situation about further the main battery power pack being controlled, and the powered battery electric current is being done relatively simply control, and may be suppressed at the powered battery overcurrent that causes under short distance user's the situation according to the present invention.In addition, also may realize reverse battery power supply and balance/imbalance mode function at an easy rate.
Below the powered battery current monitoring circuit will be described, particularly monitor the powered battery current monitoring circuit of the powered battery electric current of the battery feed circuit in the line circuit of switching system.
Powered battery current monitoring circuit (below be called monitoring circuit) monitors the powered battery electric current of assigning to from the main battery power supply, so that with scanner (SCN), detect unhook state, hook state or dial impulse, and with alarm equipment (ALM), detection of ground faults connects and other abnormal condition with the mistake of battery.In addition, it also detects the situation of powered battery electric current too big when very near (for example when to user's distance) and suppresses this electric current, and carries out many other functions.
The most important part of monitoring circuit is to detect the part of powered battery electric current, but it not only needs to detect forward current, and will detect reverse current.As previously mentioned, even this is because the in-phase signal electrorheological must be bigger than powered battery electric current, to guarantee that also normal voice signal quality can variation.Therefore, not only battery feed circuit itself must possess the function of forward and reverse bidirectional battery power supply, and monitoring circuit also must have the function of forward and reverse bidirectional current detection.In addition, even when considering the reverse battery power supply, also must have the function that detects forward and reverse current.
Figure 19 represents a total switching system, and wherein main battery power pack 5 battery-powered end OUT1 and OUT2 supply with subscriber phone TEL through subscribers feeder A41 and line B42 with the powered battery electric current I.Main battery power pack 5 comprises an operational amplifier, works under proper state for making it, through bias input end B 1And B 2Provide bias voltage by biasing circuit 80.Notice that the input-output of original voice signal AC is partly suitably selected.Among the figure, the part of biasing circuit 80 right side paintings transformers is used as the input-output part.
The powered battery current monitoring circuit is a square frame 300, in its importation resistance 311 and 312 is arranged, and the powered battery electric current I therefrom flows through.As previously mentioned, monitoring circuit 300 and the various functions of the common execution of other group device.So-called other group device is a scanner 170 as shown, alarm equipment 180, or the like.
Figure 20 is the circuit diagram of an example of common monitoring circuit, and subscribers feeder A one side of only having drawn.The structure of subscribers feeder B one side is identical.As shown in the figure, common monitoring circuit 300 comprises two transistor Q 1And Q 2, constant-current source CI detects resistance 311, and voltage/current transfer resistance 321.The periphery is a main battery power pack 5, the subscribers feeder A41 shown in powered battery end OUT1 and Figure 19.When normal forward powered battery electric current I f flows through detection resistance 311, transistor Q 1Detect the voltage V that produces on the resistance, be high impedance, emitter base voltage is by transistor Q 2Compensation, like this, at transistor Q 2Emitter produce above-mentioned voltage V.Its result is proportional to the detection current i of voltage V fThe voltage/current transfer resistance 321 of flowing through, and supply with other co-operation device group 170,180 etc.Attention: supply voltage V BBFor example be-48V that the electric current that flows out from constant-current source always remains unchanged so that make transistor Q 1Be in constant operating state.In addition, i fProvide by following formula:
i f＝R 311/R 312×I f
Wherein, R 311And R 312It is respectively the resistance of resistance 311 and 312.
In the monitoring circuit of Figure 20,, detect current i for desired supervision fFrom transistor Q 2Collector electrode flow to emitter.Yet, a very strong AC induction is arranged here.Therefore, when the in-phase signal electrorheological must be bigger than powered battery electric current I, electric current I r was reverse.In this case, transistor Q 2Must flow through an inverse detection current i rYet transistor can only flow through the electric current of a direction, so i rCan not detect.Even two transistor Q that separate in parallel 1And Q 2Or similar device, so that rightabout electric current is passed through, the scope to voltage V in practical application also limits to some extent, so this is unpractical.After all, in common monitoring circuit, be a difficult problem to the detection of forward and reverse current.
A fourth aspect of the present invention has considered just and has solved such difficult problem that the powered battery current monitoring circuit that it provided can detect the electric current of positive and negative both direction.
Figure 21 is the major part of powered battery current monitoring circuit of the present invention.Among the figure, powered battery current monitoring circuit 300 comprises powered battery current sensing means 320, and it has constituted the major part of circuit; Also comprise and detect current treatment device 330, it carries out needed processing to detected standby current.Powered battery current sensing means 320 comprises one first operational amplifier 322 and one second operational amplifier 323, and their in-phase input end is connected with the two ends of detecting resistance 311 respectively.By totally first base stage of a NPN transistor 325 and a NPN transistor 326 be connected and totally first emitter-base bandgap grading connect and compose first emitter follower circuit 324, it is connected with the output of first operational amplifier 322; One by NPN transistor 328 and PNP transistor 329 carry out totally second base stage and totally second emitter-base bandgap grading connect to form second emitter follower circuit 327, it together the output of second operational amplifier 323 connect.Voltage/stream translation resistance 321 is connected the totally first emitter-base bandgap grading tie point and between the totally second emitter-base bandgap grading tie point, the voltage between these two emitters is become electric current.First emitter is connected with the reverse input end of first operational amplifier 322, and second emitter is connected with the reverse input end of second operational amplifier 323.This device obtains flowing to from NPN transistor 328 the forward detection current i of PNP transistor 326 fWith the inverse detection current i that flows to NPN transistor 325 from PNP transistor 329 r, and with these detection current i fAnd i rSend into and detect current treatment device 320.Its course of work is as described below:
When normal forward powered battery electric current I fWhen flowing through, detect resistance 311 two ends and produce voltage V 0And V 1(V 1＞V 0).Work as V 0And V 1First and second operational amplifiers 322 by having high impedance and 323 o'clock, it is R that these two voltages just appear at transfer resistance 321(resistance 321) two ends.Here, detect electric current and count (V 1-V 0/ R 321), (=R 311/ R 321* I f), flow through the transistor 328 and 326 of first and second emitter follower circuits 324 and 327.
In general, emitter follower circuit does not have voltage gain, but has higher current gain, and collector electrode is directly connected on the power supply.In the present invention, collector electrode is not directly connected on the power supply, and is directly connected on the current treatment device 330.
On the other hand, as reverse battery supply current I rWhen flowing through, appear at the voltage V that detects resistance 311 two ends 0And V 1Become V 1＜V 0, the electric current of the transfer resistance 321 of flowing through is by i fBecome i rAt this moment, detect current i rFlow through the transistor 325 and 329 of first and second emitter follower circuits 324 and 327.
The drawn most preferred embodiment of a powered battery current monitoring circuit of the present invention of Figure 22.The part as powered battery current sensing means 320 of subscribers feeder A41 one side among Figure 21 of not only having drawn, and subscribers feeder B42 one side of having drawn, 320 ' part.Input detects resistance and is 311 '.Forward detects current i FaAnd i FbAnd inverse detection current i RaAnd i RbBy detecting current treatment device 330 at the checkout gear 320 of subscribers feeder A side with in checkout gear 320 ' inflow of subscribers feeder B side, detecting current treatment device 330 has seven current mirror circuits (CM1 to CM7) 410 to 470.They make desired addition, subtraction operation, and the detection electric current after will adding deduct by absolute value circuit (ABS1 and ABS2) and comparison circuit 530 and 540 is delivered to scanner (SCN) and alarm equipment (ALM).
At this moment must understand fully the meaning that in current mirror circuit 410 to 470, adopts addition, subtraction operation.When aforementioned harmful in-phase signal electrorheological gets when too big, just need addition, subtraction operation to be eliminated.
Figure 23 (1), (2), (3), the detection electric current when (4) and (5) expression has the in-phase signal electric current and treated waveform thereof.The subscribers feeder B42 side that is illustrated in Figure 23 (1) detects the quite big of electric current and surpasses i bThe in-phase signal electric current be superimposed upon situation on the dc-battery supply current, the inverse detection of also having drawn current i RbDetect current i with forward FbWaveform.Figure 23 (2) is illustrated in subscribers feeder A41 side and (detects current i a) sizable in-phase signal electric current is superimposed upon the situation on the dc-battery supply current, the forward that also drawn detects current i FaWith the inverse detection current i RaWaveform.These in-phase signal current components will be an impediment to the supervision precision that improves the powered battery battery, so must extract to obtain pure powered battery current component (i a+ i b), shown in Figure 23 (5).For this processing, the forward with subscribers feeder A41 side and B42 side detects current summation earlier.This adds computing (i Fa+ i Fb) provided treated waveform shape among Figure 23 (3).In the waveform of these processing, the undesirable waveform of ledge U, V and W() corresponding to Figure 23 (1) with U, V and W 23(2).
Then, again with the inverse detection current summation of subscribers feeder A41 side and subscribers feeder B42 side.This adds computing (i Ra+ i Rb) provided treated waveform among Figure 23 (4).Undesirable waveform U, V that the waveform of these processing was mentioned above being and W etc.
Therefore, the waveform of Figure 23 (4) is cut from the waveform of Figure 23 (3), to obtain the needed powered battery current component of Figure 23 (5).This is added, subtracts to handle write as arithmetic expression and be:
（i fa+i fb）-（i ra+i rb） （9）
This computing is carried out by detecting current treatment device 330.
First (i of above formula (9) Fa+ i Fb) be circuit mirror current 410 and 420 second end 412 and 422 outflow electric current sum among Figure 22; And second ((i Ra+ i Rb)) be second end 462 of circuit mirror current 460 and 470 and 472 inflow current sum.Notice that circuit mirror current makes the magnitude of current that flows out or flow into first end 411 to 471 equal to flow out or flow into the magnitude of current of corresponding second end 412 to 472.Similarly, circuit mirror current makes the magnitude of current that flows out the 3rd end 413,423 and 443 equal to flow into the magnitude of current of the 3rd end 473 again.Therefore, corresponding to (the i of Figure 23 (5) Fa+ i Fb)-(i Ra+ i Rb) appear at mouthful 560 places.Obtain the absolute value of the electric current at mouthful 560 places at absolute value circuit 510.When comparison circuit 530 detects this value greater than preset value, then think to have a powered battery electric current.Absolute value circuit 510(520 situation with) absolute value located is got is used for carrying out reverse battery and powers.
Figure 24 (1), (2), (3), the detection electric current when there is earth fault in (4) and (5) expression and treated waveform thereof.Example when these figure are illustrated in subscribers feeder A41 side generation earth fault.Electric current when earth fault takes place appears at mouth 550 places of Figure 22, and also can be applied to the battery power supply by absolute value circuit 520() and comparison circuit 540 outputs, be used for driving alarm equipment ALM.
In Figure 24 (1), the powered battery current component is 0(ib=0), only exist with believing in component.In Figure 24 (2), the in-phase signal component is applied, and forms i FaAnd i RaPoor (the i of forward current Fa-i Fb) shown in the waveform of Figure 24 (3), and emphasized the in-phase signal component.In addition, take out the poor (i of reverse current Rb-i Ra) (referring to Figure 24 (4)) be added on the waveform of Figure 24 (3), the in-phase signal component has further been emphasized (referring to Figure 24 (5)).Waveform (5) can be used for the generation of detection of ground faults.Above process is write as arithmetic expression and is:
（i fa-i fb）+（i rb-i ra） （10）
First (i of above formula (10) Fa-i Fb) be the current i that the 3rd end 413 of circuit mirror current 410 flows out from Figure 22 FaCurrent i with second end 452 that flows into circuit mirror current 450 FbSum; And second (i Rb-i Ra) be the current i that the 3rd end 443 of circuit mirror current 440 flows out from Figure 22 RbCurrent i with the 3rd end 473 that flows into circuit mirror current 470 RaSum.They appear at mouthful 550 places.When the absolute value that detects circuit 520 output when comparison circuit 540 surpasses predetermined value, alarm equipment ALM alarm.
Figure 25 is an example of interior flow pattern current mirror circuit, and Figure 26 is an example of outer flow pattern current mirror circuit.The circuit of Figure 27 is similar to the circuit of Figure 26, but more end line is arranged.
As mentioned above, powered battery current monitoring circuit of the present invention can not only detect forward and can detect the reverse battery supply current.
Below current detection circuit will be described, particularly detect the powered battery current detection circuit of the powered battery electric current that from the bidirectional battery power supply circuits, flows out in the line circuit of switching system.
The powered battery current detection circuit monitors the powered battery electric current of assigning to from the main battery power supply with normal powered battery current monitoring circuit, so that with scanner (SCN), detect unhook state, hook state or dial impulse, and, detection of ground faults, connect and other abnormal condition with the mistake of battery with alarm equipment (ALM).In addition, it also detects the situation of powered battery electric current too big when very near (for example when to user's distance) and suppresses this electric current, and carries out many other functions.
In the powered battery current detection circuit, not only need to detect forward current, and will detect reverse current.As previously mentioned, even this is because the in-phase signal electrorheological must be bigger than powered battery electric current, to guarantee that also normal quality of speech signal can variation.In addition, even when considering the reverse battery power supply, also must have the function that detects forward and reverse current.
Figure 28 represents a total switching system, wherein main battery power pack 5 battery-powered end OUT1 and OUT2, give subscriber phone TEL through subscribers feeder A41 and subscribers feeder B42 with the powered battery electric current I.Main battery power pack 5 comprises an operational amplifier, works under proper state for making it, through bias input end B 1And B 2Provide bias voltage by biasing circuit 80.Attention: the input-output of original voice signal AC is partly suitably selected.Among the figure, import an output with capacitance and the i.e. conduct of transformer that end line OUT1 links to each other with OUT2.
The square frame 600(of powered battery current detection circuit of the present invention is corresponding to 320 among Figure 21), in its importation the resistance 311 and 312 of detection is arranged, the powered battery electric current I therefrom flows through.Testing circuit 600 is carried out various functions jointly with detecting current treatment device and other device etc., and its so-called other device is driven sweep device 170, alarm equipment 180, or the like.

Claims (25)

1, a kind of battery feed circuit, it is characterized in that carrying out the dc-battery power supply from the main battery power pack to subscriber phone by subscribers feeder A and B also can be forward and reverse by the powered battery electric current, and described battery feed circuit comprises:
An operational amplifier, it has first trsanscondutance amplifier and second trsanscondutance amplifier, and battery-powered respectively end is connected to subscribers feeder A and B, and this first and second trsanscondutance amplifier has positive input, anti-phase input and output respectively,
First resistance, it is connected between bias input end and the input of described positive,
Second resistance, it is connected between described positive input and the described powered battery end,
The 3rd resistance, it is connected between described output and the described anti-phase input,
The 4th resistance, it is connected between control input end and the described anti-phase input, and
The 5th resistance, it is connected between described powered battery end and the described output.
In described battery feed circuit, described control input end is by capacitor-coupled.
2, a kind of battery feed circuit, it is characterized in that carrying out the dc-battery power supply from a main battery power pack to subscriber phone by subscribers feeder A and B also can be forward and reverse by the powered battery electric current, and described battery feed circuit has:
A biasing circuit is used to described main battery power pack that bias voltage is provided,
Described biasing circuit comprises:
Bias voltage generation device with high output impedance;
A low output impedance buffer unit is used to receive the bias voltage of described bias voltage generation device output and it is delivered to described main battery power pack, and
One exchanges shunt capacitance, and it is connected between described output point and the ground E.
3, according to the powered battery shunt of claim 2, it is characterized in that described bias generating circuit comprises one one end and power supply V BBThe current source that links to each other, one one end and reference voltage source V BRFirst resistance that links to each other, other end of described current source is connected in series with other end of described first resistance and is connected in series a little as described output point.
4, according to the battery feed circuit of claim 3, it is characterized in that, one first bias voltage generation device is equipped with in described subscribers feeder A side, one first buffer unit exchanges shunt capacitance with one first, one second bias voltage generation device is equipped with in described subscribers feeder B side with spline structure, one second buffer unit exchanges shunt capacitance with one second, and
First current source and second current source that forms the described second bias voltage generation device that forms the described first bias voltage generation device, they are driven selectively.
5, battery feed circuit according to claim 4, it is characterized in that, described first and second current sources comprise first and second current mirror circuits and reference current generation device respectively, be used to produce the reference current that its value equals bias current, described bias current is by first and second resistance of described bias voltage generation device, and described reference current is by terminal separately of described first and second current mirror circuits, described first and second current sources also have a current switching device, and being used for selectively, the described reference current of gating arrives one of other end of described first and second current mirror circuits.
6, according to the battery feed circuit of claim 5, it is characterized in that described reference current generation device comprises one the 3rd current mirror circuit, its end links to each other with described current switching device, one the 3rd resistance, it is connected on the other end and the described power supply V of described the 3rd current mirror circuit BBBetween, and the transistor of a base earth (E).
According to the battery feed circuit of claim 6, it is characterized in that 7, described current switching device comprises a current switch, it is made of a pair of transistor that is connected in the other end of described first and second current mirror circuits.
According to the battery feed circuit of claim 4, it is characterized in that 8, described first and second buffer units are made of first and second voltage follower circuits.
9, a kind of battery feed circuit can carry out the dc-battery power supply from a main battery power pack to subscriber phone by subscribers feeder A and B, and can be forward and reverse by the powered battery electric current, wherein:
Described main battery power pack has a powered battery current control circuit, and it receives bias voltage and a predetermined battery supply current is supplied with described phone from a biasing circuit, thereby described powered battery electric current I is controlled,
Described powered battery current control circuit comprises:
A powered battery current sensing means is used to detect the amplitude of described powered battery electric current I,
An overload current checkout gear is higher than predetermined value I when detecting the powered battery electric current I ThThe time, the component △ I of overload current is detected,
A bias control device is used for changing described bias voltage V according to detected overload current component △ I B1, V B2,
Along with the increase of overload current component △ I, the increment of described powered battery electric current I diminishes.
10, according to the battery feed circuit of claim 9, it is characterized in that, described overload current checkout gear comprises one first current mirror circuit, it has one first end, one with the proportional detection electric current of the detected powered battery electric current of described powered battery current sensing means this end of flowing through, and one second end, by that constant-current source produced and the described constant current i of predetermined value Ith directly proportional described powered battery electric current ThThis end of flowing through, and, at described second end and constant current i ThBetween difference be used to detect overload current △ i corresponding to described overload current component △ I.
According to the battery feed circuit of claim 10, it is characterized in that 11, described bias control device comprises:
One second current mirror circuit, it has first end that can draw from overload current △ i, this overload current △ i is corresponding to the detected overload current component of described overload current checkout gear △ I, one can equal second end of drawing the Control current of overload current △ i from its value, and this overload current △ i is used to change the bias voltage V of described biasing circuit B1Or V B2, and the 3rd end that can from its value and electric current that another electric current equates, draw, and,
One the 3rd current mirror circuit, it has first end and exportable its value that electric current can be delivered to described the 3rd end to equal the electric current of described electric current and change described bias voltage V B1Or V B2Second end.
12, according to the battery feed circuit of claim 11, it is characterized in that, one transistor seconds is arranged, the electric current of described Control current that it can equal its value to flow into second end of described second current mirror circuit is sent to the 3rd end, and wherein said first and second transistors are by its emitter-base bandgap grading coupling formation current switch.
According to the battery feed circuit of claim 11, it is characterized in that 13, the transistor that forms current switch pair links to each other with second end of described the 3rd current mirror circuit and the bias voltage of wherein said Current Control by second end is confirmed as bias voltage V B2Or V B1
14, a kind of battery feed circuit is characterized in that and can carry out the dc-battery power supply from a main battery power pack to a subscriber phone by subscribers feeder A and B, and can be forward and reverse by the powered battery electric current,
Described battery feed circuit has a powered battery current monitoring circuit, it detects current treatment device by one, and the first and second powered battery checkout gears that detect respectively by subscribers feeder A and the powered battery electric current of P from the main battery power pack to described subscriber phone constitute, described detection current treatment device is carried out the detection electric current of necessary processing to monitor that the described first and second powered battery current sensing meanss are detected
The described first and second powered battery current sensing meanss comprise:
First operational amplifier and second operational amplifier, their normal phase input end cross-over connection be in the detection resistance by described powered battery electric current,
One first and second emitter follower circuit comprises emitter coupled NPN and PNP transistor, and its base stage links to each other with the output of described first and second operational amplifiers,
The emitter-base bandgap grading Coupling point links to each other with the reverse input of described first and second operational amplifiers, and links to each other with the voltage/current transfer resistance,
Described detection current treatment device uses the electric current of described first and second emitter follower circuits of flowing through as described detection electric current.
15, according to the battery feed circuit of claim 14, it is characterized in that, the input of described detection current treatment device receives four Control current, promptly respectively at the forward and reverse detection electric current of subscribers feeder A side and B side, this device also has one to add one and subtract device, be used for these predetermined combinations that detects electric currents are summed up and subtract processing, and its result is used for monitoring.
According to the battery feed circuit of claim 15, it is characterized in that 16, described adder-subtracter comprises a plurality of current mirror lines, so that in predetermined two kinds of described four kinds of detection electric currents, add processing or in being scheduled to two kinds in addition, subtract processing.
17, according to the battery feed circuit of claim 16, it is characterized in that having first and second absolute value circuits, it is got and describedly adds one and subtract the absolute value that device adds, subtracts result, and whether surpasses predetermined value by the output that detects described absolute value and carry out described supervision.
18, a kind of battery feed circuit is characterized in that and can carry out the dc-battery power supply from a main electric welding power pack to subscriber phone by subscribers feeder A and B, and can be forward and reverse by the powered battery electric current,
Described battery feed circuit has a powered battery current detection circuit, and it has the detection resistance of a detection forward and reverse battery supply current I,
Described powered battery current detection circuit comprises:
One first checkout gear, it comprises a NPN and a PNP transistor, first cancellation element of eliminating described NPN and PNP transistor base one emitter voltage, this first checkout gear is in forward powered battery electric current I fBy the time monitor the terminal voltage of described detection resistance and this voltage delivered to first monitoring resistor, detect electric current I thereby produce a forward f,
One second checkout gear, it comprises-NPN and-the PNP transistor, and be used to eliminate second of described NPN and PNP transistor base one emitter voltage and eliminate circuit, this second checkout gear is at reverse battery supply current I rThereby by the time monitor the terminal voltage of described detection resistance and this voltage be added to second monitoring resistor and produce the inverse detection current i r
19, according to the battery feed circuit of claim 18, it is characterized in that, described first checkout gear comprises one first NPN transistor and one the one PNP transistor, described second checkout gear comprises one second NPN transistor and one the 2nd PNP transistor, and the described first and second PNP transistor common bases connect and link to each other with an end of described detection resistance.
According to the battery feed circuit of claim 19, it is characterized in that 20, circulated respectively described forward of a described NNPN transistor and second NPN transistor detects electric current I fWith described inverse detection current i r
21, according to the battery feed circuit of claim 20, it is characterized in that,
Described first cancellation element comprises one the 3rd NPN transistor that connects with the diode form, the 3rd a PNP transistor that connects with the diode form, and first constant-current source that bias current is provided, it provides bias current for described first NPN transistor and produces the transistorized basic emitter voltage of described the 3rd PNP, and
Described second cancellation element comprises one the 4th NPN transistor that connects with the diode form, one the 4th PNP transistor that connects series connection with it with the diode form, second constant-current source that bias current is provided, it provides base current and provides a basic emitter voltage for described the 4th NPN and PNP transistor for described second NPN transistor
The 4th NPN of described series connection and PNP transistor are plugged on the base stage of described second NPN transistor and other ends of described detection resistance.
22, according to the battery feed circuit of claim 1; it is characterized in that having an overload current protective circuit; by detecting an overload current checkout gear of excessive powered battery electric current, protect described main battery power pack to exempt from the damage of excessive powered battery electric current
Described overload current protective circuit comprises:
First and second device for generating voltage, it is serially connected with between the reverse and positive input of the described operational amplifier that forms described first trsanscondutance amplifier, and produces a predetermined constant voltage VL, and
First and second switching devices,
The operating state of described first and second switching devices is controlled by described overload current checkout gear.
According to the battery feed circuit of claim 22, it is characterized in that 23, described first and second device for generating voltage comprise one first diode bridge,
Described first and second switching devices comprise the first transistor switch that can pass through by the described first diode bridge rectified current, and
The operating state of described transistor switch is controlled by described overload current checkout gear.
24, according to the battery feed circuit of claim 22, it is characterized in that it comprises third and fourth device for generating voltage, it is serially connected with between the anti-phase and normal phase input end of the described operational amplifier that forms described second trsanscondutance amplifier, and produces a predetermined constant voltage V L, and
Third and fourth switching device,
The operating state of described third and fourth switching device is controlled by described overload current checkout gear.
According to the battery feed circuit of claim 24, it is characterized in that 25, described third and fourth device for generating voltage comprises one second diode bridge,
Described third and fourth switching device comprises a transistor seconds, can flow through by the electric current after the described second diode bridge rectification in it, and
Described transistor seconds switch working state is controlled by described overload current checkout gear.
CN 88103656 1987-06-17 1988-06-17 Battery feed circuit Expired CN1011653B (en)

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
JP149264/87 1987-06-17
JP149268/87 1987-06-17
JP149265/87 1987-06-17
JP62149266A JPS63314060A (en) 1987-06-17 1987-06-17 Power feeding circuit
JP149266/87 1987-06-17
JP62149264A JPS63314471A (en) 1987-06-17 1987-06-17 Feeder current monitoring circuit
JP62149268A JPH0638625B2 (en) 1987-06-17 1987-06-17 Supply current control circuit
JP62149265A JPH0638624B2 (en) 1987-06-17 1987-06-17 Bias circuit for power supply circuit

Publications (2)

Publication Number Publication Date
CN1030334A true CN1030334A (en) 1989-01-11
CN1011653B CN1011653B (en) 1991-02-13

Family

ID=27472920

Family Applications (1)

Application Number Title Priority Date Filing Date
CN 88103656 Expired CN1011653B (en) 1987-06-17 1988-06-17 Battery feed circuit

Country Status (1)

Country Link
CN (1) CN1011653B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1396918A2 (en) * 2002-09-06 2004-03-10 Bae Systems Controls, Inc. Ground fault detection system
CN103837732A (en) * 2014-03-21 2014-06-04 上海富欣智能交通控制有限公司 Passive current detecting circuit

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1396918A2 (en) * 2002-09-06 2004-03-10 Bae Systems Controls, Inc. Ground fault detection system
CN103837732A (en) * 2014-03-21 2014-06-04 上海富欣智能交通控制有限公司 Passive current detecting circuit
CN103837732B (en) * 2014-03-21 2017-07-18 上海富欣智能交通控制有限公司 Passive current detection circuit

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Publication number Publication date
CN1011653B (en) 1991-02-13

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