CN103558898A - Transient accelerating circuit of current mirror - Google Patents
Transient accelerating circuit of current mirror Download PDFInfo
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- CN103558898A CN103558898A CN201310509553.5A CN201310509553A CN103558898A CN 103558898 A CN103558898 A CN 103558898A CN 201310509553 A CN201310509553 A CN 201310509553A CN 103558898 A CN103558898 A CN 103558898A
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- current mirror
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Abstract
Disclosed is a transient accelerating circuit of a current mirror. The starting of an excitation current enables transient transitional intervals to be greatly increased. An increased current immediately changes the load capacitance of the circuit, and therefore, the starting time is reduced.
Description
Technical field
Current mirror is widely used in integrated circuit (IC) equipment.They be mainly to work in so-called electric current groove is converted to the go to circuit of current source, vice versa.Such action has changed circuit voltage, then just obtained very large level shift, and without loss direct current datum.
Background technology
In some circuit application, particularly those drive in the circuit of capacity loads, the startup of accelerating circuit, and in the later very of short duration time, to provide a current over pulse to increase switching rate be very useful starting.Such application can be used as the driving of switchgear in adjusting and voltage-reduction switch formula source of stable pressure, also can be used as the base stage discharge portion of the power switch transistor of grounded emitter.
Summary of the invention
An object of the present invention is to provide a current mirror transition accelerating circuit;
Another object of the present invention is to provide a current mirroring circuit, and this circuit has a momentary current overshoot output when it starts for the first time.
Technical solution of the present invention is:
These and other object reaches by following content.Pair of transistor is coupled together and forms a current mirror.They according to size, provide required current mirror gain.Transistorized base stage links together by a pair of resistance, and the resistance of resistance and the gain of current mirror are inversely proportional to.That is to say that larger resistance is corresponding to lower current transistor.Because the base stage of emitter follower is coupling on input crystal pipe collector, emitter-coupled, in the junction of two grounded base transistors, has been set up negative feedback, so the collector current of input transistors equals the input current of current mirror.A capacitive coupling is between the emitter and base stage of current mirror input transistor, and a diode-coupled is between resistance tie point and the base stage of current mirror output transistor.When emitter follower is worked, diode is just along polarity conducting.Two output transistor structures are through careful consideration.The first, emitter follower collector is directly got back to suitable power end, forms super strong type diode current mirror.The second, the emitter of emitter follower is also coupling on the collector of current mirror output transistor, and the collector of emitter follower, just with the form of Wilson type current mirror, has become the output terminal of current mirror.When circuit starts for the first time, input transistors base stage is not charged to the electric capacity of emitter, and input transistors will remain off state, until capacitor charging.Under such condition, current mirror input current will be transferred on output transistor by diode.This can produce a current transients when high current gain.This action will provide the zooming transient current pulse output of an abundant overshoot when starting.Then,, after of short duration transition interval, the electric capacity of input transistors charges to input transistors conducting gradually.At this moment, circuit just becomes conventional current mirror.
Contrast patent documentation: CN201134057Y current mirror start-up circuit 200720077886.5 of realizing with SELF-CASCODE, CN201765527U self-adaptive current mirror 201020273665.7.
Accompanying drawing explanation:
Fig. 1 is the schematic diagram of circuit of the present invention;
Fig. 2 is the curve map of circuit electric property in Fig. 1;
Fig. 3 is the schematic diagram of an optional example of the present invention;
Fig. 4 is a schematic diagram that can use the power transistor in Fig. 1 or Fig. 3 circuit;
Fig. 5 is the circuit working schematic diagram by voltage-controlled differential signal current source.
Embodiment:
Schematic diagram in Fig. 1 has been shown the PNP transistor key concept that the present invention uses.It will be appreciated that, when PNP transistor is shown and described, use the supplementary form of the circuit of NPN transistor also can be used.Current mirror is by a power supply being connected on terminal 10 and earth terminal 11
power supply.At circuit input end 12 places, provide an input current, this electric current just can mirror image symmetry to output terminal 13.Input
by a constant flow element 14, provided, its connecting and disconnecting are controlled by switch 15.In ensuing discussion, we suppose the transistor that adopts β larger, and base current just can be ignored with respect to collector current like this.When β is greater than 100, base current just can be less than 1% of collector current, and such being similar to is effective for first-order system.
Transistorized base stage links together by the resistance 18 and 19 of series connection.The ratio of these two resistances is identical with the correlative factor of transistor 16 and 17,
.Therefore,, when work, resistance 18 is identical and reverse with the pressure drop on 19.Electric capacity 20 has formed a low-pass filter with resistance 19.When the emitter-base capacity of transistor 16 is full of electricity, namely conventionally use in the situation of lateral transistor structure, physics electric capacity 20 can omit.Diode 21 is in parallel with resistance 18, and along polar orientation, is switched on during by pulse conducting at transistor.Pressure drop on resistance 18 is less than diode drop after starting transition, and therefore, diode 21 is on the not impact of the steady operation of circuit.
When switch 15 is opened, the input at node 12 places
be zero.Circuit is not switched on, and all transistors all end, the output at terminal 13 places
also be zero.
When switch 15 closures,
will flow out node 12, transistor 22 will be switched on.Its emitter current meeting conducting diode 21 and transistor 17, terminal 13 places will produce a large output like this
.Can see, transition overshoot produces an initial peak currents.Because transition has comprised the cascade current gain of transistor 22 and 17, so, most of electric current that terminal 13 places are flow through will be limited due to the saturated of transistor 17, and remainder can be limited by the time constant of the current gain of transistor 16 and the low-pass filter consisting of resistance 19 and electric capacity 20 again.In transient state interim, electric capacity 20 is charging constantly, and after reasonable time interval, transistor 16 will conducting,
also just can be switched on.Once this thing happens, transistor 16 will be as the input element of current mirror, and has determined output current
for
n doubly.Transistor 22 provides superpower gain current mirror function, and diode 21 is no longer conducting also.The delay that the low-pass filter that the duration of transient overshoot is comprised of resistance 19 and electric capacity 20 is introduced determines.
Current transient discussed above provides sufficient acceleration for output voltage is increased to startup value.This current mirror be used for fast driving capacitive load or be used as switching regulator in be very important during the driver of power switch.
Fig. 3 is the schematic diagram of an optional example of the present invention.Comprised same element, and coding is identical with Fig. 1.Resistance 18 and 19 contact turn back to the collector of transistor 17, and it is worked as a diode.The base stage of transistor 23 is connected on node 12, and emitter turns back to the contact of resistance 18 and 19, therefore the collector current of transistor 16 is equaled
.The collector of transistor 23 provides circuit output at terminal 13 places
.This has formed the Wilson current-mirror structure that we know.
The main difference of Fig. 3 and Fig. 1 is to start transient state, and only a transistorized β 13 of node 12 and terminals works.Equally, transistor 23 works together with transistor 17, and like this, any load being coupling on terminal 13 is just independent with the output transistor of current mirror, and the output resistance of circuit increases greatly.When transistor 23 conducting, starting between transient period, it also conducting diode 21, simultaneously also conducting transistor 17.
Fig. 4 has shown a power transistor 24 that can be connected to circuit emitter in Fig. 3 and Fig. 1, is used for increasing the driving force of output current.Its base stage is coupling on terminal 13, and collector turns back to terminal 10 places
.Emitter 13 ' becomes the output node of circuit.In circuit, had transistor 24, the output driving current that terminal 13 ' is located will increase greatly.
Fig. 5 has shown how Fig. 1 circuit sets up the principle of work of controlled voltage.In figure, similar part has adopted identical numbering.
Switch 15 in Fig. 1 is replaced by a difference control circuit.
current source 14 is coupling on the emitter of transistor 26-29.The base stage of transistor 26 is coupling in
on power supply 30.The emitter of transistor 27-29 is coupling on current source 14 by shunt resistance 31-33 respectively.The base stage of transistor 27-29 is coupling on switch 34, and this switch can select to access source of stable pressure 35 or source of stable pressure 36, the voltage of source of stable pressure 35 higher than
, the voltage of source of stable pressure 36 lower than
.
When switch 34 is allocated to lower or the position of ON, transistor 26 will conducting
to node 12 places, therefore also just started current mirror.In this case, transistor 27-29 all can end.Current mirror by the current mirror symmetry of power supply 14 to terminal 13.
When switch is allocated to higher or OFF position, transistor 26 will end, and transistor 27-29 will conducting.Resistance 31-33 will distribute in transistor 27-29
.These three electric currents will turn-on transistor 40-42.The voltage that transistor 40 draws high node 12 places extremely
.Therefore, transistor 40-42 just can guarantee that current mirror closes when switch 34 is allocated to OFF position.Resistance 37-39 just can guarantee that transistor 40-42 ends when switch 34 is allocated to ON position.
In Fig. 5, the function of circuit is similar with Fig. 3 to Fig. 1.Equally, the power transistor in Fig. 4 can be connected in the circuit of Fig. 5, with this, increases the performance of output current.
The principle according to the present invention, people can find, it can also be applied to other circuit, also there is additive method available simultaneously, for example: in Fig. 1, transistor 22 can dispense, resistance 18 and 19 can directly link together, receive on the collector of transistor 16, form a conventional current mirror structure.For purposes of illustration, the present invention is unrestricted, limited by claim of the present invention.
Claims (6)
1. a current mirror transition accelerating circuit, it is characterized in that: a current mirror with diode, its diode is coupling in the transistorized input transistors of driver output on current input signal, the terminal that acceleration output current starts and the terminal that a large amount of transient overshoots are provided respond the startup of above-mentioned current input signal, comprising: the terminal by above-mentioned current input signal direct-coupling on above-mentioned output transistor; Postpone the terminal that above-mentioned input transistors starts.
2. a kind of current mirror transition accelerating circuit according to claim 1, it is characterized in that: the diode terminal of the above-mentioned input transistors that is coupled comprises an emitter follower, they link together, and the base stage of above-mentioned input transistors are coupled on its collector.
3. a kind of current mirror transition accelerating circuit according to claim 1, it is characterized in that: the diode terminal of the above-mentioned input transistors that is coupled comprises connection above-mentioned output transistor and a transistorized diode being connected with above-mentioned output transistor cascade, the transistorized base stage that above-mentioned cascade connects is coupling in the collector of above-mentioned input transistors, emitter-coupled is at the collector of above-mentioned output transistor, and collector coupled provides the output current of above-mentioned current mirror together.
4. according to a kind of current mirror transition accelerating circuit described in claim 2 or 3, it is characterized in that: above-mentionedly for the terminal postponing, comprise a resistance-capacitance type low-pass filter, connect with the base stage of above-mentioned input transistors.
5. a kind of current mirror transition accelerating circuit according to claim 4, it is characterized in that: second resistance is connected with the base stage of above-mentioned output transistor, a diode is in parallel with above-mentioned resistance, when above-mentioned emitter-follower transistor conducting, diode is also conducting in polar orientation, because the value of above-mentioned the second resistance is chosen, so above-mentioned diode is can On current after the transition period starting.
6. a kind of current mirror transition accelerating circuit according to claim 5, is characterized in that: above-mentioned the second resistance and the above-mentioned resistance gaining in the terminal that postpones to operate by mirror currents are inversely proportional to.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310509553.5A CN103558898A (en) | 2013-10-25 | 2013-10-25 | Transient accelerating circuit of current mirror |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310509553.5A CN103558898A (en) | 2013-10-25 | 2013-10-25 | Transient accelerating circuit of current mirror |
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| CN103558898A true CN103558898A (en) | 2014-02-05 |
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| CN201310509553.5A Pending CN103558898A (en) | 2013-10-25 | 2013-10-25 | Transient accelerating circuit of current mirror |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102021125648A1 (en) | 2021-10-04 | 2023-04-06 | Infineon Technologies Ag | CURRENT MIRROR CIRCUIT |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4645999A (en) * | 1986-02-07 | 1987-02-24 | National Semiconductor Corporation | Current mirror transient speed up circuit |
| CN1748363A (en) * | 2003-02-10 | 2006-03-15 | 因芬尼昂技术股份公司 | Circuit arrangement and method for the accelerated switching over of an amplifier |
| JP2007215127A (en) * | 2006-02-13 | 2007-08-23 | New Japan Radio Co Ltd | Operational amplifier |
| CN101116248A (en) * | 2004-12-13 | 2008-01-30 | 睦塞德技术公司 | Phase-locked loop circuitry using charge pumps with current mirror circuitry |
-
2013
- 2013-10-25 CN CN201310509553.5A patent/CN103558898A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4645999A (en) * | 1986-02-07 | 1987-02-24 | National Semiconductor Corporation | Current mirror transient speed up circuit |
| CN1748363A (en) * | 2003-02-10 | 2006-03-15 | 因芬尼昂技术股份公司 | Circuit arrangement and method for the accelerated switching over of an amplifier |
| CN101116248A (en) * | 2004-12-13 | 2008-01-30 | 睦塞德技术公司 | Phase-locked loop circuitry using charge pumps with current mirror circuitry |
| JP2007215127A (en) * | 2006-02-13 | 2007-08-23 | New Japan Radio Co Ltd | Operational amplifier |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102021125648A1 (en) | 2021-10-04 | 2023-04-06 | Infineon Technologies Ag | CURRENT MIRROR CIRCUIT |
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Application publication date: 20140205 |
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