CN208707073U - Low-voltage space precision current mirror image circuit applied to laser driver - Google Patents
Low-voltage space precision current mirror image circuit applied to laser driver Download PDFInfo
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- CN208707073U CN208707073U CN201821527433.2U CN201821527433U CN208707073U CN 208707073 U CN208707073 U CN 208707073U CN 201821527433 U CN201821527433 U CN 201821527433U CN 208707073 U CN208707073 U CN 208707073U
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Abstract
The utility model provides a kind of low-voltage space precision current mirror image circuit applied to laser driver, including reference current detection unit, tail current source unit and control unit；Reference current detection unit couples reference current source, generates bias voltage and reference voltage for receiving the reference current of reference current source, and according to reference current；Tail current source unit couples reference current detection unit, for receiving and generating image current according to bias voltage；Control unit couples reference current detection unit and tail current source unit, for receiving and carrying out feedback regulation to the bias voltage that reference current detection unit exports according to reference voltage and the corresponding output voltage of image current.The utility model generates bias voltage by reference to voltage Vn and output voltage Vp feedback regulation, image current is generated by bias voltage mirror image again to export to laser, so as to avoid under low-voltage space, control unit imbalance inaccurate problem is exported with incoming current.
Description
Technical field
The utility model relates to laser actuation techniques field, in particular to a kind of low-voltage applied to laser driver
Space precision current mirror image circuit.
Background technique
The driving method of laser can be divided into common-anode driving and common cathode drives two ways.Common-anode driving method
With higher working efficiency, as shown in Figure 1, determining to flow through the variable quantity of the electric current of laser D0 by tail current source, also referred to as
Modulate electric current.The difference of the optical power emitted as needed usually modulates electric current at several milliamperes to dozens or even hundreds of milliampere
Variation in range.
However, the voltage space needs of tail current source are lower than under traditional 3.3V (2.97V~3.63V) supply voltage
0.3V is influenced by voltage space is insufficient, it is difficult to realize accurate modulation current control.
Fig. 2 show the current mirror circuit of certain traditional tail current control method, is made by error amplifier A0
The voltage Vp at the both ends voltage Vn and resistance R1~Rm at the both ends resistance R0 is approximately equal, to obtain tail current im=mi0.This
The major defect of kind method is that the offset voltage of error amplifier has a direct impact the precision of electric current.Especially i0It is smaller,
In the case that the voltage of Vp and Vn is very low, the error introduced by offset voltage of amplifier is it is even possible that current control is lost completely
Effect.Therefore additional circuit is needed to eliminate offset voltage of amplifier, to increase design complexities.
Utility model content
The utility model provides a kind of low-voltage space precision current mirror image circuit applied to laser driver, solves existing
There is above-mentioned problem.
To solve the above problems, the utility model embodiment provides a kind of low-voltage space essence applied to laser driver
True current mirror circuit, including reference current detection unit, tail current source unit and control unit；
The reference current detection unit couples reference current source, for receiving the reference current of reference current source, and root
Bias voltage and reference voltage are generated according to reference current；
The tail current source unit couples the reference current detection unit, for receiving and being generated according to bias voltage
Image current；
Described control unit couples the reference current detection unit and the tail current source unit, for receiving simultaneously root
The bias voltage that the reference current detection unit exports is carried out according to reference voltage and image current corresponding output voltage anti-
Feedback is adjusted.
As an implementation, the tail current source unit includes several groups tail current source module, tail described in several groups
Current source module includes feedback resistance and NPN triode, and described feedback resistance one end couples the reference current detection unit
Output end, for receiving bias voltage, the other end of the feedback resistance couples the base stage of the NPN triode, the NPN
One input terminal of the collector coupling described control unit of triode, the emitter ground connection of the NPN triode.
As an implementation, the reference current detection unit include the first metal-oxide-semiconductor, the first NPN triode and
Biasing resistor, the drain electrode of first metal-oxide-semiconductor couple reference current source, and it is single that the grid of first metal-oxide-semiconductor couples the control
The output end of member, the source electrode of first metal-oxide-semiconductor couple the collector of first NPN triode, first NPN triode
Base stage couple one end of the biasing resistor, the first NPN triode emitter ground connection, the other end of the biasing resistor
Couple the tail current source unit.
As an implementation, the reference current detection unit further includes the second metal-oxide-semiconductor, second metal-oxide-semiconductor
Drain electrode coupling supply voltage, the grid of second metal-oxide-semiconductor couple the drain electrode of first metal-oxide-semiconductor, the source of second metal-oxide-semiconductor
Pole couples the connecting node of the reference current detection unit and described control unit.
As an implementation, described control unit includes error amplifier, and the error amplifier includes two defeated
Enter end and an output end, one of input terminal couples the output end of the tail current source unit, described in another input terminal coupling
The connecting node of first metal-oxide-semiconductor and the first NPN triode, output end couple the grid of first metal-oxide-semiconductor.
As an implementation, the reference current detection unit includes biasing resistor, if the tail current source includes
Dry feedback resistance, the biasing resistor and the feedback resistance are same model.
The beneficial effects of the utility model compared with the prior art lie in: it is fed back by reference to voltage Vn and output voltage Vp
It adjusts and generates bias voltage, then image current is generated by bias voltage mirror image and is exported to laser, so as to avoid in low-voltage
Under space, control unit imbalance inaccurate problem is exported with incoming current.
Detailed description of the invention
Fig. 1 is the circuit diagram of the laser driving circuit of the prior art；
Fig. 2 is the circuit diagram of the current mirror circuit of the prior art；
Fig. 3 is the circuit of the low-voltage space precision current mirror image circuit applied to laser driver of the utility model
Figure.
Attached drawing mark: 1, reference current detection unit；2, tail current source unit；3, control unit.
Specific embodiment
Below in conjunction with attached drawing, the above and other technical features and advantages of the present invention are carried out clearly and completely
Description, it is clear that described embodiment is only the section Example of the utility model, rather than whole embodiments.
As shown in figure 3, a kind of low-voltage space precision current mirror image circuit applied to laser driver, including reference electricity
Flow detection unit 1, tail current source unit 2 and control unit 3；Reference current detection unit 1 couples reference current source, for connecing
Receive the reference current i of reference current source0, and bias voltage Vr and reference voltage Vn is generated according to reference current；Tail current source list
Member 2 couples reference current detection unit 1, for receiving and generating image current i according to bias voltage Vrm；Control unit 3 couples
Reference current detection unit 1 and tail current source unit 2, for receiving and according to reference voltage Vn and the corresponding output of image current
Voltage Vp carries out feedback regulation to the bias voltage Vr that reference current detection unit 1 exports.
Reference current detection unit 1 includes the first metal-oxide-semiconductor M1, the first NPN triode B1 and biasing resistor R1, and first
The drain electrode of metal-oxide-semiconductor M1 couples reference current source, the output end of the grid coupling control unit of the first metal-oxide-semiconductor M1, the first metal-oxide-semiconductor M1
Source electrode couple the first NPN triode B1 collector, the first NPN triode B1 base stage coupling biasing resistor R1 one end,
The other end of first NPN triode B1 emitter ground connection, biasing resistor R1 couples tail current source unit.First metal-oxide-semiconductor M1, first
NPN triode B1 and biasing resistor R1 forms feedback loop, guarantees loop stability.
In addition to this, reference current detection unit 1 further includes the drain electrode coupling power supply of the second metal-oxide-semiconductor M2, the second metal-oxide-semiconductor M2
The grid of voltage VDD, the second metal-oxide-semiconductor M2 couple the drain electrode of the first metal-oxide-semiconductor M1, and the source electrode of the second metal-oxide-semiconductor M2 couples reference current
The connecting node of detection unit 1 and control unit 3, the second metal-oxide-semiconductor M2 are used to provide base current for the first NPN triode B1.
Tail current source unit 2 includes several groups tail current source module, and several groups tail current source module includes feedback resistance
And NPN triode, feedback resistance one end couple the output end of reference current detection unit, for receiving bias voltage, feedback electricity
The base stage of the other end coupling NPN triode of resistance, an input terminal of the collector coupling control unit of NPN triode, tri- pole NPN
The emitter of pipe is grounded.In the present embodiment, the R2 in figure and B2 is corresponding feedback resistance and NPN triode in one group, because
This, tail current source unit includes feedback resistance R2~Rm and NPN triode B2~Bm corresponding with feedback resistance.Several groups tail electricity
The bias voltage Vr that stream source module collective effect generates the output of reference current detection unit corresponds to image current im.Also, it biases
Resistance R1 and feedback resistance R2~Rm be same model, NPN triode B1~Bm be same model, feedback resistance R2~Rm and
Biasing resistor R1 in reference current detection unit is used to reduce the mismatch problems between NPN triode B1 and B2~Bm.
Control unit 3 includes error amplifier A1, and error amplifier A1 includes two input terminals and an output end, wherein one
The output end of a input terminal coupling tail current source unit 2, the company of another input terminal coupling the first metal-oxide-semiconductor and the first NPN triode
Node is connect, output end couples the grid of the first metal-oxide-semiconductor.Since two input terminals of error amplifier A1 couple the grid of metal-oxide-semiconductor
Pole, thus, there is no current paths.
Error amplifier A1 exists the collector voltage Vp lock of the collector voltage Vn of the first NPN triode B1 and B2~Bm
Same potential, therefore guarantee three ends and the B2~Bm level having the same of the first NPN triode B1, in the present embodiment, by
The current lens unit of first NPN triode B1 and there are the relationships of 1:m by the current lens unit of NPN triode B2~Bm, so,
Accurate image current i is generated in tail current source unit output endm=mi0。
Since the voltage value of reference voltage Vn and output voltage Vp are with reference current i0With image current imChange it is unobvious,
Even if reference current i0Very little, reference voltage Vn and output voltage Vp remain at 0.3V or so, therefore error amplifier A1
Influence of the offset voltage to image current precision can be ignored.
The utility model mutually passes through reference voltage Vn and output voltage Vp feedback regulation generates bias voltage, then by biased electrical
Pressure mirror image generates image current and exports to laser, and so as to avoid under low-voltage space, control unit imbalance institute is with incoming call
Stream exports inaccurate problem.
Particular embodiments described above has carried out into one the purpose of this utility model, technical scheme and beneficial effects
The detailed description of step, it should be understood that the foregoing is merely specific embodiment of the utility model, be not used to limit this reality
With novel protection scope.Particularly point out, to those skilled in the art, it is all the spirit and principles of the utility model it
Any modification, equivalent substitution, improvement and etc. that are interior, being done, should be included within the scope of protection of this utility model.
Claims (6)
1. a kind of low-voltage space precision current mirror image circuit applied to laser driver, which is characterized in that including reference electricity
Flow detection unit, tail current source unit and control unit；
The reference current detection unit couples reference current source, for receiving the reference current of reference current source, and according to ginseng
It examines electric current and generates bias voltage and reference voltage；
The tail current source unit couples the reference current detection unit, for receiving and generating mirror image according to bias voltage
Electric current；
Described control unit couples the reference current detection unit and the tail current source unit, for receiving and according to ginseng
It examines the bias voltage that voltage and the corresponding output voltage of image current export the reference current detection unit and carries out feedback tune
Section.
2. the low-voltage space precision current mirror image circuit according to claim 1 applied to laser driver, feature
It is, the tail current source unit includes several groups tail current source module, and tail current source module described in several groups includes feedback
Resistance and NPN triode, described feedback resistance one end couple the output end of the reference current detection unit, for receiving biasing
Voltage, the other end of the feedback resistance couple the base stage of the NPN triode, and the collector of the NPN triode couples institute
State an input terminal of control unit, the emitter ground connection of the NPN triode.
3. the low-voltage space precision current mirror image circuit according to claim 1 applied to laser driver, feature
It is, the reference current detection unit includes the first metal-oxide-semiconductor, the first NPN triode and biasing resistor, the first MOS
The drain electrode coupling reference current source of pipe, the output end of the grid coupling described control unit of first metal-oxide-semiconductor, described first
The source electrode of metal-oxide-semiconductor couples the collector of first NPN triode, and the base stage of first NPN triode couples the biasing
One end of resistance, the first NPN triode emitter ground connection, the other end of the biasing resistor couple the tail current source list
Member.
4. the low-voltage space precision current mirror image circuit according to claim 3 applied to laser driver, feature
It is, the reference current detection unit further includes the second metal-oxide-semiconductor, and the drain electrode of second metal-oxide-semiconductor couples supply voltage, described
The grid of second metal-oxide-semiconductor couples the drain electrode of first metal-oxide-semiconductor, and the source electrode of second metal-oxide-semiconductor couples the reference current inspection
Survey the connecting node of unit and described control unit.
5. the low-voltage space precision current mirror image circuit according to claim 3 applied to laser driver, feature
It is, described control unit includes error amplifier, and the error amplifier includes two input terminals and an output end, wherein one
A input terminal couples the output end of the tail current source unit, and another input terminal couples first metal-oxide-semiconductor and tri- pole the first NPN
The connecting node of pipe, output end couple the grid of first metal-oxide-semiconductor.
6. the low-voltage space precision current mirror image circuit according to claim 1 applied to laser driver, feature
It is, the reference current detection unit includes biasing resistor, and the tail current source includes several feedback resistances, the biased electrical
Resistance and the feedback resistance are same model.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821527433.2U CN208707073U (en) | 2018-09-18 | 2018-09-18 | Low-voltage space precision current mirror image circuit applied to laser driver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821527433.2U CN208707073U (en) | 2018-09-18 | 2018-09-18 | Low-voltage space precision current mirror image circuit applied to laser driver |
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| CN208707073U true CN208707073U (en) | 2019-04-05 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109066290A (en) * | 2018-09-18 | 2018-12-21 | 杭州洪芯微电子科技有限公司 | Low-voltage space precision current mirror image circuit applied to laser driver |
| CN110456134A (en) * | 2019-08-27 | 2019-11-15 | 华中师范大学 | Current monitoring circuit and laser application circuit |
-
2018
- 2018-09-18 CN CN201821527433.2U patent/CN208707073U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109066290A (en) * | 2018-09-18 | 2018-12-21 | 杭州洪芯微电子科技有限公司 | Low-voltage space precision current mirror image circuit applied to laser driver |
| CN110456134A (en) * | 2019-08-27 | 2019-11-15 | 华中师范大学 | Current monitoring circuit and laser application circuit |
| CN110456134B (en) * | 2019-08-27 | 2021-06-15 | 华中师范大学 | Current monitoring circuit and laser application circuit |
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