CN203287714U

CN203287714U - Drive and control circuit applied in multichannel variable optical attenuator

Info

Publication number: CN203287714U
Application number: CN2013203486864U
Authority: CN
Inventors: 鲁佶; 吴晓平; 陈义宗; 陈辉; 孙莉萍; 郑勇志; 王文刚
Original assignee: Accelink Technologies Co Ltd
Current assignee: Accelink Technologies Co Ltd
Priority date: 2013-06-18
Filing date: 2013-06-18
Publication date: 2013-11-13
Anticipated expiration: 2023-06-18

Abstract

The utility model relates to a drive and control circuit applied in a multichannel variable optical attenuator. The drive and control circuit comprises a core control device (1), current limiting modules (2), acceleration resistors (3) and solid switch components (4). A signal channel of the core control device (1) is connected with one current limiting module (2). Each current limiting module (2) is formed by serially connecting one resistor (6) and one capacitor (5). Each current limiting module (2) is connected both one acceleration resistor (3) and one solid switch component (4). A base electrode and an emitting electrode of each solid switch component (4) are connected with one acceleration resistor (3) in parallel. A collector electrode of each solid switch component (4) is connected with one variable optical attenuator (7). The technical scheme of the drive and control circuit is that the PWM output of a core control device FPGA is directly converted into an optical attenuation value in need, and thus extra low-pass filters and circuits of operation amplifying and the like required in PWM simulation of a DAC are directly saved, and the area of a circuit is greatly reduced while the power consumption is decreased.

Description

A kind of Drive and Control Circuit that is applied to the hyperchannel variable optical attenuator

Technical field

The utility model relates to a kind of Drive and Control Circuit, more specifically, relates to a kind of Drive and Control Circuit that is applied to the hyperchannel variable optical attenuator (voa), and the utility model belongs to the optical device control field.

Background technology

Transmit without error code for the long distance High-speed that realizes dwdm system, must make each channel signal luminous power consistent, namely need multichannel light power is monitored and equilibrium.Therefore the optical devices such as dynamic channel equalizer (DCE), power-adjustable optical multiplexer (VMUX), optical add/drop multiplexer (OADM) occurred, the core component of these devices is all array variable optical attenuator (VOA variable optical attenuator variable optical attenuator).Regulate neatly VOA, can make the power of each passage be in desirable size.

As shown in Figure 1, mostly traditional VOA is current controling element, thereby control method is to control multi-channel digital analog converter 9(digital analog converter Digital to analog converter DAC by CPU 8) provide one and control voltage V, this voltage removes to control a V-I change-over circuit, thereby reaches the purpose of accurate control electric current.This V-I circuit is a closed control circuit, and the control circuit of feedback control loop is namely arranged.For example: the traditional circuit of 80 passage VOA is controlled and is illustrated in fig. 1 shown below.Element circuit in 80 passage VOA traditional circuit control circuits as shown in Figure 2, multi-channel digital analog converter 9 provides a voltage V and is added in the positive input of operational amplifier 10, because operational amplifier 10 is operated under the negative feedback pattern, so, when circuit is finally stable, the reverse input end of operational amplifier should be also V, and the voltage on sampling resistor 11 should be also V so.Relation between controlled electric current and DAC output voltage V just should be I=V/R.Adopt the control circuit of Fig. 1 structure can simply realize being applied to the control of the electric current of 80 passage VOA.The advantage of controlling like this is: circuit is easily understood; Control the negative feedback of electric current due to operational amplifier, can reach automatic control; If but this circuit be used in 80 and the application of the Current Control of greater number passage on, the quantity of the quantity of that operational amplifier and multi-channel digital analog converter DAC passage is corresponding also have so much, this has very large cost payout undoubtedly, thereby and can make the element of circuit board too much make circuit board oversize.

Summary of the invention

Defect for prior art, the purpose of this utility model is to provide a kind of novel hyperchannel variable optical attenuator control circuit, while being intended to solve existing hyperchannel variable optical attenuator control structure for hyperchannel, circuit component is complicated, with high costs, the problem that size is large.

The technical scheme that the utility model adopts is:

A kind of Drive and Control Circuit that is applied to the hyperchannel variable optical attenuator, comprise kernel control chip, current limliting module, accelerating resistor, solid switch element, the single passage of described kernel control chip is connected with the current limliting module, described current limliting module is comprised of resistance and Capacitance parallel connection, the current limliting module is connected respectively with accelerating resistor, solid switch element, accelerating resistor in parallel between the base stage of solid switch element and emitter, the collector of described solid switch element is connected with variable optical attenuator

Described solid switch element is insulation field effect transistor or bipolar transistor.

Described kernel control chip is parallel processing control device FPGA.

Set between the PWM of De Mei road and have phase differential in described parallel processing control device FPGA.

Phase differential between described parallel processing control device FPGA Zhong Demei road PWM is 180 degree.

The utility model patent has the following advantages:

Adopt a kind of Drive and Control Circuit that is applied to the hyperchannel variable optical attenuator of the present utility model, its objective is and will produce a PWM(Pulse Width Modulation width modulation of the frequency away from as far as possible from the variable optical attenuator low-pass cut-off frequencies), carry out open loop controllable current source of equivalent one-tenth.This new technique scheme has been utilized the characteristics of the inner low pass of variable optical attenuator, make and can directly change into required light decay depreciation by the PWM output of kernel control chip FPGA, the circuit such as the required extra low-pass filter of PWM analog D AC and amplifier have directly been saved, when reducing power consumption, the area that has reduced circuit also falls greatly.And FPGA can control a plurality of passages simultaneously as controller, 80 passages in present case, can also continue to expand to more hyperchannel, has good extendability.

Description of drawings

Fig. 1 is prior art 80 passage VOA circuit control circuit schematic diagram;

Fig. 2 is the element circuit schematic diagram in prior art 80 passage VOA traditional circuit control circuits;

Fig. 3 is the schematic diagram that the utility model is controlled 80 passage VOA circuit;

Wherein:

1: kernel control chip;

2: the current limliting module;

3: accelerating resistor;

4: the solid switch element;

5: electric capacity;

6: resistance;

7: variable optical attenuator;

8：CPU；

9: the multi-channel digital analog converter;

10: operational amplifier;

11: sampling resistor

Embodiment

, in order to make the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with accompanying drawing 3 and embodiment, the utility model is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the utility model, and be not used in restriction the utility model.

As shown in Fig. 3, the circuit that the present invention controls the hyperchannel variable optical attenuator comprises kernel control chip 1, current limliting module 2, accelerating resistor 3, solid switch element 4 and optical device variable optical attenuator 7, wherein, current limliting module 2 is composed in parallel by electric capacity 5 and resistance 6.Kernel control chip 1 is connected with solid switch element 4 with accelerating resistor 3 by current limliting module 2, and the switching frequency of solid switch element 4 is provided.In the present embodiment, because control simultaneously 80 passage variable optical attenuators, thereby select parallel processing control device FPGA.Solid switch element 4 is connected with variable optical attenuator 7, for variable optical attenuator provides suitable PWM(Pulse Width Modulation width modulation) signal.In the present embodiment, solid switch element 4 is insulation field effect transistor or bipolar transistor.Current limliting module 2 is composed in parallel by electric capacity 5 and resistance 6, in order to the required base stage of solid switch element 4 or grid current to be provided.Accelerating resistor 3 is comprised of a resistance, and this resistance claims again accelerating resistor, in order to improve waveform input signal.The selection of solid switch element has two kinds: a kind of is the insulation field effect transistor, and another kind is bipolar transistor.In order to make switch speed fast as much as possible, selecting the principle of insulation field effect transistor is that the total electric weight Qg of grid capacitance is the smaller the better.The selection principle of bipolar transistor is that bandwidth is wide as much as possible.Like this, in lower dutycycle, be unlikely to amplitude and diminish.

In the utility model, because control simultaneously the variable optical attenuator VOA of 80 passages, need to produce simultaneously the pwm signal on 80 tunnels by parallel processing control device FPGA, although every road PWM electric current is very little, maximum is no more than 3mA,, but so multichannel opening and closing together, so FPGA moment power consumption can be very large, this just will certainly improve the cost of the decoupling capacitor of FPGA.In order to address this problem, can set between every road PWM certain phase differential is arranged in parallel processing control device FPGA Program the inside, for example can adopt the phase differential between every road PWM is 180 degree, and guarantee that each only has a road PWM rising or descending constantly,, such as dot interlace output, move afterwards successively.

Principle of work of the present utility model is as follows: due to the variable optical attenuator of current trend, for example the variable optical attenuator VOA based on the thermo-optic effect of PLC can be used as a low-pass filter, thereby, can control it with a relatively high PWM voltage source of frequency, be equivalent to a d. c. voltage signal and control VOA.Send the PWM waveform by parallel processing control device FPGA and control the Kai Heguan of thyristor, by the duty power of controlled loading on variable optical attenuator VOA recently, thereby reach the purpose of controlling optical attenuation.

A kind of specific works flow process that is applied to the Drive and Control Circuit of hyperchannel variable optical attenuator of the utility model is: take the variable optical attenuator of 80 passages as example, by kernel control chip 1, it is the pwm signal that FPGA produces 80 passages simultaneously, the configurable different dutycycle of the pwm signal of each passage, thereby to 80 passages of variable optical attenuator different luminous power that decays respectively.Because solid switch element 4 has certain enlargement factor, so just need to add a current limliting module 2 between the kernel control chip 1 that produces pwm signal and solid switch element 4.Resistance 6 in current limliting module 2 is to protect on primary path not overcurrent; And reduced the control electric current of PWM, just will certainly slow down the switching time of solid switch element, so can also be used for making up switching time by electric capacity 5 in parallel on this resistance 6, this electric capacity only when input pulse changes equivalence play a part resistance 6 is diminished.Because the pwm signal of controlling variable optical attenuator VOA generally will be selected upper frequency, frequency is greater than 100K, at this moment be provided with an accelerating resistor 3 in circuit as shown in Figure 3, that is: accelerating resistor 3 in parallel connection between the base stage of solid switch element 4 and emitter, with accelerating resistor 3, the base stage of solid switch element 4 and the stored charge of the junction capacity between emitter are discharged, thereby make the electric weight on the junction capacity of solid switch element 4 have a path to be released, reach the purpose of acceleration.After pwm signal after adjusting is input to solid switch element 4, can control according to the PWM waveform Kai Heguan of solid switch element 4.The Duty ratio control of each passage pwm signal that this Drive and Control Circuit of the utility model can produce by FPGA is carried in the power on variable optical attenuator, thereby has controlled simultaneously the optical attenuation of 80 passage variable optical attenuators.

Those skilled in the art will readily understand; the foregoing is only preferred embodiment of the present utility model; not in order to limit the utility model; all any modifications of making within spirit of the present utility model and principle, be equal to and replace and improvement etc., within all should being included in protection domain of the present utility model.

Claims

1. Drive and Control Circuit that is applied to the hyperchannel variable optical attenuator, it is characterized in that: comprise kernel control chip (1), current limliting module (2), accelerating resistor (3), solid switch element (4), the single passage of described kernel control chip (1) is connected with current limliting module (2), described current limliting module (2) is composed in parallel by resistance (6) and electric capacity (5), current limliting module (2) and accelerating resistor (3), solid switch element (4) is connected respectively, accelerating resistor in parallel (3) between the base stage of solid switch element (4) and emitter, the collector of described solid switch element (4) is connected with variable optical attenuator (7).

2. a kind of Drive and Control Circuit that is applied to the hyperchannel variable optical attenuator as claimed in claim 1 is characterized in that: described solid switch element (4) is insulation field effect transistor or bipolar transistor.

3. a kind of Drive and Control Circuit that is applied to the hyperchannel variable optical attenuator as claimed in claim 1, it is characterized in that: described kernel control chip (1) is parallel processing control device FPGA.

4., as claim 1 or 2 or 3 described a kind of Drive and Control Circuit that are applied to the hyperchannel variable optical attenuator, it is characterized in that: set between the PWM of De Mei road and have phase differential in described parallel processing control device FPGA.

5. a kind of Drive and Control Circuit that is applied to the hyperchannel variable optical attenuator as claimed in claim 4 is characterized in that: the phase differential between described parallel processing control device FPGA Zhong Demei road PWM is 180 degree.