CN202977970U - Laser tube power control system - Google Patents
Laser tube power control system Download PDFInfo
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- CN202977970U CN202977970U CN 201220660857 CN201220660857U CN202977970U CN 202977970 U CN202977970 U CN 202977970U CN 201220660857 CN201220660857 CN 201220660857 CN 201220660857 U CN201220660857 U CN 201220660857U CN 202977970 U CN202977970 U CN 202977970U
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Abstract
The utility model discloses a laser tube power control system. The laser tube power control system comprises a comparison circuit, an adjusting circuit and a time clock control circuit, wherein the comparison circuit generates a binary comparison signal based on a real output signal and an object signal value, the adjusting circuit comprises a current generation circuit and a driving circuit, the current generation circuit is used for generating adjusting current according to the binary comparison signal, the driving circuit is used for outputting a feedback signal to a laser tube according to the adjusting current, and the time clock control circuit is used for generating a time clock signal and adjusting the adjusting current according to the time clock signal. The laser tube power control system adjusts modulation current and a bias circuit according to a detection result of a previous sending data frame within a gap of data sending, so influence of a modulation loop circuit on a main data channel is avoided.
Description
Technical field
The utility model relates to digit optical communication, more specifically, is a kind of laser tube power control system that configures for laser diode.
Background technology
In the digit optical data communication, laser diode (laser tube) is as the core devices of the electric light conversion of optical communication, and the stability of its luminous efficiency and the characteristics of luminescence has vital impact to whole communication link.How guaranteeing that laser diode keeps constant Output optical power under environmental condition, and how to guarantee to export enough difference powers are arranged between high level and output low level, is the key that guarantees communication link reliability.
As shown in Figure 1, be relation curve between laser tube Output optical power (Pout) and drive current (Ilaser).P1 wherein, P2, P3 and P4 be laser tube temperature raise gradually and constantly increase situation of degree of aging under the Output optical power of (curve S) and the relation curve between drive current, Ith1, Ith2, Ith3 and Ith4 are corresponding lasing threshold electric currents.As seen from the figure, laser tube under different temperature conditions, the altering a great deal of lasing threshold electric current and luminous efficiency, particularly, in the situation that temperature raises, it is large that the lasing threshold electric current becomes, luminous efficiency reduces simultaneously.In addition, also can be found out by Fig. 1, along with the laser tube increase of service life, the emission effciency of laser tube also can reduce, and threshold current also can correspondingly increase.
In order to address the above problem, in application, need to be to laser tube configuration driven circuit (LDD), adopt power to control (PC) circuit and realize control to the laser tube power output by regulating drive current.In laser tube power was controlled, drive current comprised bias current and modulated current.Usually, bias current keeps the electric current of constant " 0 " power level in laser tube, and accordingly, modulated current keeps the electric current of constant " 1 " power level in laser tube.
Particularly, the power of laser tube is controlled two kinds of methods are arranged usually, a kind of open Loop Power control method of tabling look-up that is based on, the method is by realizing the characteristics of luminescence of testing laser pipe under condition of different temperatures, and be made into a form and exist in the memory of chip, during actual the use, the temperature that records according to temperature sensor is tabled look-up and is accessed corresponding driving current value.Another is based on the automatic gain of feedback control principle and controls (APC), obtains the actual transmission power of laser tube by detection backlight, then compares with the power of presetting, and automatically adjusts drive circuit, makes it to be consistent with preset value.
At present, the laser tube drive circuit provides above two kinds of control models to select for the user simultaneously.Because bias current and the modulated current of laser tube all will be controlled, so two kinds of pattern uses capable of being combined.Can adopt respectively above two kinds of control modes to control laser tube bias current and modulated current.Therefore, the laser tube drive circuit can comprise following four kinds of integrated modes:
1, two open loop modes.In this pattern, bias current and modulated current are all realized by the open loop lookup table mode.
2, modulated current closed loop bias current open loop mode.Be that modulated current is controlled by APC, and bias current is by the control of tabling look-up.
3, modulated current open loop bias current closed loop mode, namely bias current is controlled by APC, and modulated current is by the control of tabling look-up.
4, two closed loop modes, namely bias current and modulated current are all controlled by APC.
For above-mentioned the 4th kind of pattern, publication number is that CN101395771, application number are that 200780007756.7 Chinese invention patent application discloses a kind of pair of close-loop control scheme.As shown in Figure 2, be the circuit diagram of an execution mode of this control program.This laser drive circuit 100a can be connected to laser diode 103.Particularly, laser drive circuit 100a comprises the laser diode drive (LDD) 106 that produces laser drive current.Laser diode drive 106 is according to the data input, and output is applied to the laser-driven signal of laser diode 103.Laser diode 103 produces laser emission 109, and the part of laser emission 109 is guided to laser detector 113.Laser detector 113 produces and the proportional feedback signal of laser emission 109, and this feedback signal is applied to laser drive circuit 100a.
In this circuit, the bias current IBias and the modulated current IMod that are transported to LDD 106 control electric current 123a generation by dual-loop power.Wherein, power control loop road 126a produces bias current IBias, and power control loop road 129a produces modulated current IMod.The working method of power control loop road 126a and power control loop road 129a is basic identical.Take power control loop road 126a as example, it comprises the current occuring circuit 131 for generation of bias current IBias, and current occuring circuit 131 comprises digital to analog converter 133 and the P0 counter 139 that is connected to laser diode drive 106.Further, power control loop road 129a also comprises d type flip flop 146, and d type flip flop 146 produces output signal D0 and is applied to P0 counter 139.And power control loop road 129a comprises comparator 153, and it produces the signal output R0 of the input R that resets that is applied to d type flip flop 146.Two inputs at comparator 153, access respectively digital to analog converter 159 and buffer/amplifier 166, wherein, P0 desired value (namely producing the corresponding electric current of expection laser power of logical zero) is converted to analog current by comparator 153, and the signal that laser photodiode 113 produces is applied to buffer/amplifier 166,153 pairs of two input signals of comparator, and output " 0 " or " 1 ".Simultaneously, clock signal C k is applied to d type flip flop 146 and P0 counter 139, and clock signal is in the time in half cycles cycle, be worth the duration of a plurality of continuous numbers greater than the maximal phase of laser diode transmission etc., be not subjected to data-signal to straddle the switching impact that input signal (namely P0 echo signal) may occur to guarantee d type flip flop 146.Working method and the 123a of power control loop road 129a are similar.
By above-mentioned feedback circuit, can according to targets threshold electric current and feedback current, bias current and modulated current be regulated.But, what this scheme was taked is the control model of bit-by-bit (BIT-TO-BIT), namely control for each emission mode, control for realizing BIT-TO-BIT power, amplifier 166 and comparator 153,156 need high-speed cruising, satisfying the code check requirement of optical communication, therefore to the having relatively high expectations of these devices, be required to be the high-speed, high precision device; In addition, be to guarantee the APC precision, two high-speed, high precision comparators 153,156 needs guarantee enough comparison precision, high speed trans-impedance amplifier 166 need to have enough large bandwidth, thereby consumes a large amount of power consumptions.And, foregoing circuit is at transmission data-signal device, bias current and modulated current to be regulated, therefore, if clock Ck adopts the clock frequency irrelevant with transmitting data, APC possibly in sending data aliasing enter undesired frequency content, on the other hand, if the Ck signal extracts by sending data, to satisfy particular requirement, need the built-in high speed clock recovery signal, this has increased again larger extra power consumption.And, due to the restriction of this circuit intermediate ring road bandwidth, can send the low-frequency ripple signal that superposes on data with APC loop bandwidth close frequencies, this has further increased additional noise.
The utility model content
The purpose of this utility model is to solve existing the problems referred to above in existing laser tube power control circuit, thereby a kind of laser tube power control system of innovation is provided.
laser tube power control system of the present utility model, be used for the power output of laser tube is controlled, wherein, this laser tube produces real output signal to this laser tube power control system, this laser tube power control system output feedback control signal is to laser tube, thereby the power to this laser tube carries out FEEDBACK CONTROL, and, by data transmitter, this laser tube power control system output is sent command signal, control this laser tube and send this real output signal, wherein, when this transmission command signal is enabled state, this laser tube sends this real output signal, when this transmission command signal is the disable state, this laser tube stops sending this real output signal, this laser tube is controlled control system and is comprised:
Comparison circuit, this comparison circuit produces a binary comparison signal based on this real output signal and echo signal value;
Regulating circuit, this regulating circuit comprises a current occuring circuit and a drive circuit, this electric current transtation mission circuit is used for comparison signal binary according to this and produces an adjusting electric current, and this drive circuit is used for exporting this feedback control signal to this laser tube according to this adjusting electric current;
Clock control circuit for generation of clock signal, and is regulated this adjusting electric current according to clock signal;
Wherein, this clock signal comprises the first clock signal and second clock signal, when this sends command signal from enabled state to the disable state-transition, this first clock signal changes, and this binary comparison signal is latched, and, in this sends the disable status slot of command signal, this second clock signal changes, and makes this regulating circuit carry out the electric current adjusting according to this comparison signal that latchs.
Preferably, described adjusting electric current is modulated current, and described echo signal value is the target current value corresponding to this laser tube output high level power level.
Preferably, described adjusting electric current is bias current, and described echo signal value is the target current value corresponding to this laser tube output low level power level.
Preferably, described comparison circuit comprises a comparator, the inverting input of this comparator is connected with first current/voltage converter and the first analog to digital converter in turn, and described target current value is delivered to this first analog to digital converter, the normal phase input end of this comparator is connected with second current/voltage converter, and described real output signal is delivered to this second current/voltage converter.
Preferably, described comparison circuit comprises a comparator, the inverting input of this comparator is connected with first current/voltage converter and the first analog to digital converter in turn, and described target current value is delivered to this first analog to digital converter, the normal phase input end of this comparator is connected with a high-level detection and the second current/voltage converter in turn, and described real output signal is delivered to this second current/voltage converter.
Preferably, described clock control circuit comprises one for generation of clock controller and a d type flip flop of clock signal, this clock controller produces described the first clock signal and second clock signal, and this d type flip flop latchs described binary comparison signal according to the transformation of described the first clock signal.
Preferably, described current occuring circuit comprises a counter and a digital to analog converter, when described second clock signal changes in described disable status slot, this counter carries out computing according to the described binary comparison signal that latchs, and this digital to analog converter is according to the described adjusting electric current of value output of this counter.
Preferably, described the first current/voltage converter and described the second current/voltage converter are low speed devices.
Preferably, described comparator is low speed devices.
Preferably, described the first current/voltage converter is low speed devices, and described the second current/voltage converter is high speed device.
Preferably, described comparator is low speed devices.
Preferably, described counter is bidirectional counter.
Laser tube power control system of the present utility model, complete during data send the detection of laser tube power output is compared, but power output is not regulated, and in the gap that sends data, modulated current and biasing circuit are regulated according to the testing result of previous transmission Frame, thereby avoided modulating loop to the impact of main data channel.
Description of drawings
Fig. 1 is at the relation curve between laser tube power output and drive current under different temperature conditions and degree of aging;
Fig. 2 is the structured flowchart of existing a kind of pair of closed-loop control;
Fig. 3 is the schematic diagram of laser tube power control system of the present utility model;
Fig. 4 is the composition schematic diagram of an execution mode of laser tube power control system of the present utility model;
Fig. 5 is the control sequential chart of the laser tube power control system in Fig. 4;
Fig. 6 is the waveform transformation figure of several signals of telecommunication in the laser tube power control system in Fig. 4.
Embodiment
Below in conjunction with the drawings and specific embodiments, formation and the operation principle of control system of the present utility model described.In description, only be briefly described or omit for the function and effect of module commonly used in prior art, and to the part of outstanding the utility model characteristics with illustrate in detail with the difference part in existing the application.
with reference to Fig. 3, in general, the utility model aims to provide a kind of power control system 100 for laser tube, it is used for the power output of the laser tube 11 of laser tube assembly 10 is controlled, wherein, laser tube 11 passes through for example photodiode of a laser detector 12() produce real output signal IPIN to laser tube power control system 100, laser tube power control system 100 output feedback control signal Id are to laser tube 11, thereby the power to this laser tube 11 carries out FEEDBACK CONTROL, and, for application of the present utility model, this system is outside sends command signal (Burst signal) by 100 outputs of 20 pairs of laser tube power control systems of data transmitter, control this laser tube and send this real output signal, wherein, when the Burst signal is enabled state (for example logical one), laser tube 11 sends real output signal IPIN, when the Burst signal is the disable state, laser tube 11 stops sending this real output signal IPIN.With reference to Fig. 5, show the transmission timing figure of Burst signal, when Burst was high level (logical one), laser tube 11 sent data (IPIN signal) by laser detector 12, when Burst was low level (logical zero), laser tube 11 stopped sending data (IPIN signal).
In laser tube assembly 10, laser tube 11 is when producing laser emission, part laser emission is detected by photodiode 11, photodiode 11 produces real output signal IPIN, in the present embodiment, this real output signal is a current signal, this current signal is transported in power control system 100 of the present utility model as feedback signal, power control system 100 is according to this feedback signal, output feedback control signal Id, laser tube 11 these Id signals of response produce the expection radiation after adjusting, i.e. the target power value of output expectation.
As previously discussed, during laser tube 11 power output, comprise output and " low level " signal (logical zero) output of " high level " signal (logical one), when the Id signal of sending is high level signal, laser tube 11 output high level power; Correspondingly, when the Id signal of sending is low level signal, laser tube 11 output low level power.Below also will be described in detail, the Id signal can produce according to the adjusting electric current that is produced by this system, and this regulates electric current after overdrive circuit (for example, drive circuit can amplify this regulating circuit), is output as the Id signal that is characterized by current signal.Similar with prior art, this regulates electric current corresponding to high level output and the low level output of above-mentioned laser tube 11, comprises modulated current (I
mod) and bias current (I
Bias).And a main purpose of the present utility model is how this adjusting electric current (modulated current and bias current) to be carried out FEEDBACK CONTROL, so that the power output of laser tube 11 is adjusted in target zone.
In addition, data transmitter 20 is as the external module of this system, and it is used for controlling data transmission, the i.e. power stage of laser tube 11.In real world applications, laser tube 11 is not to send (being power stage) for carrying out consistently data, for example at current FTTH(fiber entering household) in the GPON/EPON consensus standard in, may need to carry out different data carries, namely after one group of data is sent, produce a data time slot (namely going up the time slot between one group of data and next group data transmission), and then carry out the transmission of another group data.Control to data are carried realizes by data transmitter 20.
With further reference to Fig. 3, in power control system 100 of the present utility model, comprise comparison circuit 110, regulating circuit 120 and clock control circuit 130.
Particularly, comparison circuit 110 produces a binary comparison signal based on real output signal IPIN and echo signal value; Regulating circuit 120 comprises a current occuring circuit 121 and a drive circuit 122, electric current transtation mission circuit 121 is used for comparison signal binary according to this and produces an adjusting electric current, and drive circuit 122 is used for regulating electric current output feedback control signal Id to this laser tube 11 according to this; Clock control circuit 130 is for generation of clock signal, and according to clock signal, this adjusting electric current regulated.
Especially, in power control system 100 of the present utility model, clock signal comprises the first clock signal and second clock signal, when sending command signal (Burst) from enabled state to the disable state-transition, this first clock signal changes, and this binary comparison signal is latched, and, in the disable status slot that sends command signal (Burst), this second clock signal changes, and makes regulating circuit 120 carry out the electric current adjusting according to this comparison signal that latchs.
With reference to Fig. 4, it is the composition schematic diagram of an execution mode of power control system 100 of the present utility model.In this embodiment, modulated current control section and bias current control section all adopt power control system of the present utility model, be that the modulated current control section adopts 100a, the bias current control section adopts 100b, thus, two power control section divide 100a, 100b to consist of two closed loop laser tube power control systems that are used for laser tube.Easily understand, in modulated current control section 100a, the echo signal value that is used for comparing with real output signal IPIN is the target current value P corresponding to this laser tube output high level power level
The avg targetAccordingly, in bias current control section 100b, for the target current value P of the echo signal set that compares in real output signal IPIN corresponding to this laser tube output low level power level
0 target
Particularly, with reference to Fig. 4, divide 100a in the power control section that is used for modulated current control, comparison circuit 110a comprises comparator 111a, the inverting input of this comparator 111a is connected with current/voltage converter (I/V) 112a and analog to digital converter (DAC) 113a, target current value P in turn
The avg targetBe delivered to analog to digital converter 113a, the normal phase input end of comparator 111a is connected with current/voltage converter (I/V) 114a, and real output signal IPIN is delivered to this current/voltage converter 114a.In the illustrated embodiment, IPIN is a current signal, and it is converted to an average voltage level V by current/voltage converter 114a
Pavg(with reference to Fig. 6, namely the data of all transmission in a Burst being averaged) is transported to the normal phase input end of comparator 111a, target current value P as the comparison signal of IPIN
The avg targetCarry out the analog digital conversion through analog to digital converter 110a, and then be converted into voltage signal V by current/voltage converter 112a
Atar, and being transported to the inverting input of comparator 111a, comparator 111a is to average voltage level V
PavgWith voltage signal V
AtarCompare, and output comparative result R
avgIn the arranging of this execution mode, as average voltage level V
PavgGreater than voltage signal V
AtarThe time, comparator 111a output signal R
avgBe high level (logical one), high level luminous power of this expression laser tube 11 output is less than preset value, otherwise, as average voltage level V
PavgLess than voltage signal V
AtarThe time, comparator 111a output signal R
avgBe low level (logical zero), the high level luminous power of these expression laser tube 11 outputs is greater than preset value.The back also will be described in detail, and regulating circuit afterwards and clock circuit will be according to the output signal R of comparator 111a
avg, modulated current is regulated.
At the control section 100b that is used for bias current, setting and the 110a of comparison circuit 110b are similar, the normal phase input end of different the is amplifier 111b of this comparison circuit 110b has increased a high-level detection 115b, particularly, comparison circuit 110b comprises a comparator 111b, the inverting input of comparator 111b is connected with current/voltage converter (I/V) 112b and analog to digital converter (DAC) 113b in turn, and target current value P
0 targetBe delivered to this analog to digital converter 113b, the normal phase input end of comparator 111b is connected with high-level detection (THD) 115b and current/voltage converter (I/V) 114b in turn, and real output signal IPIN is delivered to this current/voltage converter 114b.High-level detection 115b can adopt conventional peak detection circuit to consist of.Easily understand, on parameter arranged, the gain of two current/voltage converter 112b, 114b should be identical.Target current value P
0 targetCarry out digital-to-analogue conversion and convert voltage signal V to through current/voltage converter 112b through digital to analog converter 113b
P0tarAfter, be transported to the inverting input of comparator 111b, on the other hand, real output signal IPIN is through after the current/voltage-converted of 114b, again by high-level detection 115b during to laser tube 11 high level corresponding real output signal IPIN detect (specifically see following sequential to Fig. 6 describe) and output comparison signal V
p0Be conveyed into the normal phase input end of comparator 111b.Comparator 111b exports high level or low level output signal R according to the comparative result of two signals
p0Similar with the output principle of comparator 111a, work as V
p0Greater than V
P0tarThe time, comparator 111b output signal R
p0Be high level (logical one), low level luminous power of this expression laser tube 11 output is less than preset value, otherwise, work as V
p0Less than V
P0tarThe time, comparator 111b output signal R
P0Be low level (logical zero), the low level luminous power of these expression laser tube 11 outputs is greater than preset value.Afterwards, follow-up regulating circuit and clock circuit will be according to the output signal R of comparator 111b
P0, bias current to be regulated, this will more be described in detail hereinafter.
In above-mentioned comparison circuit 110a and 110b, the comparison signal that is input to comparator 111a, two inputs of 111b is voltage signal.Easily understand, also can adopt the mode of current signal, two inputs that real output signal and echo signal are applied to comparator compare.
Further, regulating circuit in control section 100a and control section 100b comprises respectively current occuring circuit 121a, 121b and drive circuit 122a, 122b, more specifically, current occuring circuit 121a, 121b comprise respectively counter 1211a, 1211b and digital to analog converter 1212a, 1212b.Counter 1211a, 1211b are under the control of separately clock control circuit, respectively to binary comparison signal R
avgAnd R
P0Count, then result is outputed to digital to analog converter 1212a, 1212b, carry out digital-to-analogue conversion, produce respectively modulated current signal I
modWith bias current signal I
Bias, modulated current signal I
modWith bias current signal I
BiasAfter carrying out a certain proportion of amplification by drive circuit 122a, 122b respectively, generate feedback control signal Id and output to laser tube 11.Drive circuit 122a, 122b are respectively modulated current driver and bias current driver, and they can discretely arrange, and also can be integrated in same laser tube driver.
Alternately, current occuring circuit 121a, 121b also can adopt other set-up modes to produce modulated current signal and bias current signal.For example, current occuring circuit 121a, 121b can be analog circuits, binary comparison signal output R
avgAnd R
P0Can pass through loop filter, draw rear modulated current and the bias current of producing of analog signal output and passing ratio conversion.
As mentioned above, current occuring circuit 121a, 121b are the adjustings of carrying out two kinds of electric currents under the control of clock control circuit.Particularly, in control section 100a, 100b, clock control circuit comprises respectively for generation of clock controller 131a, the 131b of clock signal and d type flip flop 132a, 132b, clock controller 131a, 131b produce the first clock signal clk1 and second clock signal clk2, d type flip flop 132a, 132b are according to the transformation of this first clock signal clk1, to binary comparison signal R
avgAnd R
P0Latch.On the other hand, counter 1211a, 1211b are according to the transformation of second clock signal clk2, to R
avgAnd R
P0Counting behaviour and electric current regulates.In the present embodiment, clock controller 131a, 131b can be two independently unit, can be also the clock control cells that two control section 100a, 100b share.
With reference to Fig. 4, clock controller produces the first clock signal clk1 and second clock signal clk2 according to sending command signal (Burst), and, when (Burst off) changes from enabled state (Burston) to the disable state when the Burst signal, namely at the trailing edge of the transmission command signal shown in Fig. 4 clock, the first clock signal clk1 changes (T1 constantly), and this moment is by d type flip flop 132a, 132b latch signal R
avgAnd R
P0After this enter the disable status slot of transmission command signal (during this period of time namely, laser 11 does not carry out data and sends), and, utilize clock controller 131a, 131b, make second clock signal clk2 change (T2 constantly) in this time slot, thereby make counter 1211a, 1211b begin binary signal R to latching
avgAnd R
P0Count, in this embodiment, counter 1211a, 1211b are bidirectional counter, the result that namely latchs according to d type flip flop 132a, 132b adds 1 or subtract 1 computing, when d type flip flop 132a, 132b are output as high level (logical one), counter 1211a, 1211b add 1, otherwise subtract 1.In a time slot (two moment that do not comprise the counter-rotating of Burst signal), second clock signal clk1 only changes once, and namely time slot counter 1211a, a 1211b only complete plus and minus calculation one time.Take modulated current control section 100a as example, if Counter Value increases, the output current (being modulated current Imod) of corresponding digital to analog converter 1212a increases, and is delivered to laser tube 11 after amplifying certain proportion by drive circuit 122a.If supposition this moment bias current is constant, the average light power of laser tube 11 also can increase, and the increase of average light power can cause V
PavgReduce, thus, can make Vpavg approach gradually Vatar, thus finally make the power of output and default power consistent, realize the control to power output.The principle of bias current control section 100b and modulated current control section 100a is similar.
In conjunction with Fig. 4, in this embodiment, when instruction transmitted signal Burst gets back to enabled state from the disable state, the first clock signal clk1 and second clock signal clk2 also change, and (the first clock signal ckl1 is low level from the high level upset, second clock signal clk2 is high level from the low level upset), thereby complete this time adjustment operation, and enter next cycle period.In addition, easily understand, second clock signal clk2 is in T2 conversion constantly, should complete at trigger and carry out after latching, and namely the time difference of T1 and T2 should be satisfied the latch operation of trigger.
For modulated current control section 100a, current/voltage converter 112a, 114a can adopt low speed devices, and for bias current control section 100b, current/voltage converter 114b need adopt high speed device, and current/voltage converter 112b adopts common low speed devices to get final product.This is because at modulated current control section 100a, can real output signal IPIN be converted into average voltage level by the current/voltage converter 114a of low speed, so not need high speed processing in transfer process.And for bias current control section 100b, due to need by high-level detection 115b detection laser pipe 11 corresponding output signal IPIN when the low-level of power, current/voltage converter 114b need complete the current/voltage-converted to the IPIN signal at high speed, because it need adopt high speed device.Particularly, as shown in Figure 6, be the waveform transformation figure of IPIN signal through current/voltage converter 114b and high-level detection 115b, wherein, real output signal IPIN is the electric current output of photodiode 12, wherein high impulse is corresponding to the testing circuit of (being output logic " 1 ") under high level state, and low pulse is corresponding to (being the detection electric current of output logic " 0 " under low level state.The IPIN signal is through output voltage signal Vipin after current/voltage-converted, due to the polarity conversion of current/voltage-converted circuit, this moment high impulse corresponding to the transmitted power of low level state, and low pulse is corresponding to the transmitted power of high level state.Voltage signal Vipin passes through output voltage signal Vp0 after high-level detection 115b again.When sending the disable state of command signal (Burst off stage), this output is pre-set into a scheduled voltage Vpo_reset.When the enabled state that sends command signal begins (Burst start), high-level detection 115b starts working, and after one section stabilization time Tset, circuit output equals the high value of Vipin, thereby realizes the high level measuring ability.This secondary data send finish after, Vpo is reset to Vpo_reset again, with the Rapid Establishment in (during Burst) during adapting to different data and sending, satisfies specific protocol (as the PON agreement etc.) demand.
In the above-described embodiment, adopt two close-loop power control patterns, i.e. bias current control and modulated current control section all adopt FEEDBACK CONTROL scheme of the present utility model.Alternately, also only bias current control and the modulation control loop in this FEEDBACK CONTROL scheme of a kind of employing, and the another kind of open loop control program that adopts, for example, can adopt " modulation circuit open loop biasing circuit closed loop " pattern, also can adopt " biasing circuit open-loop modulation circuit closed loop " pattern.For open loop is controlled, as previously mentioned, can adopt the open-loop control methods commonly used such as look-up table.
Laser tube power control system of the present utility model is particularly suitable for the communication networks such as GPON/EPON based on burst (BURST) pattern.(BURSTON) completes the detection of laser tube power output compared during data send, but power output is not regulated, and in the gap (BURST OFF) that sends data, modulated current and biasing circuit are regulated according to the testing result of previous transmission Frame (data that namely send during a BURST ON), thereby avoided modulating loop to the impact of main data channel.
Compare with existing power control system, the utility model is not to send data according to each to regulate, but regulate according to each data slot, this regulative mode meets the gradual feature of the aging and variations in temperature of laser tube, avoid simultaneously the use of high-speed comparator, high-frequency clock generative circuit, greatly reduce thus design difficulty and the circuit power consumption of circuit.
In addition, in control system of the present utility model, adopted bidirectional counter to preserve the adjusting result, this has been avoided adopting electric capacity to store the precision disappearance of easily leaking electricity and causing, thereby greatly improved the control precision of circuit, and be applicable to the application of long BURST OFF.And modulated current control loop and bias current are controlled all can select control system of the present utility model, work alone respectively, thus the combination of convenient different control models.
Claims (12)
1. laser tube power control system, be used for the power output of laser tube is controlled, wherein, this laser tube produces real output signal to this laser tube power control system, this laser tube power control system output feedback control signal is to laser tube, thereby the power to this laser tube carries out FEEDBACK CONTROL, and, by data transmitter, this laser tube power control system output is sent command signal, control this laser tube and send this real output signal, wherein, when this transmission command signal is enabled state, this laser tube sends this real output signal, when this transmission command signal is the disable state, this laser tube stops sending this real output signal, it is characterized in that, this laser tube is controlled control system and is comprised:
Comparison circuit, this comparison circuit produces a binary comparison signal based on this real output signal and echo signal value;
Regulating circuit, this regulating circuit comprises a current occuring circuit and a drive circuit, this electric current transtation mission circuit is used for comparison signal binary according to this and produces an adjusting electric current, and this drive circuit is used for exporting this feedback control signal to this laser tube according to this adjusting electric current;
Clock control circuit for generation of clock signal, and is regulated this adjusting electric current according to clock signal;
Wherein, this clock signal comprises the first clock signal and second clock signal, when this sends command signal from enabled state to the disable state-transition, this first clock signal changes, and this binary comparison signal is latched, and, in this sends the disable status slot of command signal, this second clock signal changes, and makes this regulating circuit carry out the electric current adjusting according to this comparison signal that latchs.
2. laser tube power control system according to claim 1, is characterized in that, described adjusting electric current is modulated current, and described echo signal value is the target current value corresponding to this laser tube output high level power level.
3. laser tube power control system according to claim 1, is characterized in that, described adjusting electric current is bias current, and described echo signal value is the target current value corresponding to this laser tube output low level power level.
4. laser tube power control system according to claim 2, it is characterized in that, described comparison circuit comprises a comparator, the inverting input of this comparator is connected with first current/voltage converter and the first analog to digital converter in turn, and described target current value is delivered to this first analog to digital converter, the normal phase input end of this comparator is connected with second current/voltage converter, and described real output signal is delivered to this second current/voltage converter.
5. laser tube power control system according to claim 3, it is characterized in that, described comparison circuit comprises a comparator, the inverting input of this comparator is connected with first current/voltage converter and the first analog to digital converter in turn, and described target current value is delivered to this first analog to digital converter, the normal phase input end of this comparator is connected with a high-level detection and the second current/voltage converter in turn, and described real output signal is delivered to this second current/voltage converter.
6. laser tube power control system according to claim 1, it is characterized in that, described clock control circuit comprises one for generation of clock controller and a d type flip flop of clock signal, this clock controller produces described the first clock signal and second clock signal, and this d type flip flop latchs described binary comparison signal according to the transformation of described the first clock signal.
7. according to claim 1 or 6 described laser tube power control systems, it is characterized in that, described current occuring circuit comprises a counter and a digital to analog converter, when described second clock signal changes in described disable status slot, this counter carries out computing according to the described binary comparison signal that latchs, and this digital to analog converter is according to the described adjusting electric current of value output of this counter.
8. laser tube power control system according to claim 4, is characterized in that, described the first current/voltage converter and described the second current/voltage converter are low speed devices.
9. laser tube power control system according to claim 4, is characterized in that, described comparator is low speed devices.
10. laser tube power control system according to claim 5, is characterized in that, described the first current/voltage converter is low speed devices, and described the second current/voltage converter is high speed device.
11. laser tube power control system according to claim 5 is characterized in that, described comparator is low speed devices.
12. laser tube power control system according to claim 7 is characterized in that, described counter is bidirectional counter.
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| CN 201220660857 CN202977970U (en) | 2012-12-04 | 2012-12-04 | Laser tube power control system |
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| CN 201220660857 CN202977970U (en) | 2012-12-04 | 2012-12-04 | Laser tube power control system |
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| CN202977970U true CN202977970U (en) | 2013-06-05 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103022895A (en) * | 2012-12-04 | 2013-04-03 | 上海贝岭股份有限公司 | Laser tube power control system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103022895A (en) * | 2012-12-04 | 2013-04-03 | 上海贝岭股份有限公司 | Laser tube power control system |
| CN103022895B (en) * | 2012-12-04 | 2015-03-18 | 上海贝岭股份有限公司 | Laser tube power control system |
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