CN103458586B - Trsanscondutance amplifier and constant current driver circuit for LED - Google Patents
Trsanscondutance amplifier and constant current driver circuit for LED Download PDFInfo
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- CN103458586B CN103458586B CN201310415096.3A CN201310415096A CN103458586B CN 103458586 B CN103458586 B CN 103458586B CN 201310415096 A CN201310415096 A CN 201310415096A CN 103458586 B CN103458586 B CN 103458586B
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Abstract
The invention provides a kind of trsanscondutance amplifier and constant current driver circuit for LED, this trsanscondutance amplifier comprises: differential input stage circuit, comprises the first Voltage-current conversion circuit and the second Voltage-current conversion circuit; Current transfer circuit, transmits the electric current that differential input stage circuit exports; Input switch network, switches the positive input signal inputted and negative input signal, makes it alternately input to the input of the first Voltage-current conversion circuit and the second Voltage-current conversion circuit; Current delivery switching network, switches the current delivery path of current transfer circuit, makes the output signal of trsanscondutance amplifier and positive input signal keep positive polarity, and keeps reversed polarity with negative input signal; Clock-signal generator, produce first to fourth clock signal of periodically non-overlapping, the first and second clock signals are anti-phase, and the third and fourth clock signal is anti-phase.The present invention can reduce the imbalance because device matching and encapsulation stress cause, and is conducive to the consistency improving circuit.
Description
Technical field
The present invention relates to trsanscondutance amplifier technical field, particularly relate to a kind of trsanscondutance amplifier and constant current driver circuit for LED.
Background technology
With reference to figure 1, traditional step-down LED drive circuit mainly comprises: constant-current control circuit 100, sustained diode 1, inductance L 1, electric capacity C1, switching tube M1, sampling resistor Rcs.Wherein, the negative pole of sustained diode 1 is connected to positive pole and the power end Vin of load LED, and the positive pole of sustained diode 1 is connected to the first end of inductance L 1, and the second end of inductance L 1 is connected to the negative pole of load LED; Switching tube M1 is connected between inductance L 1 and sampling resistor Rcs, and this switching tube M1 controls by constant-current control circuit 100.
Wherein, constant-current control circuit 100 comprises: peak sampling hold circuit 106, and during power switch M1 conducting, sample streams is through the sampled voltage Vcs of peak current on sampling resistor Rcs of power switch; Output equivalent Current calculation circuit 105, the peak meter according to the sampled voltage Vcs on sampling resistor Rcs calculates output equivalent electric current; Trsanscondutance amplifier 101, does error to output equivalent electric current and fiducial value Vref1 and amplifies, and output error signal is to loop compensation end COMP; Loop compensation end COMP, this loop compensation end COMP can additional compensating element,s, are generally made up of resistance, electric capacity connection in series-parallel, carry out control loop by error signal Vcomp; Pwm signal generation circuit 102, receive error signal Vcomp, produce pwm signal to logic control circuit 103, the duty ratio of pwm signal is relevant to error signal Vcomp, and logic control circuit 103 produces pre-drive signal GT1 through drive circuit 104 driving power switch M1.
Wherein, the precision of output current and fiducial value Vref1, peak value sampling retention value are relevant, also relevant to the precision of trsanscondutance amplifier 101, and for the consistency of circuit, the precision of trsanscondutance amplifier 101 has conclusive effect.
With reference to figure 2, in traditional transconductance type error amplifier circuit, MOS transistor N1, N2 are as input to pipe, and resistance R1 and resistance R2 is used for widening the input linear scope of error amplifier, if input linear scope is enough, resistance R1 and resistance R2 can omit.MOS transistor P1, P2, P3, P4, N4, N5 are as intergrade, and mirror image delivered current, makes output current Iout=Gm*(Vp-Vn), Iout is output current, and Gm is mutual conductance, and Vp is the magnitude of voltage of positive input signal, and Vn is the magnitude of voltage of negative input signal.Wherein, the size of mutual conductance Gm with as the MOS transistor N1 of input pipe, the size of N2, the size of resistance R1 and resistance R2, and the ratio that image current transmits is correlated with.
The mismatch of trsanscondutance amplifier can cause actual value and the desired value generation deviation of control.
Especially use in the LED drive circuit of trsanscondutance amplifier at LED drive circuit, in order to the consistency of circuit is carried out, with regard to requiring, the mutual conductance of circuit is done accurately, and reduce the imbalance of circuit as far as possible.But due at the deviation of processes manufacture process and encapsulation stress, symmetrical input pipe, synistor and the image current designed can be caused to become mismatch, thus cause the mutual conductance of side circuit no longer accurate, the imbalance of circuit obviously increases.In order to reduce this mismatch, general need all meetings cause the element of mismatch to do symmetrical as much as possible, comprise the Central Symmetry of domain, and strengthen the size of symmetric element, but can cause like this needing larger chip area, also just add coupling cost.In addition, even if use these measures, still not can solve the problem that mismatch causes, especially mismatch is subject to the impact of encapsulation stress, strengthens the effect of size of symmetric element and not obvious.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of trsanscondutance amplifier and constant current driver circuit for LED, can reduce the trsanscondutance amplifier imbalance because device matching and encapsulation stress cause, be conducive to the consistency improving circuit.
For solving the problems of the technologies described above, the invention provides a kind of trsanscondutance amplifier, comprising:
Differential input stage circuit, comprises the first Voltage-current conversion circuit and the second Voltage-current conversion circuit;
Current transfer circuit, transmits the electric current that described differential input stage circuit exports;
Input switch network, switches the positive input signal inputted and negative input signal, makes described positive input signal and negative input signal alternately input to the input of described first Voltage-current conversion circuit and the second Voltage-current conversion circuit;
Current delivery switching network, switches the current delivery path of described current transfer circuit, makes the output signal of described trsanscondutance amplifier and described positive input signal keep positive polarity, and keeps reversed polarity with described negative input signal;
Clock-signal generator, described clock-signal generator produces the first clock signal and the second clock signal of periodic non-overlapping, this first clock signal and second clock signal inversion, this first clock signal and second clock signal are for controlling described input switch network and current delivery switching network, described clock-signal generator also produces the 3rd clock signal and the 4th clock signal of periodic non-overlapping, 3rd clock signal and the 4th clock signal anti-phase, the 3rd clock signal and the 4th clock signal are for controlling described current delivery switching network.
According to one embodiment of present invention, described input switch network comprises:
First switch, its first end receives described negative input signal, and its second end connects the input of described first Voltage-current conversion circuit, and its control end receives described first clock signal;
Second switch, its first end receives described positive input signal, and its second end connects the input of described first Voltage-current conversion circuit, and its control end receives described second clock signal;
3rd switch, its first end receives described positive input signal, and its second end connects the input of described second Voltage-current conversion circuit, and its control end receives described first clock signal;
4th switch, its first end receives described negative input signal, and its second end connects the input of described second Voltage-current conversion circuit, and its control end receives described second clock signal.
According to one embodiment of present invention,
Described current transfer circuit comprises:
First mirror current source, its input is connected with the output of described first Voltage-current conversion circuit;
Second mirror current source, its input is connected with the output of described second Voltage-current conversion circuit;
First mirror image pipe;
Second mirror image pipe, its source electrode is connected with the source electrode of described first mirror image pipe, and its grid is connected with the grid of described first mirror image pipe;
Described current delivery switching network comprises:
5th switch, its first end connects the output of described first mirror current source, and its second end connects the output of described trsanscondutance amplifier, and its control end receives described second clock signal;
6th switch, its first end connects the output of described first mirror current source, and its control end receives described first clock signal;
7th switch, its first end connects the output of described second mirror current source, and its second end connects the second end of described 6th switch, and its control end receives described second clock signal;
8th switch, its first end connects the output of described second mirror current source, and its second end connects the second end of described 5th switch, and its control end receives described first clock signal;
9th switch, its first end connects the second end of described 7th switch, and its second end connects the drain electrode of described first mirror image pipe, and its control end receives described 4th clock signal;
Tenth switch, its first end connects the second end of described 7th switch and the grid of described first mirror image pipe and the second mirror image pipe, and its second end connects the drain electrode of described second mirror image pipe, and its control end receives described 3rd clock signal;
11 switch, its first end connects the second end of described 8th switch, and its second end connects the drain electrode of described first mirror image pipe, and its control end receives described 3rd clock signal;
Twelvemo is closed, and its first end connects the second end of described 8th switch, and its second end connects the drain electrode of described second mirror image pipe, and its control end receives described 4th clock signal.
According to one embodiment of present invention, the duty ratio of described first clock signal, second clock signal, the 3rd clock signal and the 4th clock signal is 0.5.
According to one embodiment of present invention, described first Voltage-current conversion circuit comprises the first Differential Input to pipe, and described second Voltage-current conversion circuit comprises the second Differential Input to pipe.
According to one embodiment of present invention, described first differential pair tube and the first resistant series, described second differential pair tube and the second resistant series.
According to one embodiment of present invention, described first Differential Input to pipe and the second Differential Input to pipe for nmos pass transistor, NPN triode, PMOS transistor or PNP triode.
Present invention also offers a kind of constant current driver circuit for LED, comprise the trsanscondutance amplifier described in above any one.
According to one embodiment of present invention, this constant current driver circuit for LED comprises constant-current control circuit, transformer, switching tube, sampling resistor, fly-wheel diode and output capacitance, wherein,
The Same Name of Ends of the former limit winding of described transformer receives input voltage, the Same Name of Ends ground connection of the vice-side winding of described transformer, and the different name end of the vice-side winding of described transformer connects the positive pole of described fly-wheel diode;
The drain electrode of described switching tube connects the different name end of the former limit winding of described transformer, and the grid of described switching tube connects the output of described constant-current control circuit;
The first end of described sampling resistor connects the source electrode of described switching tube and the sampling input of described constant-current control circuit, the second end ground connection of described sampling resistor;
The first end of described output capacitance connects the negative pole of described fly-wheel diode, the second end ground connection of described output capacitance,
Described constant-current control circuit comprises:
Peak sampling hold circuit, its input connects the sampling input of described constant-current control circuit, samples to the sampled voltage on described sampling resistor;
Output equivalent Current calculation circuit, its input is connected with the output of described peak sampling hold circuit, calculates output equivalent electric current according to described sampled voltage, and exports the equivalent voltage representing this output equivalent electric current;
Trsanscondutance amplifier described in above-mentioned any one, its first input end connects the output of described output equivalent Current calculation circuit, and its second input receives reference voltage, carries out error amplification to described equivalent voltage and reference voltage;
Pwm signal generation circuit, its input connects the output of described trsanscondutance amplifier, and produce pwm signal according to the error signal that described trsanscondutance amplifier exports, the duty ratio of described pwm signal is regulated by described error signal;
Logic and driver circuitry, its input connects the output of described pwm signal generation circuit, and described pwm signal transfers to the grid of described switching tube via this logic and driver circuitry.
Compared with prior art, the present invention has the following advantages:
In the trsanscondutance amplifier of the embodiment of the present invention, adopt input switch network positive input signal and negative input signal to be replaced in other words periodically alternately and input to two inputs of differential input stage circuit, and adopt the current delivery path of current delivery switching network to current transfer circuit to switch, make the output signal of trsanscondutance amplifier and positive input signal remain positive polarity.On the one hand, because positive and negative input signal alternately inputs to two inputs of differential input stage circuit, therefore the imbalance between the first Voltage-current conversion circuit of differential input stage circuit inside and the second Voltage-current conversion circuit can be cancelled out each other, and drastically increases the consistency of circuit; On the other hand, because current delivery path is alternately switching, the imbalance therefore in current transfer circuit between each device is also cancelled out each other, and is conducive to the consistency improving circuit.
Accompanying drawing explanation
Fig. 1 is the electrical block diagram of a kind of LED drive circuit in prior art;
Fig. 2 is the electrical block diagram of a kind of trsanscondutance amplifier in prior art;
Fig. 3 is the electrical block diagram of the trsanscondutance amplifier of the embodiment of the present invention;
Fig. 4 is the oscillogram of the clock signal of the embodiment of the present invention;
Fig. 5 is the structural representation of the clock-signal generator of the embodiment of the present invention;
Fig. 6 is the electrical block diagram of the constant current driver circuit for LED of the embodiment of the present invention.
Embodiment
Below in conjunction with specific embodiments and the drawings, the invention will be further described, but should not limit the scope of the invention with this.
With reference to figure 3, the trsanscondutance amplifier of the present embodiment comprises: input switch network 200, differential input stage circuit 201, current transfer circuit, current delivery switching network and clock-signal generator.
Furthermore, differential input stage circuit 201 comprises the first Voltage-current conversion circuit and the second Voltage-current conversion circuit.In the present embodiment, first Voltage-current conversion circuit comprises the first resistance R1 of the first Differential Input to pipe N1 and series connection with it, second Voltage-current conversion circuit comprises the second resistance R2 of the second Differential Input to pipe N2 and series connection with it, differential input stage circuit 201 is connected to ground via transistor N3, and the grid of transistor N3 receives bias voltage Vbias.Wherein, the first resistance R1 and the second resistance R2, for increasing input linear scope, is optional.First Differential Input can be nmos pass transistor, NPN triode, PMOS transistor or PNP tri-machine pipe to pipe N1 and the second Differential Input to pipe N2, or also can be other suitable transistors.As a nonrestrictive example, in the example shown in Fig. 3, the first Differential Input is nmos pass transistor to pipe N1 and the second Differential Input to pipe N2.
Input switch network 200 carries out periodicity to the positive input signal Vp of input and negative input signal Vn and switches, and makes positive input signal Vp and negative input signal Vn alternately input to the input of the first Voltage-current conversion circuit and the second Voltage-current conversion circuit.It should be noted that, " just " and " bearing " herein in positive input signal Vp and negative input signal Vn is only for distinguishing two-way input signal, and the non-limiting voltage of two-way input signal or the polar relationship of electric current, the two can be such as positive voltage signal.
In the present embodiment, this input switch network 200 comprises switch S 1, switch S 2, switch S 3, switch S 4.Wherein, the first end of switch S 1 receives negative input signal Vn, and the second end connects the input (being specially the grid of MOS transistor N1 in the present embodiment) of the first Voltage-current conversion circuit, and its control end receives the first clock signal C H0; The first end of switch S 2 receives positive input signal Vp, and its second end connects the input (being specially the grid of MOS transistor N1 in the present embodiment) of the first Voltage-current conversion circuit, and its control end receives second clock signal CL0; The first end of switch S 3 receives positive input signal Vp, and its second end connects the input (being specially the grid of MOS transistor N2 in the present embodiment) of the second Voltage-current conversion circuit, and its control end receives the first clock signal C H0; The first end of switch S 4 receives negative input signal Vn, and its second end connects the input (being specially the grid of MOS transistor N2 in the present embodiment) of the second Voltage-current conversion circuit, and its control end receives second clock signal CL0.
The electric current that current transfer circuit is used for differential input stage circuit 201 exports transmits, and in the present embodiment, this current transfer circuit comprises the first mirror current source 203, second mirror current source 204, mirror image pipe N4 and mirror image pipe N5.Wherein, the input of the first mirror current source 203 is connected with the output of the first Voltage-current conversion circuit; The input of the second mirror current source 204 is connected with the output of the second Voltage-current conversion circuit.As a nonrestrictive example, the first mirror current source 203 comprises mirror image pipe P1 and mirror image pipe P2; Second mirror current source 204 comprises mirror image pipe P3 and mirror image pipe P4.
It will be appreciated by those skilled in the art that each mirror current source 203,204 above-mentioned can adopt MOS transistor transmission, also can adopt triode transmission, amplifier architecture can also be used to realize transmitting.
Current delivery switching network comprises: switching network 202, switching network 205 and mirror image pipe switch unit 207, and wherein, switching network 202 comprises switch S 5 and switch S 6; Switching network 205 comprises switch S 7 and S8; Mirror image pipe switch unit 207 comprises switch S 9, switch S 10, switch S 11 and switch S 12; The current mirror relation of this mirror image pipe switch unit 207 couples of mirror image pipe N4 and mirror image pipe N5 carries out alternately switching, switching state comprises following two kinds: be passed to mirror image pipe N5 by mirror image pipe N4, and be passed to mirror image pipe N4 by mirror image pipe N5, that is, under different clock signals controls, mirror image pipe N4 and N5 will form mirror current source, and the current mirror relation of the mirror current source formed also is done periodically to switch under control of the clock signal.
Furthermore, the first end of switch S 5 connects the output of the first mirror current source 203, and the second end of switch S 5 connects the output of trsanscondutance amplifier, and the control end of switch S 5 receives second clock signal CL0; The first end of switch S 6 connects the output of the first mirror current source 103, and the control end of switch S 6 receives the first clock signal C H0; The first end of switch S 7 connects the output of the second mirror current source 204, second end of the second end connecting valve S6 of switch S 7, and the control end of switch S 7 receives second clock signal CL0; The first end of switch S 8 connects the output of the second mirror current source 204, second end of the second end connecting valve S5 of switch S 8, and the control end of switch S 8 receives the first clock signal C H0; Second end of the first end connecting valve S7 of switch S 9, the second end of switch S 9 connects the drain terminal of mirror image pipe N4, and the control end of switch S 9 receives the 4th clock signal C L1; Second end of the first end connecting valve S7 of switch S 10, the second end of switch S 10 connects the drain terminal of mirror image pipe N5, and the control end of switch S 10 receives the 3rd clock signal C H1; Second end of the first end connecting valve S8 of switch S 11, the second end of switch S 11 connects the drain terminal of mirror image pipe N4, and the control end of switch S 11 receives the 3rd clock signal C H1; Second end of the first termination switch S 8 of switch S 12, the second end of switch S 12 connects the drain terminal of mirror image pipe N5, and the control end of switch S 12 receives the 4th clock signal C L1; Mirror image pipe N4 is connected with the grid of mirror image pipe N5 and is connected to the second end of switch S 7, and the source electrode of mirror image pipe N4 and mirror image pipe N5 links together (such as can ground connection).
Composition graphs 3 to Fig. 5 simultaneously, the first clock signal C H0, second clock signal CL0, the 3rd clock signal C H1 and the 4th clock signal C L1 can be produced by clock-signal generator 220.This first clock signal C H0 and second clock signal CL0 is periodic, inverting each other and non-overlapping; 3rd clock signal C H1 and the 4th clock signal C L1 is also periodic, inverting each other and non-overlapping.This clock-signal generator 220 can adopt any suitable structure in prior art to realize.Preferably, this first clock signal C H0, second clock signal CL0, the 3rd clock signal C H1 and the 4th clock signal C L1 can be the square-wave signal of duty ratio 0.5.
As a nonrestrictive example, when second clock signal CL0 for logic is high and the first clock signal C H0 is logic low time, switch S 2, S4, S5, S7 conducting, switch S 1, S3, S6, S8 disconnects, the first input end of trsanscondutance amplifier meets negative input signal Vn, second input termination positive input signal Vp of trsanscondutance amplifier, the output of negative input signal Vn and trsanscondutance amplifier is reversed polarity, namely negative input signal Vn adds conference and causes the voltage of output to reduce, the output signal of the output of positive input signal Vp and trsanscondutance amplifier is positive polarity, namely positive input signal Vp adds conference and causes the voltage of output to raise.
When when second clock signal CL0 is logic low, the first clock signal C H0 is logic height, switch S 1, S3, S6, S8 conducting, switch S 2, S4, S5, S7 disconnects, the first input end of trsanscondutance amplifier meets positive input signal Vp, second input termination negative input signal Vn of trsanscondutance amplifier, the output signal of the output of negative input signal Vn and trsanscondutance amplifier is still in reversed polarity, namely negative input signal Vn adds conference and causes the voltage of output to reduce, the output signal of the output of positive input signal Vp and trsanscondutance amplifier is still in positive polarity, namely positive input signal Vp adds conference and causes the voltage of output to raise.
Like this, under second clock signal CL0 and the first clock signal C H0 controls, by the transitive relation of switch current transfer circuit while switching the input signal that the input of trsanscondutance amplifier receives, remain output and the negative input signal Vn reversed polarity of mutual conductance error amplifier, keep output and the positive input signal Vp positive polarity of trsanscondutance amplifier.
The 4th clock signal C L1 for high and the 3rd clock signal C H1 is low time, switch S 9, S12 conducting, switch S 10, S11 turn off, and current mirror is transmitted to mirror image pipe N5 by mirror image pipe N4; The 4th clock signal C L1 for low and the 3rd clock signal C H1 is high time, switch S 9, S12 turn off, switch S 10, S11 conducting, current mirror is transmitted to mirror image pipe N4 by mirror image pipe N5, can effectively reduce the imbalance that the mismatch due to mirror image pipe N4 and mirror image pipe N5 causes thus.
Under controlling at clock signal C L0 and CH0, mirror image pipe P1 and mirror image pipe P2, mirror image pipe P3 and mirror image pipe P4 is fixedly connected on Differential Input to the drain terminal of pipe N1 and Differential Input to the drain terminal of pipe N2, when Differential Input receives positive input signal Vp and negative input signal Vn to pipe N1 and Differential Input in turn to pipe N2, mirror image pipe P1 and P2, the electric current of mirror image pipe P3 and P4 is also in turn corresponding to flowing through the electric current of Differential Input to pipe N1 and N2, according to analysis identical above, mirror image pipe P1 and P2, the mismatch of mirror image pipe P3 and P4 is also be eliminated under the clock signal C L0 of 0.5 and CH0 controls in duty ratio, therefore, for mirror image pipe P1 and P2, mirror image pipe P3 and P4 does not need the way adopting similar mirror image pipe N4 and N5, the switching carrying out current mirror relation is not namely needed yet.
In trsanscondutance amplifier, the size of current Iout of output is expressed as: Iout=Gm*(Vp-Vn), wherein Gm is the mutual conductance of setting, and Vp is the magnitude of voltage of positive input signal, and Vn is the magnitude of voltage of negative input signal.The correlative factor of the size of mutual conductance Gm has: Differential Input to pipe N1 and Differential Input to the size of pipe N2, the size of resistance R1 and resistance R2, mirror image pipe P1 and mirror image pipe P2 size, mirror image pipe P3 and mirror image pipe P4 size, mirror image pipe N4 and mirror image pipe N5 size.
When requiring mutual conductance Gm precision higher, need Differential Input symmetrical to pipe N2 to pipe N1 and Differential Input, resistance R1 and resistance R2 is symmetrical, and mirror image pipe P1 and mirror image pipe P2 is symmetrical, and mirror image pipe P3 and mirror image pipe P4 is symmetrical, and mirror image pipe N4 and mirror image pipe N5 is symmetrical.Above symmetrical device in fact can not accomplish full symmetric, can there is imbalance, thus can cause the imbalance of amplifier.When the trsanscondutance amplifier of lacking of proper care is used as loop control, the reduction of control precision can be caused, affect the consistency of circuit.Such as, be constant voltage generation deviation for Isobarically Control, be constant current generation deviation for current constant control, is firm power generation deviation for invariable power, etc.
Suppose, under the differential input stage circuit mismatch of trsanscondutance amplifier causes identical positive input signal Vp, negative input signal Vn, flow through the electric current of Differential Input to pipe N1 and be greater than and flow through the electric current of Differential Input to pipe N2.When controlling when adopting a pair inverting clock signal CL0 and CH0 of periodic non-overlapping to switch, because the Differential Input of trsanscondutance amplifier receives positive input signal Vp and negative input signal Vn in turn to pipe N1 and N2.When negative input signal Vn transfers to Differential Input to pipe N1, the electric current that negative input signal Vn is corresponding is relatively large; When positive input signal Vp is connected to Differential Input to pipe N1, the electric current that positive input signal Vp is corresponding is relatively large.If the duty ratio arranging second clock signal CL0 and the first clock signal C H0 is 0.5, then in whole one-period, the imbalance of the electric current that the negative input signal Vn caused due to differential input stage circuit and positive input signal Vp is corresponding will be repealed by implication, and drastically increase the consistency of circuit.
From above scheme, the major function of differential input stage circuit 201 is that voltage transitions is become electric current, and the major function of current transfer circuit transmits electric current, therefore, the voltage transitions circuit configuration of any appropriate format can be used to replace differential input stage circuit 201, the current delivery structure of any appropriate format can be used to replace current transfer circuit, include but not limited to various current-mirror structure.
Show the constant current driver circuit for LED of the present embodiment with reference to figure 6, Fig. 6, comprising: constant-current control circuit 900, transformer T1, switching tube M1, sampling resistor Rcs, sustained diode 2, output capacitance Cbulk.Wherein, the Same Name of Ends of the former limit winding L 2 of transformer T1 receives input voltage vin, and the different name end of the vice-side winding L3 of transformer T1 connects the positive pole of sustained diode 2, the Same Name of Ends ground connection of vice-side winding L3; The drain electrode of switching tube M1 connects the different name end of former limit winding L 2, and the grid of switching tube M1 connects the output of constant-current control circuit 900; The source electrode of first end connecting valve pipe M1 of sampling resistor Rcs and the sampling input of constant-current control circuit 900, the second end ground connection of sampling resistor Rcs; The first end of output capacitance Cbulk connects the negative pole of sustained diode 2, the second end ground connection of output capacitance Cbulk.It should be noted that, " ground connection " refers to and is connected to conventional ground herein, and non-floatingly.
Furthermore, constant-current control circuit 900 comprises: trsanscondutance amplifier 901, pwm signal generation circuit 902, logic and driver circuitry 903, output equivalent Current calculation circuit 904 and peak sampling hold circuit 905.。
Wherein, the input of peak sampling hold circuit 905 connects the sampling input of constant-current control circuit 900, samples to the sampled voltage on sampling resistor Rcs; The input of output equivalent Current calculation circuit 904 is connected with the output of peak sampling hold circuit 905, according to adopting the sampled voltage obtained to calculate output equivalent electric current, and exports the equivalent voltage representing this output equivalent electric current; The first input end of trsanscondutance amplifier 901 connects the output of output equivalent Current calculation circuit 904, and its second input receives reference voltage Vref 1, carries out error amplification to equivalent voltage and reference voltage Vref 1; The input of pwm signal generation circuit 902 connects the output of trsanscondutance amplifier 901, and produce pwm signal GT1 according to the error signal that trsanscondutance amplifier 901 exports, the duty ratio of this pwm signal GT1 is regulated by above-mentioned error signal; The input of logic and driver circuitry 903 connects the output of pwm signal generation circuit 902, pwm signal GT1 obtains drive singal GT via after the process of this logic and driver circuitry 903, this drive singal GT transfers to the grid of switching tube M1, in order to the turn-on and turn-off of control switch pipe M1.
In addition, this constant-current control circuit 900 can also have compensation port COMP, and this compensation port COMP is connected with the output of trsanscondutance amplifier 901 and the input of pwm signal generation circuit 902.This compensation port COMP can external compensating element, such as, by resistance, capacitances in series or be formed in parallel.
The structure of the trsanscondutance amplifier 901 in Fig. 6 is the transconductance amplifier circuit structure shown in Fig. 3, no longer elaborates here.Because trsanscondutance amplifier 901 adopts the bang path of input switch network and current delivery switching network switched differential input stage circuit and mirror current source in turn, the consistency of output current therefore can be significantly improved.
It will be appreciated by those skilled in the art that Fig. 6 is only signal, in fact, the trsanscondutance amplifier structure of the present embodiment can be applied to any comprising in the LED drive circuit of trsanscondutance amplifier.
The above is only preferred embodiment of the present invention, not does any pro forma restriction to the present invention.Therefore, every content not departing from technical solution of the present invention, just according to technical spirit of the present invention to any simple amendment made for any of the above embodiments, equivalent conversion, all still belong in the protection range of technical solution of the present invention.
Claims (9)
1. for a trsanscondutance amplifier for constant current driver circuit for LED, it is characterized in that, comprising:
Differential input stage circuit, comprises the first Voltage-current conversion circuit and the second Voltage-current conversion circuit;
Current transfer circuit, transmits the electric current that described differential input stage circuit exports;
Input switch network, switches the positive input signal inputted and negative input signal, makes described positive input signal and negative input signal alternately input to the input of described first Voltage-current conversion circuit and the second Voltage-current conversion circuit;
Current delivery switching network, switches the current delivery path of described current transfer circuit, makes the output signal of described trsanscondutance amplifier and described positive input signal keep positive polarity, and keeps reversed polarity with described negative input signal;
Clock-signal generator, produce the first clock signal and the second clock signal of periodic non-overlapping, this first clock signal and second clock signal inversion, this first clock signal and second clock signal are for controlling described input switch network and current delivery switching network, described clock-signal generator also produces the 3rd clock signal and the 4th clock signal of periodic non-overlapping, 3rd clock signal and the 4th clock signal anti-phase, the 3rd clock signal and the 4th clock signal are for controlling described current delivery switching network;
Wherein, the external compensating element, of output of described trsanscondutance amplifier, described compensating element, is by resistance, capacitances in series or be formed in parallel.
2. trsanscondutance amplifier according to claim 1, is characterized in that, described input switch network comprises:
First switch, its first end receives described negative input signal, and its second end connects the input of described first Voltage-current conversion circuit, and its control end receives described first clock signal;
Second switch, its first end receives described positive input signal, and its second end connects the input of described first Voltage-current conversion circuit, and its control end receives described second clock signal;
3rd switch, its first end receives described positive input signal, and its second end connects the input of described second Voltage-current conversion circuit, and its control end receives described first clock signal;
4th switch, its first end receives described negative input signal, and its second end connects the input of described second Voltage-current conversion circuit, and its control end receives described second clock signal.
3. trsanscondutance amplifier according to claim 1, is characterized in that,
Described current transfer circuit comprises:
First mirror current source, its input is connected with the output of described first Voltage-current conversion circuit;
Second mirror current source, its input is connected with the output of described second Voltage-current conversion circuit;
First mirror image pipe;
Second mirror image pipe, its source electrode is connected with the source electrode of described first mirror image pipe, and its grid is connected with the grid of described first mirror image pipe;
Described current delivery switching network comprises:
5th switch, its first end connects the output of described first mirror current source, and its second end connects the output of described trsanscondutance amplifier, and its control end receives described second clock signal;
6th switch, its first end connects the output of described first mirror current source, and its control end receives described first clock signal;
7th switch, its first end connects the output of described second mirror current source, and its second end connects the second end of described 6th switch, and its control end receives described second clock signal;
8th switch, its first end connects the output of described second mirror current source, and its second end connects the second end of described 5th switch, and its control end receives described first clock signal;
9th switch, its first end connects the second end of described 7th switch, and its second end connects the drain electrode of described first mirror image pipe, and its control end receives described 4th clock signal;
Tenth switch, its first end connects the second end of described 7th switch and the grid of described first mirror image pipe and the second mirror image pipe, and its second end connects the drain electrode of described second mirror image pipe, and its control end receives described 3rd clock signal;
11 switch, its first end connects the second end of described 8th switch, and its second end connects the drain electrode of described first mirror image pipe, and its control end receives described 3rd clock signal;
Twelvemo is closed, and its first end connects the second end of described 8th switch, and its second end connects the drain electrode of described second mirror image pipe, and its control end receives described 4th clock signal.
4. trsanscondutance amplifier according to claim 1, is characterized in that, the duty ratio of described first clock signal, second clock signal, the 3rd clock signal and the 4th clock signal is 0.5.
5. trsanscondutance amplifier according to claim 1, is characterized in that, described first Voltage-current conversion circuit comprises the first Differential Input to pipe, and described second Voltage-current conversion circuit comprises the second Differential Input to pipe.
6. trsanscondutance amplifier according to claim 5, is characterized in that, described first differential pair tube and the first resistant series, described second differential pair tube and the second resistant series.
7. trsanscondutance amplifier according to claim 5, is characterized in that, described first Differential Input to pipe and the second Differential Input to pipe for nmos pass transistor, NPN triode, PMOS transistor or PNP triode.
8. a constant current driver circuit for LED, is characterized in that, comprises the trsanscondutance amplifier according to any one of claim 1 to 7.
9. constant current driver circuit for LED according to claim 8, is characterized in that, described constant current driver circuit for LED comprises constant-current control circuit, transformer, switching tube, sampling resistor, fly-wheel diode and output capacitance, wherein,
The Same Name of Ends of the former limit winding of described transformer receives input voltage, the Same Name of Ends ground connection of the vice-side winding of described transformer, and the different name end of the vice-side winding of described transformer connects the positive pole of described fly-wheel diode;
The drain electrode of described switching tube connects the different name end of the former limit winding of described transformer, and the grid of described switching tube connects the output of described constant-current control circuit;
The first end of described sampling resistor connects the source electrode of described switching tube and the sampling input of described constant-current control circuit, the second end ground connection of described sampling resistor;
The first end of described output capacitance connects the negative pole of described fly-wheel diode, the second end ground connection of described output capacitance,
Described constant-current control circuit comprises:
Peak sampling hold circuit, its input connects the sampling input of described constant-current control circuit, samples to the sampled voltage on described sampling resistor;
Output equivalent Current calculation circuit, its input is connected with the output of described peak sampling hold circuit, calculates output equivalent electric current according to described sampled voltage, and exports the equivalent voltage representing this output equivalent electric current;
Trsanscondutance amplifier according to any one of claim 1 to 7, its first input end connects the output of described output equivalent Current calculation circuit, and its second input receives reference voltage, carries out error amplification to described equivalent voltage and reference voltage;
Pwm signal generation circuit, its input connects the output of described trsanscondutance amplifier, and produce pwm signal according to the error signal that described trsanscondutance amplifier exports, the duty ratio of described pwm signal is regulated by described error signal;
Logic and driver circuitry, its input connects the output of described pwm signal generation circuit, and described pwm signal transfers to the grid of described switching tube via this logic and driver circuitry.
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| CN104238614A (en) * | 2014-09-03 | 2014-12-24 | 李倩 | Reference voltage circuit |
| CN109275233B (en) * | 2018-11-12 | 2024-04-23 | 厦门芯达茂微电子有限公司 | Constant-power LED driver |
| CN111867183B (en) * | 2019-04-08 | 2022-11-22 | 华润微集成电路(无锡)有限公司 | LED drive circuit, power frequency square wave signal sampling circuit and method |
| CN113014074B (en) * | 2021-02-25 | 2022-07-29 | 杭州士兰微电子股份有限公司 | Constant current control circuit, constant current drive circuit and constant current control method |
| CN113114179A (en) * | 2021-03-18 | 2021-07-13 | 杭州士兰微电子股份有限公司 | Comparator circuit, constant current control circuit and constant current drive circuit |
| CN113473671B (en) | 2021-07-28 | 2022-09-23 | 上海晶丰明源半导体股份有限公司 | Control circuit for constant current type drive circuit and constant current type drive circuit |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101394163B (en) * | 2008-10-09 | 2011-06-15 | 豪威国际控股有限公司 | Signal conditioning circuit and dual sampling-hold circuit |
| JP2011008028A (en) * | 2009-06-25 | 2011-01-13 | Sony Corp | Signal line driving circuit, display device, and electronic equipment |
| CN203504817U (en) * | 2013-09-12 | 2014-03-26 | 杭州士兰微电子股份有限公司 | Transconductance amplifier and LED constant current drive circuit |
-
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