CN103906314A - LED drive circuit and method based on voltage memory and segmented current limiting - Google Patents
LED drive circuit and method based on voltage memory and segmented current limiting Download PDFInfo
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Abstract
The invention discloses an LED drive circuit and method based on voltage memory and segmented current limiting. The circuit comprises a rectifying circuit, a voltage division circuit, a voltage increasing and reducing detection module, a voltage memory module, a comparator set, a control logic module, a high-voltage switch circuit, a detection resistor, a current detection comparator and an LED lamp string. According to the drive method of the circuit, according to the increasing and reducing characteristics of the directly-rectified direct-current ripple voltages, the segmented type lightening control mode is adopted in the load of the LED lamp string. The drive circuit solves the problem of the influence of the difference of voltage current characteristics of an LED chip adopted by the lamp string in the actual application on drive currents, the work current of the LED lamp string in the whole work period is limited within the designed largest current value Imax, the problems of lower brightness caused by undercurrents and damage, caused by overcurrents, to the LED chip are solved, the light-emitting efficiency of the LED lamp is improved, and meanwhile overcurrent protection can be carried out on an LED device well.
Description
Technical field
The present invention relates to a kind of LED drive circuit and method, especially a kind ofly utilize DC pulse moving voltage after the direct rectification of electric main to power, use LED drive circuit and the method for voltage memory and segmentation current limliting, belong to LED Driving technique field.
Background technology
LED illumination driving circuit, can make to adopt LED as the lighting apparatus of the luminescent device needed power circuit of can normally working exactly, can provide required voltage and current for the normal work of LED device.LED illumination driving circuit structural framing as shown in Figure 1, is mainly made up of rectification circuit, auxiliary power circuit, power converting circuit and feedback loop.The electric main of input is transformed into high direct voltage through rectification circuit, high direct voltage produces stable DC low-voltage power supply source translation circuit by auxiliary power circuit and uses, power converting circuit is converted into the required voltage and current of LED device work high direct voltage, feedback loop detects the operating state of LED, makes the operating voltage of LED device and current stabilization on design point by FEEDBACK CONTROL.
At present, because LED has higher efficiency than conventional light source at energy-saving square mask, its application is more and more extensive, and the driving power structure using in various LED illuminating products is also more and more abundanter.As shown in Figure 2, its course of work is as follows to existing LED segmented power supply: when Output Voltage in Rectified Circuits is during lower than U1, and NMOS pipe Q1, Q2, Q3, Q4 conducting, L1 section LED work; Output Voltage in Rectified Circuits is higher than U1 during lower than U2, and NMOS pipe Q1 turn-offs, Q2, Q3, Q4 conducting, L1, L2 section LED work; Output Voltage in Rectified Circuits is higher than U2 during lower than U3, and NMOS pipe Q1, Q2 turn-off, Q3, Q4 conducting, L1, L2, L3 section LED work; Output Voltage in Rectified Circuits is higher than U3 during lower than U4, and NMOS pipe Q1, Q2, Q3 turn-off, Q4 conducting, L1, L2, L3, L4 section LED work; When Output Voltage in Rectified Circuits is during higher than U4, NMOS pipe Q1, Q2, Q3, Q4 turn-off, and L1, L2, L3, L4 section LED do not work.
LED segmented drive circuit described above carries out voltage energy storage without electrochemical capacitor, power factor (PF) is higher, the whole lamp life-span can not be limited by electric capacity yet, but this type of drive also has weak point, from the voltage-current characteristic of LED device, under its normal working voltage condition, the tiny difference of voltage can cause the obvious fluctuation of electric current, and the light intensity of LED is main and flow through the current related of LED; In actual applications, even the LED chip of same batch of production of same producer, its volt-ampere characteristic also can exist difference, therefore according to fixed partial pressure than the type of drive of carrying out segmentation, due to the reference voltage precision for comparing and the reason of LED chip voltage-current characteristic difference, make the operating current of LED in lamp string can not accurately predicting and design, occur the driving condition of undercurrent or overcurrent.Undercurrent can cause the brightness of lamp string partially dark, and overcurrent can cause damage to LED chip.
Summary of the invention
The object of the invention is the defect in order to solve above-mentioned prior art, provide a kind of simple in structure, easy to use, neither need to adopt perceptual device, the LED drive circuit with segmentation current limliting based on voltage memory that also need not electrochemical capacitor.
Another object of the present invention is to provide a kind of driving method of the LED drive circuit based on voltage memory and segmentation current limliting.
Object of the present invention can be by taking following technical scheme to reach:
LED drive circuit based on voltage memory with segmentation current limliting, comprise rectification circuit, bleeder circuit, comparator bank, high voltage switch circuit and LED lamp string, described rectification circuit is connected with bleeder circuit, described high voltage switch circuit and LED lamp series winding connect, described LED lamp string is connected with rectification circuit, it is characterized in that: also comprise voltage rise and fall detection module, voltage memory module, control logic module, inspection leakage resistance and inspection stream comparator, described voltage memory module, comparator bank, control logic module, high voltage switch circuit and LED lamp string are connected successively; Described bleeder circuit is connected with voltage rise and fall detection module and voltage memory module respectively, and described voltage rise and fall detection module is connected with voltage memory module and control logic module respectively, and described control logic module is connected with voltage memory module; Described high voltage switch circuit is held and is connected altogether with power supply by inspection leakage resistance, an input termination of described inspection stream comparator is examined the points of common connection of leakage resistance and high voltage switch circuit, another input termination reference voltage, the output of described inspection stream comparator is connected with control logic module.
Preferably, described voltage memory module is made up of multiple voltage retainers, and the output of described each voltage retainer is connected with comparator bank respectively.
Preferably, described each voltage retainer is made up of electric capacity and operational amplifier.
Preferably, described comparator bank is made up of multiple voltage comparators, an input of described each voltage comparator and the output of each voltage retainer connect one to one, after another input is connected together, be connected with bleeder circuit, the output of described each voltage comparator is connected with control logic module respectively.
Preferably, described control logic module is by multiple d type flip flops and complete the required combined digital logical constitution of function, and described control logic module is using output, the output of voltage rise and fall detection module and the output of inspection stream comparator of each voltage comparator in comparator bank as input signal.
Preferably, described voltage rise and fall detection module is made up of differentiation element circuit and voltage comparator, the square-wave signal of output instruction DC pulse moving voltage rise and fall state.
Preferably, described high voltage switch circuit is made up of multiple high pressure NMOS pipes, and the on off state of the store status of described each d type flip flop and each high pressure NMOS pipe is corresponding one by one; After the source electrode of described each high pressure NMOS pipe is connected together, holds and be connected altogether with power supply through inspection leakage resistance, the points of common connection of an input termination inspection leakage resistance of described inspection stream comparator and the source electrode of each high pressure NMOS pipe, another input termination reference voltage; The drain electrode of described each high pressure NMOS pipe and LED lamp series winding connect.
Preferably, described LED lamp string is composed in series by multiple LED lamp sections, and the quantity of described LED lamp section is consistent with the quantity of high pressure NMOS pipe.
Another object of the present invention can be by taking following technical scheme to reach:
Driving method based on voltage memory with the LED drive circuit of segmentation current limliting, is characterized in that comprising the following steps:
1) electric main, after rectification circuit rectification, is exported high voltage direct current pulsating voltage;
2) the high voltage direct current pulsating voltage of bleeder circuit after to rectification circuit rectification carries out dividing potential drop according to a certain percentage, output low-voltage direct pulsating voltage;
3) voltage rise and fall detection module converts the low-voltage direct pulsating voltage after dividing potential drop to be used to indicate the uphill process of low-voltage direct pulsating voltage and the square-wave signal of decline process to;
4) in the uphill process of low-voltage direct pulsating voltage, voltage is in the time of valley, each high pressure NMOS pipe is in conducting state, now only have the LED lamp section being directly connected with high voltage direct current pulsating voltage to be access in effective driver output port, when rising, voltage make the drive current of this LED lamp section reach cut-off current, pressure drop on inspection leakage resistance is higher than reference voltage, the output voltage generation overcurrent upset of inspection stream comparator, control logic module detects the upset of this signal, the high pressure NMOS pipe being connected with this LED lamp section negative pole is turned off, together with next the LED lamp section being connected with this LED lamp section, be access in effective driver output port, electric current on LED lamp string is got back to below cut-off current, before the output voltage of inspection stream comparator returns to overcurrent upset occurs, according to this rule, often reach primary current cut-off current and just turn-off the high pressure NMOS pipe being connected with the part negative pole being access in LED lamp string, the LED lamp hop count amount that is access in effective driver output port is progressively increased, when all LED lamp Duan Jun are access in, the rising of high voltage direct current pulsating voltage makes electric current reach cut-off current again, turn-off all high pressure NMOS pipes in high voltage switch circuit, the disconnection that is connected by all LED lamp sections in LED lamp string with power supply, the control procedure in the uphill process of this DC pulse moving voltage is called forward control procedure, in forward control procedure, the instantaneous voltage of low-voltage direct pulsating voltage when the operating current that voltage memory module is write down LED lamp string successively reaches cut-off current at every turn,
5) in the decline process of low-voltage direct pulsating voltage, the magnitude of voltage of voltage memory module memory remains unchanged, be input to comparator bank and compare processing, the square wave sequence of comparator bank output has oppositely reappeared in voltage uphill process when LED lamp string reaches Current Limits flow valuve at every turn that each controls node; Control node at each, the output state of comparator bank can change, control logic module detects this state variation, oppositely progressively recovers that in high voltage switch circuit, each is turned off the conducting state of high pressure NMOS pipe, realizes the reverse symmetry control to LED lamp string; In the process of reverse symmetry control, if all high pressure NMOS pipes in the peak point place of high voltage direct current pulsating voltage high voltage switch circuit are in off state, in the time that high voltage direct current pulsating voltage declines through the 1st control node, control logic module makes the high pressure NMOS pipe being finally turned off in forward control procedure recover conducting state, and in LED lamp string, all LED lamp sections are access in effective driver output port; In the time that high voltage direct current pulsating voltage declines through the 2nd control node, control logic module makes the high pressure NMOS pipe that in forward control procedure, second-to-last is turned off recover conducting state, makes the LED lamp section that is access in effective driver output port in LED lamp string reduce 1 section; According to this rule, after this high voltage direct current pulsating voltage declines and often controls when node through 1, just recover the conducting state of 1 high pressure NMOS pipe being turned off, the LED lamp section that is access in effective driver output port in LED lamp string is gradually reduced, until all high pressure NMOS pipes all recover conducting state, till the quantity that is access in the LED lamp section of effective driver output port in LED lamp string is 1 section.
Preferably, step 3) described voltage rise and fall detection module converts the low-voltage direct pulsating voltage after dividing potential drop to be used to indicate the uphill process of low-voltage direct pulsating voltage and the square-wave signal of decline process is specially to:
Voltage rise and fall detection module converts the low-voltage direct pulsating voltage after dividing potential drop to the square-wave signal that only has two kinds of level of height, two kinds of varying levels of this square-wave signal uphill process and decline process of indication low-voltage DC pulse moving voltage respectively, wherein high level instruction uphill process, low level instruction decline process, can obtain the indicating mode contrary with original signal by this square wave signal inversion.
The present invention has following beneficial effect with respect to prior art:
The present invention is based on the LED drive circuit of voltage memory and segmentation current limliting according to the rise and fall characteristic of the DC pulse moving voltage after direct rectification, the control mode that adopts segmented to light to the load of LED lamp string, the problem of the difference that has solved the LED chip voltage-current characteristic that in practical application, lamp string uses on drive current impact, the operating current of LED lamp string within the whole work period is limited in the lowest high-current value Imax of design, avoid occurring the problem that brightness LED chip partially dark and that overcurrent causes that undercurrent causes damages, in improving LED lamp luminescence efficiency, better LED device is carried out to overcurrent protection.
Brief description of the drawings
Fig. 1 is LED drive circuit structural framing figure.
Fig. 2 is the structural principle block diagram of existing linear segmented formula LED drive circuit.
Fig. 3 is the structural principle block diagram that the present invention is based on the LED drive circuit of voltage memory and segmentation current limliting.
Fig. 4 is the driving method working waveform figure that the present invention is based on the LED drive circuit of voltage memory and segmentation current limliting.
Embodiment
Embodiment 1:
Below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are not limited to this.
As shown in Figure 3, the present embodiment comprises rectification circuit 1, bleeder circuit 2, voltage rise and fall detection module 3, voltage memory module 4, comparator bank 5, control logic module 6, high voltage switch circuit 7, inspection leakage resistance 8 (Ris), inspection stream comparator 9 (Icomp) and LED lamp string 10 based on voltage memory and the LED drive circuit of segmentation current limliting; Described voltage rise and fall detection module 3 is made up of differentiation element circuit and voltage comparator; Described voltage memory module 4 is made up of 4 voltage retainers, and numbering is respectively H1, H2, H3 and H4 from top to bottom, and described each voltage retainer is made up of electric capacity and operational amplifier; Described comparator bank 5 is made up of 4 voltage comparators, and numbering is respectively Comp1, Comp2, Comp3 and Comp4 from top to bottom; Described control logic module 6 is by 4 d type flip flops and complete the required combined digital logical constitution of function; Described high voltage switch circuit 7 is made up of 4 high pressure NMOS pipes, and numbering is respectively Q1, Q2, Q3 and Q4 from top to bottom; Described LED lamp string 10 is made up of 4 LED lamp sections, and numbering is respectively L1, L2, L3 and L4 from top to bottom, wherein:
Electric main is after described rectification circuit 1 rectification, output has periodic high voltage direct current pulsating voltage (referred to as HVDCP), in the one-period of HVDCP, the process that voltage changes to peak value from valley is uphill process, and the process of voltage from peak change to valley is decline process;
The HVDCP of described bleeder circuit 2 after to rectification circuit 1 rectification carries out linear dividing potential drop according to a certain percentage, obtain low-voltage direct pulsating voltage (referred to as LVDCP), as the input signal of voltage rise and fall detection module 3, voltage memory module 4 and comparator bank 5, compare with the HVDCP after rectification, the phase place of LVDCP is identical with it with the cycle, is proportional routine relation in magnitude of voltage size;
Described voltage rise and fall detection module 3 converts the LVDCP after bleeder circuit 2 dividing potential drops to the square-wave signal RFC that only has two kinds of level of height, two kinds of varying levels of this square-wave signal RFC are indicated respectively rising and the decline process of LVDCP, as high level instruction uphill process, low level is indicated decline process, after this signal inversion, can obtain the indicating mode contrary with original signal; The circuit module that need to use RFC signal when work has voltage memory module 4 and control logic module 6;
Described voltage memory module 4 is in the uphill process of DC pulse moving voltage (HVDCP or LVDCP), the instantaneous value of LVDCP when the drive current of writing down successively LED lamp string 10 reaches cut-off current at every turn, due to the linear ratio relation of bleeder circuit 2, the instantaneous voltage of the LVDCP recording also becomes linear ratio relation one to one with the instantaneous voltage of HVDCP this moment, it adopts the mode of simulation to carry out voltage memory, the number of the voltage retainer using is the number of required memory voltage instantaneous value in a voltage uphill process of DC pulse moving voltage (HVDCP or LVDCP), also be the number of fragments (being 4) of LED lamp string 10, described voltage memory module 4 is in the decline process of DC pulse moving voltage (HVDCP or LVDCP), and the magnitude of voltage of its memory remains unchanged, and is input in comparator bank 5 and compares processing,
In described comparator bank 5, an input of described voltage comparator Comp1, Comp2, Comp3 and Comp4 connects one to one with the output of voltage retainer H1, H2, H3 and H4 respectively, after another input is connected together, be connected with bleeder circuit 2, LVDCP is as the input signal of this input, described comparator bank 5 is in the decline process of DC pulse moving voltage (HVDCP or LVDCP), the output of voltage memory module 4 and LVDCP are compared, output and voltage comparator Comp1, Comp2, the square wave sequence that Comp3 and Comp4 are corresponding, the square wave of each output, whether the variation instruction LVDCP of its low and high level has dropped to the memory voltage value that corresponding voltage comparator is inputted, the party's wave train has oppositely reappeared in voltage uphill process that when LED lamp string 10 reaches current limit value at every turn, each controls node, and be input to control logic module 6 and process,
In described control logic module 6, the on off state of the high pressure NMOS pipe in the store status of described each d type flip flop and high voltage switch circuit 7 is corresponding one by one, and the exportable switching signal of control logic module 6 is carried out switch control to high pressure NMOS pipe Q1, Q2, Q3 and the Q4 of high voltage switch circuit 7; The HVDCP that the positive pole of described LED lamp section L1 is exported with rectification circuit 1 is connected, and tie point is N0; The negative pole of described LED lamp section L1 is connected with the positive pole of LED lamp section L2, and tie point is N1, and tie point N1 is connected with the drain electrode of high pressure NMOS pipe Q1; The negative pole of described LED lamp section L2 is connected with the positive pole of LED lamp section L3, and tie point is N2, and tie point N2 is connected with the drain electrode of high pressure NMOS pipe Q2; The negative pole of described LED lamp section L3 is connected with the positive pole of LED lamp section L4, and tie point is N3, and tie point N3 is connected with the drain electrode of high pressure NMOS pipe Q3; The negative pole of described LED lamp section L4 is connected with the drain electrode of high pressure NMOS pipe Q4, and tie point is N4; After the source electrode of described high pressure NMOS pipe Q1, Q2, Q3 and Q4 is connected together, be connected with one end of inspection leakage resistance Ris, tie point is N5, examines the holding of another termination power of leakage resistance Ris commonly; An input termination of described inspection stream comparator Icomp is examined the points of common connection N5 of the source electrode of leakage resistance Ris and high pressure NMOS pipe Q1, Q2, Q3 and Q4, another input termination reference voltage Vref;
As shown in Figure 4, for the working waveform figure of the LED drive circuit of the present embodiment based on voltage memory and segmentation current limliting, the first half dotted line is the waveform of low-voltage direct pulsating voltage signal LVDCP, heavy line is the square-wave waveform of the output signal RFC of voltage rise and fall testing circuit, the peak value that Umax is LCDCP; The latter half dotted line is the waveform of low-voltage direct pulsating voltage signal LVDCP, the peak value that Umax is LCDCP, and heavy line is the electric current I that flows through LED lamp string
lEDoscillogram, Imax is I
lEDpeak value (being cut-off current), determined I by the reference voltage Vref and the inspection leakage resistance Ris that are input to inspection stream comparator Icomp
lED=Vref/Ris.
As shown in Figure 3 and Figure 4, the present embodiment is the driving method with the LED drive circuit of segmentation current limliting based on voltage memory, comprises the following steps:
1) electric main, after rectification circuit 1 rectification, is exported HVDCP;
2) HVDCP of bleeder circuit 2 after to rectification circuit 1 rectification carries out dividing potential drop according to a certain percentage, output LVDCP;
3) voltage rise and fall detection module 3 converts the low-voltage direct pulsating voltage after dividing potential drop to the square-wave signal RFC that only has two kinds of level of height, within a rise and fall cycle of LVDCP, in uphill process, the output signal RFC of voltage rise and fall detection module 3 is high level, in decline process, the output signal RFC of voltage rise and fall detection module 3 is low level, control logic module 6 is according to its control model of low and high level Determines of RFC, below respectively the control flow of the uphill process to LVDCP and decline process be described:
4) in the uphill process of LVDCP, voltage is in the time of valley, and each high pressure NMOS pipe Q1, Q2, Q3 and Q4 be in conducting state, the time point t0 in corresponding diagram 4; In the process of time period t 0 to t1, high pressure NMOS pipe Q1, Q2, Q3 and Q4 are in conducting state, tie point N1, N2, N3 and N4 are all shorted to tie point N5 by the conducting state of Q1, Q2, Q3 and Q4, LED lamp section L2, L3 and L4 are invalid, and LED lamp section L1 is access between HVDCP and tie point N5 and is effectively driven; At time point t1, flow through the drive current I of the LED lamp section being access in LED lamp string 10
lEDarrive cut-off current Imax, the output state generation overcurrent upset of inspection stream comparator Icomp, control logic module 6 detects overcurrent upset, output signal control voltage memory module 4 is remembered the now instantaneous voltage value Ua of LVDCP by voltage retainer H1, make high pressure NMOS pipe Q1 in off state, high pressure NMOS pipe Q2, Q3 and Q4 keep conducting state; In the process of time period t 1 to t2, high pressure NMOS pipe Q1 is in off state, high pressure NMOS pipe Q2, Q3 and Q4 keep conducting state, tie point N2, N3 and N4 are all shorted to tie point N5 by the conducting state of high pressure NMOS pipe Q2, Q3 and Q4, LED lamp section L3 and L4 are invalid, and LED lamp section L1 and L2 are connected effectively to be driven between access HVDCP and tie point N5; After Q1 is turned off, I
lEDagain drop to below Imax, the output of inspection stream comparator Icomp returns to the state occurring before overcurrent upset.At time point t2, flow through the drive current I of the LED lamp section being access in LED lamp string 10
lEDarrive cut-off current Imax, the output state generation overcurrent upset of inspection stream comparator Icomp, control logic module 6 detects overcurrent upset, output signal control voltage memory module 4 is remembered the now instantaneous voltage value Ub of LVDCP by voltage retainer H2, make high pressure NMOS pipe Q1 and Q2 in off state, high pressure NMOS pipe Q3 and Q4 keep conducting state; In the process of time period t 2 to t3, high pressure NMOS pipe Q1, Q2 are in off state, Q3, Q4 keep conducting state, tie point N3, N4 are all shorted to N5 by the conducting state of Q3, Q4, L4 is invalid for LED lamp section, and LED lamp section L1, L2 and L3 are connected effectively to be driven between access HVDCP and tie point N5; After Q1 and Q2 are turned off, I
lEDagain drop to below Imax, the output of inspection stream comparator Icomp returns to the state occurring before overcurrent upset; At time point t3, flow through the drive current I of the LED lamp section being access in LED lamp string 10
lEDarrive cut-off current Imax, the output state generation overcurrent upset of inspection stream comparator Icomp, control logic module 6 detects overcurrent upset, output signal control voltage memory module 4 is remembered the now instantaneous voltage value Uc of LVDCP by voltage retainer H3, make high pressure NMOS pipe Q1, Q2 and Q3 in off state, high pressure NMOS pipe Q4 keeps conducting state; In the process of time period t 3 to t4, high pressure NMOS pipe Q1, Q2 and Q3 are in off state, high pressure NMOS pipe Q4 keeps conducting state, tie point N4 is all shorted to tie point N5 by the conducting state of high pressure NMOS pipe Q4, and LED lamp section L1, L2, L3 and L4 are connected effectively to be driven between access HVDCP and tie point N5; After Q1, Q2 and Q3 are turned off, I
lEDagain drop to below Imax, the output of inspection stream comparator Icomp returns to the state occurring before overcurrent upset; At time point t4, flow through the drive current I of the LED lamp section being access in LED lamp string 10
lEDarrive cut-off current Imax, the output state generation overcurrent upset of inspection stream comparator Icomp, control logic module 6 detects overcurrent upset, output signal control voltage memory module 4 is remembered the now instantaneous voltage value Ud of LVDCP by voltage retainer H4, makes high pressure NMOS pipe Q1, Q2, Q3 and Q4 in off state; Reach in the process of peak value in time period t 4 to LCDCP, high pressure NMOS pipe Q1, Q2, Q3 and Q4 are in off state, and LED lamp section L1, L2, L3 and L4 disconnect from effective output port, I
lEDvalue be 0, avoid the continuation of voltage to rise and cause LED lamp string 10 overcurrents and suffer damage; After Q1, Q2, Q3 and Q4 are turned off, I
lEDagain drop to below Imax, the output of inspection stream comparator Icomp returns to the state occurring before overcurrent upset;
5), in the decline process of LVDCP, control logic module 6 determines the on off state of high pressure NMOS pipe Q1, Q2, Q3 and Q4 according to the output signal of comparator bank 5; At the peak point of LVDCP in the process of t5, the now magnitude of voltage U of LVDCP
lV>Ud>Uc>UbGreat T.GreaT.GTUa, the output state of voltage comparator Comp1, Comp2, Comp3 and Comp4 in comparator bank 5 remains unchanged, high pressure NMOS pipe Q1, Q2, Q3 and Q4 keep off state, LED lamp section L1, L2, L3 and L4 disconnect from effective output port, I
lEDvalue be 0; At time point t5 in the process of t6, Ud>U
lV>Uc>Ub>Ua, the output state of voltage comparator Comp1 changes, the output state of voltage comparator Comp2, Comp3 and Comp4 remains unchanged, at this moment control logic module 6 makes high pressure NMOS pipe Q4 conducting according to the output state of Comp1, Comp2, Comp3 and Comp4, high pressure NMOS pipe Q1, Q2 and Q3 keep off state, and LED lamp section L1, L2, L3 and L4 are connected effectively to be driven between access HVDCP and tie point N5; At time point t5, due to the voltage of LVDCP, the magnitude of voltage of LVDCP equates during with t4 time point, and the LED lamp section of access is identical, therefore t5 and t4 time point I
lEDvalue equate, and equal Imax, the process from time point t5 to t6, electric current I
lEDreduce with voltage drop; At time point t6 in the process of t7, Ud>Uc>U
lV>Ub>Ua, the output state of voltage comparator Comp2 changes, the output state of voltage comparator Comp1, Comp3 and Comp4 remains unchanged, at this moment control logic module 6 makes high pressure NMOS pipe Q3 and Q4 conducting according to the output state of voltage comparator Comp1, Comp2, Comp3 and Comp4, high pressure NMOS pipe Q1 and Q2 keep off state, LED lamp section L1, L2 and L3 are connected effectively to be driven between access HVDCP and tie point N5, and L4 is invalid for LED lamp section; At time point t6, due to the voltage of LVDCP, the magnitude of voltage of LVDCP equates during with t3 time point, and the LED lamp section of access is identical, therefore t6 and t3 time point I
lEDvalue equate, and equal Imax, the process from time point t6 to t7, electric current I LED reduces with voltage drop.At time point t7 in the process of t8, Ud>Uc>Ub>U
lV>Ua, the output state of voltage comparator Comp3 changes, the output state of voltage comparator Comp1, Comp2 and Comp4 remains unchanged, at this moment control logic module 6 makes high pressure NMOS pipe Q2, Q3 and Q4 conducting according to the output state of voltage comparator Comp1, Comp2, Comp3 and Comp4, high pressure NMOS pipe Q1 keeps off state, LED lamp section L1 and L2 are connected effectively to be driven between access HVDCP and tie point N5, and LED lamp section L3 and L4 are invalid; At time point t7, due to the voltage of LVDCP, the magnitude of voltage of LVDCP equates during with t2 time point, and the LED lamp section of access is identical, therefore t7 and t2 time point I
lEDvalue equate, and equal Imax, the process from time point t7 to t8, electric current I LED reduces with voltage drop.At time point t8 in the process of t9, Ud>Uc>Ub>UaGre atT.GreaT.GTULV, the output state of voltage comparator Comp4 changes, voltage comparator Comp1, the output state of Comp2 and Comp3 remains unchanged, at this moment control logic module 6 is according to voltage comparator Comp1, Comp2, the output state of Comp3 and Comp4 makes high pressure NMOS pipe Q1, Q2, Q3 and Q4 conducting, LED lamp section L1 is connected effectively to be driven between access HVDCP and tie point N5, LED lamp section L2, L3 and L4 are invalid, at time point t8, due to the voltage of LVDCP, the magnitude of voltage of LVDCP equates during with t1 time point, and the LED lamp section of access is identical, therefore t8 and t1 time point I
lEDvalue equate, and equal Imax, the process from time point t8 to t9, electric current I LED reduces with voltage drop, completes a LED driving control flow in the LCDCP cycle to this.
The above; it is only patent preferred embodiment of the present invention; but the protection range of patent of the present invention is not limited to this; for example can change the quantity of voltage retainer, voltage comparator, high pressure NMOS pipe etc.; anyly be familiar with those skilled in the art in the disclosed scope of patent of the present invention; according to the present invention, the technical scheme of patent and inventive concept thereof are equal to replacement or are changed, and all belong to the protection range of patent of the present invention.
Claims (10)
1. the LED drive circuit with segmentation current limliting based on voltage memory, comprise rectification circuit, bleeder circuit, comparator bank, high voltage switch circuit and LED lamp string, described rectification circuit is connected with bleeder circuit, described high voltage switch circuit and LED lamp series winding connect, described LED lamp string is connected with rectification circuit, it is characterized in that: also comprise voltage rise and fall detection module, voltage memory module, control logic module, inspection leakage resistance and inspection stream comparator, described voltage memory module, comparator bank, control logic module, high voltage switch circuit and LED lamp string are connected successively; Described bleeder circuit is connected with voltage rise and fall detection module and voltage memory module respectively, and described voltage rise and fall detection module is connected with voltage memory module and control logic module respectively, and described control logic module is connected with voltage memory module; Described high voltage switch circuit is held and is connected altogether with power supply by inspection leakage resistance, an input termination of described inspection stream comparator is examined the points of common connection of leakage resistance and high voltage switch circuit, another input termination reference voltage, the output of described inspection stream comparator is connected with control logic module.
2. the LED drive circuit based on voltage memory and segmentation current limliting according to claim 1, is characterized in that: described voltage memory module is made up of multiple voltage retainers, and the output of described each voltage retainer is connected with comparator bank respectively.
3. the LED drive circuit based on voltage memory and segmentation current limliting according to claim 2, is characterized in that: described each voltage retainer is made up of electric capacity and operational amplifier.
4. the LED drive circuit based on voltage memory and segmentation current limliting according to claim 2, it is characterized in that: described comparator bank is made up of multiple voltage comparators, an input of described each voltage comparator and the output of each voltage retainer connect one to one, after another input is connected together, be connected with bleeder circuit, the output of described each voltage comparator is connected with control logic module respectively.
5. the LED drive circuit based on voltage memory and segmentation current limliting according to claim 4, it is characterized in that: described control logic module is by multiple d type flip flops and complete the required combined digital logical constitution of function, described control logic module is using output, the output of voltage rise and fall detection module and the output of inspection stream comparator of each voltage comparator in comparator bank as input signal.
6. the LED drive circuit based on voltage memory and segmentation current limliting according to claim 5, it is characterized in that: described voltage rise and fall detection module is made up of differentiation element circuit and voltage comparator the square-wave signal of output instruction DC pulse moving voltage rise and fall state.
7. the LED drive circuit based on voltage memory and segmentation current limliting according to claim 5, it is characterized in that: described high voltage switch circuit is made up of multiple high pressure NMOS pipes, the on off state of the store status of described each d type flip flop and each high pressure NMOS pipe is corresponding one by one; After the source electrode of described each high pressure NMOS pipe is connected together, holds and be connected altogether with power supply through inspection leakage resistance, the points of common connection of an input termination inspection leakage resistance of described inspection stream comparator and the source electrode of each high pressure NMOS pipe, another input termination reference voltage; The drain electrode of described each high pressure NMOS pipe and LED lamp series winding connect.
8. the LED drive circuit based on voltage memory and segmentation current limliting according to claim 7, is characterized in that: described LED lamp string is composed in series by multiple LED lamp sections, and the quantity of described LED lamp section is consistent with the quantity of high pressure NMOS pipe.
9. the driving method with the LED drive circuit of segmentation current limliting based on voltage memory, is characterized in that comprising the following steps:
1) electric main, after rectification circuit rectification, is exported high voltage direct current pulsating voltage;
2) the high voltage direct current pulsating voltage of bleeder circuit after to rectification circuit rectification carries out dividing potential drop according to a certain percentage, output low-voltage direct pulsating voltage;
3) voltage rise and fall detection module converts the low-voltage direct pulsating voltage after dividing potential drop to be used to indicate the uphill process of low-voltage direct pulsating voltage and the square-wave signal of decline process to;
4) in the uphill process of low-voltage direct pulsating voltage, voltage is in the time of valley, each high pressure NMOS pipe is in conducting state, now only have the LED lamp section being directly connected with high voltage direct current pulsating voltage to be access in effective driver output port, when rising, voltage make the drive current of this LED lamp section reach cut-off current, pressure drop on inspection leakage resistance is higher than reference voltage, the output voltage generation overcurrent upset of inspection stream comparator, control logic module detects the upset of this signal, the high pressure NMOS pipe being connected with this LED lamp section negative pole is turned off, together with next the LED lamp section being connected with this LED lamp section, be access in effective driver output port, electric current on LED lamp string is got back to below cut-off current, before the output voltage of inspection stream comparator returns to overcurrent upset occurs, according to this rule, often reach primary current cut-off current and just turn-off the high pressure NMOS pipe being connected with the part negative pole being access in LED lamp string, the LED lamp hop count amount that is access in effective driver output port is progressively increased, when all LED lamp Duan Jun are access in, the rising of high voltage direct current pulsating voltage makes electric current reach cut-off current again, turn-off all high pressure NMOS pipes in high voltage switch circuit, the disconnection that is connected by all LED lamp sections in LED lamp string with power supply, the control procedure in the uphill process of this DC pulse moving voltage is called forward control procedure, in forward control procedure, the instantaneous voltage of low-voltage direct pulsating voltage when the operating current that voltage memory module is write down LED lamp string successively reaches cut-off current at every turn,
5) in the decline process of low-voltage direct pulsating voltage, the magnitude of voltage of voltage memory module memory remains unchanged, be input to comparator bank and compare processing, the square wave sequence of comparator bank output has oppositely reappeared in voltage uphill process when LED lamp string reaches Current Limits flow valuve at every turn that each controls node; Control node at each, the output state of comparator bank can change, control logic module detects this state variation, oppositely progressively recovers that in high voltage switch circuit, each is turned off the conducting state of high pressure NMOS pipe, realizes the reverse symmetry control to LED lamp string; In the process of reverse symmetry control, if all high pressure NMOS pipes in the peak point place of high voltage direct current pulsating voltage high voltage switch circuit are in off state, in the time that high voltage direct current pulsating voltage declines through the 1st control node, control logic module makes the high pressure NMOS pipe being finally turned off in forward control procedure recover conducting state, and in LED lamp string, all LED lamp sections are access in effective driver output port; In the time that high voltage direct current pulsating voltage declines through the 2nd control node, control logic module makes the high pressure NMOS pipe that in forward control procedure, second-to-last is turned off recover conducting state, makes the LED lamp section that is access in effective driver output port in LED lamp string reduce 1 section; According to this rule, after this high voltage direct current pulsating voltage declines and often controls when node through 1, just recover the conducting state of 1 high pressure NMOS pipe being turned off, the LED lamp section that is access in effective driver output port in LED lamp string is gradually reduced, until all high pressure NMOS pipes all recover conducting state, till the quantity that is access in the LED lamp section of effective driver output port in LED lamp string is 1 section.
According to claim 9 based on voltage memory the driving method with the LED drive circuit of segmentation current limliting, it is characterized in that: step 3) described voltage rise and fall detection module converts the low-voltage direct pulsating voltage after dividing potential drop to be used to indicate the uphill process of low-voltage direct pulsating voltage and the square-wave signal of decline process is specially to:
Voltage rise and fall detection module converts the low-voltage direct pulsating voltage after dividing potential drop to the square-wave signal that only has two kinds of level of height, two kinds of varying levels of this square-wave signal uphill process and decline process of indication low-voltage DC pulse moving voltage respectively, wherein high level instruction uphill process, low level instruction decline process, can obtain the indicating mode contrary with original signal by this square wave signal inversion.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104812118A (en) * | 2015-04-17 | 2015-07-29 | 华南理工大学 | Light emitting diode illumination drive circuit and method using alternating current commercial power |
| CN106102232A (en) * | 2016-06-30 | 2016-11-09 | 华南理工大学 | A kind of multipath LED drive circuit model of High Power Factor |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100308738A1 (en) * | 2009-06-04 | 2010-12-09 | Exclara Inc. | Apparatus, Method and System for Providing AC Line Power to Lighting Devices |
| TW201212710A (en) * | 2010-05-07 | 2012-03-16 | Cree Inc | AC driven solid state lighting apparatus with LED string including switched segments |
| CN102387639A (en) * | 2011-02-16 | 2012-03-21 | 凹凸电子（武汉）有限公司 | Driving circuit, method and dimming controller for driving light source |
| CN202353874U (en) * | 2011-11-18 | 2012-07-25 | 上海晶丰明源半导体有限公司 | Light emitting diode (LED) linear constant-current control circuit and LED linear circuit |
| CN203748074U (en) * | 2014-03-04 | 2014-07-30 | 华南理工大学 | LED driving circuit based on voltage memorization and subsection current limitation |
-
2014
- 2014-03-04 CN CN201410076451.3A patent/CN103906314B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100308738A1 (en) * | 2009-06-04 | 2010-12-09 | Exclara Inc. | Apparatus, Method and System for Providing AC Line Power to Lighting Devices |
| TW201212710A (en) * | 2010-05-07 | 2012-03-16 | Cree Inc | AC driven solid state lighting apparatus with LED string including switched segments |
| CN102387639A (en) * | 2011-02-16 | 2012-03-21 | 凹凸电子（武汉）有限公司 | Driving circuit, method and dimming controller for driving light source |
| CN202353874U (en) * | 2011-11-18 | 2012-07-25 | 上海晶丰明源半导体有限公司 | Light emitting diode (LED) linear constant-current control circuit and LED linear circuit |
| CN203748074U (en) * | 2014-03-04 | 2014-07-30 | 华南理工大学 | LED driving circuit based on voltage memorization and subsection current limitation |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104812118A (en) * | 2015-04-17 | 2015-07-29 | 华南理工大学 | Light emitting diode illumination drive circuit and method using alternating current commercial power |
| CN104812118B (en) * | 2015-04-17 | 2017-03-01 | 华南理工大学 | A kind of LED illumination drive circuit of employing electric main and method |
| CN106102232A (en) * | 2016-06-30 | 2016-11-09 | 华南理工大学 | A kind of multipath LED drive circuit model of High Power Factor |
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|---|---|
| CN103906314B (en) | 2016-05-04 |
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