CN103442484B - A kind of linear switch constant current LED drive circuit and LED lamp - Google Patents

A kind of linear switch constant current LED drive circuit and LED lamp Download PDF

Info

Publication number
CN103442484B
CN103442484B CN201310356131.9A CN201310356131A CN103442484B CN 103442484 B CN103442484 B CN 103442484B CN 201310356131 A CN201310356131 A CN 201310356131A CN 103442484 B CN103442484 B CN 103442484B
Authority
CN
China
Prior art keywords
led
current
drive circuit
voltage
output
Prior art date
Application number
CN201310356131.9A
Other languages
Chinese (zh)
Other versions
CN103442484A (en
Inventor
李进
张利刚
Original Assignee
辉芒微电子(深圳)有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 辉芒微电子(深圳)有限公司 filed Critical 辉芒微电子(深圳)有限公司
Priority to CN201310356131.9A priority Critical patent/CN103442484B/en
Publication of CN103442484A publication Critical patent/CN103442484A/en
Application granted granted Critical
Publication of CN103442484B publication Critical patent/CN103442484B/en

Links

Abstract

The present invention relates to a kind of linear switch constant current LED drive circuit and LED lamp.This LED lamp comprises alternating current input power supplying, bridge rectifier, linear switch constant current LED drive circuit and LED.This linear switch constant current LED drive circuit comprises: input sample module, for Gather and input sampled voltage; Export sampling module, for gathering the output current information of LED; Feedback control module, keeps substantially invariable integral voltage for generating according to output current information and exporting in a power frequency period; Drive control module, for generating according to input sample voltage and integral voltage and exporting drive control signal; Power control module, for driving and current constant control LED according to drive control signal, and bears the pressure drop in circuit.Implement linear switch constant current LED drive circuit of the present invention and LED lamp, the average output current of LED and the constant of average output power can be realized, improve system effectiveness, effectively reduce the working temperature of drive circuit.

Description

A kind of linear switch constant current LED drive circuit and LED lamp

Technical field

The present invention relates to LED drive circuit technical field, more particularly, relate to a kind of linear switch constant current LED drive circuit and LED lamp.

Background technology

Under the overall background of global energy-saving and emission-reduction, be more and more subject to the favor in market as LED illumination that is green, environmental protection and energy saving.Be different from traditional lighting system, LED lamp bead can not directly incoming transport utility grid, but first electric main will be converted into DC power supply by drive circuit, and then drives.LED drive circuit can be divided into switch power supply type and the large class of linear constant current formula two by its working method.Drive relative to switch power supply type, the advantage that linear constant current formula drives is: the EMI problem caused without HF switch; Without the need to electrochemical capacitor, and the life-span bottleneck of electrochemical capacitor LED lamp just; Without the need to inductance and transformer, peripheral circuit is simple, is convenient to realize the integration of photoelectricity engine; Volume is less, and cost is cheaper.These advantages make linear constant current formula be driven in order to illumination LED drives the emphasis of area research.

Adopt in the prior art in the LED lamp of linear constant current LED drive circuit, as shown in Figure 1, it comprises stream input power (civil power) 10, bridge rectifier 20, LED 30, power MOS pipe 40, output current sampling resistor 50, error amplifier 60.Wherein, power MOS pipe 40, output current sampling resistor 50 and error amplifier 60 form feedback control loop, i.e. linear constant current LED drive circuit, are used for the output current Io of control flow check through LED 30.

Fig. 2 shows the key operation waveforms figure of the linear constant current LED drive circuit in Fig. 1.As shown in Figure 2, in figure, VF is the conduction voltage drop of LED; Vin is the voltage of electric main after bridge rectifier rectification, and its waveform is sinusoidal wave absolute value; Iin is input current, and Io is the output current flowing through LED, and Io and Iin is equal; Vref is the reference voltage (i.e. reference voltage) that error amplifier 60 receives.The main operational principle of this circuit is as follows: system controls output current Io automatically according to the change of Vin sine wave.As the conduction voltage drop VF of Vin lower than LED (in Fig. 2 during 0 to t), LED is not enough to conducting, Iin and Io equals zero, and the feedback control loop that power MOS pipe 40, output current sampling resistor 50 and error amplifier 60 are formed is in holding state; When Vin rises to the conduction voltage drop VF of LED (in Fig. 2 t), the automatic conducting of LED, feedback control loop is started working and Io is adjusted to steady state value (Vref/Rs); Vin continues by sinusoidal wave change (in Fig. 2 t to t ' period), and the pressure drop of LED remains VF, and unnecessary pressure drop (Vin-VF) will be born by high-voltage power metal-oxide-semiconductor 40, and feedback control loop makes Io remain steady state value always during this period; When Vin drops to VF (in Fig. 2 t ' moment), LED is not enough to conducting, Iin and Io equals zero, and feedback control loop is in holding state.This course of work will constantly repeat.

Below the average output current, average output power, efficiency etc. of above-mentioned LED lamp are derived.

V in = 2 V ac sin 2 πft - - - ( 1 )

t = 1 2 πf arcsin V F 2 V ac = 1 2 πf · θ - - - ( 2 )

θ = arcsin V F 2 V ac

t , = 1 2 f - t = 1 2 f - 1 2 πf · θ - - - ( 3 )

Average output current in one-period:

I ‾ o = 2 f · I o · ( t , - t ) = ( 1 - 2 θ π ) · V ref R s - - - ( 4 )

Average output power in one-period:

P out = 2 f · V F · I o · ( t , - t ) = ( 1 - 2 θ π ) · V F · V ref R s - - - ( 5 )

Mean Input Power in one-period:

P in = 2 f · ∫ t t , V in · I o dt = 2 f · 2 V ac · I o · ∫ t t , sin 2 πftdt = 2 2 V ac · I o · cos θ π - - - ( 6 )

System effectiveness:

η = P out P in = V F 2 V ac · ( π 2 - θ ) cos θ - - - ( 7 )

There is following defect in existing linear constant current LED drive circuit:

(1) average output current of LED and the constant of average output power cannot be realized.As can be seen from formula (4) and (5), average output current in one-period and average output power are all relevant with VF and Vac, therefore, when the conduction voltage drop VF of LED and input voltage Vac changes, average output current and average output power also can change thereupon.Therefore, when input voltage is unstable, the brightness of LED can change.

(2) when input voltage is higher, system effectiveness is too low.As can be seen from formula (7), system effectiveness and input voltage are inversely proportional to, and when after LED conducting, unnecessary pressure drop (Vin-VF) will produce useless power consumption, and this part power consumption will reduce system effectiveness.That is, the power consumption that linear constant current LED drives mainly is produced by unnecessary pressure drop (Vin-VF), and input voltage is larger, and unnecessary pressure drop (Vin-VF) is larger, and power consumption is larger, and system effectiveness is lower.

(3) generate heat when LED drive chip works too high.In existing linear constant current LED drive circuit, after LED conducting, unnecessary pressure drop (Vin-VF) is born by the high-voltage power pipe MOSFET of chip internal, and this pressure drop can produce a large amount of useless power consumption, this part power consumption is the most all converted into heat energy, therefore the high-voltage power pipe MOSFET of chip internal can produce a large amount of heats, and chip cooling (thermal resistance is larger) limited in one's ability, can generate heat during final chip operation too high in addition.

Summary of the invention

The technical problem to be solved in the present invention is, linear constant current LED drive circuit for prior art cannot realize the average output current of LED and the constant of average output power, when input voltage is higher, system effectiveness is too low, and too high defect of generating heat during LED drive chip work, a kind of linear switch constant current LED drive circuit and LED lamp are provided, the average output current of LED and average output power and its input voltage can be made to have nothing to do, thus realize the average output current of LED and the constant of average output power, simultaneously, system effectiveness can be improved and reduce the working temperature of driving chip.

The technical solution adopted for the present invention to solve the technical problems is: construct a kind of linear switch constant current LED drive circuit, and for carrying out current constant control to LED, wherein, described linear switch constant current LED drive circuit comprises:

Input sample module, for Gather and input sampled voltage;

Export sampling module, for gathering the output current information of described LED;

Feedback control module, is connected with described output sampling module, keeps substantially invariable integral voltage for generating according to described output current information and exporting in a power frequency period;

Drive control module, is connected with described input sample module and described feedback control module respectively, for generating according to described input sample voltage and described integral voltage and export drive control signal;

Power control module, is connected with described drive control module, for driving according to described drive control signal and LED described in current constant control, and bears the pressure drop in circuit.

Preferably, described feedback control module comprises reference voltage maker, mutual conductance error amplifier and integrating capacitor; The in-phase input end of described mutual conductance error amplifier connects described reference voltage maker to obtain reference voltage, the inverting input of described mutual conductance error amplifier connects described output sampling module to obtain described output current information, and the output of described mutual conductance error amplifier is by described integrating capacitor ground connection; Described mutual conductance error amplifier is used for that described output current information and described reference voltage are compared rear output gain electric current and carries out discharge and recharge to described integrating capacitor, to generate described integral voltage.

Preferably, described power control module comprises the first metal-oxide-semiconductor and current-limited power resistance; The grid of described first metal-oxide-semiconductor connects the output of described drive control module, the source electrode of described first metal-oxide-semiconductor connects described output sampling module, the drain electrode of described first metal-oxide-semiconductor connects the first end of described current-limited power resistance, and the second end of described current-limited power resistance connects described LED; Described current-limited power resistance is for bearing the pressure drop in circuit.

Preferably, described input sample module comprises the first resistance and the second resistance; Ground connection after described first resistance and described second resistant series, one end of described first resistance connects the input power of described LED, and the tie point of described first resistance and described second resistance is as the output of described input sample module.

Preferably, described drive control module comprises drive circuit and comparator; The in-phase input end of described comparator connects the output of described feedback control module to obtain described integral voltage, the inverting input of described comparator connects the output of described input sample module to obtain described input sample voltage, the output of described comparator connects the input of described drive circuit, and the output of described drive circuit connects the grid of described first metal-oxide-semiconductor.

Preferably, described output sampling module comprises sampling resistor; The first end of described sampling resistor connects the source electrode of described first metal-oxide-semiconductor and the inverting input of described mutual conductance error amplifier, the second end ground connection of described sampling resistor respectively.

Preferably, described reference voltage maker, described mutual conductance error amplifier, described first metal-oxide-semiconductor, described drive circuit and described comparator are integrated in chip piece.

Preferably, described power control module also comprises the second metal-oxide-semiconductor be connected between described first metal-oxide-semiconductor and described current-limited power resistance; The grid of described second metal-oxide-semiconductor connects high level, and the source electrode of described two metal-oxide-semiconductors connects the drain electrode of described first metal-oxide-semiconductor, and the drain electrode of described two metal-oxide-semiconductors connects the first end of described current-limited power resistance.

Preferably, the capacitance scope of described integrating capacitor is 1 microfarad to 10 microfarad.

Another technical scheme that the present invention solves the employing of its technical problem is, construct a kind of LED lamp, comprise alternating current input power supplying, rectifier bridge, linear switch constant current LED drive circuit and LED, wherein, described linear switch constant current LED drive circuit adopts above-mentioned linear switch constant current LED drive circuit.

Implement linear switch constant current LED drive circuit of the present invention and LED lamp, the average output current of LED and the constant of average output power is achieved by utilizing " integration constant current " mode, the average output current of LED and average output power and input voltage have nothing to do, therefore, when line voltage changes, the average output current of LED and average output power can not change thereupon, and the brightness of LED can remain unchanged.Meanwhile, the present invention also can solve the conventional linear constant-current LED driving chip problem that efficiency is too low when input voltage is higher.Circuit structure of the present invention improves system effectiveness when input voltage is higher, and when unnecessary pressure drop is larger, efficiency improves more obvious.The present invention to generate heat too high problem when also can solve the work of conventional linear constant-current LED driving chip.Bear unnecessary pressure drop by current-limited power resistance, significantly reduce the working temperature of chip circuit.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the invention will be further described, in accompanying drawing:

Fig. 1 is the circuit theory diagrams of the linear switch constant current LED drive circuit of prior art;

Fig. 2 is the working waveform figure of the linear switch constant current LED drive circuit shown in Fig. 1;

Fig. 3 is the circuit theory diagrams of linear switch constant current LED drive circuit first embodiment of the present invention;

Fig. 4 is the working waveform figure of the linear switch constant current LED drive circuit shown in Fig. 3;

Fig. 5 is the circuit theory diagrams of linear switch constant current LED drive circuit second embodiment of the present invention.

Embodiment

In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.

Fig. 3 is the circuit theory diagrams of linear switch constant current LED drive circuit first embodiment of the present invention.As shown in Figure 3, linear switch constant current LED drive circuit comprises output sampling module 100, feedback control module 200, drive control module 300, power control module 400 and input sample module 500.Wherein, input sample module 500 is connected between the input power of LED and drive control module 300, export sampling module 100 to be connected with feedback control module 200 and power control module 400 respectively, feedback control module 200 is connected with drive control module 300, and drive control module 300 is connected with power control module 400.Input sample module 500 is for Gather and input sampled voltage; Export sampling module 100 for gathering the output current information of LED D1; Feedback control module 200 keeps substantially invariable integral voltage for generating according to this output current information and exporting in a power frequency period; Drive control module 300 is for generating according to input sample voltage and integral voltage and exporting drive control signal; Power control module 400, for driving and current constant control LED D1 according to this drive control signal, and bears the pressure drop in circuit, the difference as input voltage vin and LED conduction voltage drop VF: Vin-VF, namely unnecessary pressure drop.

In the present embodiment, input sample module 500 comprises the first resistance R1 and the second resistance R2; Export sampling module 100 and comprise sampling resistor Rs; Feedback control module 200 comprises reference voltage maker 201, mutual conductance error amplifier 202 and integrating capacitor C1; Drive control module 300 comprises drive circuit 301 and comparator 302; Power control module 400 comprises the first metal-oxide-semiconductor M1 and current-limited power resistance Rp.

Alternating current input power supplying AC and bridge rectifier provide input voltage vin for LED.Ground connection after first resistance R1 and described second resistance R2 connects, one end of the first resistance R1 connects the input power of LED, namely connects the output of bridge rectifier, and the tie point of the first resistance R1 and the second resistance R2 is as the output of input sample module 500.Certainly, those skilled in the art can know, input sample module 500 of the present invention also can adopt the electronic components such as transformer to realize.

The grid of the first metal-oxide-semiconductor M1 connects the output of drive circuit 301, the drain electrode of the first metal-oxide-semiconductor M1 connects the first end of current-limited power resistance Rp, second end of current-limited power resistance Rp connects LED, the source electrode of the first metal-oxide-semiconductor M1 connects the first end of sampling resistor Rs, the second end ground connection of sampling resistor Rs.The output current of LED flows through sampling resistor Rs and draws above-mentioned output current information, and this output current information is CS=Io × Rs.

The in-phase input end of mutual conductance error amplifier 202 connects reference voltage maker 201 to obtain reference voltage Vref 1, the inverting input of mutual conductance error amplifier 202 connects the first end of sampling resistor RS to obtain output current information, and the output of mutual conductance error amplifier 202 is by integrating capacitor C1 ground connection.Obtained output current information and reference voltage Vref 1 are compared rear output gain electric current and carry out discharge and recharge to integrating capacitor C1 by mutual conductance error amplifier 202, thus formation product component voltage Vcomp.Preferably, the capacitance scope of integrating capacitor C1 is 1 microfarad to 10 microfarad.Certainly, the present invention is not limited to this, and the capacitance of integrating capacitor C1 also can get other value.

The in-phase input end of comparator 302 connects the output (i.e. the ungrounded end of integrating capacitor C1) of feedback control module 200 to obtain integral voltage Vcomp, the inverting input of comparator 302 connects the output (tie point namely between the first resistance R1 and the second resistance R2) of input sample module 500 to obtain input sample voltage Vin-sen, the output of comparator 302 connects the input of drive circuit 301, and the output of drive circuit 301 connects the grid of the first metal-oxide-semiconductor M1.Input sample voltage and integral voltage are compared rear output pwm signal controls the first metal-oxide-semiconductor M1 conducting or cut-off to drive circuit 301 by comparator 302, thus control LED.Therefore, pwm signal here can be understood as the conductivity control signal of LED.

In the present embodiment, the first metal-oxide-semiconductor M1 is mainly used to do switch use, and current-limited power resistance Rp, for bearing unnecessary pressure drop (Vin-VF), namely shares unnecessary pressure drop (Vin-VF) with the form of dividing potential drop.

Preferably, in the present embodiment, reference voltage maker 201, mutual conductance error amplifier 202, first metal-oxide-semiconductor M1, drive circuit 301 and comparator 302 are integrated in chip piece.And current-limited power resistance Rp is placed on chip exterior, to avoid chip internal temperature too high.Sampling resistor Rs is generally also placed in chip exterior, because sampling resistor Rs needs very high precision, integrated resistor does not reach this precision, and sampling resistor Rs can adjust power output in addition, is placed on chip exterior and is convenient to according to different application adjustment power output.Because the capacitance of electric capacity C1 is comparatively large, be generally also placed in chip exterior.And the first resistance R1 and the equal accessible site of the second resistance R2 are in chip, also can be placed on outside chip.Certainly, this is preferred embodiment of the present invention, and the present invention is not limited to this.

The operation principle of the linear switch constant current LED drive circuit of first embodiment of the invention is described below in conjunction with Fig. 4.Fig. 4 shows the working waveform figure of linear switch constant current LED drive circuit in a power frequency period (namely half electric main cycle T/2=1/2f, f is ac power frequency) of the present embodiment.As shown in Figure 4, Vin is the voltage of electric main after bridge rectifier rectification, and its waveform is sinusoidal wave absolute value; VF is the conduction voltage drop of LED; Iin is input current, and Io is the output current flowing through LED, and Io and Iin is equal; Vin-sen is input sample voltage, and Vcomp is the output signal (i.e. integral voltage) of mutual conductance error amplifier 202; PWM is the on off state of LED conduction ratio control signal, this signal controlling first metal-oxide-semiconductor.

The circuit working principle of the present embodiment is as follows: during 0-t1, and input voltage vin is lower than the conduction voltage drop VF of LED, and LED is not enough to conducting, Iin and Io equals zero, and Vin_sen is high level lower than Vcomp, PWM, and the first metal-oxide-semiconductor M1 is in conducting state; In the t1 moment, Vin rises to the conduction voltage drop VF of LED, the automatic conducting of LED, Iin and Io starts to rise; During t1-t2, Vin continues to rise by sinusoidal wave, Iin and Io is also along with rising, and LED pressure drop remains VF, and unnecessary pressure drop (Vin-VF) will be born by current-limited power resistance Rp (because the resistance of Rp is probably for about 1K Europe, and the conducting resistance of M1 is about 20 Europe, the resistance of Rs is about 10 Europe, and therefore the pressure drop of M1 with Rs is very little relative to the pressure drop of Rp, can ignore), during this period, the first metal-oxide-semiconductor M1 keeps conducting state; In the t2 moment, Vin rises to and makes its sampled signal Vin_sen become low level more than Vcomp, PWM, and the first metal-oxide-semiconductor M1 ends, Iin and Io equals zero; When Vin declines, then process is just contrary.

What illustrate is, in the present invention, when system has just been started working also unstable time, if the sampled signal CS(CS=Io*Rs of the output current of LED, be foregoing output current information) mean value less than reference voltage Vref 1, then in a power frequency period, the charge volume of mutual conductance error amplifier 202 couples of integrating capacitor C1 can be more than discharge capacity, therefore Vcomp can constantly rise, conduction ratio also can increase thereupon, the integrated value of output current in a power frequency period also can increase thereupon, (mean value of CS equals the integrated value of output current in a power frequency period and is multiplied by Rs finally to make the mean value of CS increase, then divided by the power frequency period time), if the mean value of the sampled signal CS of output current is larger than reference voltage Vref 1, then in a power frequency period, the charge volume of mutual conductance error amplifier 202 couples of integrating capacitor C1 can be fewer than discharge capacity, therefore Vcomp can constantly decline, conduction ratio also can reduce thereupon, the integrated value of output current in a power frequency period also can reduce thereupon, finally makes the mean value of CS reduce.Under the effect of this negative feedback mechanism, when system reaches stable, the mean value of the sampled signal CS of output current finally can keep constant and equal Vref1, thus in a power frequency period, the charge volume of mutual conductance error amplifier 202 couples of integrating capacitor C1 is equal with discharge capacity, therefore Vcomp keeps constant, and conduction ratio keeps constant, and therefore the mean value of output current also can keep constant and equal Vref1/Rs.If electric capacity C1 is enough large, the fluctuating range of Vcomp in a power frequency period is very little, and this fluctuation can be ignored, and therefore, after system stability, can think, Vcomp keeps constant.In the present embodiment, system can according to different input voltage effective values, LED conduction voltage drop and current-limited power resistance Rp, and automatically adjustment Vcomp and conduction ratio make the mean value of output current remain on constant set point (Vref1/Rs) always.The mode that this employing mutual conductance error amplifier and an integrating capacitor make the mean value of output current reach constant, " integration constant current " mode that we are referred to as.

In order to the advantage of linear switch constant current LED drive circuit first embodiment of the present invention is described more easily, below the average output current to this circuit, average output power etc. are derived.

Mention above, when system reaches stable, in a power frequency period, the variable quantity of Vcomp is zero, therefore can draw:

ΔV comp = 1 C 1 ∫ 0 1 / 2 f G m · ( V ref 1 - I o · R s ) · dt = 0

⇒ 2 f · ∫ 0 1 / 2 f I o · dt = V ref 1 R s ⇒ 2 f · ( ∫ t 1 t 2 I o · dt + ∫ t 2 ′ t 1 ′ I o · dt ) = V ref 1 R s

Average output current in a power frequency period is:

I ‾ o = 2 f · ( ∫ t 1 t 2 I o · dt + ∫ t 2 ′ t 1 ′ I o · dt ) = V ref 1 R s - - - ( 8 )

Average output current in a power frequency period is:

P out = 2 f · V F · ( ∫ t 1 t 2 I o · dt + ∫ t 2 ′ t 1 ′ I o · dt ) = V F · V ref 1 R s - - - ( 9 )

Therefore, the advantage of the linear switch constant current LED drive circuit of the present embodiment comprises:

(1) average output current of LED and the constant of average output power is realized.As can be seen from above-mentioned formula (8) and (9), the average output current of LED and average output power and input voltage have nothing to do, and therefore when line voltage changes, the brightness of LED can remain unchanged.Especially, the resistance Rs of the conduction voltage drop VF of LED, reference voltage Vref 1, sampling resistor is chosen as a particular value usually.

(2) improve system effectiveness, solve the conventional linear constant-current LED driving chip problem that efficiency is too low when input voltage is higher.In the present embodiment, owing to adding input sample module 500 and correspondingly adopting different drive control modules 300 and power control module 400, first metal-oxide-semiconductor M1 is turned off at t2-t2 ' period (namely when unnecessary pressure drop (Vin-VF) is larger), now, the output current Io vanishing of LED, power consumption is also zero, thus improves system effectiveness.Therefore relatively traditional structure (circuit structure as Fig. 1), the linear switch constant current LED drive circuit of the present embodiment improves system effectiveness when input voltage is higher, and unnecessary pressure drop (Vin-VF) is larger, and efficiency improves more obvious.

(3) to generate heat when solving the work of conventional linear constant-current LED driving chip too high problem.In the present embodiment, unnecessary pressure drop (Vin-VF) is born by the current-limited power resistance Rp of chip exterior, and non-traditional structure is born by the power MOSFET of chip internal like that, thermal source is transferred to chip exterior by chip internal, thus significantly reduce the working temperature of chip, and heat-sinking capability also can not be subject to the restriction of chip package thermal resistance.

Fig. 5 is the circuit theory diagrams of linear switch constant current LED drive circuit second embodiment of the present invention.The main distinction of the present embodiment and linear switch constant current LED drive circuit first embodiment of the present invention is power control module 400, and remaining circuit module is substantially identical with linear switch constant current LED drive circuit first embodiment of the present invention, does not repeat them here.

In the present embodiment, power control module 400 also comprises the second metal-oxide-semiconductor M2 be connected between the first metal-oxide-semiconductor M1 and current-limited power resistance Rp.The grid of the second metal-oxide-semiconductor M2 meets fixing high level Vcc, and the source electrode of two metal-oxide-semiconductor M2 connects the drain electrode of the first metal-oxide-semiconductor M1, and the drain electrode of two metal-oxide-semiconductor M2 connects the first end of current-limited power resistance Rp.The present embodiment is its type of drive from the different of the first embodiment of the present invention.In the present embodiment, the grid of the first metal-oxide-semiconductor M1 connects the drive control signal of the output of driver module 300, the on off state of the second metal-oxide-semiconductor M2 is controlled by its source signal (i.e. the drain signal of the first metal-oxide-semiconductor M1), and therefore, what the present embodiment adopted is " source drive " mode.And in the first embodiment of the present invention, only adopting a metal-oxide-semiconductor (i.e. the first metal-oxide-semiconductor M1), the on off state of M1 is directly controlled by its signal, and therefore, what it adopted is " raster data model " mode.Except type of drive difference, the operation principle of the present embodiment is identical with the first embodiment of the present invention, does not repeat them here.

Implementing linear switch constant current LED drive circuit of the present invention and LED lamp, realizing the average output current of LED and the constant of average output power by utilizing the mode of " integration constant current ".When line voltage changes, the brightness of LED can remain unchanged.In addition, this invention also solves the conventional linear constant-current LED driving chip problem that efficiency is too low when input voltage is higher, improve system effectiveness, and too high problem of generating heat when solving the work of conventional linear constant-current LED driving chip, significantly reduce the working temperature of chip.

Although the present invention is described by specific embodiment, it will be appreciated by those skilled in the art that, without departing from the present invention, various conversion can also be carried out and be equal to substituting to the present invention.Therefore, the present invention is not limited to disclosed specific embodiment, and should comprise the whole execution modes fallen within the scope of the claims in the present invention.

Claims (6)

1. a linear switch constant current LED drive circuit, for carrying out current constant control to LED, is characterized in that, described linear switch constant current LED drive circuit comprises:
Input sample module (500), for Gather and input sampled voltage;
Export sampling module (100), for gathering the output current information of described LED;
Feedback control module (200), is connected with described output sampling module (100), keeps substantially invariable integral voltage for generating according to described output current information and exporting in a power frequency period;
Drive control module (300), be connected with described input sample module (500) and described feedback control module (200) respectively, for generating according to described input sample voltage and described integral voltage and export drive control signal;
Power control module (400), is connected with described drive control module (300), for driving according to described drive control signal and LED described in current constant control, and bears the pressure drop in circuit;
Described feedback control module (200) comprises reference voltage maker (201), mutual conductance error amplifier (202) and integrating capacitor (C1); The in-phase input end of described mutual conductance error amplifier (202) connects described reference voltage maker (201) to obtain reference voltage, the inverting input of described mutual conductance error amplifier (202) connects described output sampling module (100) to obtain described output current information, and the output of described mutual conductance error amplifier (202) is by described integrating capacitor (C1) ground connection; Described mutual conductance error amplifier (202) carries out discharge and recharge to described integrating capacitor (C1), to generate described integral voltage for voltage corresponding for described output current information and described reference voltage are compared rear output gain electric current;
Described power control module (400) comprises the first metal-oxide-semiconductor (M1) and current-limited power resistance (Rp); The grid of described first metal-oxide-semiconductor (M1) connects the output of described drive control module (300), the source electrode of described first metal-oxide-semiconductor (M1) connects described output sampling module (100), the drain electrode of described first metal-oxide-semiconductor (M1) connects the first end of described current-limited power resistance (Rp), and the second end of described current-limited power resistance (Rp) connects described LED; Described current-limited power resistance (Rp) is for bearing the pressure drop in circuit;
Described drive control module (300) comprises drive circuit (301) and comparator (302); The in-phase input end of described comparator (302) connects the output of described feedback control module (200) to obtain described integral voltage, the inverting input of described comparator (302) connects the output of described input sample module (500) to obtain described input sample voltage, the output of described comparator (302) connects the input of described drive circuit (301), and the output of described drive circuit (301) connects the grid of described first metal-oxide-semiconductor (M1);
Wherein, described reference voltage maker (201), described mutual conductance error amplifier (202), described first metal-oxide-semiconductor (M1), described drive circuit (301) and described comparator (302) are integrated in chip piece, and described current-limited power resistance (Rp) and integrating capacitor (C1) are in chip exterior.
2. linear switch constant current LED drive circuit according to claim 1, is characterized in that, described input sample module (500) comprises the first resistance (R1) and the second resistance (R2); Described first resistance (R1) and the rear ground connection of described second resistance (R2) series connection, one end of described first resistance (R1) connects the input power of described LED, and the tie point of described first resistance (R1) and described second resistance (R2) is as the output of described input sample module (500).
3. linear switch constant current LED drive circuit according to claim 2, is characterized in that, described output sampling module (100) comprises sampling resistor (Rs); The first end of described sampling resistor (Rs) connects the source electrode of described first metal-oxide-semiconductor (M1) and the inverting input of described mutual conductance error amplifier (202), the second end ground connection of described sampling resistor (Rs) respectively.
4. linear switch constant current LED drive circuit according to claim 3, it is characterized in that, described power control module (400) also comprises the second metal-oxide-semiconductor (M2) be connected between described first metal-oxide-semiconductor (M1) and described current-limited power resistance (Rp); The grid of described second metal-oxide-semiconductor (M2) connects high level, the source electrode of described two metal-oxide-semiconductors (M2) connects the drain electrode of described first metal-oxide-semiconductor (M1), and the drain electrode of described two metal-oxide-semiconductors (M2) connects the first end of described current-limited power resistance (Rp).
5. linear switch constant current LED drive circuit according to claim 1, is characterized in that, the capacitance scope of described integrating capacitor (C1) is 1 microfarad to 10 microfarad.
6. a LED lamp, comprise alternating current input power supplying, rectifier bridge, linear switch constant current LED drive circuit and LED, it is characterized in that, described linear switch constant current LED drive circuit adopts the linear switch constant current LED drive circuit as described in any one of claim 1-5.
CN201310356131.9A 2013-08-15 2013-08-15 A kind of linear switch constant current LED drive circuit and LED lamp CN103442484B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201310356131.9A CN103442484B (en) 2013-08-15 2013-08-15 A kind of linear switch constant current LED drive circuit and LED lamp

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201310356131.9A CN103442484B (en) 2013-08-15 2013-08-15 A kind of linear switch constant current LED drive circuit and LED lamp

Publications (2)

Publication Number Publication Date
CN103442484A CN103442484A (en) 2013-12-11
CN103442484B true CN103442484B (en) 2015-08-12

Family

ID=49696129

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201310356131.9A CN103442484B (en) 2013-08-15 2013-08-15 A kind of linear switch constant current LED drive circuit and LED lamp

Country Status (1)

Country Link
CN (1) CN103442484B (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104219832B (en) * 2014-07-22 2017-04-26 易美芯光(北京)科技有限公司 Constant-power feedback structure of segmented LED driving circuit
CN105338718B (en) * 2015-12-08 2018-09-18 王汉忠 It is a kind of based on linearly with the LED constant current driving method and device of PWM operating modes
CN106163009B (en) * 2016-08-18 2019-01-29 杰华特微电子(杭州)有限公司 Illumination driving circuit and lighting system
CN106132030B (en) * 2016-08-18 2018-02-09 杰华特微电子(杭州)有限公司 A kind of illumination driving circuit and illuminator
CN106505513B (en) * 2016-12-26 2019-06-25 广东工业大学 A kind of LED drive power and its output end short-circuit protection circuit
CN107564432A (en) * 2017-08-16 2018-01-09 杭州鸟人光电科技有限公司 Programmable image demonstrating apparatus
CN109287042A (en) * 2018-12-12 2019-01-29 昂宝电子(上海)有限公司 Multi-stage constant current control system and method for LED illumination

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101720148A (en) * 2009-07-21 2010-06-02 海洋王照明科技股份有限公司 LED driving circuit and LED device
CN101868094A (en) * 2010-06-22 2010-10-20 海洋王照明科技股份有限公司 LED driving circuit and LED lamp
CN101925232A (en) * 2010-08-12 2010-12-22 无锡科尔华电子有限公司 LED street lamp constant current control power supply
CN102076138A (en) * 2009-11-25 2011-05-25 北京交通大学 Electric supply input LED (Light Emitting Diode) constant current driver
WO2012022088A1 (en) * 2010-08-16 2012-02-23 深圳市航嘉驰源电气股份有限公司 Current feedback circuit and led lamp driving circuit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101720148A (en) * 2009-07-21 2010-06-02 海洋王照明科技股份有限公司 LED driving circuit and LED device
CN102076138A (en) * 2009-11-25 2011-05-25 北京交通大学 Electric supply input LED (Light Emitting Diode) constant current driver
CN101868094A (en) * 2010-06-22 2010-10-20 海洋王照明科技股份有限公司 LED driving circuit and LED lamp
CN101925232A (en) * 2010-08-12 2010-12-22 无锡科尔华电子有限公司 LED street lamp constant current control power supply
WO2012022088A1 (en) * 2010-08-16 2012-02-23 深圳市航嘉驰源电气股份有限公司 Current feedback circuit and led lamp driving circuit

Also Published As

Publication number Publication date
CN103442484A (en) 2013-12-11

Similar Documents

Publication Publication Date Title
US9055629B2 (en) SCR dimming circuit and method
CN103281849B (en) Light-adjusting device and method of LED illuminating lamp
CN102781139B (en) Lighting device for lighting solid-state light source and illumination apparatus using same
US9307586B2 (en) Flyback AC-to-DC converter
CN102340911B (en) Control circuit and control method for light emitting diode (LED) driver
CN102752940B (en) High-efficiency LED (light-emitting diode) drive circuit and drive method thereof
TWI565355B (en) High efficiency, high power factor LED driver circuit
CN102480828B (en) Led drive device
CN103491682B (en) Linear switching constant-current LED drive circuit for control over peak current
CN102065600B (en) LED dimming drive system
CN103440848B (en) Backlight drive circuit
CN103152956B (en) LED drive circuit and constant-current control circuit thereof
EP2389046A2 (en) Triac dimmer compatible switching mode power supply and the method thereof
CN103546047B (en) A kind of circuit of synchronous rectification and Switching Power Supply being applicable to electronic transformer
CN102497711B (en) LED drive circuit and comprise the Switching Power Supply of this drive circuit
JP5592613B2 (en) Power supply device and lighting apparatus using the same
US20120056551A1 (en) High power-factor control circuit and method for switched mode power supply
CN103580470B (en) For the mixed self-adapting power factor correction scheme of switching power converter
CN102369496B (en) Stabilized DC power source device
US20130181626A1 (en) High efficiency led driver and driving method thereof
CN102474953B (en) Dimming device for a lighting apparatus
TW201230858A (en) High efficient LED driving circuit and method thereof
CN102340251A (en) Alternating-current to direct-current converter and control circuit thereof
CN201976288U (en) Drive power supply for LED illuminating light
CN102263492A (en) Semiconductor device and power supply device

Legal Events

Date Code Title Description
PB01 Publication
C06 Publication
SE01 Entry into force of request for substantive examination
C10 Entry into substantive examination
GR01 Patent grant
C14 Grant of patent or utility model