CN104168696A - Compatible LED power circuit - Google Patents

Compatible LED power circuit Download PDF

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Publication number
CN104168696A
CN104168696A CN201410374478.0A CN201410374478A CN104168696A CN 104168696 A CN104168696 A CN 104168696A CN 201410374478 A CN201410374478 A CN 201410374478A CN 104168696 A CN104168696 A CN 104168696A
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diode
circuit
capacitor
resistance
rectifier bridge
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CN104168696B (en
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罗吉国
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Dongguan stable core electronic technology Co., Ltd.
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罗吉国
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Abstract

The invention relates to a compatible LED power circuit which comprises an AC connecting end, a power inductor L1, a first rectifier bridge, a second rectifier bridge, a first filter circuit, a PWM controller, an EMC circuit, a coupling transformer T1 and an LED output circuit. The AC connecting end is connected to a primary coil of the coupling transformer T1 through the power inductor L1, the second rectifier bridge and the EMC circuit, and a secondary coil of the coupling transformer T1 is connected with the LED output circuit; the input end of the first rectifier bridge is connected with the AC connecting end, and the output end of the first rectifier bridge is connected with the first filter circuit; the first filter circuit is connected with the first input end of a first error amplifier of the PWM controller; the signal output end of the PWM controller is connected with the second end of the primary coil of the coupling transformer T1. Impedance matched with different electronic ballasts can be effectively adjusted through the compatible LED power circuit, the electronic ballasts are protected and meet the requirements for actual use, and compatibility is achieved; besides, the compatible LED power circuit is compatible with inductive ballasts and common AC input, and the fact that LED lamp tubes replace traditional fluorescent lamp tubes is truly achieved.

Description

Compatible type LED power circuit
Technical field
The present invention relates to the power circuit of LED fluorescent tube, be specifically related to a kind of can compatible electronic ballast, the LED tube power circuit of Inductive ballast and AC power.
Background technology
Traditional daylight illumination is to adopt the mode of fluorescent tube and ballast combinations to realize, and generally has Inductive ballast to add starter, or two kinds of forms of electric ballast.And universal along with novel illumination material LED engenders the LED fluorescent tube of multiple replacement fluorescent tube, LED fluorescent tube is all with driving power circuit, to coordinate existing light fixture to use, and directly replace fluorescent lamps pipe.For the LED fluorescent tube that adopts Inductive ballast or adopt alternating current directly to drive, owing to directly adopting the 50-60Hz alternating current of civil power, its power circuit is easily realized.But for the LED fluorescent tube driving with electric ballast, because electric ballast is output as high-frequency alternating current, general frequency is at 35-65kHz, its constant output current.If the load of electric ballast is not mated, when the equiva lent impedance of load is higher than the impedance of electric ballast design itself, the alternating voltage of output becomes large; Otherwise the alternating voltage of output diminishes.Therefore, how mating the output impedance of electric ballast, is the difficult point that LED driving power circuit will solve.Lack on the market the compatible LED fluorescent tube that uses different electric ballasts, can be compatible even if claim, also compatible poor performance substantially.There will be LED fluorescent tube not light, or electric ballast is crossed cause thermal damage.On the other hand, if directly compatible electronic ballast, Inductive ballast and exchange the use driving of LED fluorescent tube will further meet actual use needs.
Summary of the invention
For above-mentioned prior art deficiency, the technical problem to be solved in the present invention is to provide a kind of LED driving power circuit, make the equivalent input impedance of LED driving power circuit follow the output impedance variation of electric ballast, to reach the object of compatible different electric ballasts.
For solving the problems of the technologies described above, the technical solution used in the present invention is, compatible type LED power circuit, comprises and exchanges link, power inductance L1, the first rectifier bridge, the second rectifier bridge, the first filter circuit, PWM controller, EMC circuit, coupling transformer T1 and LED output circuit; Exchange link is connected to the primary coil of coupling transformer T1 successively first end by power inductance L1, the second rectifier bridge and EMC circuit, the secondary coil of coupling transformer T1 connects LED output circuit; The input of the first rectifier bridge is connected with interchange link, and the output of the first rectifier bridge is connected with the first filter circuit; The first filter circuit is connected with the first input end of the first error amplifier of PWM controller, and the second input of the first error amplifier is for being connected with the first reference voltage; The signal output part of PWM controller is connected with the second end of the primary coil of coupling transformer T1.Such scheme can change by the ECG of input the pulsewidth of EMC, thereby changes matched impedance.
Further technical scheme is that described the first filter circuit comprises resistance R 5, capacitor C 6, diode D15 and electrochemical capacitor C7; The parallel branch of resistance R 5 and capacitor C 6 is connected between the positive output end and negative output terminal of the first rectifier bridge, and the positive output end of the first rectifier bridge is VECG end, the negative output terminal ground connection of the first rectifier bridge; The positive output end of the first rectifier bridge is also connected to the anode of diode D15, and the negative electrode of diode D15 is connected with the positive pole of electrochemical capacitor C7, the minus earth of electrochemical capacitor C7; The just very VCC end of electrochemical capacitor C7, is connected with the energization pins of PWM controller; The VECG end of the first filter circuit is connected to the first input end of the first error amplifier of PWM controller by a diode D17, the anodic bonding of VECG end and diode D17.
Further technical scheme is, described the first filter circuit also comprises voltage stabilizing didoe ZD4; Described voltage stabilizing didoe ZD4 is connected between VECG end and diode D15, and the negative electrode of voltage stabilizing didoe ZD4 is connected with VECG end, the anodic bonding of the anode of voltage stabilizing didoe ZD4 and diode D15.Such scheme can be applicable to the compatibility of preheating start-up type and OnNow type, for preheating start-up type, while arriving starting resistor, just PWM controller is powered to voltage.
Further technical scheme is, signal isolation circuit; Described signal isolation circuit comprises switching tube Q6, resistance R 9, resistance R 10 and diode D16; The source ground of switching tube Q6, resistance R 9 is connected between the source electrode and grid of switching tube Q6; The grid of switching tube Q6 is also connected to VECG end; The drain electrode of switching tube Q6 is connected to canonical reference voltage end by resistance R 10; The drain electrode of switching tube Q6 is also connected to the anode of diode D16, and the negative electrode of diode D16 is connected to the first input end of the first error amplifier.Such scheme can be avoided, in the time of the non-ECG of access, avoiding VECG end signal to affect the pulse-width modulation of PWM controller.
Further technical scheme is, also comprises frequency-selecting bleeder circuit and charging circuit; Described frequency-selecting bleeder circuit comprises capacitive portion; Described power inductance L1 is series between the anode and the second rectifier bridge that exchanges link; Described interchange link is connected to the first rectifier bridge by frequency-selecting bleeder circuit, and capacitive portion is connected with the anode that exchanges link; Described coupling transformer T1 also comprises second subprime coil, and this second subprime coil is connected with charging circuit, and charging circuit is provided with power supply output, and this power supply output is connected with the energization pins of PWM controller; The current detection voltage end of LED output circuit is connected to the second input of the second error amplifier of PWM controller, and the first input end of this second error amplifier is for being connected with the second reference voltage.Such scheme makes PWM controller carry out in a different manner pulse-width modulation, the use of comprehensive compatible CCG, AC and ECG according to the difference of input starter.
Further technical scheme is, described charging circuit comprises diode D7, switching tube Q2, transistor Q3, voltage stabilizing didoe ZD3, voltage stabilizing didoe ZD6, diode D9, diode D10, electrochemical capacitor C4, electrochemical capacitor C5, resistance R 3 and resistance R 6; The anode of diode D7 is connected with the first end of coupling transformer T1 primary coil, the negative electrode of diode D7 is connected with the negative electrode of voltage stabilizing didoe ZD3, the anode of voltage stabilizing didoe ZD3 is connected to the drain electrode of switching tube Q2 by resistance R 3, the grid of switching tube Q2 is connected with the collector electrode of transistor Q3, the source electrode of switching tube Q2 is connected to the positive pole of electrochemical capacitor C5, the grounded emitter of transistor Q3; The base stage of transistor Q3 is connected to the anode of voltage stabilizing didoe ZD6 by resistance R 6; The negative electrode of voltage stabilizing didoe ZD6 is connected to the negative electrode of diode D9; The anode of diode D9 is connected with the first end of the second subprime coil of coupling transformer T1, the second end ground connection of second subprime coil; The negative electrode of diode D9 also with the anodic bonding of diode D10, the negative electrode of diode D10 is also connected to the positive pole of electrochemical capacitor C5, the minus earth of electrochemical capacitor C5, the anodic bonding of the positive pole of electrochemical capacitor C4 and diode D10, the minus earth of electrochemical capacitor C4.
Preferably, described frequency-selecting bleeder circuit also comprises the perceptual portion that forms bleeder circuit with capacitive portion; Described capacitive portion is capacitor C S1, and described perceptual portion is instrument transformer LS1; One end of capacitor C S1 is connected with the anode that exchanges link, and the other end of capacitor C S1 is connected with one end of the primary coil of instrument transformer LS1, and the other end of the primary coil of instrument transformer LS1 is connected to the negative terminal that exchanges link; The secondary coil two ends of instrument transformer LS1 are connected respectively to the input of the first rectifier bridge; The capacitance of capacitor C S1 is not more than 0.3 μ F; The inductance value of the primary coil of instrument transformer LS1 is 0.3mH-6mH.
Preferred technical scheme is also, and described capacitive portion is capacitor C S2; Described frequency-selecting bleeder circuit also comprises capacitor C S3; One end of capacitor C S2 and the anode that exchanges link, the other end of capacitor C S2 is connected to an input of the first rectifier bridge; One end of capacitor C S3 is connected to another input of the first rectifier bridge, and the capacitor C S3 other end is connected to the negative terminal that exchanges link.
Further technical scheme is, also comprises secondary signal buffer circuit, and described secondary signal buffer circuit comprises diode D18 and voltage stabilizing didoe ZD7; The first filter circuit is connected to the first input end of the first error amplifier of PWM controller by a diode D17, wherein the negative electrode of diode D17 is connected with the first input end of the first error amplifier; The negative electrode of voltage stabilizing didoe ZD7 is connected to the anode of diode D17, the anodic bonding of the anode of voltage stabilizing didoe ZD7 and diode D18, and the negative electrode of diode D18 is connected to the first input end of the second error amplifier.Such scheme had both made not arrange the maximum pulse width Dmax of PWM controller, and PWM output pulse width D is not subject to the impact of the second error amplifier yet.
Further technical scheme is also to comprise protective circuit; Described protective circuit comprises resistance R 1, resistance R 7, resistance R 8, transistor Q5, voltage stabilizing didoe ZD1, switching tube Q1 and capacitor C 2; The series arm of resistance R 7 and resistance R 8 is connected between the positive output end and reference edge of EMC circuit; The base stage of transistor Q5 is connected to the node of resistance R 7 and resistance R 8; The emitter of transistor Q5 is connected to the reference edge of EMC circuit; The collector electrode of transistor Q5 is connected to the grid of switching tube Q1; The source electrode of switching tube Q1 is connected to the reference edge of EMC circuit, the grounded drain of switching tube Q1; The anodic bonding of voltage stabilizing didoe ZD1 is to the emitter of transistor Q5, and the negative electrode of voltage stabilizing didoe ZD1 is connected to the collector electrode of transistor Q5; The collector electrode of transistor Q5 is also by being connected to the positive output end of EMC circuit by resistance R 1; One end of capacitor C 2 is connected to the positive output end of EMC circuit, the other end ground connection of capacitor C 2.
Compatible type LED power circuit of the present invention can effectively regulate the impedance of the electric ballast that coupling is different, and actual use protection electric ballast and satisfied, realizes compatible; In addition can also compatible Inductive ballast exchange input with common, realize real LED fluorescent tube and replace conventional fluorescent fluorescent tube.
Brief description of the drawings
Fig. 1 is the circuit theory diagrams of the first embodiment of compatible type LED power circuit of the present invention.
Fig. 2 is the circuit theory diagrams of the second embodiment of compatible type LED power circuit of the present invention.
Fig. 3 is the input voltage schematic diagram of electric ballast.
Fig. 4 is the input voltage schematic diagram of Inductive ballast or alternating current.
Fig. 5 is the Inductive ballast input voltage schematic diagram of preheating start-up type.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail
As shown in Figure 1, the first embodiment of compatible type LED power circuit of the present invention, comprises and exchanges link (anode LA1, anode LA2, negative terminal RA1 and negative terminal RA2), power inductance L1, the first rectifier bridge (diode D11, diode D12, diode D13 and diode D14), the second rectifier bridge (diode D1, diode D2, diode D3 and diode D4), the first filter circuit, PWM controller, EMC circuit, coupling transformer T1 and LED output circuit.Exchange link is connected to the primary coil of coupling transformer T1 successively first end by power inductance L1, the second rectifier bridge and EMC circuit, particularly, the anode LA1 that exchanges link is connected to the first end of power inductance L1 by fuse F3, anode LA2 is connected to anode LA1 by fuse F1; Power inductance L1 is connected to the input anode of EMC circuit by the second rectifier bridge, the input of EMC circuit is connected with the negative output terminal of the second rectifier bridge, and between the positive output end (node of diode D1, diode D2) of the second rectifier bridge and negative output terminal, also cross-over connection has a capacitor C 1; The positive output end of EMC circuit is connected to the primary coil first end of coupling transformer T1.The secondary coil of coupling transformer T1 connects LED output circuit, particularly, in the present embodiment, LED output circuit comprises diode D8, electrochemical capacitor C3 and resistance R 4, the anodic bonding of diode D8 is to the first end of the secondary coil of coupling transformer T1, the second end ground connection of coupling transformer secondary coil; The positive pole of electrochemical capacitor C3 is connected with the negative electrode of diode D8, the minus earth of electrochemical capacitor C3; The just very VO end of electrochemical capacitor C3, for the anodic bonding of LED lamp string; The negative electrode of electrochemical capacitor C3 is connected with the first end of resistance R 4, and the second end of resistance R 4 is the current detection voltage end of LED output circuit (being IO end), simultaneously for being connected with the negative electrode of LED lamp string; Wherein primary coil the second end of coupling transformer T1 and secondary coil first end are Same Name of Ends.The current detection voltage end of LED output circuit is connected to the second input (being positive input terminal in the present embodiment) of the second error amplifier EA2 of PWM controller, and the first input end (negative input end) of this second error amplifier EA2 is for being connected with the second reference voltage REF2.By the power supply of coupling transformer T1, to electrochemical capacitor, C3 is charged to burning voltage, thereby realizes the power supply to LED lamp string; It should be noted that, LED output circuit is not consideration category of the present invention, only proposes a kind of mode of the LED of realization power supply output here, not in order to limit the present invention, can adopt the LED output circuit of other forms, other functions in actual enforcement.
The input of the first rectifier bridge (being diode D11 and the node of diode D13, the diode D12 node with diode D14) with exchange link and be connected.Particularly, also comprise frequency-selecting bleeder circuit in the present invention, described frequency-selecting bleeder circuit comprises capacitive portion, and in the present embodiment, described capacitive portion is capacitor C S1, and described perceptual portion is instrument transformer LS1; One end of capacitor C S1 connects with the anode (being specially anode LA1, anode LA2 after being connected with fuse F3) that exchanges link, the other end of capacitor C S1 is connected with one end of the primary coil P of instrument transformer LS1, and the other end of the primary coil P of instrument transformer LS1 is connected to the negative terminal (negative terminal RA1 and the negative terminal RA2 that has been connected fuse F2) that exchanges link; The secondary coil S two ends of instrument transformer LS1 are connected respectively to the input of the first rectifier bridge.The capacitance of capacitor C S1 is not more than 0.3 μ F; The inductance value of the primary coil of instrument transformer LS1 is 0.3mH-6mH.In the time being input as ECG (electric ballast), ac frequency generally reaches 35KHz-65KHz, as shown in Figure 3, under the alternating current of high frequency, capacitive portion is that the impedance of capacitor C S1 is very little, and that perceptual portion is the primary coil P impedance of instrument transformer LS1 is larger, thereby the secondary coil S of instrument transformer LS1 can obtain the larger dividing potential drop of input voltage; On the other hand, in the time being input as CCG (Inductive ballast) or common current, its ac frequency is the approximately 50Hz of civil power, as shown in Figure 4, belongs to the alternating current of low frequency, the impedance of capacitor C S1 is larger, and the impedance of the primary coil P of instrument transformer LS1 is relatively little, thereby the upper voltage obtaining of the secondary coil S of instrument transformer LS1 is by being the voltage obtaining much smaller than ECG input, with this scheme, can judge the kind of input voltage, that judgement is inputted is ECG or CCG/AC; On the other hand, in the time being input as ECG, input voltage can be by frequency-selecting bleeder circuit dividing potential drop, thereby frequency-selecting bleeder circuit also has the function of the input voltage that detects ECG.Without carrying out the situation (only for ECG) of high frequency judgement and the lower situation of accuracy of detection to input ECG voltage, can cancel the setting of frequency-selecting bleeder circuit.
The output of the first rectifier bridge is connected with the first filter circuit; Particularly, described the first filter circuit comprises resistance R 5, capacitor C 6, diode D15 and electrochemical capacitor C7; The parallel branch of resistance R 5 and capacitor C 6 is connected between the positive output end (node of diode D11 and diode D12) and negative output terminal (node of diode D13 and diode D14) of the first rectifier bridge, the positive output end of the first rectifier bridge is VECG end (obtaining the voltage after the conversion of ECG input voltage of detection), the negative output terminal ground connection of the first rectifier bridge; The positive output end of the first rectifier bridge is also connected to the anode of diode D15, and the negative electrode of diode D15 is connected with the positive pole of electrochemical capacitor C7, the minus earth of electrochemical capacitor C7; The just very VCC end of electrochemical capacitor C7, is connected with the energization pins of PWM controller; The VECG end of the first filter circuit is connected to the first input end (the present embodiment is negative input end) of the first error amplifier EA1 of PWM controller by a diode D17, the anodic bonding of VECG end and diode D17.The second input (positive input terminal) of the first error amplifier EA2 is for being connected with the first reference voltage REF1; The signal output part (i.e. PWM end in figure) of PWM controller is connected with the second end of the primary coil of coupling transformer T1, particularly, this signal output part is connected to the grid of a switching tube Q4, the source ground of this switching tube Q4, drain electrode is connected to primary coil the second end of coupling transformer T1.When the first filter circuit obtains after ECG input voltage, by charging, saturated electrochemical capacitor C7 powers to PWM controller, makes the work of PWM controller.For the electric ballast of preheating start-up type, as shown in Figure 5, input voltage can, in a lower value at the beginning time, generally just can be increased to stable operating voltage through the time of about 500ms left and right.For this situation, the voltage stabilizing didoe ZD4 that can connect between VECG end and diode D15 more, wherein the negative electrode of voltage stabilizing didoe ZD4 is connected with VECG end, the anodic bonding of the anode of voltage stabilizing didoe ZD4 and diode D15.(during being low-voltage) between warming up period because voltage stabilizing didoe ZD4 does not have reverse-conducting, electrochemical capacitor C7 does not charge, and the startup of not powering of PWM controller, after voltage stabilization is operating voltage, voltage stabilizing didoe ZD4 reverse-conducting, PWM controls and obtains power supply; For the electric ballast of OnNow type (there is no warm-up time), even input voltage voltage stabilizing didoe ZD4 reverse-conducting when unlatching, do not affect the startup of PWM controller, because can realize the compatibility between the electric ballast of OnNow type and the electric ballast of preheating start-up type.
Operation principle: the saturation current of power inductance L1 is greater than the peak current that flows through power inductance L1.The general value 0.1-1mH of power inductance L1 inductance value.
In the time of input CCG or AC, because frequency is low to moderate 50/60Hz, the equiva lent impedance of power inductance L1 is very little, is almost equivalent to short circuit, and circuit is not affected.
In the time of input ECG, because frequency is up to 35-65kHz, the equiva lent impedance on power inductance L1 is between tens of extremely hundreds of ohm.Now, get
IECG≈ICS1+IL1
(in above formula, IECG is the output current effective value of the design of ECG, ICS1 is the current effective value that flows through capacitor C S1, IL1 is the current effective value that flows through power inductance L1) can allow the input equiva lent impedance of LED fluorescent tube mate with the output impedance of the design of ECG, LED fluorescent tube and the ECG compatibility of order design.According to ECG output characteristic, if IECG>ICS1+IL1, ECG output voltage VO ECG rises; If IECG<ICS1+IL1, ECG output voltage VO ECG declines.Shown in figure, there is the inside equivalent structure figure of PWM controller, the FB signal end of PWM controller, the pwm signal of the current drives module output 20-100kHz by PWM controller, the break-make of driving switch pipe Q4, in the time that FB signal voltage rises, PWM pulsewidth D decline; Otherwise PWM pulsewidth D rises.
When the detection signal by capacitor C S1 and instrument transformer LS1 is after rectifying and wave-filtering, the detection signal VECG that becomes the output voltage VO ECG of electric ballast (is the voltage on WECG end, VECG is directly proportional to VOECG, the parameter correlation of concrete proportionate relationship and circuit devcie), VECG inputs to the first error amplifier after diode D17, compare with the first reference voltage REF1, after amplification, export FB signal through a diode.
In this process:
FB↓=>D↑=>IL1↑=>ICS1+IL1↑=>VOECG↓=>VECG↓=>FB↑=>D↓=>IL1↓=>ICS1+IL1↓=>VOECG↑=>VECG↑=>FB↓
Form thus a closed feedback loop, the input equiva lent impedance of LED fluorescent tube can match different equiva lent impedances to different ECG, reaches the object of compatible ECG.When setting PWM is maximum pulse width Dmax, LED lamp string stream detects voltage IO and is still less than reference voltage REF2, i.e. " EA2->EA2+ ", so the second error amplifier EA2 no-output, IO signal, and then does not affect PWM output pulse width D without impact FB signal.
In the time being input as CCG or AC, the second error amplifier EA2 normally works,
In this process:
FB↓=>D↑=>IO↑=>FB↑=>D↓=>IO↓=>FB↓
Form thus a closed feedback loop, the operating current of LED lamp string can be effectively controlled.
Further, the present invention also comprises signal isolation circuit; Described signal isolation circuit comprises switching tube Q6, resistance R 9, resistance R 10 and diode D16; The source ground of switching tube Q6, resistance R 9 is connected between the source electrode and grid of switching tube Q6; The grid of switching tube Q6 is also connected to VECG end; The drain electrode of switching tube Q6 is connected to canonical reference voltage end REF by resistance R 10; The drain electrode of switching tube Q6 is also connected to the anode of diode D16, and the negative electrode of diode D16 is connected to the first input end of the first error amplifier EA1.
Set the first reference voltage REF1 and diode D16 forward conduction voltage sum much smaller than canonical reference voltage REF.In the time being input as CCG or AC, VECG is close to 0, switching tube Q6 cut-off,
REF is through the negative input end of resistance R 10, diode D16 to the first error amplifier EA1, its magnitude of voltage is higher than the first reference voltage REF1, i.e. " EA1->EA1+ ", the first error amplifier EA1 no-output so, VECG signal does not affect PWM output pulse width D.
The present invention also comprises charging circuit, and coupling transformer T1 also comprises second subprime coil, and this second subprime coil is connected with charging circuit, and charging circuit is provided with power supply output, and this power supply output is connected with the energization pins of PWM controller.Particularly, described charging circuit comprises diode D7, switching tube Q2, transistor Q3, voltage stabilizing didoe ZD3, voltage stabilizing didoe ZD6, diode D9, diode D10, electrochemical capacitor C4, electrochemical capacitor C5, resistance R 3 and resistance R 6; The anode of diode D7 is connected with the first end of coupling transformer T1 primary coil, the negative electrode of diode D7 is connected with the negative electrode of voltage stabilizing didoe ZD3, the anode of voltage stabilizing didoe ZD3 is connected to the drain electrode of switching tube Q2 by resistance R 3, the grid of switching tube Q2 is connected with the collector electrode of transistor Q3, the source electrode of switching tube Q2 is connected to the positive pole of electrochemical capacitor C5, the grounded emitter of transistor Q3; The base stage of transistor Q3 is connected to the anode of voltage stabilizing didoe ZD6 by resistance R 6; The negative electrode of voltage stabilizing didoe ZD6 is connected to the negative electrode of diode D9; The anode of diode D9 is connected with the first end of the second subprime coil of coupling transformer T1, the second end ground connection of second subprime coil; The negative electrode of diode D9 also with the anodic bonding of diode D10, the negative electrode of diode D10 is also connected to the positive pole of electrochemical capacitor C5, the minus earth of electrochemical capacitor C5, the anodic bonding of the positive pole of electrochemical capacitor C4 and diode D10, the minus earth of electrochemical capacitor C4.In the time being input as CCG or AC, if input voltage is lower, now the output voltage of EMC circuit is also lower, and voltage stabilizing didoe ZD3 can reverse-conducting, does not therefore have starting resistor and offer the energization pins of PWM controller, and PWM controller is not worked;
In the time of input normal voltage, voltage stabilizing didoe ZD3 reverse-conducting, switching tube Q2 conducting, the output voltage of EMC circuit charges to electrochemical capacitor C5 through diode D7, voltage stabilizing didoe ZD3, resistance R 3, switching tube Q2, when the magnitude of voltage of electrochemical capacitor C5 reaches the starting resistor of PWM controller, PWM controller startup work.Then PWM has pulsewidth output, and the coil-induced voltage of the second subprime of coupling transformer T1 is through diode D9 rectification thereupon, electrochemical capacitor C4 filtering, then the energization pins of passing through diode D10 to PWM controller.Voltage stabilizing didoe ZD6 reverse-conducting after starting, transistor Q3 conducting thereupon, is pulled to switching tube Q2 grid voltage to approach 0V, makes switching tube Q2 cut-off.The start-up circuit being made up of diode D7, voltage stabilizing didoe ZD3, resistance R 3, switching tube Q2, resistance R 2, voltage stabilizing didoe ZD5 while being the startup of PWM controller is powered, and the current rectifying and wave filtering circuit being made up of through diode D9, electrochemical capacitor C4, diode D10, electrochemical capacitor C5 the second subprime coil of coupling transformer T1 after startup is powered; In the time that fluorescent tube input is ECG, the supply power voltage of PWM controller is obtained after the first rectifier bridge rectification by the secondary coil S of instrument transformer LS1, controls ingenious.
The present invention also comprises protective circuit; Described protective circuit comprises resistance R 1, resistance R 7, resistance R 8, transistor Q5, voltage stabilizing didoe ZD1, switching tube Q1 and capacitor C 2; The series arm of resistance R 7 and resistance R 8 is connected between the positive output end and reference edge of EMC circuit; The base stage of transistor Q5 is connected to the node of resistance R 7 and resistance R 8; The emitter of transistor Q5 is connected to the reference edge of EMC circuit; The collector electrode of transistor Q5 is connected to the grid of switching tube Q1; The source electrode of switching tube Q1 is connected to the reference edge of EMC circuit, the grounded drain of switching tube Q1; The anodic bonding of voltage stabilizing didoe ZD1 is to the emitter of transistor Q5, and the negative electrode of voltage stabilizing didoe ZD1 is connected to the collector electrode of transistor Q5; The collector electrode of transistor Q5 is also by being connected to the positive output end of EMC circuit by resistance R 1; One end of capacitor C 2 is connected to the positive output end of EMC circuit, the other end ground connection of capacitor C 2.Occur when abnormal at circuit; ECG exports the voltage of fluorescent tube to through the second rectifier bridge (diode D1-diode D4) rectification; again by capacitor C 1 filtering; pass through again EMC circuit, through resistance R 7, resistance R 8 dividing potential drops, once branch pressure voltage is greater than the knot conducting voltage of transistor Q5; transistor Q5 conducting; switching tube Q1 grid voltage is dragged down by transistor Q5, and switching tube Q1 ends, thereby reaches the object of protection switch pipe Q1 late-class circuit and ECG.
Figure 2 shows that the second embodiment of the present invention, be with the difference of above-mentioned the first embodiment, described capacitive portion is capacitor C S2; Described frequency-selecting bleeder circuit also comprises capacitor C S3; One end of capacitor C S2 and the anode that exchanges link, the other end of capacitor C S2 is connected to an input of the first rectifier bridge; One end of capacitor C S3 is connected to another input of the first rectifier bridge, and the capacitor C S3 other end is connected to the negative terminal that exchanges link.In the present embodiment, the capacitance of capacitor C S2 is much larger than the capacitance of capacitor C S3, although capacitor C S3 is electric capacity, the device of capacitive in fact, but because its capacitance is much smaller than the capacitor C S2 that is mated use, on the circuit of high frequency dividing potential drop, realize equally the object that dividing potential drop detects, its operation principle is identical with above-mentioned the first embodiment.In addition, the capacitance of capacitor C S2 and capacitor C S3 can be suitable, also can not establish capacitor C S3, and capacitor C S2 (or do not establish instrument transformer LS1 capacitor C S1 is only set) is set separately, capacitor C S2 also forms dividing potential drop with resistance R 5 like this, can obtain equally dividing potential drop; But to the shunting action of frequency-selecting dividing potential drop not as the arranging effect of the capacitor C S1 in above-mentioned the first embodiment and instrument transformer LS1 good.Instrument transformer LS1 connects with capacitor C S1 as a load of ECG output, make wherein a part of output current of ECG flow through this load, effectively reduce the electric current that flows through frequency-selecting bleeder circuit, reduced the loss of rectifying tube D1-D4, and then reduced the loss of whole circuit, promote power-efficient.
On the other hand, the present embodiment also comprises secondary signal buffer circuit, and described secondary signal buffer circuit comprises diode D18 and voltage stabilizing didoe ZD7; The first filter circuit is connected to the first input end (negative input end) of the first error amplifier EA1 of PWM controller by a diode D17, wherein the negative electrode of diode D17 is connected with the first input end of the first error amplifier EA1; The negative electrode of voltage stabilizing didoe ZD7 is connected to the anode of diode D17, the anodic bonding of the anode of voltage stabilizing didoe ZD7 and diode D18, and the negative electrode of diode D18 is connected to the first input end (negative input end) of the second error amplifier EA2.The current detection voltage IO that sets LED lamp string is still less than VECG and deducts the reverse voltage stabilizing of voltage stabilizing didoe ZD7, deduct again diode D18 forward voltage, there is " EA2->EA2+ ", the second error amplifier EA2 no-output so, IO signal does not affect PWM output pulse width D.Now, both made not arrange the maximum pulse width Dmax of PWM, PWM output pulse width D is not affected by the second error amplifier EA2 yet.This secondary signal buffer circuit also can be applicable to above-mentioned the first embodiment.
The foregoing is only preferred embodiment of the present invention, in order to limit the present invention, within the spirit and principles in the present invention not all, any amendment of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (10)

1. compatible type LED power circuit, is characterized in that: comprise and exchange link, power inductance L1, the first rectifier bridge, the second rectifier bridge, the first filter circuit, PWM controller, EMC circuit, coupling transformer T1 and LED output circuit; Exchange link is connected to the primary coil of coupling transformer T1 successively first end by power inductance L1, the second rectifier bridge and EMC circuit, the secondary coil of coupling transformer T1 connects LED output circuit; The input of the first rectifier bridge is connected with interchange link, and the output of the first rectifier bridge is connected with the first filter circuit; The first filter circuit is connected with the first input end of the first error amplifier of PWM controller, and the second input of the first error amplifier is for being connected with the first reference voltage; The signal output part of PWM controller is connected with the second end of the primary coil of coupling transformer T1.
2. compatible type LED power circuit according to claim 1, is characterized in that: described the first filter circuit comprises resistance R 5, capacitor C 6, diode D15 and electrochemical capacitor C7; The parallel branch of resistance R 5 and capacitor C 6 is connected between the positive output end and negative output terminal of the first rectifier bridge, and the positive output end of the first rectifier bridge is VECG end, the negative output terminal ground connection of the first rectifier bridge; The positive output end of the first rectifier bridge is also connected to the anode of diode D15, and the negative electrode of diode D15 is connected with the positive pole of electrochemical capacitor C7, the minus earth of electrochemical capacitor C7; The just very VCC end of electrochemical capacitor C7, is connected with the energization pins of PWM controller; The VECG end of the first filter circuit is connected to the first input end of the first error amplifier of PWM controller by a diode D17, the anodic bonding of VECG end and diode D17.
3. compatible type LED power circuit according to claim 2, is characterized in that: described the first filter circuit also comprises voltage stabilizing didoe ZD4; Described voltage stabilizing didoe ZD4 is connected between VECG end and diode D15, and the negative electrode of voltage stabilizing didoe ZD4 is connected with VECG end, the anodic bonding of the anode of voltage stabilizing didoe ZD4 and diode D15.
4. compatible type LED power circuit according to claim 3, is characterized in that: signal isolation circuit; Described signal isolation circuit comprises switching tube Q6, resistance R 9, resistance R 10 and diode D16; The source ground of switching tube Q6, resistance R 9 is connected between the source electrode and grid of switching tube Q6; The grid of switching tube Q6 is also connected to VECG end; The drain electrode of switching tube Q6 is connected to canonical reference voltage end by resistance R 10; The drain electrode of switching tube Q6 is also connected to the anode of diode D16, and the negative electrode of diode D16 is connected to the first input end of the first error amplifier.
5. compatible type LED power circuit according to claim 1, is characterized in that: also comprise frequency-selecting bleeder circuit and charging circuit; Described frequency-selecting bleeder circuit comprises capacitive portion; Described power inductance L1 is series between the anode and the second rectifier bridge that exchanges link; Described interchange link is connected to the first rectifier bridge by frequency-selecting bleeder circuit, and capacitive portion is connected with the anode that exchanges link; Described coupling transformer T1 also comprises second subprime coil, and this second subprime coil is connected with charging circuit, and charging circuit is provided with power supply output, and this power supply output is connected with the energization pins of PWM controller; The current detection voltage end of LED output circuit is connected to the second input of the second error amplifier of PWM controller, and the first input end of this second error amplifier is for being connected with the second reference voltage.
6. compatible type LED power circuit according to claim 5, is characterized in that: described charging circuit comprises diode D7, switching tube Q2, transistor Q3, voltage stabilizing didoe ZD3, voltage stabilizing didoe ZD6, diode D9, diode D10, electrochemical capacitor C4, electrochemical capacitor C5, resistance R 3 and resistance R 6; The anode of diode D7 is connected with the first end of coupling transformer T1 primary coil, the negative electrode of diode D7 is connected with the negative electrode of voltage stabilizing didoe ZD3, the anode of voltage stabilizing didoe ZD3 is connected to the drain electrode of switching tube Q2 by resistance R 3, the grid of switching tube Q2 is connected with the collector electrode of transistor Q3, the source electrode of switching tube Q2 is connected to the positive pole of electrochemical capacitor C5, the grounded emitter of transistor Q3; The base stage of transistor Q3 is connected to the anode of voltage stabilizing didoe ZD6 by resistance R 6; The negative electrode of voltage stabilizing didoe ZD6 is connected to the negative electrode of diode D9; The anode of diode D9 is connected with the first end of the second subprime coil of coupling transformer T1, the second end ground connection of second subprime coil; The negative electrode of diode D9 also with the anodic bonding of diode D10, the negative electrode of diode D10 is also connected to the positive pole of electrochemical capacitor C5, the minus earth of electrochemical capacitor C5, the anodic bonding of the positive pole of electrochemical capacitor C4 and diode D10, the minus earth of electrochemical capacitor C4.
7. compatible type LED power circuit according to claim 5, is characterized in that: described frequency-selecting bleeder circuit also comprises the perceptual portion with capacitive portion composition bleeder circuit; Described capacitive portion is capacitor C S1, and described perceptual portion is instrument transformer LS1; One end of capacitor C S1 is connected with the anode that exchanges link, and the other end of capacitor C S1 is connected with one end of the primary coil of instrument transformer LS1, and the other end of the primary coil of instrument transformer LS1 is connected to the negative terminal that exchanges link; The secondary coil two ends of instrument transformer LS1 are connected respectively to the input of the first rectifier bridge; The capacitance of capacitor C S1 is not more than 0.3 μ F; The inductance value of the primary coil of instrument transformer LS1 is 0.3mH-6mH.
8. compatible type LED power circuit according to claim 5, is characterized in that: described capacitive portion is capacitor C S2; Described frequency-selecting bleeder circuit also comprises capacitor C S3; One end of capacitor C S2 and the anode that exchanges link, the other end of capacitor C S2 is connected to an input of the first rectifier bridge; One end of capacitor C S3 is connected to another input of the first rectifier bridge, and the capacitor C S3 other end is connected to the negative terminal that exchanges link.
9. compatible type LED power circuit according to claim 5, is characterized in that: also comprise secondary signal buffer circuit, described secondary signal buffer circuit comprises diode D18 and voltage stabilizing didoe ZD7; The first filter circuit is connected to the first input end of the first error amplifier of PWM controller by a diode D17, wherein the negative electrode of diode D17 is connected with the first input end of the first error amplifier; The negative electrode of voltage stabilizing didoe ZD7 is connected to the anode of diode D17, the anodic bonding of the anode of voltage stabilizing didoe ZD7 and diode D18, and the negative electrode of diode D18 is connected to the first input end of the second error amplifier.
10. compatible type LED power circuit according to claim 1, is characterized in that: also comprise protective circuit; Described protective circuit comprises resistance R 1, resistance R 7, resistance R 8, transistor Q5, voltage stabilizing didoe ZD1, switching tube Q1 and capacitor C 2; The series arm of resistance R 7 and resistance R 8 is connected between the positive output end and reference edge of EMC circuit; The base stage of transistor Q5 is connected to the node of resistance R 7 and resistance R 8; The emitter of transistor Q5 is connected to the reference edge of EMC circuit; The collector electrode of transistor Q5 is connected to the grid of switching tube Q1; The source electrode of switching tube Q1 is connected to the reference edge of EMC circuit, the grounded drain of switching tube Q1; The anodic bonding of voltage stabilizing didoe ZD1 is to the emitter of transistor Q5, and the negative electrode of voltage stabilizing didoe ZD1 is connected to the collector electrode of transistor Q5; The collector electrode of transistor Q5 is also by being connected to the positive output end of EMC circuit by resistance R 1; One end of capacitor C 2 is connected to the positive output end of EMC circuit, the other end ground connection of capacitor C 2.
CN201410374478.0A 2014-07-31 2014-07-31 Compatible type LED power circuit Expired - Fee Related CN104168696B (en)

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CN104640322A (en) * 2015-02-06 2015-05-20 深圳市豪恩光电照明有限公司 LED (Light Emitting Diode) lamp tube driver compatible with electronic ballast
CN104994655A (en) * 2015-07-14 2015-10-21 盐城工学院 LED constant current driving circuit
CN106385733A (en) * 2016-10-13 2017-02-08 厦门阳光恩耐照明有限公司 LED fluorescent lamp driving circuit compatible with electronic and inductive and alternating current
CN106793265A (en) * 2016-12-02 2017-05-31 晨辉光宝科技有限公司 Led drive circuit and led lamp tube
CN107635302A (en) * 2016-07-19 2018-01-26 常州明石晶电科技有限公司 A kind of LED light source driving circuit and LED light source device
CN108430129A (en) * 2017-02-14 2018-08-21 朗德万斯公司 LED light for being placed in florescent lamp fitting
CN108650752A (en) * 2018-07-25 2018-10-12 东莞市灿光电子科技有限公司 A kind of compatible ballast and the electrically driven (operated) LED lamp tube of exchange
CN110062491A (en) * 2018-01-18 2019-07-26 朗德万斯公司 Electronic driver and lighting module
CN110650563A (en) * 2018-06-27 2020-01-03 朗德万斯公司 Driver, method for controlling driver, and lighting module

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Cited By (15)

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Publication number Priority date Publication date Assignee Title
CN104640322A (en) * 2015-02-06 2015-05-20 深圳市豪恩光电照明有限公司 LED (Light Emitting Diode) lamp tube driver compatible with electronic ballast
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CN104994655A (en) * 2015-07-14 2015-10-21 盐城工学院 LED constant current driving circuit
CN107635302A (en) * 2016-07-19 2018-01-26 常州明石晶电科技有限公司 A kind of LED light source driving circuit and LED light source device
CN107635302B (en) * 2016-07-19 2019-03-12 常州明石晶电科技有限公司 A kind of LED light source driving circuit and LED light source device
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CN106385733A (en) * 2016-10-13 2017-02-08 厦门阳光恩耐照明有限公司 LED fluorescent lamp driving circuit compatible with electronic and inductive and alternating current
CN106793265A (en) * 2016-12-02 2017-05-31 晨辉光宝科技有限公司 Led drive circuit and led lamp tube
CN108430129A (en) * 2017-02-14 2018-08-21 朗德万斯公司 LED light for being placed in florescent lamp fitting
CN108430129B (en) * 2017-02-14 2020-10-09 朗德万斯公司 LED lamp for placing in a fluorescent lamp fixture
CN110062491A (en) * 2018-01-18 2019-07-26 朗德万斯公司 Electronic driver and lighting module
CN110062491B (en) * 2018-01-18 2022-04-29 朗德万斯公司 Electronic driver and lighting module
CN110650563A (en) * 2018-06-27 2020-01-03 朗德万斯公司 Driver, method for controlling driver, and lighting module
CN110650563B (en) * 2018-06-27 2022-04-05 朗德万斯公司 Driver, method for controlling driver, and lighting module
CN108650752A (en) * 2018-07-25 2018-10-12 东莞市灿光电子科技有限公司 A kind of compatible ballast and the electrically driven (operated) LED lamp tube of exchange

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