CN105530739A - Light emitting diode driving circuit and power factor rectification circuit thereof - Google Patents
Light emitting diode driving circuit and power factor rectification circuit thereof Download PDFInfo
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- CN105530739A CN105530739A CN201510673729.XA CN201510673729A CN105530739A CN 105530739 A CN105530739 A CN 105530739A CN 201510673729 A CN201510673729 A CN 201510673729A CN 105530739 A CN105530739 A CN 105530739A
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Abstract
The invention provides a light emitting diode driving circuit and a power factor rectification circuit thereof. The light emitting diode circuit is provided with a light emitting diode loop, the power factor rectification circuit, a pulse width modulation device and a voltage-controlled current source. The light emitting diode loop is provided with a first end and a second end. The second end of the light emitting diode loop is electrically connected with a power supply. The power factor rectification circuit is electrically connected with the power supply and generates a reference signal according to output voltage and a gain control signal of the power supply. The pulse width modulation device is electrically connected with the power factor rectification circuit and generates a pulse width modulation signal according to a feedback signal, a clock signal and the reference signal. The voltage-controlled current source is electrically connected with the light emitting diode loop and the pulse width modulation device, selectively provides driving current for the light emitting diode loop according to the pulse width modulation signal and generates a feedback signal according to the driving current.
Description
Technical field
The present invention relates to a kind of LED driving circuit and merit thereof because of circuit for rectifying, particularly the merit that has nothing to do of a kind of power factor and input exchange signal peak value size is because of circuit for rectifying and the adjustable LED driving circuit applying this circuit.
Background technology
Be applicable to exchange the field that electrically driven (operated) LED driving circuit is widely used in illumination.But the electrically driven (operated) LED driving circuit of existing interchange is the function realizing light modulation in addition with three-pole AC switch (TRI-electrodeACswitch, TRIAC) usually.Or realize light modulation in the mode of pulse width modulation after built-in AC-DC converter (AC-DCconverter).Or realize light modulation in the mode of current-limiting resistance.
If carry out light modulation with three-pole AC switch, then due to the on state characteristic of three-pole AC switch itself, easily there is significantly flicker.If carry out light modulation in the mode of pulse width modulation, due to the built-in AC-DC converter of needs, have extra power consumption.If realize light modulation in the mode of current-limiting resistance, then current-limiting resistance can consume most energy in some cases, and its luminous efficiency is low.
Summary of the invention
Technical problem to be solved by this invention is to provide a kind of LED driving circuit and merit thereof because of circuit for rectifying, the reference signal of pulse width modulation device is directly converted to the output voltage of AC power, by the proportionate relationship between adjustment output voltage and reference signal, realize the function of light modulation.
To achieve these goals, the invention provides a kind of LED driving circuit, there is LED circuit, merit because of circuit for rectifying, pulse width modulation device and voltage-controlled current source.LED circuit has first end and the second end, and the first end of LED circuit is electrically connected at power supply.Merit is electrically connected at power supply because of circuit for rectifying, according to output voltage and the gain control signal of power supply, produces reference signal.Pulse width modulation device is electrically connected merit because of circuit for rectifying, according to feedback signal, clock signal and reference signal, produces pulse width modulation signal.Voltage-controlled current source is electrically connected LED circuit and pulse width modulation device, optionally provides drive current to LED circuit according to pulse width modulation signal, and produces feedback signal according to drive current.
In order to realize realizing above-mentioned purpose better, present invention also offers a kind of merit because of circuit for rectifying, having: peak detector, division circuit and mlultiplying circuit.Peak detector is electrically connected at power supply, in order to produce the peak signal about the output voltage of power supply.Division circuit is electrically connected power supply and peak detector, according to output voltage and the peak signal of power supply, produces the unit signal about output voltage.Mlultiplying circuit is electrically connected division circuit, according to unit signal and gain control signal, produces reference signal.
Technique effect of the present invention is:
LED driving circuit of the present invention, directly comes to produce corresponding reference signal with input voltage with gain control signal, carries out pulse width modulation, to realize the function of light modulation with this reference signal.
Describe the present invention below in conjunction with the drawings and specific embodiments, but not as a limitation of the invention.
Accompanying drawing explanation
Fig. 1 is the LED driving circuit schematic diagram of one embodiment of the invention.
Wherein, Reference numeral
100 LED driving circuit
110 LED circuits
120 merits are because of circuit for rectifying
121 peak detectors
123 division circuits
125 mlultiplying circuits
130 pulse width modulation devices
131 comparators
133 triggers
140 voltage-controlled current sources
141 voltage-current converter circuits
200 full-bridge rectifiers
AC AC power
B1 buffer
C1 electric capacity
CLK clock signal
D1 unidirectional element
Gain gain control signal
ID drive current
L1 inductance
LED1 ~ LED3 light-emitting diode
Q1 transistor switch
RST reset signal
Vout output voltage
Vp peak signal
Vref reference signal
VPWM pulse width modulation signal
Vf feedback signal
Vu unit signal
Embodiment
Below in conjunction with accompanying drawing, structural principle of the present invention and operation principle are described in detail:
Please refer to Fig. 1, it is the LED driving circuit schematic diagram of one embodiment of the invention.As shown in Figure 1, the LED driving circuit 100 of the present embodiment has LED circuit 110, merit because of circuit for rectifying (PowerFactorCorrectionCircuit, PFC) 120, pulse width modulation device (pulse-widthmodulator, PWM) 130 and voltage-controlled current source 140.And this LED driving circuit 100 is electrically connected to an AC power AC by full-bridge rectifier 200.Below full-bridge rectifier 200 is called power supply together with AC power AC, described output voltage is the voltage that full-bridge rectifier 200 pairs of LED driving circuit 100 provide.
LED circuit 110 has first end and the second end, and the first end of LED circuit 110 is electrically connected at power supply.In an embodiment, as shown in Figure 1, LED circuit 110 has unidirectional element D1, LED serial (being made up of LED 1 to LED3) and inductance L 1.The negative terminal of unidirectional element D1 is electrically connected power supply, and the anode of unidirectional element D1 is electrically connected voltage-controlled current source 140.The anode (anode of LED 1) of LED serial is electrically connected the negative terminal of unidirectional element D1.The first end of inductance L 1 is electrically connected the anode of unidirectional element D1, and the second end of inductance L 1 is electrically connected the negative terminal (negative terminal of LED 3) of LED serial.In another embodiment, inductance L 1 also can be electrically connected between the anode (anode of LED 1) of LED serial and the negative terminal of unidirectional element D1.In an embodiment, LED circuit 110 also comprises an electric capacity (not illustrating), is parallel to LED serial.Unidirectional element D1 in the present embodiment is such as diode (diode) or the field-effect transistor (diode-connectedMOSFET) or its equivalence element that connect into diode form.
Merit is electrically connected at power supply because of circuit for rectifying 120, according to output voltage Vout and the gain control signal Gain of power supply, produces reference signal Vref.In an embodiment, merit has peak detector 121, division circuit 123 and mlultiplying circuit 125 because of circuit for rectifying 120.Peak detector 121 is electrically connected power supply, in order to produce the peak signal Vp about output voltage Vout.Because output voltage is through full-bridge rectifier 200 rectification, therefore its magnitude of voltage is just.For example, output voltage Vout roughly can be considered as Vp*|sin ω t|.Division circuit 123 is electrically connected power supply and peak detector 121, according to output voltage Vout and peak signal Vp, produces the unit signal Vu about output voltage Vout.Specifically, division circuit 123 is by output voltage Vout divided by peak signal Vp, and therefore with previous example, unit signal Vu is | sin ω t|.Mlultiplying circuit 125 is electrically connected division circuit 123, according to unit signal Vu and gain control signal Gain, produces reference signal Vref.Specifically, unit signal Vu is multiplied with gain control signal Gain by mlultiplying circuit 125, thus obtains reference signal Vref, and therefore reference signal Vref can write Gain*|sin ω t|.
In actual environment for use, its voltage of the electric energy that AC power AC exports, electric current often offrating.For example, for the civil power in Taiwan, rated voltage is 110 volts (r.m.s. is planted), and namely its peak value should at 155 volts.But rule of thumb, its voltage root mean square value is in fact often all possible from 95 volts to 120 volts, and corresponding its range of drift of peak value is 134 volts to 169 volts.The output voltage Vout that directly AC power AC sent via full-bridge rectifier 200 because of correcting signal (reference signal) of merit in general circuit in the mode of dividing potential drop or fixed multiplying power to produce reference signal.Therefore its reference signal is directly positively correlated with output voltage Vout.Even if its fixed multiplying power is adjustable, but often need manually to set adjustment.And immediately cannot eliminate the correlation of reference signal and output voltage Vout.
If apply disclosed merit because of circuit for rectifying 120, then above-mentioned paragraph is known, and the voltage peak that its reference signal Vref produced and AC power AC provides has nothing to do.Therefore, the various circuit of the power factor of degree of precision, independence and stability that needs all can use merit of the present invention because of circuit for rectifying 120.
Pulse width modulation device 130 is electrically connected merit because of circuit for rectifying 120, according to feedback signal Vf, clock signal CLK and reference signal Vref, produces pulse width modulation signal VPWM.In an embodiment, pulse width modulation device 130 has comparator 131 and trigger 133.Comparator 131 is electrically connected merit because of circuit for rectifying 120 and voltage-controlled current source 140, and comparison reference signal Vref and feedback signal Vf, to produce reset signal RST.Specifically, when the voltage of feedback signal Vf is greater than the voltage of reference signal Vref, reset signal RST is high logic level.When the voltage of feedback signal Vf is not more than the voltage of reference signal Vref, reset signal RST is low logic level.Trigger (SR-latch) 133 is electrically connected comparator 131 and voltage-controlled current source 140, according to reset signal RST and clock signal CLK, produces pulse width modulation signal VPWM.Wherein reset signal RST holds corresponding to the R of trigger 133, and clock signal CLK holds corresponding to the S of trigger 133.The start how producing pulse width modulation signal VPWM about trigger 133 repeats no more.
Voltage-controlled current source 140 is electrically connected LED circuit 110 and pulse width modulation device 130, optionally provides drive current ID to LED circuit 110 according to pulse width modulation signal VPWM, and produces feedback signal Vf according to drive current ID.Specifically, voltage-controlled current source 140 has transistor switch Q1 and current-to-voltage converting circuit 141.Transistor switch Q1 has first end, the second end and control end, the first end of transistor switch Q1 is electrically connected LED circuit 110, the control end of transistor switch Q1 is electrically connected pulse width modulation device 130, transistor switch Q1 and is controlled by pulse width modulation device 130 to determine drive current ID.Current-to-voltage converting circuit 141 can be specifically a resistance as Fig. 1, is electrically connected at the earth terminal of second end of transistor switch Q1, pulse width modulation circuit 130 and system, in order to drive current ID is converted to feedback signal Vf.In addition, current-to-voltage converting circuit 141 also can be the bleeder circuit of multiple passive device composition.Feedback signal Vf wherein through changing and the relation of drive current ID can be frequency functions.In some embodiments, because the transistor switch Q1 in voltage-controlled current source 140 is power transistor switch, therefore in order to promote its reaction rate, reducing its conducting/closedown delay, to improve the precision of pulse width modulation, be connected to buffer B1 in the output of trigger 133 in pulse width modulation device 130, the pulse width modulation signal VPWM that trigger 133 exports through buffer B1 to control transistor switch Q1.
LED driving circuit of the present invention, directly comes to produce corresponding reference signal with input voltage with gain control signal, carries out pulse width modulation, to realize the function of light modulation with this reference signal.
Certainly; the present invention also can have other various embodiments; when not deviating from the present invention's spirit and essence thereof; those of ordinary skill in the art are when making various corresponding change and distortion according to the present invention, but these change accordingly and are out of shape the protection range that all should belong to the claim appended by the present invention.
Claims (10)
1. a LED driving circuit, is characterized in that, comprises:
One LED circuit, has first end and the second end, and the first end of this LED circuit is electrically connected at a power supply;
One merit, because of circuit for rectifying, is electrically connected this power supply, with according to the output voltage of this power supply and a gain control signal, produces a reference signal;
One pulse width modulation device, is electrically connected this merit because of circuit for rectifying, according to a feedback signal, a clock signal and this reference signal, produces a pulse width modulation signal; And
One voltage-controlled current source, is electrically connected this LED circuit and this pulse width modulation device, optionally provides a drive current to this LED circuit, and produce this feedback signal according to this drive current according to this pulse width modulation signal.
2. LED driving circuit as claimed in claim 1, it is characterized in that, this LED circuit comprises:
One unidirectional element, has anode and negative terminal, and the negative terminal of this unidirectional element is electrically connected this power supply, and the anode of this unidirectional element is electrically connected this voltage-controlled current source;
One LED serial, has anode and negative terminal, and the anode of this LED serial is electrically connected the negative terminal of this unidirectional element; And
One inductance, has first end and the second end, and the first end of this inductance is electrically connected the anode of this unidirectional element, and the second end of this inductance is electrically connected the negative terminal of this LED serial.
3. LED driving circuit as claimed in claim 1, it is characterized in that, this LED circuit comprises:
One unidirectional element, has anode and negative terminal, and the negative terminal of this unidirectional element is electrically connected this power supply, and the anode of this unidirectional element is electrically connected this voltage-controlled current source;
One LED serial, has anode and negative terminal, and the negative terminal of this LED serial is electrically connected the anode of this unidirectional element; And
One inductance, has first end and the second end, and the first end of this inductance is electrically connected the negative terminal of this unidirectional element, and the second end of this inductance is electrically connected the anode of this LED serial.
4. LED driving circuit as claimed in claim 2 or claim 3, it is characterized in that, this LED circuit also comprises an electric capacity, is parallel to this LED serial.
5. LED driving circuit as claimed in claim 1, it is characterized in that, this voltage-controlled current source comprises:
One transistor switch, there is first end, the second end and control end, the first end of this transistor switch is electrically connected this LED circuit, the control end of this transistor switch is electrically connected this pulse width modulation device, and this transistor switch is controlled by this pulse width modulation device to determine this drive current; And
One current-to-voltage converting circuit, is electrically connected at the second end and this pulse width modulation circuit of this transistor switch, in order to this drive current is converted to this feedback signal.
6. LED driving circuit as claimed in claim 1, it is characterized in that, this pulse width modulation device comprises:
One comparator, is electrically connected this merit because of circuit for rectifying and this voltage-controlled current source, compares this reference signal and this feedback signal, to produce a reset signal; And
One trigger, is electrically connected this comparator and this voltage-controlled current source, according to this reset signal and this clock signal, produces this pulse width modulation signal.
7. LED driving circuit as claimed in claim 6, it is characterized in that, this pulse width modulation device also comprises a buffer, and this trigger is electrically connected to this voltage-controlled current source through this buffer, and this trigger drives this voltage-controlled current source by this buffer.
8. LED driving circuit as claimed in claim 1, is characterized in that, this merit comprises because of circuit for rectifying:
One peak detector, is electrically connected this power supply, in order to produce the peak signal about the output voltage of this power supply;
One division circuit, is electrically connected this power supply and this peak detector, according to output voltage and this peak signal of this power supply, produces the unit signal about this output voltage; And
One mlultiplying circuit, is electrically connected this division circuit, according to this unit signal and this gain control signal, produces this reference signal.
9. the merit irrelevant with input exchange signal peak value, because of a circuit for rectifying, is characterized in that, comprise:
One peak detector, is electrically connected at a power supply, in order to produce the peak signal about the output voltage of this power supply;
One division circuit, is electrically connected this power supply and this peak detector, according to output voltage and this peak signal of this power supply, produces the unit signal about this output voltage; And
One mlultiplying circuit, is electrically connected this division circuit, according to this unit signal and a gain control signal, produces a reference signal.
10. merit as claimed in claim 9 is because of circuit for rectifying, it is characterized in that, this division circuit by this output voltage divided by this peak signal to obtain this unit signal.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US201462065264P | 2014-10-17 | 2014-10-17 | |
| US62/065,264 | 2014-10-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN105530739A true CN105530739A (en) | 2016-04-27 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510673729.XA Pending CN105530739A (en) | 2014-10-17 | 2015-10-16 | Light emitting diode driving circuit and power factor rectification circuit thereof |
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| CN (1) | CN105530739A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106061037A (en) * | 2016-07-19 | 2016-10-26 | 湖州绿明微电子有限公司 | LED driving circuit with power factor correction and driver |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100754887B1 (en) * | 2006-05-30 | 2007-09-04 | 서울반도체 주식회사 | Alternating current driving apparatus for light emitting diode |
| CN102958246A (en) * | 2011-08-11 | 2013-03-06 | 半导体元件工业有限责任公司 | Light-emitting device control circuit |
| CN203554743U (en) * | 2013-09-29 | 2014-04-16 | 欧普照明股份有限公司 | LED drive circuit |
-
2015
- 2015-10-16 CN CN201510673729.XA patent/CN105530739A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100754887B1 (en) * | 2006-05-30 | 2007-09-04 | 서울반도체 주식회사 | Alternating current driving apparatus for light emitting diode |
| CN102958246A (en) * | 2011-08-11 | 2013-03-06 | 半导体元件工业有限责任公司 | Light-emitting device control circuit |
| CN203554743U (en) * | 2013-09-29 | 2014-04-16 | 欧普照明股份有限公司 | LED drive circuit |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106061037A (en) * | 2016-07-19 | 2016-10-26 | 湖州绿明微电子有限公司 | LED driving circuit with power factor correction and driver |
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Application publication date: 20160427 |
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