CN209627751U - A kind of linear LED constant-current control circuit of efficient closed loop - Google Patents
A kind of linear LED constant-current control circuit of efficient closed loop Download PDFInfo
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- CN209627751U CN209627751U CN201822097118.7U CN201822097118U CN209627751U CN 209627751 U CN209627751 U CN 209627751U CN 201822097118 U CN201822097118 U CN 201822097118U CN 209627751 U CN209627751 U CN 209627751U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
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Abstract
The utility model discloses a kind of efficient linear LED constant-current control circuits of closed loop, it is characterised in that: including rectifier bridge (100), light emitting diode group (200), current regulator (P1), closed control circuit (P) and line voltage resistance sampling network (300)；The rectifier bridge (100) is internal circuit power supply by light emitting diode group (200) for carrying out full-wave rectification to alternating current；The cathode of input terminal (VIN) connection light emitting diode group (200) of the current regulator (P1)；The line voltage resistance sampling network (300), obtains sampled voltage VBS；The closed control circuit (P) includes reference voltage chip (400), second operational amplifier (Gm), subtracter, loop compensation capacitor (C1) and resistance (RCS).The utility model solves conventional linear LED drive circuit, and modulating voltage range of choice is narrow, inefficiency, the problem of line regulation difference.
Description
Technical field
The utility model relates to a kind of LED drive circuit, especially a kind of linear LED constant-current control circuit of efficient closed loop.
Background technique
By the electrology characteristic of LED it is found that significantly line is presented with the increase of forward voltage in the mean forward current of LED
Property increase, LED tiny variation of its forward voltage after forward conduction will cause the great changes of LED current, and electric current is to LED
Junction temperature influence is very big, and excessive electric current easilys lead to LED lamp bead junction temperature and increases and damage.In addition, can by the optical characteristics of LED
Know the increase with forward current, LED light flux increases with it, i.e. brightness increases.Therefore the perseverance in order to keep LED light emission luminance
The fixed stabilization it is necessary to guarantee LED forward current.Therefore designing reasonable driving power just seems very for LED illumination lamp
It is important.
Conventional linear LED driving mostly uses opened loop control, when LED is connected, what LED current was kept constant, by leading for LED
Logical principle it is found that when AC string wave voltage is just marginally larger than LED light voltage, efficiency be it is highest, with raising for AC string wave voltage,
Higher greater than the amplitude of modulating voltage, loss is bigger, and efficiency is lower.Such as applied for 220V, modulating voltage must be connected in series to
250V or so, efficiency could reach 85% or so reluctantly, and modulating voltage more low-loss is bigger.
Simultaneously because LED light electric current is opened loop control within the entire AC period, and when power network fluctuation, the angle of flow of LED
It can be fluctuated with power network fluctuation, and electric current when LED conducting is constant, so when power network fluctuation direction is that AC voltage increases,
The angle of flow becomes larger, and the average current of LED will increase, conversely, power network fluctuation direction is the reduction of AC voltage, the angle of flow becomes smaller, LED
Average current will reduce, cause line regulation poor.
As shown in Figure 1, LED light is series-connected to the anode of input rectifying bridge in traditional linear LED drive circuit, lead to
The linear current control ring P1 that is made of OP, metal-oxide-semiconductor M1, VREF voltage, RCS resistance is crossed to set the electric current Io for flowing through LED；
Principle is connected according to LED, only when input voltage is higher than LED forward conduction voltage VLED, LED light string just can quilt
Light, effective power PO=VLED*IO of system, and system loss PLOSS=(VBUS-VLED) * IO, by two above formula and
Efficiency is highest when DCBUS voltage known to the working principle of linear circuit is just marginally larger than LED voltage, as shown in Fig. 2, due to
The electric current IO of LED is kept constant, so the loss of system is maximum when AC string wave voltage reaches peak point.
According to the asterisk alignment request of american energy, linear efficiency, which will reach 84% or more, PF value, will reach 0.7 or more, traditional
Linear circuit is difficult to reach above-mentioned efficiency requirements under 120V power grid.
Utility model content
The goal of the invention of the utility model is: in view of the above problems, it is permanent to provide a kind of linear LED of efficient closed loop
Flow control circuit solves conventional linear LED drive circuit, and modulating voltage range of choice is narrow, inefficiency, line regulation difference
Problem；By controlling lamp current waveform, when making AC string wave voltage just above modulating voltage, lamp current is maximum, and AC string wave voltage is got over
Height, lamp current is smaller, greatly promotes efficiency；Simultaneously because closed-loop control, is able to maintain output LED average current constant again.
The technical solution adopted in the utility model is as follows:
A kind of efficient linear LED constant-current control circuit of closed loop of the utility model, including rectifier bridge 100, light-emitting diodes nest of tubes
Group 200, current regulator P1, closed control circuit P and line voltage resistance sampling network 300；The rectifier bridge 100, for pair
Alternating current carries out full-wave rectification, and generates output voltage VBUS, is internal circuit power supply by light emitting diode group 200；Institute
State the cathode of the input terminal VIN connection light emitting diode group 200 of current regulator P1；The line voltage resistance sampling network
300, for sampling line voltage, obtain sampled voltage VBS；
The closed control circuit P includes reference voltage chip 400, second operational amplifier Gm, subtracter SUB, loop
Compensating electric capacity C1 and resistance RCS；
The input terminal VIN of the input terminal connection current regulator P1 of the reference voltage chip 400, reference voltage chip
The non-inverting input terminal of 400 output end connection second operational amplifier Gm；
The reverse input end of the second operational amplifier (Gm) connects current regulator P1, and output end connects subtracter
The A input terminal of SUB, output voltage COMP；
The B input terminal connecting line voltage resistance sampling network 300 of the subtracter SUB, output end connect current regulator
P1, output voltage SUB_OUT；
Described one end loop compensation capacitor C1 is connect with the output end of the second operational amplifier Gm, other end ground connection；
One end of the resistor RCS is connect with the inverting input terminal of second operational amplifier Gm, other end ground connection.
Preferably, the line voltage resistance sampling network 300 includes concatenated resistance RSUB1 and resistance RSUB2；It is described
300 one end of line voltage resistance sampling network connects the cathode of light emitting diode group 200, other end ground connection.
Preferably, the anode of 300 one end of line voltage resistance sampling network connection light emitting diode group 200, separately
One end ground connection.
Preferably, the current regulator P1 includes the first operational amplifier OP, the first operational amplifier OP's is in the same direction
Input terminal connects subtracter output voltage SUB_OUT, and inverting input terminal connects resistance RCS, and output end connects MOS switch pipe M1's
Grid；The input terminal VIN of the drain electrode connection current regulator P1 of MOS switch pipe M1, source electrode connect the output of current regulator P1
End.
Preferably, the subtracter SUB receives the output voltage COMP of second operational amplifier Gm and line voltage is adopted
The sampled voltage VBS of sample network 300, and two voltages are made the difference.
Preferably, what the second operational amplifier Gm and loop compensation capacitor C1 composition integrated LED current
Integrator.
In conclusion by adopting the above-described technical solution, the beneficial effects of the utility model are: with prior art phase
Than the invention discloses the linear LED constant-current control circuits of efficient closed loop, and by control lamp current waveform, make AC string wave voltage
When just above modulating voltage, lamp current is maximum, and AC string wave voltage is higher, and lamp current is smaller, greatly promotes efficiency；Simultaneously because closing
Ring control is able to maintain output LED average current again constant.
Detailed description of the invention
Fig. 1 is traditional LED linear constant-current control circuit figure.
Fig. 2 is traditional LED linear current constant control waveform diagram.
Fig. 3 is a kind of efficient linear LED constant-current control circuit figure of closed loop of the present invention.
Fig. 4 is that efficient closed loop linear constant current controls each important node timing diagram in embodiment.
Fig. 5 is the high VBS sampled voltage important node waveform diagram of efficient closed loop linearity constant current control circuit.
Fig. 6 is the linear LED constant-current control circuit figure of efficient closed loop of another embodiment.
Marked in the figure: 100 be rectifier bridge, 200 be light emitting diode group, 300 be line voltage resistance sampling network, 400
For benchmark voltage chips.
Specific embodiment
With reference to the accompanying drawing, the utility model is described in detail.
In order to make the purpose of the utility model, technical solutions and advantages more clearly understood, below in conjunction with attached drawing and implementation
Example, the present invention will be further described in detail.It should be appreciated that specific embodiment described herein is only to explain this
Utility model is not used to limit the utility model.
As shown in figure 3, a kind of efficient linear LED constant-current control circuit of closed loop of the utility model, including rectifier bridge 100, hair
Optical diode group 200, current regulator P1, closed control circuit P and line voltage resistance sampling network 300；The rectifier bridge
100, for carrying out full-wave rectification to alternating current, and output voltage VBUS is generated, is internal electricity by light emitting diode group 200
Road power supply；The cathode of the input terminal VIN connection light emitting diode group 200 of the current regulator P1；The line voltage resistance
Sampling network 300 obtains sampled voltage VBS for sampling line voltage；The line voltage resistance sampling network 300 includes series connection
Resistance RSUB1 and resistance RSUB2；
The closed control circuit P includes reference voltage chip 400, second operational amplifier Gm, subtracter SUB, loop
Compensating electric capacity C1 and resistance RCS；The input terminal VIN of the input terminal connection current regulator P1 of the reference voltage chip 400,
The non-inverting input terminal of the output end connection second operational amplifier Gm of reference voltage chip 400；The second operational amplifier Gm
Reverse input end connect current regulator P1, output end connect subtracter SUB A input terminal, output voltage COMP；It is described to subtract
The B input terminal connecting line voltage resistance sampling network 300 of musical instruments used in a Buddhist or Taoist mass SUB, output end connect current regulator P1, output voltage SUB_
OUT；Described one end loop compensation capacitor C1 is connect with the output end of the second operational amplifier Gm, other end ground connection；It is described
One end of resistor RCS is connect with the inverting input terminal of second operational amplifier Gm, other end ground connection；The closed control circuit
P, for determining average current ILEDAVG=VREF/RCS of LED, wherein VREF is the reference voltage of second operational amplifier Gm,
RCS is the resistance value of resistor RCS.
In one embodiment, 300 one end of line voltage resistance sampling network connection light emitting diode group 200 is negative
Pole, other end ground connection.
In embodiment, the current regulator P1 includes the first operational amplifier OP, and the first operational amplifier OP's is same
Subtracter output voltage SUB_OUT is connected to input terminal, inverting input terminal connects resistance RCS, and output end connects MOS switch pipe M1
Grid；The drain electrode of MOS switch pipe M1 connects input terminal VIN, and source electrode connects output end；The current regulator P1 is determined single
Electric current ILEDSINGLE=VSUB_OUT/RCS of LED when a period L ED is connected, wherein VSUB_OUT is the output electricity of subtracter
Pressure, RCS is the resistance value of resistor RCS.
In embodiment, the subtracter SUB receives the output voltage COMP and line voltage of second operational amplifier Gm
The sampled voltage VBS of resistance sampling network 300, and two voltages are made the difference, VSUB_OUT is obtained, when control LED is connected
Transient current waveform.
In embodiment, the second operational amplifier Gm and loop compensation capacitor C1 constitutes integrator；The integrator,
For being integrated to LED current.
As shown in figure 4, rectifier bridge carries out full-wave rectification to alternating current VAC, and generates output voltage in system electrification
VBUS, when voltage of VBUS is greater than light emitting diode group forward conduction voltage, IC takes electricity by VIN foot, and starts to work, IC
Inside carries out quick pre-charging electricity to VCOMP, obtains the initial voltage of COMP, and COMP voltage and VBS foot sample resulting VBS voltage
Subtraction process is done, VSUB_OUT is obtained, the size of current of LED conducting: VSUBOUT=K (m*VCOMP-n* is determined by VSUB_OUT
VBS)；
By the working principle of linear circuit it is found that the effective power of system is PO=VLED*IO, and system loss is equal to
PLOSS=(VBUS-VLED) * IO, when the voltage of VBUS after rectification is just marginally larger than LED voltage, system effectiveness be it is highest, when
When the voltage of VBUS reaches peak value, the loss highest of system.
In LED conducting, i.e., in the Ton period, loop compensation capacitor C1 electric discharge causes VCOMP to decline；And simultaneously because adopting
Sample voltage VBS rises as input voltage VBUS is increased, according to subtracter calculation formula, the output voltage of subtracter
VSUBOUT decline；The electric current of the electric current ILEDSINGLE=VSUB_OUT/RCS, LED of LED when again due to signal period LED conducting
Io decline；So the electric current Io of LED reduces with the raising of VBUS, increase with the decline of VBUS.
In the linear LED constant-current control circuit work of efficient closed loop, when voltage of VBUS just reaches LED voltage, pass through
Second operational amplifier Gm is integrated the resulting output voltage VCOMP of CS voltage and line voltage resistance sampling network by subtracter SUB
300 sampled voltage VBS, which is done, subtracts each other processing, amplifies the conducting electric current of LED；With gradually rising for string wave voltage, by LED current
It is gradually reduced, when voltage of VBUS reaches near peak point, LED current is minimized；As string wave voltage further crosses peak
Value point is begun to decline, and the electric current of LED is gradually increased, and when string wave voltage drops near LED voltage, LED current reaches maximum.
When voltage of VBUS just reaches LED voltage, amplifies the conducting electric current of LED as far as possible, make LED effective power at this time
Accounting highest in whole cycle, and gradually rising with string wave voltage, LED current are gradually reduced, when voltage of VBUS reaches
When near to peak point, LED current is minimized, according to lossy formula it is found that can reduce damage to the greatest extent in this way
Consumption, to achieve the purpose that the lifting system efficiency in whole cycle.
In embodiment, current regulator P1 and closed control circuit P are encapsulated on one single chip IC, VIN, IS, GND,
COMP, VBS represent chip IC pin；Loop compensation capacitor C1 and resistor Rcs can be encapsulated in IC, also can be set in core
Outside piece.
It, in embodiment can also be by adjusting the voltage VBS's of line voltage resistance sampling network samples as shown in Fig. 5 figure
Size adjusts the ratio of sampling resistor network RSUB1 and RSUB2, to adjust the amplitude of raising efficiency；When the electricity of VBS sampling
When pressing sufficiently large, when subtracter output voltage can drop to zero, LED conducting electric current near peak point and be only limitted to LED and just be connected
A period of time in, simultaneously because the ducting capacity of MOS limits, will limit the peak of SUB_OUT voltage inside circuit；By line
Known to sex work principle: VBS sampled voltage is higher, and the efficiency of system is higher.
As shown in fig. 6, in another embodiment, described 300 one end of line voltage resistance sampling network connects light-emitting diodes
The anode of nest of tubes group 200, other end ground connection.
The above is only the preferred embodiment of the utility model only, is not intended to limit the utility model, all at this
Made any modifications, equivalent replacements, and improvements etc., should be included in the utility model within the spirit and principle of utility model
Protection scope within.
Claims (6)
1. a kind of linear LED constant-current control circuit of efficient closed loop, it is characterised in that: including rectifier bridge (100), light-emitting diodes nest of tubes
Group (200), current regulator (P1), closed control circuit (P) and line voltage resistance sampling network (300)；The rectifier bridge
(100), for carrying out full-wave rectification to alternating current, and output voltage VBUS is generated, is interior by light emitting diode group (200)
The power supply of portion's circuit；The cathode of input terminal (VIN) connection light emitting diode group (200) of the current regulator (P1)；It is described
Line voltage resistance sampling network (300) obtains sampled voltage VBS for sampling line voltage；
The closed control circuit (P) include reference voltage chip (400), second operational amplifier (Gm), subtracter (SUB),
Loop compensation capacitor (C1) and resistance (RCS)；
The input terminal (VIN) of input terminal connection current regulator (P1) of the reference voltage chip (400), reference voltage core
The non-inverting input terminal of output end connection second operational amplifier (Gm) of piece (400)；
The reverse input end of the second operational amplifier (Gm) connects current regulator (P1), and output end connects subtracter
(SUB) A input terminal, output voltage COMP；
The B input terminal connecting line voltage resistance sampling network (300) of the subtracter (SUB), output end connect current regulator
(P1), output voltage SUB_OUT；
Described loop compensation capacitor one end (C1) is connect with the output end of the second operational amplifier (Gm), other end ground connection；
One end of the resistance (RCS) is connect with the inverting input terminal of second operational amplifier (Gm), other end ground connection.
2. the efficiently linear LED constant-current control circuit of closed loop as described in claim 1, it is characterised in that: the line voltage resistance
Sampling network (300) includes concatenated resistance (RSUB1) and resistance (RSUB2)；The line voltage resistance sampling network (300) one
The cathode of end connection light emitting diode group (200), other end ground connection.
3. the efficiently linear LED constant-current control circuit of closed loop as described in claim 1, it is characterised in that: the line voltage resistance
Sampling network (300) one end connects the anode of light emitting diode group (200), other end ground connection.
4. the efficiently linear LED constant-current control circuit of closed loop as described in claim 1, it is characterised in that: the current regulator
It (P1) include the first operational amplifier (OP) that the noninverting input of the first operational amplifier (OP) connects subtracter output voltage
SUB_OUT, inverting input terminal connect resistance (RCS), and output end connects the grid of MOS switch pipe (M1)；MOS switch pipe (M1)
Drain electrode connection current regulator (P1) input terminal (VIN), source electrode connect current regulator (P1) output end.
5. the efficiently linear LED constant-current control circuit of closed loop as described in claim 1, it is characterised in that: the subtracter (SUB)
Receive the output voltage COMP of second operational amplifier (Gm) and the sampled voltage of line voltage resistance sampling network (300)
VBS, and two voltages are made the difference.
6. the efficiently linear LED constant-current control circuit of closed loop as described in claim 1, it is characterised in that: second operation is put
Big device (Gm) and loop compensation capacitor (C1) constitute the integrator integrated to LED current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201822097118.7U CN209627751U (en) | 2018-12-14 | 2018-12-14 | A kind of linear LED constant-current control circuit of efficient closed loop |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201822097118.7U CN209627751U (en) | 2018-12-14 | 2018-12-14 | A kind of linear LED constant-current control circuit of efficient closed loop |
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| CN209627751U true CN209627751U (en) | 2019-11-12 |
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| CN201822097118.7U Active CN209627751U (en) | 2018-12-14 | 2018-12-14 | A kind of linear LED constant-current control circuit of efficient closed loop |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109462917A (en) * | 2018-12-14 | 2019-03-12 | 普诚创智（成都）科技有限公司 | A kind of linear LED constant-current control circuit of efficient closed loop and control method |
| CN114205963A (en) * | 2021-12-21 | 2022-03-18 | 欧普照明股份有限公司 | Linear LED driving circuit and driving method |
-
2018
- 2018-12-14 CN CN201822097118.7U patent/CN209627751U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109462917A (en) * | 2018-12-14 | 2019-03-12 | 普诚创智（成都）科技有限公司 | A kind of linear LED constant-current control circuit of efficient closed loop and control method |
| CN109462917B (en) * | 2018-12-14 | 2023-11-14 | 普诚创智（成都）科技有限公司 | Efficient closed-loop linear LED constant current control circuit and control method |
| CN114205963A (en) * | 2021-12-21 | 2022-03-18 | 欧普照明股份有限公司 | Linear LED driving circuit and driving method |
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