CN103547042A - LED constant current drive circuit based on power factor correction - Google Patents
LED constant current drive circuit based on power factor correction Download PDFInfo
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- CN103547042A CN103547042A CN201310545008.1A CN201310545008A CN103547042A CN 103547042 A CN103547042 A CN 103547042A CN 201310545008 A CN201310545008 A CN 201310545008A CN 103547042 A CN103547042 A CN 103547042A
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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
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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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
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
An LED constant current drive circuit based on power factor correction is composed of a current sampling amplifier, a first voltage comparator, a ramp generator, a square wave comparator, a first reference voltage and a logic drive circuit, wherein the current sampling amplifier samples inductive currents; the ramp generator outputs periodic triangular waves with the constant slope and width; the output signal of the logic drive circuit is used for driving a power switch tube; the logic drive circuit has the following functions that the opening time length of the power switch tube is equal to the duration length of high levels output by the square wave comparator, and when the first reference voltage is lower than the output voltage of the current sampling amplifier, the power switch tube is closed. By the adoption of the LED constant current drive circuit, an LED constant current drive circuit mode with the simple application circuit structure is provided for an LED constant current drive power supply, and the high power factor can be achieved.
Description
Technical field
The invention belongs to field of power electronics, relate to a kind of design of Switching Power Supply, particularly a kind of LED constant-current drive circuit based on power factor correction.
Background technology
Non-isolated DC/DC transducer in Switching Power Supply, press the relation between input voltage and output voltage, can be divided into buck (Buck) DC/DC transducer, boost type (Boost) DC/DC transducer, three kinds of Basic Topologicals of step-down/up type (Buck Boost) DC/DC transducer, this three basic structures forms by inductance, one way conducting device and switching device, and just three's annexation is different.
Use Switching Power Supply can utilize alternating current to power to LED, AC-powered LED illumination can reduce costs, but voltage ripple of power network can cause LED overcurrent to drive and affect its useful life, so LED is carried out to constant current driving in the occasion of Alternating Current Power Supply, is important.
LED drive circuit mainly adopts scheme, the non-isolated buck schemes such as Linear Control LED constant current scheme, PSR former limit feedback and isolation pulse width modulation (PWM) Switching Power Supply at present.Although linear LED constant current scheme is simple in structure, can bear huge ripple voltage on LED lamp string, influential to the LED life-span itself, current ripples is also larger simultaneously.The former limit of PSR feedback requires high to transformer, the bad control of batch production consistency, and production cost is relatively high.PWM Switching Power Supply scheme constant-current circuit mainly contains two kinds of methods: a kind of direct application PWM integrated circuit carries out peak value current limliting, and this method is simple in structure, but constant current accuracy is poor.
Another method is sampled to LED operating current, obtaining sampled voltage and reference voltage compares and enlarges rear drive optocoupler PWM integrated circuit is carried out to closed loop feedback control, this method constant current accuracy is high, but the constant-current circuit due to needs special use, peripheral circuit is complicated, be not easy, cost compare is high.Non-isolated buck scenario-frame is relatively simple, do not need transformer, electric current on inductance is adopted and can obtain high-precision constant current effect simultaneously, but conventional step-down scheme itself can not obtain good power factor, easily to electrical network, cause larger pollution to be difficult to meet the environmental protection standard of strengthening day by day.
Summary of the invention
Poor for overcoming prior art power factor, the technological deficiency that running efficiency of system is low, the invention discloses a kind of LED constant-current drive circuit based on power factor correction.
LED constant-current drive circuit based on power factor correction of the present invention, is comprised of current sample amplifier, the first voltage comparator, ramp generator, square wave comparator, the first reference voltage and logic drive circuit;
Described current sample amplifier is sampled to inductive current, its output is connected with the first input end of square wave comparator with the first voltage comparator respectively, the second input of described the first voltage comparator connects the first reference voltage, output is connected with logic drive circuit, the second input of described square wave comparator connects the output of ramp generator, output connects logic drive circuit, the periodicity triangular wave of described ramp generator output constant-slope and width, the output signal of described logic drive circuit is for driving power switching tube;
Described logic drive circuit possesses following functions: make the opening time length of power switch pipe equal the high level lasting time length that square wave comparator is exported; When the first reference voltage is during lower than the output voltage of current sample amplifier, close power switch pipe.
Preferably, described inductance is connected with a sampling resistor, and two inputs of described current sample amplifier connect respectively sampling resistor two ends.
Further, described sampling resistor resistance is 1-10 ohm.
Preferably, also comprise inductive drop sample circuit, described inductive drop sample circuit is by second voltage comparator, the second reference voltage, form with the resistance string of inductance in parallel;
Two inputs of described second voltage comparator connect respectively the output of the second reference voltage and the intermediate node of resistance string, and the output of described second voltage comparator and trailing edge testing circuit is all connected with logic drive circuit;
Described logic drive circuit also possesses following functions: when second voltage comparator detects reference voltage when being compared voltage, power switch pipe is opened.
Further, described the first reference voltage and the second reference voltage are that same reference voltage source produces by electric resistance partial pressure.
Adopt the LED constant-current drive circuit based on power factor correction of the present invention, the present invention provides a kind of application circuit LED constant-current drive circuit mode simple in structure for LED constant-current driving power supply, and can realize High Power Factor.Whole circuit structure is simple, has High Power Factor and low harmonics distortion degree.User's debugging, easy for installation, is used flexibly, and production cost is low.
Accompanying drawing explanation
Fig. 1 illustrates the perfect condition schematic diagram after power factor correction;
Fig. 2 illustrates the circuit structure diagram of a kind of embodiment of the present invention;
Sequential logic figure when Fig. 3 illustrates inductive drop sampling of the present invention;
In each figure, Reference numeral name is called: 1-current sample amplifier 2-first voltage comparator 3-square wave comparator 4-logic drive circuit 5-ramp generator 6-second voltage comparator 7-first reference voltage 8-the second reference voltage.
Embodiment
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in further detail.
Take step-up/step-down circuit as example, as shown in Figure 2, in dotted line frame, it is the LED constant-current drive circuit based on power factor correction of the present invention, peripheral cell comprises inductance L, power switch pipe Q and the sustained diode that forms buck structure (BUCK-BOOST), and the full bridge rectifier to input rectifying, output VOUT.
Full-bridge, from AC end input sine wave alternating voltage, after the full bridge rectifier rectification forming, forms the half-sinusoid voltage as shown in Fig. 1 the first half at VIN end through four diodes.
The object of power factor correction is that the waveform of the voltage and current of input is calibrated to the as far as possible consistent perfect condition of phase place, when initial phase is consistent, phase changing capacity in same time is consistent and can obtains high power factor.As shown in Figure 1, AC/DC(is exchanged and turns direct current) Switching Power Supply, in a complete half-wave, have a plurality of power switch pipes and open the cycle, the mean value of electric current in a complete half-wave keeps phase place consistent with voltage, is the perfect condition that switch power supply power factor is proofreaied and correct.
According to inductance, in the conduction period operation principle of charging, have
.By
visible, as the inductance value L of inductance L
mwhile all remaining unchanged with the each opening time Ton of power switch pipe Q, at VIN end, the variable quantity of voltage
, the variable quantity of electric current
become equal proportion to change.
LED constant-current drive circuit based on power factor correction of the present invention, is comprised of current sample amplifier, the first voltage comparator, ramp generator, square wave comparator, the first reference voltage and logic drive circuit;
1 pair of inductive current of described current sample amplifier is sampled, its output is connected with the first input end of square wave comparator 3 with the first voltage comparator 2 respectively, the second input of described the first voltage comparator connects the first reference voltage 7, output is connected with logic drive circuit 4, the second input of described square wave comparator connects the output of ramp generator, output connects logic drive circuit 4, the periodicity triangular wave of described ramp generator 5 output constant-slope and width, the output signal of described logic drive circuit is for driving power switching tube;
Described logic drive circuit possesses following functions: make the opening time length of power switch pipe equal the high level lasting time length that square wave comparator is exported; When the first reference voltage is during lower than the output voltage of current sample amplifier, close power switch pipe.
Current sample amplifier is by inductive current amplifier, the implementation of sample circuit can be the sampling resistor of connecting with inductance, as shown in Figure 2, resistance R 3 is sampling resistor, connect with inductance L, two inputs of current sample amplifier are contact resistance R3 two ends respectively, while having electric current to flow through R3, at R3 two ends, produce pressure reduction, current sample amplifier amplifies rear output to this pressure reduction.
The sample mode of inductive current can be also other modes, the tie point voltage of direct-detection inductance L and power switch pipe Q for example, this voltage is divided by the dead resistance of the inductance L of measuring in advance, also can obtain inductive current, but inductance parasitic resistance may be with factors vary such as electric current, temperature, adopt the above-mentioned optimal way of the present invention, select temperature and the insensitive outer meeting resistance of load, can overcome this defect.
For alleviating the power consumption in resistance R 3, resistance R 3 resistances are unsuitable large, but for meeting the accuracy of detection of current sample amplifier, the pressure drop at resistance R 3 two ends should be not less than 10 millivolts when work.Consider, the value of resistance R 3 is in 1-10 ohm left and right.
The triangular signal of the output analog voltage signal A1 of described current sample amplifier and ramp generator output is together input to square wave comparator, according to comparator principle, in the situation that triangular signal is constant, the signal of output is square-wave signal, and duty ratio changes with the variation of output analog voltage signal A1.
Described A1 is input to the first voltage comparator simultaneously, and with the first reference voltage comparison, first the two voltage of voltage comparator comparison is also exported comparison signal.
The first voltage comparator 1 is by the output signal comparison to current sample amplifier, actual is detection to inductive current, take Fig. 2 as example, when the pressure drop on R3 is greater than a predefined reference voltage, the output level of the first voltage comparator is closed power switch pipe by upset and by logic drive circuit.By the way, realized the constant current of output loading, the capacitor C 3 in Fig. 2 is to be regulated output voltage VOUT, makes output when power tube is closed, have the ability to provide stable electric current for load.
For example the voltage amplification factor of current sample amplifier is A, and predefined reference voltage is VREF1, and those skilled in the art, according to circuit provided by the present invention, easily obtain the average current of output loading
The output signal of square wave comparator 3 and the first voltage comparator 2 is all input to logic drive circuit, described logic drive circuit carries out logical operation to input signal, realizes and makes the opening time length of power switch pipe equal the high level lasting time length that square wave comparator is exported; Simultaneously logic drive circuit, when the first reference voltage is during lower than the output voltage of current sample amplifier, is closed power switch pipe.
By detecting the pressure drop on R3, the Average Current Control outputing on LED lamp string is existed:
, coordinate with square wave comparator, make R3 pressure drop greatly delay the opening time, R3 pressure drop is little shifts to an earlier date the opening time, has realized power factor correction and output loading constant current simultaneously.
Logic drive circuit is realized logical operation function and drive amplification function, to those skilled in the art, realizing above-mentioned logical operation and drive amplification function all easily realizes, to complex logic, can utilize hardware program language for example VHDL or VERILOG programming generation gate-level logic circuit, in the present invention, above-mentioned logic function is quite simple, and those skilled in the art can be directly according to logical relation, and the gate level circuit combinations such as utilization and door or door, transmission gate, trigger realize.Drive amplification is that the signal with logical message of input is not being changed under the prerequisite of its logical message, adjusts signal level and driving force, with driving power switching tube Q.
As long as T
oNfixing, inductance value L
mfixing, the voltage magnitude that pulse current amplitude will be followed on AC line changes, and the average current waveform morphology on AC line also can be followed the voltage waveform metamorphosis on AC line, thereby realizes power factor correction.
For further improving switch power efficiency, the invention provides a kind of preferred implementation, added inductive drop sample circuit, described inductive drop sample circuit is by second voltage comparator 6, the second reference voltage 8, form with the resistance string of inductance in parallel.
Two inputs of wherein said second voltage comparator connect respectively the output of the second reference voltage and the intermediate node of resistance string, the intermediate node of the input contact resistance string of described trailing edge testing circuit, the output of described second voltage comparator and trailing edge testing circuit is all connected with logic drive circuit;
Described logic drive circuit also possesses following functions: when second voltage comparator detects reference voltage when being compared voltage, power switch pipe is opened.
In embodiment as shown in Figure 2, resistance string is comprised of resistance R 4 and R6, and resistance string is in parallel with inductance L, the common port of R4 and R6, and intermediate node is connected to the input of second voltage comparator as sampled point.
As shown in Figure 3, in power switch pipe Q conduction period, the electric current I in inductance L
pKfrom 0 linearity, be increased to peak value, 0 to T1 or T3 to the T4 stage, when Q is turned off, sustained diode is opened afterflow, the energy being stored in inductance progressively discharges, electric current starts to drop to 0 from peak value linearity, and T1 is to the T2 stage, when current reduction is 0, T2-T3 is in the moment, and inductance L 1 can be vibrated with output capacitance C1; Divider resistance R4, R6 carry out dividing potential drop to inductive drop, when second voltage comparator detects ZCD terminal voltage V
zCDwhile dropping to lower than the second reference voltage, logic drive circuit is opened power switch pipe, makes Q enter conducting state next time; The unlatching of Q is each time always in the low the lowest point conducting of inductive drop.
Because power switch pipe Q is because breadth length ratio is very large, between the drain-source utmost point, there is a parasitic capacitance " C who can not ignore
ds", by capacitance energy storage formula "
" known when power switch pipe is opened drain-source voltage higher, the energy of storage is larger; When lower voltage is born at the above-mentioned leakage two ends, source by Q, open, the unlatching each time of setting power switching tube is all at drain-source voltage V
dcvoltage hour occurs, thereby has reduced the turn-on consumption of Q, has improved system effectiveness.
The value of the second reference voltage is generally lower, span is conventionally at 0-100 millivolt, because the first reference voltage and the second reference voltage are steady state value, the first reference voltage and the second reference voltage can utilize same reference voltage source, for example bandgap voltage reference produces by electric resistance partial pressure, to simplify circuit design.Make two reference voltages consistent with the bias direction of integrated circuit technology simultaneously, be conducive to circuit steady operation.
Previously described is each preferred embodiment of the present invention, preferred implementation in each preferred embodiment is if not obviously contradictory or take a certain preferred implementation as prerequisite, each preferred implementation arbitrarily stack combinations is used, design parameter in described embodiment and embodiment is only the invention proof procedure for clear statement inventor, not in order to limit scope of patent protection of the present invention, scope of patent protection of the present invention is still as the criterion with its claims, the equivalent structure that every utilization specification of the present invention and accompanying drawing content are done changes, in like manner all should be included in protection scope of the present invention.
Claims (5)
1. the LED constant-current drive circuit based on power factor correction, it is characterized in that, by current sample amplifier (1), the first voltage comparator (2), ramp generator (5), square wave comparator (3), the first reference voltage (7) and logic drive circuit (4), formed;
Described current sample amplifier (1) is sampled to inductive current, its output is connected with the first input end of square wave comparator with the first voltage comparator respectively, the second input of described the first voltage comparator connects the first reference voltage, output is connected with logic drive circuit, the second input of described square wave comparator connects the output of ramp generator (5), output connects logic drive circuit, the periodicity triangular wave of described ramp generator (5) output constant-slope and width, the output signal of described logic drive circuit (4) is for driving power switching tube,
Described logic drive circuit (4) possesses following functions: make the opening time length of power switch pipe equal the high level lasting time length that square wave comparator is exported; When the first reference voltage is during lower than the output voltage of current sample amplifier, close power switch pipe.
2. the LED constant-current drive circuit based on power factor correction as claimed in claim 1, is characterized in that, described inductance is connected with a sampling resistor, and two inputs of described current sample amplifier connect respectively sampling resistor two ends.
3. the LED constant-current drive circuit based on power factor correction as claimed in claim 2, is characterized in that, described sampling resistor resistance is 1-10 ohm.
4. the LED constant-current drive circuit based on power factor correction as claimed in claim 1, it is characterized in that, also comprise inductive drop sample circuit, described inductive drop sample circuit is by second voltage comparator (6), the second reference voltage (8), form with the resistance string of inductance in parallel;
Two inputs of described second voltage comparator connect respectively the output of the second reference voltage and the intermediate node of resistance string, and the output of described second voltage comparator is connected with logic drive circuit;
Described logic drive circuit (4) also possesses following functions: when second voltage comparator detects reference voltage when being compared voltage, power switch pipe is opened.
5. the LED constant-current drive circuit based on power factor correction as claimed in claim 4, is characterized in that, described the first reference voltage (7) and the second reference voltage (8) produce by electric resistance partial pressure for same reference voltage source.
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| CN201310545008.1A CN103547042B (en) | 2013-11-07 | 2013-11-07 | Based on the constant current driver circuit for LED of power factor correction |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201310545008.1A CN103547042B (en) | 2013-11-07 | 2013-11-07 | Based on the constant current driver circuit for LED of power factor correction |
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| CN103547042A true CN103547042A (en) | 2014-01-29 |
| CN103547042B CN103547042B (en) | 2016-03-02 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106533140A (en) * | 2017-01-04 | 2017-03-22 | 西南应用磁学研究所 | High-efficiency magnetic tuning device drive circuit |
| CN108091949A (en) * | 2017-12-27 | 2018-05-29 | 银隆新能源股份有限公司 | Voltage sampling circuit, battery protecting plate and battery pack |
| CN113359927A (en) * | 2021-06-30 | 2021-09-07 | 合肥博雷电气有限公司 | Output voltage feedback circuit for differential pressure weighted compensation of redundant diode and application method thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090224686A1 (en) * | 2004-12-14 | 2009-09-10 | Matsushita Electric Industrial Co., Ltd. | Semiconductor circuit for driving light emitting diode, and light emitting diode driving apparatus |
| CN101588664A (en) * | 2008-05-21 | 2009-11-25 | 原景科技股份有限公司 | Light emitting diode drive circuit and circuit for controlling power switch |
| CN102187736A (en) * | 2008-10-20 | 2011-09-14 | 赤多尼科有限公司 | Operating circuit for leds |
| CN102523650A (en) * | 2011-12-02 | 2012-06-27 | 赵修平 | Light-emitting diode (LED) current detection and control circuit |
-
2013
- 2013-11-07 CN CN201310545008.1A patent/CN103547042B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090224686A1 (en) * | 2004-12-14 | 2009-09-10 | Matsushita Electric Industrial Co., Ltd. | Semiconductor circuit for driving light emitting diode, and light emitting diode driving apparatus |
| CN101588664A (en) * | 2008-05-21 | 2009-11-25 | 原景科技股份有限公司 | Light emitting diode drive circuit and circuit for controlling power switch |
| CN102187736A (en) * | 2008-10-20 | 2011-09-14 | 赤多尼科有限公司 | Operating circuit for leds |
| CN102523650A (en) * | 2011-12-02 | 2012-06-27 | 赵修平 | Light-emitting diode (LED) current detection and control circuit |
Non-Patent Citations (1)
| Title |
|---|
| 胡雪峰: "一种新颖的Buck-PFC变换器研究", 《电气应用》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106533140A (en) * | 2017-01-04 | 2017-03-22 | 西南应用磁学研究所 | High-efficiency magnetic tuning device drive circuit |
| CN108091949A (en) * | 2017-12-27 | 2018-05-29 | 银隆新能源股份有限公司 | Voltage sampling circuit, battery protecting plate and battery pack |
| CN113359927A (en) * | 2021-06-30 | 2021-09-07 | 合肥博雷电气有限公司 | Output voltage feedback circuit for differential pressure weighted compensation of redundant diode and application method thereof |
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| CN103547042B (en) | 2016-03-02 |
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Address after: 610000 innovation center, No. 4, West core road, hi tech West District, Sichuan, Chengdu C341-343 Patentee after: Chengdu Qi Chen electronic Limited by Share Ltd Address before: 610000 innovation center, No. 4, West core road, hi tech West District, Sichuan, Chengdu C341-343 Patentee before: Chengdu Chip-Rail Microelectronic Co., Ltd. |