CN110831291B - Sepic soft switch-based LED driver and hybrid driving method thereof - Google Patents

Sepic soft switch-based LED driver and hybrid driving method thereof Download PDF

Info

Publication number
CN110831291B
CN110831291B CN201911155353.8A CN201911155353A CN110831291B CN 110831291 B CN110831291 B CN 110831291B CN 201911155353 A CN201911155353 A CN 201911155353A CN 110831291 B CN110831291 B CN 110831291B
Authority
CN
China
Prior art keywords
capacitor
diode
inductor
working frequency
output
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201911155353.8A
Other languages
Chinese (zh)
Other versions
CN110831291A (en
Inventor
王懿杰
高珊珊
刘怡宁
管乐诗
姚友素
张相军
徐殿国
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Harbin Institute of Technology
Original Assignee
Harbin Institute of Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Harbin Institute of Technology filed Critical Harbin Institute of Technology
Priority to CN201911155353.8A priority Critical patent/CN110831291B/en
Publication of CN110831291A publication Critical patent/CN110831291A/en
Application granted granted Critical
Publication of CN110831291B publication Critical patent/CN110831291B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H02M1/0054—Transistor switching losses
    • H02M1/0058—Transistor switching losses by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero
    • 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

Abstract

The invention relates to an LED driver based on a Sepic soft switch and a hybrid driving method thereof. The driver includes: sampling circuit, control chip, drive circuit, boost unit I, boost unit II, voltage source VinInductor L1And a switching tube Q1Capacitor CPDiode DPCapacitor CsInductor L3Diode DoAn output capacitor CoSampling resistor RrefAnd a diode RL. The invention relates to a PWM + PFM hybrid control method designed for an LED driver with a dimming function, which can ensure that the output current is constant when the load changes, and a main switching tube is always in a soft switching state, thereby reducing the loss of the system under high-frequency work.

Description

Sepic soft switch-based LED driver and hybrid driving method thereof
Technical Field
The invention relates to the technical field of LED drivers, in particular to an LED driver based on a Sepic soft switch and a hybrid driving method thereof.
Background
With the development and progress of global economy, energy problems become the fate of development in every country. The pollution problem caused by the traditional fossil energy and the increasing exhaustion of non-renewable resources on the earth have raised serious requirements for the development of new green renewable energy. The Light Emitting Diode (LED) is used as a fourth-generation novel green Light source, has the characteristics of energy conservation, environmental protection, safety, long service life, low power consumption and the like, and can be applied to the fields of various indications, decoration, backlight sources, common illumination and the like. The biggest problem faced by the LEDs in the current market is the design of the driving circuit, and the efficiency, brightness, and lifetime of the LEDs are greatly affected by the quality of the driving circuit. With the miniaturization development of the boost converter, the frequency of the boost converter is gradually increased, so that the design of a main switching tube soft switch of the boost converter is particularly important for reducing loss and improving the system efficiency. In addition, according to the design problem of the dimming function required by the LED illumination, the requirement that the converter can realize the load regulation from full load to different loads under the condition of constant current is required. In this context, the following requirements are therefore placed on the converter:
1. the output voltage can be regulated according to the change of the load by adopting methods such as PWM (pulse width modulation) or PFM (pulse frequency modulation) control and the like, and the constant current output can be kept in the load regulation process.
2. In the adjusting process, the switching tube is required to be kept to be capable of realizing zero voltage switching-on or minimum voltage switching-on all the time, and loss is reduced.
Disclosure of Invention
The invention provides an LED driver based on a Sepic soft switch and a mixed driving method thereof for ensuring constant output current when load changes, and provides the following technical scheme:
a Sepic soft switch LED-based driver, the driver comprising: sampling circuit, control chip, drive circuit, boost unit I, boost unit II, voltage source VinInductor L1And a switching tube Q1Capacitor CPDiode DPCapacitor CsInductor L3Diode DoAn output capacitor CoSampling resistor RrefAnd a diode RL；
The boosting unit II comprises a switching tube Q2Capacitor CQDiode DQAnd an inductance L2Capacitor CQAnd a diode DQIs connected in parallel to the switching tube Q2Both ends of (a); the boosting unit I comprises a diode DMAnd a capacitor CM；
Voltage source VinPositive terminal of the inductor L1One terminal of (1), inductance L1Another end of (a) is connected toA capacitor CsAnd a switching tube Q1One terminal of (C), a capacitorsAnother end of the diode DoAnd an inductance L3One terminal of (D), diode DoThe other end of the first capacitor is connected with an output capacitor CoAnd a diode RLOne terminal of (1), diode RLThe other end of the sampling resistor is connected with a sampling resistor RrefOne end of (1), a sampling resistor RrefThe other end of the first capacitor is connected with an output capacitor CoThe other end of (a);
output capacitor CoThe other end of the capacitor C is connected with a capacitor CMOne terminal of (C), a capacitorMAnother end of the inductor L is connected with the inductor L3Another terminal of (1), a capacitor CMAnother end of the diode DMOne terminal of (D), diode DMThe other end of the switch tube Q is connected with1One end of (1), a switching tube Q1Is connected with a voltage source V at the other endinThe negative electrode of (1);
inductor L1One end of the switch tube Q is connected with2One end of (1), a switching tube Q2Another end of the inductor L is connected with the inductor L2One terminal of (1), inductance L2Is connected with a voltage source V at the other endinNegative electrode of (1), inductor L2One end of which is connected with a capacitor CMOne end of (a);
resistance RrefThe other end of the sampling circuit is connected with one end of a control chip, the other end of the control chip is connected with a driving circuit, and the driving circuit respectively controls and connects a switch tube Q1And Q2Capacitor CPAnd a diode DPIs connected in parallel to the switching tube Q1At both ends of the same.
Preferably, the switching tube Q1And Q2And in a soft switching state to reduce the loss under high-frequency operation.
A mixed driving method based on a Sepic soft switch LED driver comprises the following steps:
step 1: by sampling the resistance RrefSampling the output current and comparing the sampled output current with a rated value;
step 2: when judging whether the output current is larger than the rated value or not, extracting a steady-state error when the output current is smaller than the rated value, and taking the difference value between the output current and the rated value as the steady-state error;
and step 3: performing digital compensation according to the extracted steady-state error to obtain a working frequency;
and 4, step 4: and judging whether the working frequency meets the frequency range, and if so, driving the circuit to perform PWM output.
Preferably, the nominal value is 0.3A.
Preferably, the step 3 is to perform digital compensation according to the extracted steady-state error, calculate values of the working frequency and the duty ratio under different output voltages, and express the duty ratio and the working frequency by the following formula:
Figure BDA0002284651250000021
wherein D is the duty cycle, fsTo the operating frequency, VinIs a voltage source, LeqFor resonant equivalent inductance value, IoIs rated output current, alpha is a phase angle value corresponding to the moment from resonance to zero, omega is resonance angular frequency, M is steady-state error,
Figure BDA0002284651250000022
is an intermediate variable.
Preferably, the step 4 specifically includes:
step 4.1: judging whether the working frequency meets the frequency range, and when the working frequency is greater than the upper limit value of 1.16MHz, making the working frequency be 1.16 MHz; when the working frequency is less than the lower limit value of 1MHz, the working frequency is made to be 1 MHz; when the working frequency is greater than the lower limit value of 1MHz and less than the upper limit value of 1.16MHz, outputting the working frequency;
step 4.2: and according to the output working frequency, the driving circuit carries out PWM output.
The invention has the following beneficial effects:
the invention relates to a PWM + PFM hybrid control method designed for an LED driver with a dimming function, which can ensure that the output current is constant when the load changes, and a main switching tube is always in a soft switching state, thereby reducing the loss of the system under high-frequency work.
Drawings
FIG. 1 is a Sepic soft switch based LED driver topology;
FIG. 2 is a Sepic soft switch based LED driver mode diagram;
FIG. 3 is a waveform diagram of an LED driver based on Sepic soft switching;
FIG. 4 shows a capacitor CQVoltage current waveform diagram of (a);
FIG. 5 is a switching tube voltage waveform at different output voltages;
FIG. 6 is a mixed control flow chart of an LED driver based on Sepic soft switch;
FIG. 7 is a graph of the drive of the switching tube under rated load and its voltage waveform;
FIG. 8 is a graph of output current and voltage waveforms at rated load;
FIG. 9 shows the switching tube drive and its voltage waveform at 90% load;
FIG. 10 is a graph showing the output voltage and current variation dynamic waveforms;
fig. 11 is a drive control schematic diagram.
Detailed Description
The present invention will be described in detail with reference to specific examples.
The first embodiment is as follows:
according to fig. 1, the present invention provides a Sepic soft switch based LED driver, which includes: sampling circuit, control chip, drive circuit, boost unit I, boost unit II, voltage source VinInductor L1And a switching tube Q1Capacitor CPDiode DPCapacitor CsInductor L3Diode DoAn output capacitor CoSampling resistor RrefAnd a diode RL；
The boosting unit II comprises a switching tube Q2Capacitor CQDiode DQAnd an inductance L2Capacitor CQAnd a diode DQIs connected in parallel to the switching tube Q2Both ends of (a); the boosting unit I comprises a diode DMAnd a capacitor CM；
Voltage source VinPositive terminal of the inductor L1One terminal of (1), inductance L1The other end of the capacitor C is connected with a capacitor CsAnd a switching tube Q1One terminal of (C), a capacitorsAnother end of the diode DoAnd an inductance L3One terminal of (D), diode DoThe other end of the first capacitor is connected with an output capacitor CoAnd a diode RLOne terminal of (1), diode RLThe other end of the sampling resistor is connected with a sampling resistor RrefOne end of (1), a sampling resistor RrefThe other end of the first capacitor is connected with an output capacitor CoThe other end of (a);
output capacitor CoThe other end of the capacitor C is connected with a capacitor CMOne terminal of (C), a capacitorMAnother end of the inductor L is connected with the inductor L3Another terminal of (1), a capacitor CMAnother end of the diode DMOne terminal of (D), diode DMThe other end of the switch tube Q is connected with1One end of (1), a switching tube Q1Is connected with a voltage source V at the other endinThe negative electrode of (1);
inductor L1One end of the switch tube Q is connected with2One end of (1), a switching tube Q2Another end of the inductor L is connected with the inductor L2One terminal of (1), inductance L2Is connected with a voltage source V at the other endinNegative electrode of (1), inductor L2One end of which is connected with a capacitor CMOne end of (a);
resistance RrefThe other end of the sampling circuit is connected with one end of a control chip, the other end of the control chip is connected with a driving circuit, and the driving circuit respectively controls and connects a switch tube Q1And Q2Capacitor CPAnd a diode DPIs connected in parallel to the switching tube Q1At both ends of the same.
According to fig. 2, the working mode of modifiedseric mainly has the following 5 stages:
mode 1 (t)0-t1): due to the fact that at t0Before, the body diode is turned on first, so t0At any moment, two switching tubes can be switched on at zero voltage simultaneously, and L is1、L2Charging by a power supply, L3Through Vin-Q2-L3-Q1-path charging of GND, capacitance CoDischarging to the load. This phase is called the switch-on phase and the duration is denoted td＝t1-t0＝DTsWhere D is the duty cycle, Ts＝1/fsFor a switching period, fsIs the switching frequency. The voltages of the devices in this phase can be expressed as:
VL(mode1)＝VL1(mode1)＝VL2(mode1)＝Vin (1)
VL3(mode1)＝Vin+VCM-VCs (2)
wherein, VL(mode1)Is the voltage, V, across the inductors L1, L2 in mode 1L1(mode1)Is the voltage, V, across the inductor L1 in mode 1L2(mode1)Is the voltage, V, across the inductor L2 in mode 1L3(mode1)Is the voltage, V, across the inductor L3 in mode 1CMIs the voltage across the capacitor CM, VCsIs the voltage across the capacitor Cs.
Mode 2 (t)1-t2)：t1Time, Q1、Q2Simultaneously open, capacitance CQAnd starting charging, wherein the voltage stress at two ends of the switching tube is gradually increased from 0. With CQThe voltage gradually rises, and the voltage on the inductor gradually decreases and then increases reversely. On the other hand, due to the capacitance CQThe capacitance value is very small, so the charging time is very short and can be approximately ignored. When the voltage increases to (V)CM+VL(mode2)) When charging is complete, the modality ends.
Mode 3 (t)2-t3): parallel capacitance and inductance L3The rise of the voltage at both ends is diode DMAnd DoA conduction condition is provided. Thus, L1And L2The energy in (A) begins to pass through (D)MIs transmitted to CMWhile the energy in all three inductors passes through DoThe duration of modality 3 transmitted to the output side is denoted tδ＝t3-t2＝DδTs，DδThe time taken for transferring energy to the load is the total time of a cycleTo the ratio of (d) to (d). In this mode, a current flows through the diode DMAnd DoUntil the current decreases to zero, mode 3 ends. In this mode, the inductor voltage can be represented as (3), and the voltages (4), (5) of the two capacitors in one period can be obtained accordingly.
Figure BDA0002284651250000051
Figure BDA0002284651250000052
Figure BDA0002284651250000053
Wherein, VL3Is the voltage across the inductor L3, VLIs the voltage V across the inductors L1, L2oTo output a voltage, VCMIs the voltage across capacitor CM;
mode 4 (t)3-t4): at this time, the diode DMAnd DoAnd (6) turning off. Two parallel capacitors CQCan be considered as resonating with an equivalent inductance, respectively, denoted as
Figure BDA0002284651250000054
LeqIs the resonant equivalent inductance value. When C is presentQThe mode is ended when the voltage at two ends resonates to zero, which means that the voltage at two ends of the switching tube is zero at the moment, and the duration of the mode satisfies tr＝t4-t3＝DrTs，DrIs the ratio of the resonant phase time to the total period.
Mode 5 (t)4-t0'): the body diode D of the switch tube is in back pressure at two endsQBegins to conduct, at which time the inductor L1And L2The voltage across is equal to the input voltage VinInductance L1、L2And L3The inductor current increases linearly as energy begins to be stored. At presentWhen a periodic drive signal arrives, the mode ends, with a duration tb＝t0'-t4＝DbTs，DbThe ratio of the body diode freewheeling stage time to the total period of one cycle.
According to FIG. 3, wherein vgs.Q1,2For switching tube drive voltage vds.Q1,2For switching tube voltage stress, ids.Q1,2For switching tube current stress, iDM,DoIs a diode DM，DoCurrent, iCQIs a resonant capacitor CQCurrent, iL1，2Is an inductance L1And L2Current, iL3Is an inductance L3Current, vL1，2Is an inductance L1And L2A voltage.
From the analysis of mode 4, the waveform of the capacitor voltage current in this resonance phase can be obtained, as shown in fig. 3 and 4, and the relational expression of the two is written:
Figure BDA0002284651250000055
after the processing, a differential equation shown in the formula (7) can be obtained, and then the voltage expression at the two ends of the switching tube is obtained by solving:
Figure BDA0002284651250000056
Figure BDA0002284651250000057
since at the end of this phase vCQWhen the value is 0, the resonance time t can be obtainedr：
Figure BDA0002284651250000061
Wherein the content of the first and second substances,
Figure BDA0002284651250000062
from modal analysis, we define here at t0-t3And t3-t0In the two periods, the inductances respectively satisfy volt-second balance. From this, the relation between four modalities can be written:
Figure BDA0002284651250000063
further, according to equation (8), a voltage boosting ratio range in which zero-voltage turn-on can be realized can also be obtained, as shown in fig. 5, that is: m ═ Vo/VinWhen the voltage is more than or equal to 5, zero voltage switching-on of the switching tube can be realized by adjusting duty ratio and frequency, and M is<At 5, only minimum voltage turn-on can be achieved.
Thus, a specific boost ratio expression can be written:
Figure BDA0002284651250000064
since the average current of the output capacitor in one period is 0, the output diode DoThe peak current of (d) can be expressed as:
Figure BDA0002284651250000065
Figure BDA0002284651250000066
Figure BDA0002284651250000067
IDopkis the peak value of the current flowing through the diode Do, Δ iDIs the amount of change, Δ i, in the current flowing through the diode Do in a cycleLIs the change in the current through the inductors L1, L2 in a cycle, Δ iL3Is the amount of change in the current through inductor L3 over a period.
From (13) and (14), a relation between the total time of one cycle and the time for transferring energy to the load can be obtained, as shown in equation (15). The time relationship of each segment in a cycle satisfies equation (16). The joint type (10), (15) and (16) can obtain specific numerical values corresponding to the frequency and the duty ratio under different output voltages, as shown in a formula (17).
td+tδ+tr+tb＝Ts (16)
Figure BDA0002284651250000071
Here, IoIs rated output current, omega is resonance angular frequency, alpha is phase angle value corresponding to the moment when resonance reaches zero,
Figure BDA0002284651250000072
as an intermediate variable
Figure BDA0002284651250000073
fsIs the switching frequency.
Wherein D is the duty cycle, fsTo the operating frequency, VinIs a voltage source, LeqFor resonant equivalent inductance value, IoIs rated output current, alpha is a phase angle value corresponding to the moment from resonance to zero, omega is resonance angular frequency, M is steady-state error,
Figure BDA0002284651250000074
is an intermediate variable.
Therefore, for the digital control to be realized, first of all by means of the sampling resistor RrefSampling the output current, comparing with the rated value of 0.3A, regulating the frequency of the output square wave drive signal according to the error to regulate the output voltage of the converter, and the switching frequency fsThe relationship with the output voltage is shown in equation (14). The switching frequency is increased when the sampled current is greater than the nominal value and decreased when the sampled current is less than the nominal value. In the change of loadIn the case of chemical conversion, if the voltage V is adjusted only by changing the frequencyoAnd the zero voltage switching-on of the switching tube in the whole load regulation range cannot be guaranteed, which is not favorable for the system efficiency. Therefore, to ensure soft switching at the same time. According to the formula (17), the duty ratio D meeting the soft switching condition under the specific output voltage can be calculated, and constant current output can be realized under the condition of ensuring the ZVS on of the switching tube. The control strategy flow diagram is shown in fig. 6.
A hybrid driving method based on the Sepic soft switch LED driver, which is based on the Sepic soft switch LED driver of claim 1, and is characterized in that: the method comprises the following steps:
step 1: by sampling the resistance RrefSampling the output current and comparing the sampled output current with a rated value;
step 2: and judging whether the output current is equal to the given current or not, extracting a steady-state error when the output current is not equal to the given value, and taking the difference value between the output current and the rated value as the steady-state error.
And step 3: performing digital compensation according to the extracted steady-state error to obtain a working frequency;
and 4, step 4: and judging whether the working frequency meets the frequency range, and when the working frequency is in the frequency range, the driving circuit performs PWM output.
The step 4 specifically comprises the following steps:
step 4.1: judging whether the working frequency meets the frequency range, and when the working frequency is greater than the upper limit value of 1.16MHz, making the working frequency be 1.16 MHz; when the working frequency is less than the lower limit value of 1MHz, the working frequency is made to be 1 MHz; when the working frequency is greater than the lower limit value of 1MHz and less than the upper limit value of 1.16MHz, outputting the working frequency;
step 4.2: and according to the output working frequency, the driving circuit carries out PWM output.
Specific example 3:
the converter used by the invention has the following input and output parameters under the full load condition: 12Vvin, 120V Vout, 300mA of output current and 1MHz of rated switching frequency. The driving and voltage waveforms of the switching tube under the full load condition are shown in fig. 7, the output voltage and current under the full load condition are shown in fig. 8, the driving, voltage at two ends and output voltage and current waveforms of the switching tube under the 90% load condition are shown in fig. 9, and the dynamic waveform of the output voltage and current change when the finally obtained load changes within the range of 100% -75% is shown in fig. 10.
And calculating according to specific parameters of the circuit to obtain corresponding switching frequency and duty ratio change curves under different loads in the graph of fig. 6, and compiling a corresponding PWM + PFM control program to realize closed-loop control.
For a 1MHz high-frequency DC/DC converter, a driving control circuit of a switching tube is very important, and the generation of problems such as delay distortion of a driving signal is avoided, so that a si8271 driving chip is selected in the experiment, and voltage conversion chips LM7805 and B0509XT are used as auxiliary power supplies to realize on-off control of the switching tube. A specific pcb circuit schematic is shown in fig. 11.
The foregoing is only a preferred embodiment based on the Sepic soft switch LED driver and the hybrid driving method thereof, and the protection scope of the Sepic soft switch LED driver and the hybrid driving method thereof is not limited to the foregoing embodiments, and all technical solutions belonging to the idea belong to the protection scope of the present invention. It should be noted that modifications and variations which do not depart from the gist of the invention will be those skilled in the art to which the invention pertains and which are intended to be within the scope of the invention.

Claims (3)

1. A hybrid driving method based on a Sepic soft switch LED driver, the method is based on an improved Sepic soft switch LED driver, and the driver comprises: sampling circuit, control chip, drive circuit, boost unit I, boost unit II, voltage source VinInductor L1And a switching tube Q1Capacitor CPDiode DPCapacitor CsInductor L3Diode DoAn output capacitor CoSampling resistor RrefAnd a diode RL；
The boosting unit II comprises a switching tube Q2Capacitor CQDiode DQAnd an inductance L2Capacitor CQAnd a diode DQIs connected in parallel to the switching tube Q2Both ends of (a); the boosting unit I comprises a diode DMAnd a capacitor CM；
Voltage source VinPositive terminal of the inductor L1One terminal of (1), inductance L1The other end of the capacitor C is connected with a capacitor CsAnd a switching tube Q1One terminal of (C), a capacitorsAnother end of the diode DoAnd an inductance L3One terminal of (D), diode DoThe other end of the first capacitor is connected with an output capacitor CoAnd a diode RLOne terminal of (1), diode RLThe other end of the sampling resistor is connected with a sampling resistor RrefOne end of (1), a sampling resistor RrefThe other end of the first capacitor is connected with an output capacitor CoThe other end of (a);
output capacitor CoThe other end of the capacitor C is connected with a capacitor CMOne terminal of (C), a capacitorMAnother end of the inductor L is connected with the inductor L3Another terminal of (1), a capacitor CMAnother end of the diode DMOne terminal of (D), diode DMThe other end of the switch tube Q is connected with1One end of (1), a switching tube Q1Is connected with a voltage source V at the other endinThe negative electrode of (1);
inductor L1One end of the switch tube Q is connected with2One end of (1), a switching tube Q2Another end of the inductor L is connected with the inductor L2One terminal of (1), inductance L2Is connected with a voltage source V at the other endinNegative electrode of (1), inductor L2One end of which is connected with a capacitor CMOne end of (a);
resistance RrefThe other end of the sampling circuit is connected with one end of a control chip, the other end of the control chip is connected with a driving circuit, and the driving circuit respectively controls and connects a switch tube Q1And Q2Capacitor CPAnd a diode DPIs connected in parallel to the switching tube Q1Both ends of (a); the switch tube Q1And Q2The switch is in a soft switching state to reduce the loss under high-frequency work;
the method is characterized in that: the method comprises the following steps:
step 1: by sampling the resistance RrefSampling the output current and comparing the sampled output current with a rated value;
step 2: judging whether the output current is equal to the given current or not, extracting a steady-state error when the output current is not equal to the given value, and taking the difference value between the output current and a rated value as the steady-state error;
and step 3: performing digital compensation according to the extracted steady-state error to obtain a working frequency;
performing digital compensation according to the extracted steady-state error, calculating values of working frequency and duty ratio under different output voltages, and expressing the duty ratio and the working frequency by the following formula:
Figure FDA0002961983570000021
wherein D is the duty cycle, fsTo the operating frequency, VinIs a voltage source, LeqFor resonant equivalent inductance value, IoIs rated output current, alpha is a phase angle value corresponding to the moment from resonance to zero, omega is resonance angular frequency, M is steady-state error,
Figure FDA0002961983570000022
is an intermediate variable;
and 4, step 4: and judging whether the working frequency meets the frequency range, and when the working frequency is in the frequency range, the driving circuit performs PWM output.
2. The Sepic soft switch LED driver-based hybrid driving method according to claim 1, wherein: the nominal value is 0.3A.
3. The Sepic soft switch LED driver-based hybrid driving method of claim 2, wherein: the step 4 specifically comprises the following steps:
step 4.1: judging whether the working frequency meets the frequency range, and when the working frequency is greater than the upper limit value of 1.16MHz, making the working frequency be 1.16 MHz; when the working frequency is less than the lower limit value of 1MHz, the working frequency is made to be 1 MHz; when the working frequency is greater than the lower limit value of 1MHz and less than the upper limit value of 1.16MHz, outputting the working frequency;
step 4.2: and according to the output working frequency, the driving circuit carries out PWM output.
CN201911155353.8A 2019-11-22 2019-11-22 Sepic soft switch-based LED driver and hybrid driving method thereof Active CN110831291B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911155353.8A CN110831291B (en) 2019-11-22 2019-11-22 Sepic soft switch-based LED driver and hybrid driving method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911155353.8A CN110831291B (en) 2019-11-22 2019-11-22 Sepic soft switch-based LED driver and hybrid driving method thereof

Publications (2)

Publication Number Publication Date
CN110831291A CN110831291A (en) 2020-02-21
CN110831291B true CN110831291B (en) 2021-07-20

Family

ID=69558465

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201911155353.8A Active CN110831291B (en) 2019-11-22 2019-11-22 Sepic soft switch-based LED driver and hybrid driving method thereof

Country Status (1)

Country Link
CN (1) CN110831291B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112039318A (en) * 2020-09-21 2020-12-04 江苏信息职业技术学院 Novel MOS tube isolation driving circuit
CN112351547B (en) * 2020-12-04 2022-05-10 华源智信半导体(武汉)有限公司 Intelligent adjusting method and system for driving LED
CN116599343B (en) * 2023-07-19 2024-03-15 深圳市恒运昌真空技术股份有限公司 High-gain Sepic converter and control method thereof

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108684104A (en) * 2018-05-23 2018-10-19 哈尔滨工业大学 Based on the automotive LED headlamp driver for improving SEPIC Sofe Switch

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105744678B (en) * 2016-03-11 2018-01-26 浙江大学 Electrochemical capacitor LED driver is gone based on PWM duty cycle control strategy
CN109951072A (en) * 2019-03-26 2019-06-28 哈尔滨工业大学 Novel Soft Switching high step-up ratio converter and its working method based on Sepic circuit

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108684104A (en) * 2018-05-23 2018-10-19 哈尔滨工业大学 Based on the automotive LED headlamp driver for improving SEPIC Sofe Switch

Also Published As

Publication number Publication date
CN110831291A (en) 2020-02-21

Similar Documents

Publication Publication Date Title
CN110831291B (en) Sepic soft switch-based LED driver and hybrid driving method thereof
Wang et al. A CLCL resonant DC/DC converter for two-stage LED driver system
EP2676528B1 (en) A dimmable led driver and a method for controlling the same
Yun et al. Improvement of power-conversion efficiency of a DC–DC boost converter using a passive snubber circuit
Wu et al. Multi-channel constant current (MC 3) LLC resonant LED driver
CN102801329B (en) High-efficiency and low-loss AC/DC (Alternating Current/Direct Current) power supply circuit and control method thereof
Ye et al. A topology study of single-phase offline AC/DC converters for high brightness white LED lighting with power factor pre-regulation and brightness dimmable
Cheng et al. Design and implementation of a high-power-factor LED driver with zero-voltage switching-on characteristics
CN203775058U (en) LED driving power supply based on single-end flyback transformer leakage inductor energy utilization
CN101034854A (en) Voltage-adjustable multi-output power supply and method for adjusting output voltage thereof
Li A novel control scheme of quasi-resonant valley-switching for high-power-factor AC-to-DC LED drivers
CN111224555B (en) Wide-range output control method of LLC resonant conversion circuit
CN105554956A (en) Light emitting diode (LED) lamp lighting system based on pulse width modulation (PWM) dimming
CN102137524A (en) High-efficiency control method for balance-driving light-emitting diode (LED)
CN114679808B (en) Wide-input-voltage soft-switching n-way current-sharing LED output circuit
CN101553071A (en) Discharge lamp system and control method thereof
TWI420970B (en) Lighting devices
CN205378285U (en) LED lamp lighting system based on PWM adjusts luminance
CN203896538U (en) LED driving power source employing single switch tube and two Buck-Boost circuits in cascade connection
CN108925012A (en) Single switch multichannel flows output translator circuit again
CN110677063B (en) Series-parallel DCM Boost PFC converter and working method thereof
CN204408690U (en) A kind of LED drive circuit
CN110012574B (en) LED drive circuit of hybrid control single-stage bridgeless Sepic and LLC
Sreedevi et al. Analysis and simulation of a single stage power supply for LED lighting
Sekhar et al. Input Regulated Soft Switched Ripple Free Current LED Driver

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant