CN107635302B - A kind of LED light source driving circuit and LED light source device - Google Patents
A kind of LED light source driving circuit and LED light source device Download PDFInfo
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- CN107635302B CN107635302B CN201610574995.1A CN201610574995A CN107635302B CN 107635302 B CN107635302 B CN 107635302B CN 201610574995 A CN201610574995 A CN 201610574995A CN 107635302 B CN107635302 B CN 107635302B
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Abstract
A kind of driving circuit and LED light source device of LED light source, the driving circuit includes: first and second rectifier bridge, the first filter capacitor, buck route, first switch, second switch and control unit, in which: first rectifier bridge is suitable for power supply of the rectification from electric ballast；Second rectifier bridge, suitable for rectifying the power supply from AC industrial frequency AC；First filter capacitor, is adapted for filter rectification；The buck route, suitable for constructing the current loop of the LED light source；Described control unit, suitable for when the driving circuit for detecting the LED light source is powered by the electric ballast, control formation passes through the current loop of one and the second switch in the energy storage inductor, freewheeling diode, the LED light source and second filter capacitor.Using the above scheme the pressure resistance of switching tube can be reduced to avoid LED light source underpower when electric ballast power supply.
Description
Technical field
The present invention relates to electronic circuit technology field more particularly to a kind of LED light source driving circuit and LED light source devices.
Background technique
Light emitting diode (Light Emitting Diode, LED) light source is illuminated because of bloom efficiency, long-life and low cost
The advantages that, it is usually used by people to replace the fluorescent lamp as conventional light source.LED light source is divided into three types in the market: first
Kind is the LED light source of compatible electronic ballast；Second is the LED light source powered by industrial-frequency alternating current；The third is outside needing
The LED light source for the LED light source driver set.Since the first and the replacement of the second inter-species are simple, market acceptance is relatively high, thus
The market demand of the LED light source of compatible electronic ballast simultaneously and industrial frequency AC input is just expedited the emergence of.For compatible electronic ballast
The LED light source of device, circuit topology are typically only capable to select decompression (Buck) scheme.This means that while compatible electronic ballast
It is driven with the LED light source of industrial frequency AC, majority is also to select decompression scheme.Simultaneously under industrial frequency AC input condition, in order to full
The standard of sufficient power factor (PF) and harmonic wave, the load voltage of LED light source again cannot be too high, so, compatible electronic ballast and power frequency
The lower decompression scheme of load voltage is selected in the LED light source driving of exchange mostly.Decompression scheme will cause electric ballast power supply
When LED light source underpower, the problems such as switching tube in reduction voltage circuit is high pressure resistant.
In order to solve the problems, such as LED light source underpower, currently, the LED light source of compatible electronic ballast and industrial frequency AC selects
With buck topological circuit as driving circuit.
But if above-mentioned circuit drives LED light source, will cause when being powered with electric ballast, switching tube needs
Very high pressure resistance, therefore cause the at high cost and reliability of LED light source device low, and cause to constrain to the voltage of LED light source, it limits
The design of LED light source.
Summary of the invention
Problems solved by the invention is LED light source underpower when how electric ballast to be avoided to power, and reduces switching tube
The cost of pressure resistance and LED light source device, improves the reliability of LED light source device, avoids proposing the constraint of the voltage of LED light source
The scope of application of high LED light source driving circuit, so that the design of LED light source is more flexible.
To solve the above problems, the embodiment of the invention provides a kind of driving circuit of LED light source, the LED light source
Driving circuit includes: the first rectifier bridge, the second rectifier bridge, the first filter capacitor, buck route, first switch, second switch
And control unit, in which: first rectifier bridge, suitable for rectifying the power supply from electric ballast；Second rectifier bridge is fitted
In power supply of the rectification from AC industrial frequency AC；First filter capacitor, with first rectifier bridge and second rectifier bridge
It is respectively coupled to, suitable for being filtered rectification to the electric current from first rectifier bridge and the second rectifier bridge；The lifting crimping
Road suitable for receiving the electric current from first filter capacitor, and constructs the current loop of the LED light source, and include: energy storage
Inductance, the second filter capacitor, freewheeling diode, PWM control and driving unit and switching tube；One end of the energy storage inductor and institute
It states one end of the first filter capacitor, the high-voltage end of first rectifier bridge, the high-voltage end of second rectifier bridge, described first open
One end of pass couples, the other end of the energy storage inductor anode with one end of the switching tube and the freewheeling diode respectively
Coupling；One end of the anode of the freewheeling diode and the switching tube couples, the cathode of the freewheeling diode respectively with institute
State the anode coupling of the positive and described LED light source of the second filter capacitor；The first switch, one end and first rectifier bridge
High-voltage end and the second rectifier bridge high-voltage end coupling, the other end of the first switch and second filter capacitor it is negative
The cathode of pole, one end of the second switch and the LED light source couples；The second switch, one end and second filtering
The cathode of the cathode of capacitor, the other end of the first switch and the LED light source couples, the other end of the second switch with
The other end coupling of the low-pressure end of first rectifier bridge, the low-pressure end of the second rectifier bridge, the switching tube；The control is single
Member distinguishes coupling with output end, the buck route, the first switch and the second switch of the electric ballast
Connect, suitable for when detecting that the driving circuit of the LED light source is powered by the electric ballast, control the switching tube and
First switch is in an off state, the second switch is in closed state, and formation passes through the energy storage inductor, two pole of afterflow
The current loop of pipe, the LED light source and the second filter capacitor one of both and the second switch.
Optionally, described control unit is also coupled with the input terminal of the AC industrial frequency AC, suitable for described when detecting
When LED light source is by the power supply of the AC industrial frequency AC, controls the second switch and be in an off state and the first switch
In closed state, buck-boost mode is in control the driving circuit of the LED light source.
Optionally, first rectifier bridge, comprising: first diode, the second diode, third diode and the four or two pole
Pipe, in which: the output end of the electric ballast is input to the anode of the first diode and the sun of second diode
Pole；The cathode of the cathode of the first diode and second diode couples, the anode of the first diode with it is described
The cathode of third diode couples；The cathode of second diode and the cathode of the first diode couple, and described second
The cathode of the anode of diode and the 4th diode couples；The cathode of the third diode and the first diode
The anode of cathode coupling, the anode of the third diode and the 4th diode couples；The cathode of 4th diode
It is coupled with the anode of second diode, the anode of the 4th diode and the anode of the third diode couple.
Optionally, the driving circuit of the LED light source further include: third switch, the third switch one end with it is described
The coupling of the output end of the anode of first diode and the electric ballast, the other end and the described 2nd 2 of the third switch
The output end of the anode of pole pipe and electric ballast coupling, suitable for being more than default when the voltage for detecting the LED light source
Voltage threshold when, be in closed state.
Optionally, the first switch is diode.
Optionally, the second switch is metal-oxide-semiconductor.
Optionally, described control unit, comprising: third capacitor, zener diode, the 7th diode, second resistance and
Four capacitors, in which: third capacitor one end couples the output end of the electric ballast, the other end coupling of the third capacitor
Connect the anode of the 7th diode and the cathode of the zener diode；The anode of the zener diode couples the switch
The other end of pipe and PWM control and driving unit；The cathode of 7th diode couples the second switch, the 4th electricity
One end of appearance and one end of the second resistance；The other end of the second resistance couples the other end of the 4th capacitor, institute
State the other end of switching tube, the PWM is controlled and the anode of driving unit and the zener diode；Described 4th capacitor one end
Couple one end of the second switch, the cathode of the 7th diode and the second resistance, the 4th capacitor it is another
End couple the other end of the switching tube, PWM control and driving unit, the second switch, the second resistance it is another
The anode of one end and the zener diode.
The embodiment of the invention provides a kind of LED light source device, the LED light source device includes: above-described any
The driving circuit and LED light source of kind LED light source；The driving circuit of the LED light source is coupled with the LED light source, is suitable for driving
The LED light source work.
Compared with prior art, technical solution of the present invention has the advantage that
By be arranged one end and first rectifier bridge high-voltage end and the second rectifier bridge high-voltage end coupling, the other end with
The cathode of second filter capacitor, one end of the second switch and the LED light source cathode coupling first switch and
The cathode of the cathode of one end and second filter capacitor, the other end of the first switch and the LED light source couples, another
Couple with the other end of the low-pressure end of first rectifier bridge, the low-pressure end of the second rectifier bridge, the switching tube second is held to open
Close, when detecting that the driving circuit of the LED light source is powered by the electric ballast, as control unit control described in open
It closes pipe and first switch is in an off state, the second switch is in closed state, formation passes through the energy storage inductor, afterflow
The current loop of diode, the LED light source and the second filter capacitor one of both and the second switch, can keep away
Exempt from LED light source underpower when electric ballast power supply, reduce the pressure resistance of switching tube and the cost of LED light source device, improves LED light
The reliability of source device avoids the constraint to the voltage of LED light source, improves the scope of application of LED light source driving circuit, so that
The design of LED light source is more flexible.
Further, when control unit detects the power supply of the driving circuit of LED light source by the AC industrial frequency AC, control
Make the second switch is in an off state and the first switch is in closed state, to control the driving of the LED light source
Circuit is in buck-boost mode, can be according to the operating mode of input condition difference switching circuit, and reduces the resistance to of switching tube
The cost of pressure and LED light source device, improves the reliability of LED light source device, avoids the constraint to the voltage of LED light source, improves
The scope of application of LED light source driving circuit, so that the design of LED light source is more flexible.
Further, by the way that the anode of one end and the first diode and the output end coupling of the electric ballast is arranged
It connects, the third of the output end coupling of the anode and the electric ballast of the other end and second diode switchs, and is examining
When measuring the voltage of the LED light source more than preset voltage threshold the third is switched, is in closed state, can keep away
Exempt from the overtension on the driving circuit and LED light source of LED light source, so as to form open-circuit-protection to LED light source device.
Detailed description of the invention
Fig. 1 is a kind of structural schematic diagram of LED light source driving circuit in the prior art；
Fig. 2 is the structural schematic diagram of another LED light source driving circuit in the prior art；
Fig. 3 is the structural schematic diagram of one of embodiment of the present invention LED light source driving circuit；
Fig. 4 is the structural schematic diagram of another LED light source driving circuit in the embodiment of the present invention.
Specific embodiment
Light emitting diode (Light Emitting Diode, LED) illumination is excellent because of bloom efficiency, long-life and low cost etc.
Point is usually used by people to replace the fluorescent lamp as conventional light source.
LED light source is divided into three types currently on the market, and one is the LED light sources of compatible electronic ballast, directly by electricity
Sub-ballast output end takes electricity, directly replaces original conventional fluorescent, and Unite States Standard is known as Type A class；One is handed over by power frequency
The LED light source of galvanic electricity power supply, Unite States Standard are known as Type B class；There are also one is the LED for needing external LED light source driver
Light source, Unite States Standard are known as Type C class.Three kinds of light sources can not be replaced mutually because input is different.Wherein Type A and
The replacement of Type B class is simple, and easy to use, market acceptance is relatively high.This has just expedited the emergence of compatible electronic ballast and power frequency simultaneously
Exchange the market demand of the LED light source of input, that is, the LED light source for needing Type A and Type B to combine, to make LED
The scope of application of light source is more extensive.
There are three types of the driving circuit canonical topologies of LED light source, be respectively decompression (Buck), buck (Buck-boost) and
Flyback (Flyback).The switching tube pressure resistance of wherein buck route and flyback route, selection needs to be higher by direct current after rectifier bridge
There are many pressure.And there are high pressures and unstable for the DC voltage after electric ballast output rectification, according to buck and flyback line
Road, switching tube just need to select the device of very high voltage, are difficult selection and at high cost.So for compatible electronic ballast
LED light source, circuit topology are typically only capable to select decompression (Buck) scheme.This means that while compatible electronic ballast and work
The LED light source driving of frequency exchange, majority are also to select decompression scheme.Simultaneously under industrial frequency AC input condition, in order to meet function
The standard of rate factor and harmonic wave, the load voltage of LED light source again cannot be too high, so, compatible electronic ballast and industrial frequency AC
LED light source driving mostly select the lower decompression scheme of load voltage.
Fig. 1 shows a kind of structure chart of LED light source driving circuit using decompression scheme in the prior art, such as Fig. 1
Shown, when the driving circuit includes: diode D1, D2, D3 and D4 composition correspondence electric ballast power supply rectifier bridge 11, two
Pole pipe D2, D4, D5 and D6 constitute the rectifier bridge 12 when the power supply of corresponding A C industrial frequency AC, suitable for what is be filtered to rectified current
Filter capacitor C1, switching tube Q1, suitable for control switch pipe Q1 on-off Buck control and driving unit 14, diode D7, storage
Can inductance L1, the filter capacitor C2 and LED light source 13 in parallel with LED light source, in which: the both ends of the filter capacitor C1 respectively with
The coupling of the both ends of above-described rectifier bridge 11 and rectifier bridge 12, one end coupling of the cathode of diode D7 and the filter capacitor C1
It connects, one end of one end and switching tube Q1 of the anode of diode D7 and the energy storage inductor L1 couples；One end of energy storage inductor L1
One end of the switching tube Q1 and the anode of the diode D7 are coupled, the other end of energy storage inductor L1 couples the filter capacitor
The cathode of C2 and the cathode of LED light source 13；The anode of the filter capacitor C2 couples the cathode and the LED of the diode D7
The anode of light source 13.
With reference to Fig. 1 it is found that decompression scheme although AC industrial frequency AC input under reliable operation, stabilization, due to decompression side
Case is limited by load voltage, and power factor (PF) and harmonic wave are difficult to be made fine.In order to pursue higher power factor and lower
Harmonic wave, load voltage can also select lower.By taking 18W LED lamp tube as an example, decompression route is selected, LED load about 60V, electric current are about
300mA.When being powered with industrial frequency AC, power can achieve 18W.And the output current scope of many electric ballasts on the market
In 120-250mA, therefore, when being powered with electric ballast, the actual power of fluorescent tube only has 7.2W~15W, and power is obviously not
It is enough.Such fluorescent tube connects behind the electric ballast of low output, it will underpower, luminous flux is insufficient, is unable to satisfy client's
Use demand.
Also, even if using decompression scheme, before being depressured line work, the output electric current of electric ballast can not flow
LED load is crossed, this energy will accumulate on the capacitor after rectifier bridge, high generally for guaranteeing when industrial frequency AC is powered
Power factor (PF), the capacitance after rectifier bridge can select very little, this results in when electric ballast is powered capacitor after rectifier bridge
On voltage can overshoot it is very high, to decompression route in switching tube bring very big voltage stress, if switching tube pressure resistance not enough,
It often will cause switching tube excessive pressure damages, influence the reliability of LED light source driving.
In order to avoid the LED light source driving that compatible electronic ballast and industrial frequency AC input is owed in electric ballast power supply
The problem of power is preferably to select using buck scheme, and Fig. 2 shows in the prior art a kind of using buck scheme
LED light source driving circuit structure chart, with Fig. 1 the difference is that, the position of the energy storage inductor L1 and diode D7's
Position is exchanged, and LED light source 23 is contrary with LED light source 13, and PWM control and driving unit 24 replace Buck to control
And driving unit 14, the positive and negative anodes of filter C2 are exchanged.
With reference to Fig. 2 as it can be seen that due to when electric ballast is powered, there are high pressure after rectifier bridge, opening in buck route
It closes pipe and needs very high pressure resistance, implementing cost can be very high.
To solve the above problems, being opened the embodiment of the invention provides LED light source driving circuit by first switch and second
Close, when detecting that the driving circuit of the LED light source is powered by the electric ballast, as control unit control described in open
It closes pipe and first switch is in an off state, the second switch is in closed state, formation passes through the energy storage inductor, afterflow
The current loop of diode, the LED light source and the second filter capacitor one of both and the second switch, can keep away
Exempt from LED light source underpower when electric ballast power supply, reduce the pressure resistance of switching tube and the cost of LED light source device, improves LED light
The reliability of source device avoids the constraint to the voltage of LED light source, improves the scope of application of LED light source driving circuit, so that
The design of LED light source is more flexible.
To make the above purposes, features and advantages of the invention more obvious and understandable, with reference to the accompanying drawing to the present invention
Specific embodiment be described in detail.
Fig. 3 shows the structural schematic diagram of the driving circuit of one of embodiment of the present invention LED light source, participates in Fig. 3 institute
Show, the driving circuit may include: the first rectifier bridge 31, the second rectifier bridge 32, the first filter capacitor C1, buck route
33, first switch SW1, second switch SW2 and control unit 34, in which:
First rectifier bridge 31, suitable for rectifying the power supply from electric ballast；
Second rectifier bridge 32, suitable for rectifying the power supply from AC industrial frequency AC；
The first filter capacitor C1 is respectively coupled to first rectifier bridge 31 and second rectifier bridge 32, is suitable for
Rectification is filtered to the electric current from first rectifier bridge 31 and the second rectifier bridge 32；
The buck route 33 suitable for receiving the electric current from the first filter capacitor C1, and constructs the LED light
The current loop in source 35, comprising: energy storage inductor L1, the second filter capacitor C2, sustained diode 7, PWM control and driving unit
36 and switching tube Q1, in which:
The high pressure of one end of the energy storage inductor L1 and one end of the first filter capacitor C1, first rectifier bridge 31
One end coupling at end, the high-voltage end of second rectifier bridge 32, the first switch SW1, the other end of the energy storage inductor L1
It is coupled respectively with the anode of one end of the switching tube Q1 and the sustained diode 7；
One end of the anode of the sustained diode 7 and the switching tube Q1 couple, the cathode of the sustained diode 7
It is coupled respectively with the anode of the positive and described LED light source 35 of the second filter capacitor C2；
The first switch SW1, one end and the high-voltage end of first rectifier bridge 31 and the high-voltage end of the second rectifier bridge 32
Coupling, the other end of the first switch SW1 and the cathode of the second filter capacitor C2, one end of the second switch SW2
And the cathode coupling of the LED light source 35；
The cathode of the second switch SW2, one end and the second filter capacitor C2, the first switch SW1 it is another
The coupling of the cathode of end and the LED light source 35, the low pressure of the other end of the second switch SW2 and first rectifier bridge 31
The other end coupling at end, the low-pressure end of the second rectifier bridge 32, the switching tube Q1；
Described control unit 34, output end, the buck route 33, the first switch with the electric ballast
SW1 and the second switch SW2 are respectively coupled to, suitable for passing through the electronics when the driving circuit for detecting the LED light source 35
Ballast power when, control the switching tube Q1 and first switch SW1 be in an off state, the second switch SW2 be in close
Conjunction state, formation pass through the energy storage inductor L1, sustained diode 7, the LED light source 35 and the second filter capacitor C2
The current loop of one of both and the second switch SW2.
It should be noted that the first switch SW1 and second switch SW2 are the electronics that can be at two states of on-off
Device, their concrete form can be diode, or triode, or metal-oxide-semiconductor, or it is silicon-controlled,
It can also be that relay class switchs.Those skilled in the art can select suitable electronic device as according to actual needs
One switch SW1 and second switch SW2.The specific structure of first switch SW1 and second switch SW2 is not to protection model of the invention
Enclose composition any restrictions.
In summary it is found that passing through setting one end and the high-voltage end of first rectifier bridge and the high-voltage end of the second rectifier bridge
Coupling, the other end are negative with the cathode of the second filter capacitor C2, one end of the second switch SW2 and the LED light source
The cathode of the first switch SW1 of pole coupling and one end and the second filter capacitor C2, the first switch SW1 the other end and
The cathode of the LED light source couples, the low-pressure end, described of the low-pressure end of the other end and first rectifier bridge, the second rectifier bridge
The second switch SW2 of the other end coupling of switching tube Q1, when the driving circuit for detecting the LED light source passes through the electronics town
Flow device power supply when, by control unit control the switching tube Q1 and first switch SW1 be in an off state, the second switch
SW2 is in closed state, is formed through the energy storage inductor L1, sustained diode 7, the LED light source and second filtering
The current loop of capacitor C2 one of both and the second switch SW2 can be owed to avoid LED light source when electric ballast power supply
Power reduces the pressure resistance of switching tube Q1 and the cost of LED light source device, improves the reliability of LED light source device, avoid to LED
The constraint of the voltage of light source improves the scope of application of LED light source driving circuit, so that the design of LED light source is more flexible.
In order to adapt to different power supply sources, that is, make under different power supply sources, can meet on switching tube Q1
Voltage is low and the high-power condition of LED light source 35, in an embodiment of the present invention, described control unit 34, also with the AC
The input terminal of industrial frequency AC couples, suitable for passing through the AC industrial frequency AC when the driving circuit for detecting the LED light source 35
When power supply, control that the second switch SW2 is in an off state and the first switch SW1 is in closed state, to control
The driving circuit for stating LED light source is in buck-boost mode.Thus, it is possible to reduce the pressure resistance and LED light source device of switching tube Q1
Cost improves the reliability of LED light source device, avoids the constraint of the voltage to LED light source 35, improves LED light source 35 and drives electricity
The scope of application on road, so that the design of LED light source 35 is more flexible.
It is understood that since described control unit 34 can be controlled separately first switch SW1 and second switch SW2,
Therefore described control unit 34 can include only a control subelement, i.e., one control subelement both can control described
First switch SW1, and can control the second switch SW2；It also may include two independent control subelements, in other words,
Described control unit 34 may include the first control subelement and the second control subelement, and the first control subelement is suitable for control
The on-off of the first switch SW1 is made, the second control subelement can control the on-off of the second switch SW2.Ability
Can the quantity that subelement is controlled included by described control unit 34, the control be arranged according to actual needs in field technique personnel
Subunit it is how much specific amount of, not to protection scope of the present invention constitute any restrictions.
In specific implementation, first rectifier bridge 31 may include: first diode D1, the second diode D2, third
Diode D3 and the 4th diode D4；The output end of the electric ballast is input to anode and the institute of the first diode D1
State the anode of the second diode D2；The cathode of the cathode of the first diode D1 and the second diode D2 couple, described
The cathode of the anode of first diode D1 and the third diode D3 couple；
The cathode of the second diode D2 and the cathode of the first diode D1 couple, the second diode D2's
The cathode of anode and the 4th diode D4 couple；
The cathode of the third diode D3 and the cathode of the first diode D1 couple, the second diode D2's
The anode of anode and the 4th diode D4 couple；
The anode of the cathode of the 4th diode D4 and the second diode D2 couple, the 4th diode D4's
The anode of anode and the third diode D3 couple.
In order to avoid the overtension on the driving circuit and LED light source 35 of LED light source, in an embodiment of the present invention,
The driving circuit further includes third switch SW3, the anode and institute of described one end third switch SW3 and the first diode D1
State the output end coupling of electric ballast, the anode and institute of the other end of the third switch SW3 and the second diode D2
State electric ballast output end coupling, suitable for when detect the LED light source 35 voltage be more than preset voltage threshold when,
In closed state.It is possible thereby to form the open-circuit-protection to LED light source device.Similarly, in specific implementation, third switchs
SW3 may include but be not limited to triode, metal-oxide-semiconductor, silicon-controlled, discharge tube, varistor, transient state suppressive diode,
Triggering pipe and relay class switch etc., the concrete form of the third switch SW3 will not be constituted protection scope of the present invention
Any restrictions.
In specific implementation, second rectifier bridge 32, comprising: the second diode D2, the 4th diode D4,
5th diode D5 and the 6th diode D6；
The cathode of the second diode D2 and the cathode of the 5th diode D5 couple, the second diode D2's
The cathode of anode and the 4th diode D4 couple；
The anode of the cathode of the 4th diode D4 and the second diode D2 couple, the 4th diode D4's
The anode of anode and the 6th diode D6 couple；
The cathode of the cathode of the 5th diode D5 and the second diode D2 couple, the 5th diode D5's
The cathode of anode and the 6th diode D6 couple；
The cathode of the 6th diode D6 and the anode of the 5th diode D5 couple, the 6th diode D6's
The anode of anode and the 4th diode D4 couple；
The input terminal of the AC industrial frequency AC is input to the anode and the 5th diode D5 of the second diode D2
Anode；
One end of the first filter capacitor C1 and the first diode D1, the second diode D2 and the 5th diode D5
Cathode coupling, the other end of the first filter capacitor C1 respectively with the third diode D3, the 4th diode D4, the 6th
The anode of diode D6 couples.
In an embodiment of the present invention, the first switch SW1 is diode.
In an embodiment of the present invention, the second switch SW2 is metal-oxide-semiconductor.
In an embodiment of the present invention, described control unit 34 include: third capacitor, zener diode, the 7th diode,
Second resistance and the 4th capacitor, in which: third capacitor one end couples the output end of the electric ballast, the third electricity
The other end of appearance couples the anode of the 7th diode and the cathode of the zener diode；The anode of the zener diode
It couples the other end of the switching tube Q1 and the PWM is controlled and driving unit 36；The cathode of 7th diode couples institute
State one end of second switch SW2, one end of the 4th capacitor and the second resistance；Described in the other end coupling of the second resistance
The other end of 4th capacitor, the other end of the switching tube Q1, PWM control and driving unit 36 and the zener diode
Anode；Described 4th capacitor one end couples the second switch SW2, the cathode of the 7th diode and the second resistance
One end, the other end of the 4th capacitor couple the other end of the switching tube Q1, the PWM control and driving unit 36,
The anode of the second switch SW2, the other end of the second resistance and the zener diode.
To more fully understand those skilled in the art and realizing the present invention, it has been illustrated below another in implementation of the present invention
A kind of structural schematic diagram of the driving circuit of LED light source, as shown in figure 4, the first rectifier bridge 41, which is suitable for rectification, comes from electronic ballast
The power supply of device, the second rectifier bridge 42 are suitable for power supply of the rectification from AC industrial frequency AC, and the first switch is diode D8, described
Second switch is metal-oxide-semiconductor Q2, third switch is varistor VD1, described control unit includes: third capacitor C3, pressure stabilizing
Diode Z1, the 7th diode D9, second resistance R2 and the 4th capacitor CS1.Resistance R1 belongs to PWM control and driving unit 45
A part, is suitable for PWM control and driving unit 45 provides electrifying startup electric current.Below by taking Fig. 4 as an example, to LED light source 44
The working principle of driving circuit is illustrated.
Described control unit, suitable for judging the mode of input, and in turn according to mode decision as a result, to control buck
PWM control and driving unit 45 in route 43.Wherein, the mode of the judgement input, is the driving for judging LED light source 44
The power supply source of circuit power supply.
When detecting electric ballast is the drive circuitry of LED light source 44, described control unit is powered on, with driving
Second switch Q2 conducting, the output of electric ballast is by first diode D1, the second diode D2, third diode D3 and the
After four diode D4 rectification, at DC voltage after the first filter capacitor C1 filtering, due to PWM control at this time and driving unit 45
Vcc power supply by second switch Q2 shorted to earth, PWM control and driving unit 45 do not work, and then switching tube Q1 is caused to turn off,
And diode D8 is reversely by obstructed, that is, first switch D8 is in an off state, then electric current is through energy storage inductor L1, afterflow
Diode D7, LED light source 44 and the second filter capacitor C2 in parallel with the LED light source 44 and second switch Q2 forming circuit,
LED light source 44 is lit work.Since the capacity of the second filter capacitor C2 is very big, after the voltage of LED light source 44 is with rectification
Voltage slowly rises, and does not have high pressure on the first filter capacitor C1 when starting, also there will be no high pressure stress by switching tube Q1.?
LED light source 44 is lit after work, and second switch Q2 and sustained diode 7 are constantly on state, the electricity of switching tube Q1
Voltage and the sum of voltage in sustained diode 7 that pressure is equal to LED light source 44, rather than the first filter capacitor C1 before and
The sum of the voltage of both energy storage inductor L1, therefore after LED light source 44 is lit work, also without high pressure stress on switching tube Q1.
When detecting with the drive circuitry that AC industrial frequency AC is LED light source 44, control unit is not powered on, control
PWM control and driving unit 45 power on, with driving switch pipe Q1 work in PWM switch state, due to first diode D1 at this time
And there is no voltage between third diode D3, and control unit does not have electric current, second switch Q2 is constantly in off state.Therefore work as
When switching tube Q1 is opened, energy storage inductor L1 charging, when switching tube Q1 shutdown, energy storage inductor L1 is through sustained diode 7, LED light
Source 44 and the second filter capacitor C2 one of both, first switch D8 electric discharge, light work for LED light source 44, in other words, whole at this time
A circuit work is under buck-boost mode.
In summary it is found that the present invention detects the input condition of power supply source by control unit, and according to input condition
Difference carrys out the operating mode of switching circuit, therefore can be with the input of compatible electronic ballast and the input of AC industrial frequency AC.It solves simultaneously
Switching tube needs high tension apparatus and in electric ballast power supply the problem of underpower in existing scheme, so that circuit is reliable
Property is higher.And load voltage is unfettered, and the scope of application of entire circuit is wider, designs LED light source 44 more flexible.
Also, the electricity being approximately equal on LED light source 44 due to the voltage being set on the first filter capacitor C1 after rectifier bridge
Pressure, therefore the voltage of third switch VD1 is the sum of the pressure drop of voltage and two diodes on the first filter capacitor C1.Work as LED light source
When 44 normal work, the voltage of third switch VD1 is not high, and VD1 is in an off state；When LED light source 44 is opened a way, first
Voltage on filter capacitor C1 can increase, and the voltage on third switch VD1 also can be increased correspondingly, when the electricity of third switch VD1
For pressure when being increased to the turning-on voltage of third switch VD1, VD1 can be in the conductive state, so as to will be on the first filter capacitor C1
Voltage control in the voltage range that third switch VD1 is set, so as to protect subsequent other components not by high crushing
It is bad.
It is understood that described control unit can be by detecting whether power supply source powers on to the judgement of the mode of input
To realize.Also, the difference of selected device is switched according to first and second, correspondingly, the structure of described control unit has
It is distinguished.Described control unit can realize the control of the state to first and second switch by a variety of methods, such as can
With by itself, above electric control first switch is in an off state and second switch is in closed state；It is not powered on by itself,
And control PWM control and driving unit power on, to realize that the first switch is in closed state and the second switch is in
Off-state.For example the control of the state to first and second switch can also be realized by enable signal.The control is single
Member is not construed as limiting the control method of first and second state switched to protection scope of the present invention.
In specific implementation, a kind of LED light source device is additionally provided in the embodiment of the present invention, the LED light source device can
To include: the driving circuit and LED light source of above-described any LED light source, the driving circuit of the LED light source, with institute
LED light source coupling is stated, is suitable for driving the LED light source work.
Although present disclosure is as above, present invention is not limited to this.Anyone skilled in the art are not departing from this
It in the spirit and scope of invention, can make various changes or modifications, therefore protection scope of the present invention should be with claim institute
Subject to the range of restriction.
Claims (8)
1. a kind of driving circuit of LED light source characterized by comprising the first rectifier bridge, the second rectifier bridge, the first filtered electrical
Appearance, buck route, first switch, second switch and control unit, in which:
First rectifier bridge, suitable for rectifying the power supply from electric ballast；
Second rectifier bridge, suitable for rectifying the power supply from AC industrial frequency AC；
First filter capacitor is respectively coupled to first rectifier bridge and second rectifier bridge, is suitable for from described
The electric current of first rectifier bridge and the second rectifier bridge is filtered rectification；
The buck route suitable for receiving the electric current from first filter capacitor, and constructs the electric current of the LED light source
Circuit, and include: energy storage inductor, the second filter capacitor, freewheeling diode, PWM control and driving unit and switching tube；The storage
Can inductance one end and one end of first filter capacitor, the high-voltage end of first rectifier bridge, second rectifier bridge
High-voltage end, the first switch one end coupling, the other end of the energy storage inductor respectively with one end of the switching tube and institute
State the anode coupling of freewheeling diode；
One end of the anode of the freewheeling diode and the switching tube couples, the cathode of the freewheeling diode respectively with it is described
The anode coupling of the positive and described LED light source of second filter capacitor；
The first switch, the high-voltage end of one end and first rectifier bridge and the high-voltage end of the second rectifier bridge couple, and described the
The other end of one switch and cathode, one end of the second switch and the cathode of the LED light source of second filter capacitor
Coupling；
The cathode of the second switch, one end and second filter capacitor, the other end of the first switch and the LED light
The cathode in source couples, the low-pressure end of the other end of the second switch and first rectifier bridge, the second rectifier bridge low-pressure end,
The other end of the switching tube couples；
Described control unit, output end, the buck route, the first switch and described with the electric ballast
Two switches are respectively coupled to, suitable for controlling when the driving circuit for detecting the LED light source is powered by the electric ballast
The switching tube and first switch are in an off state, the second switch is in closed state, are formed through the energy storage electricity
Sense, freewheeling diode, the LED light source and the second filter capacitor one of both and the second switch current loop.
2. the driving circuit of LED light source according to claim 1, which is characterized in that described control unit, also with the AC
The input terminal of industrial frequency AC couples, suitable for being powered when the driving circuit for detecting the LED light source by the AC industrial frequency AC
When, control that the second switch is in an off state and the first switch is in closed state, to control the LED light source
Driving circuit is in buck-boost mode.
3. the driving circuit of LED light source according to claim 1, which is characterized in that first rectifier bridge, comprising: the
One diode, the second diode, third diode and the 4th diode, in which:
The output end of the electric ballast is input to the anode of the first diode and the anode of second diode；Institute
The cathode of the cathode and second diode of stating first diode couples, the anode of the first diode and the described 3rd 2
The cathode of pole pipe couples；
The cathode of second diode and the cathode of the first diode couple, the anode of second diode with it is described
The cathode of 4th diode couples；
The cathode of the third diode and the cathode of the first diode couple, the anode of the third diode with it is described
The anode of 4th diode couples；
The anode of the cathode of 4th diode and second diode couples, the anode of the 4th diode with it is described
The anode of third diode couples.
4. the driving circuit of LED light source according to claim 3, which is characterized in that further include: third switch, described the
The output end of the anode and the electric ballast of three switch one end and the first diode couples, and the third switchs another
The output end of the anode and the electric ballast of one end and second diode couples, and detects the LED light suitable for working as
When the voltage in source is more than preset voltage threshold, it is in closed state.
5. the driving circuit of LED light source according to claim 1, which is characterized in that the first switch is diode.
6. the driving circuit of LED light source according to claim 1, which is characterized in that the second switch is metal-oxide-semiconductor.
7. the driving circuit of LED light source according to claim 1, which is characterized in that described control unit, comprising: third
Capacitor, zener diode, the 7th diode, second resistance and the 4th capacitor, in which:
Third capacitor one end couples the output end of the electric ballast, the other end coupling of the third capacitor described the
The cathode of the anode of seven diodes and the zener diode；
The anode of the zener diode couples the other end of the switching tube and the PWM is controlled and driving unit；Described
The cathode of seven diodes couples one end of the second switch, one end of the 4th capacitor and the second resistance；
The other end of the second resistance couples the other end of the 4th capacitor, the other end of the switching tube, PWM control
The anode of system and driving unit and the zener diode；Described 4th capacitor one end couples the second switch, the described 7th
One end of the cathode of diode and the second resistance, the other end of the 4th capacitor couple the other end of the switching tube,
PWM control and driving unit, the second switch, the other end of the second resistance and the zener diode sun
Pole.
8. a kind of LED light source device characterized by comprising the driving electricity of the described in any item LED light sources of claim 1~7
Road and LED light source；The driving circuit of the LED light source is coupled with the LED light source, is suitable for driving the LED light source work.
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| CN201610574995.1A CN107635302B (en) | 2016-07-19 | 2016-07-19 | A kind of LED light source driving circuit and LED light source device |
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| CN201610574995.1A CN107635302B (en) | 2016-07-19 | 2016-07-19 | A kind of LED light source driving circuit and LED light source device |
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| CN107635302B true CN107635302B (en) | 2019-03-12 |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104168696A (en) * | 2014-07-31 | 2014-11-26 | 罗吉国 | Compatible LED power supply circuit |
| CN105704867A (en) * | 2016-04-26 | 2016-06-22 | 杰华特微电子（杭州）有限公司 | Voltage control circuit, light emitting diode (LED) driving circuit and control method of LED driving circuit |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI523580B (en) * | 2013-02-22 | 2016-02-21 | Compatible with LED ballast with electronic ballast with preheat current | |
| US9338853B2 (en) * | 2014-09-17 | 2016-05-10 | Greco Tech Industries Inc. | LED tube driver circuitry for ballast and non-ballast fluorescent tube replacement |
-
2016
- 2016-07-19 CN CN201610574995.1A patent/CN107635302B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104168696A (en) * | 2014-07-31 | 2014-11-26 | 罗吉国 | Compatible LED power supply circuit |
| CN105704867A (en) * | 2016-04-26 | 2016-06-22 | 杰华特微电子（杭州）有限公司 | Voltage control circuit, light emitting diode (LED) driving circuit and control method of LED driving circuit |
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| CN107635302A (en) | 2018-01-26 |
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