CN106787854A - A kind of LED drive circuit - Google Patents
A kind of LED drive circuit Download PDFInfo
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- CN106787854A CN106787854A CN201710117982.6A CN201710117982A CN106787854A CN 106787854 A CN106787854 A CN 106787854A CN 201710117982 A CN201710117982 A CN 201710117982A CN 106787854 A CN106787854 A CN 106787854A
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- 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
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of ac power input into dc power output without possibility of reversal 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
- H02M7/217—Conversion of ac power input into dc power output without possibility of reversal 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
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Abstract
The invention provides a kind of LED drive circuit, LED drive circuit includes：High-frequency pulse current source, isolating transformer and secondary side rectification circuit；The isolating transformer includes：First winding, the second winding；And the high-frequency pulse current source is connected with first winding；The secondary side rectification circuit includes：First load circuit and the second load circuit of alternate conduction, the first drive control circuit, the second drive control circuit, the first electric capacity and the first diode；First load circuit includes the first synchronous rectifier, and second load circuit includes the second synchronous rectifier；First synchronous rectifier and the second synchronous rectifier alternate conduction；DC power supply, for the first drive control circuit is powered, and is powered by first electric capacity and the first diode directly to the second drive control circuit.The LED drive circuit can solve the problems, such as that the big drive control circuit that can solve synchronous rectifier again of on-state loss is powered.
Description
Technical field
The present invention relates to LED drive circuit technical field, more specifically to a kind of LED drive circuit.
Background technology
Common is the Switching Power Supply of DC load driving, including：High-frequency pulse current source, isolating transformer and setting
In the rectification circuit of isolating transformer secondary.Wherein, high-frequency pulse current source is by HF switch control；The electricity of secondary side rectification circuit
Road form is the circuit forms such as full bridge rectifier or voltage doubling rectifing circuit.
In the prior art, secondary side rectification circuit is to use diode as rectifying device, but due to diode
Conduction voltage drop is very high, in the case where output current is larger, causes the on-state loss of diode very big, and then makes Switching Power Supply
The efficiency of circuit is very low.
Solve the problems, such as that on-state loss is big as rectifying device by introducing synchronous rectifier, but synchronous rectifier
Need of work drive control circuit, and drive control circuit due to the difference of reference edge causes that same direct current supply can not be used
Power supply is powered.
So, how providing a kind of on-state loss that can solve can solve all drive control circuit powerup issues again greatly
Drive circuit, is those skilled in the art's problem demanding prompt solution.
The content of the invention
To solve the above problems, the invention provides a kind of LED drive circuit, solve because diode is used as rectifying device
The big problem of the on-state loss that causes, and solve the powerup issue of different drive control circuits.
To achieve the above object, the present invention provides following technical scheme：
A kind of LED drive circuit, including：High-frequency pulse current source, isolating transformer, secondary side rectification circuit；
Wherein, the isolating transformer includes：First winding and the second winding；The high-frequency pulse current source and described
One winding is connected；
The secondary side rectification circuit includes：First load circuit and the second load circuit of alternation；Described first is negative
Carrying loop includes the first synchronous rectifier, and second load circuit includes the second synchronous rectifier；First synchronous rectification
Pipe and the second synchronous rectifier alternate conduction；The secondary side rectification circuit is also included for driving first synchronous rectification
First drive control circuit of pipe, the second drive control circuit for driving second synchronous rectifier, the first electric capacity and
First diode；
The source electrode of first synchronous rectifier is connected with the first end of second winding, is loaded back as described first
The input on road；The drain electrode of first synchronous rectifier is output plus terminal；The output end of first load circuit is connected to
Second end of second winding；
The input of second load circuit connects the second end of second winding, second synchronous rectifier
The first end of drain electrode connection second winding, as the output end of second load circuit；Second synchronous rectifier
Source electrode for output ground terminal；
The reference edge of the first drive control circuit connects the source electrode of first synchronous rectifier；
The reference edge of the second drive control circuit connects the source electrode of second synchronous rectifier；Described second drives
The feeder ear connection DC power supply of circuit is controlled, the earth terminal of the DC power supply is second drive control electricity
The reference edge on road；
The anode of first diode connects the DC power supply, the negative electrode connection first of first diode
The feeder ear of drive control circuit；One end of first electric capacity connects the feeder ear of the first drive control circuit, described
The other end of the first electric capacity connects the reference edge of the first drive control circuit.
Preferably, in above-mentioned LED drive circuit, the first drive control circuit includes：First processing units and
One detection unit；First detection unit is in parallel with first synchronous rectifier, for detecting first synchronous rectification
The source-drain voltage of pipe, and testing result is sent to the first processing units；
The first processing units are used to produce drive signal according to the testing result；And send the drive signal
To the grid of first synchronous rectifier；
The second drive control circuit includes：Second processing unit and the second detection unit；
Second detection unit is in parallel with second synchronous rectifier, for detecting second synchronous rectifier
Source-drain voltage, and testing result is sent to the second processing unit；
The second processing unit is used to produce drive signal according to the testing result；And send the drive signal
To the grid of second synchronous rectifier.
Preferably, in above-mentioned LED drive circuit, when first detection unit detects first synchronous rectifier
Source-drain voltage when being forward conduction voltage, first processing units generation first turns on drive signal；When the described first inspection
It is zero or during for reverse pressure drop to survey unit and detect the source-drain voltage forward voltage drop of first synchronous rectifier, at described first
Reason unit generation first turns off drive signal；
When the source-drain voltage that second detection unit detects second synchronous rectifier is forward conduction voltage,
The second processing unit generation second turns on drive signal；When second detection unit detects second synchronous rectification
The source-drain voltage forward voltage drop of pipe is zero or during for reverse pressure drop, and the second processing unit generation second turns off drive signal.
Preferably, in above-mentioned LED drive circuit, first load circuit also includes the 3rd electric capacity, and described second is negative
Carrying loop also includes the second electric capacity；
In first load circuit, one end of the 3rd electric capacity is the output end of first load circuit, connection
Second end of second winding；The other end of the 3rd electric capacity connects the output ground terminal；
In second load circuit, one end of second electric capacity is the input of second load circuit, connection
Second end of second winding；The other end of second electric capacity connects the output plus terminal.
Preferably, in above-mentioned LED drive circuit, first load circuit also includes the 4th synchronous rectifier, described
Second load circuit also includes the 3rd synchronous rectifier；
The secondary side rectification circuit also includes the 4th drive control circuit, the use for driving the 4th synchronous rectifier
In the 3rd drive control circuit, the second diode and the 4th electric capacity that drive the 3rd synchronous rectifier；Wherein, described first
The synchronously conducting of synchronous rectifier and the 4th synchronous rectifier, second synchronous rectifier and the 3rd synchronous rectifier
Synchronous conducting；
In first load circuit, the drain electrode of the 4th synchronous rectifier is the output of first load circuit
End, connects the second end of second winding, and the source electrode of the 4th synchronous rectifier connects the output ground terminal；
In second load circuit, the source electrode of the 3rd synchronous rectifier is the input of second load circuit
End, connects the second end of second winding, and the drain electrode of the 3rd synchronous rectifier connects the output plus terminal；
The reference edge of the 3rd drive control circuit connects the source electrode of the 3rd synchronous rectifier；Described 3rd drives
The output end of circuit is controlled to be connected with the grid of the 3rd synchronous rectifier；The anode connection of second diode is described straight
Stream power supply, the negative electrode of second diode connects the feeder ear of the 3rd drive control circuit；4th electric capacity
One end connect the feeder ear of the 3rd drive control circuit；The other end connection the described 3rd of the 4th electric capacity drives control
The reference edge of circuit processed；
The reference edge of the 4th drive control circuit connects the source electrode of the 4th synchronous rectifier；Described 4th drives
The output end of circuit is controlled to be connected with the grid of the 4th synchronous rectifier；The feeder ear of the 4th drive control circuit connects
Connect the DC power supply.
Preferably, in above-mentioned LED drive circuit, the 3rd drive control circuit includes：3rd processing unit and
Three detection units；
3rd detection unit is in parallel with the 3rd synchronous rectifier, for detecting the 3rd synchronous rectifier
Source-drain voltage, and testing result is sent to the 3rd processing unit；
3rd processing unit is used to produce drive signal according to the testing result, and the drive signal is sent
To the grid of the 3rd synchronous rectifier；
The 4th drive control circuit includes：Fourth processing unit and the 4th detection unit；
4th detection unit is in parallel with the 4th synchronous rectifier, for detecting the 4th synchronous rectifier
Source-drain voltage, and testing result is sent to the fourth processing unit；
The fourth processing unit is used to produce drive signal according to the testing result, and the drive signal is sent
To the grid of the 4th synchronous rectifier；
Wherein, when the source-drain voltage that the 3rd detection unit detects the 3rd synchronous rectifier is forward conduction electricity
During pressure, the 3rd processing unit generation the 3rd turns on drive signal；When the 3rd detection unit, to detect the described 3rd same
The source-drain voltage forward voltage drop for walking rectifying tube is zero or during for reverse pressure drop, and the shut-off of the 3rd processing unit generation the 3rd drives
Signal；
When the source-drain voltage that the 4th detection unit detects the 4th synchronous rectifier is forward conduction voltage,
The fourth processing unit generation the 4th turns on drive signal；When the 4th detection unit detects the 4th synchronous rectification
The source-drain voltage forward voltage drop of pipe is zero or during for reverse pressure drop, and the fourth processing unit generation the 4th turns off drive signal.
Preferably, in above-mentioned LED drive circuit, first synchronous rectifier is integrated in the first drive control circuit
In first synchronous rectifier；
First synchronous rectifier includes：Source electrode, drain electrode and feeder ear；The source electrode of first synchronous rectifier is
The source electrode of first synchronous rectifier；The drain electrode of first synchronous rectifier is the leakage of first synchronous rectifier
Pole, the feeder ear of first synchronous rectifier is the feeder ear of the first drive control circuit；
Or second synchronous rectifier is integrated in the second synchronous rectifier with the second drive control circuit；
Second synchronous rectifier includes：Source electrode, drain electrode and feeder ear；The source electrode of second synchronous rectifier is
The source electrode of second synchronous rectifier；The drain electrode of second synchronous rectifier is the leakage of second synchronous rectifier
Pole, the feeder ear of second synchronous rectifier is the feeder ear of the second drive control circuit.
Preferably, in above-mentioned LED drive circuit, the 3rd synchronous rectifier and the 3rd drive control circuit collection
In the synchronous rectifiers of Cheng tri-；
3rd synchronous rectifier includes：Source electrode, drain electrode and feeder ear；The source electrode of the 3rd synchronous rectifier is
The source electrode of the 3rd synchronous rectifier；The drain electrode of the 3rd synchronous rectifier is the leakage of the 3rd synchronous rectifier
Pole, the feeder ear of the 3rd synchronous rectifier is the feeder ear of the 3rd drive control circuit；
Or the 4th synchronous rectifier is integrated in the 4th synchronous rectifier with the 4th drive control circuit；
4th synchronous rectifier includes：Source electrode, drain electrode and feeder ear；The source electrode of the 4th synchronous rectifier is
The source electrode of the 4th synchronous rectifier；The drain electrode of the 4th synchronous rectifier is the leakage of the 4th synchronous rectifier
Pole, the feeder ear of the 4th synchronous rectifier is the feeder ear of the 4th drive control circuit.
Preferably, in above-mentioned LED drive circuit, the DC power supply is the auxiliary source of the LED drive circuit
Circuit, the isolating transformer also includes the tertiary winding, and the input of the auxiliary source circuit is connected with the tertiary winding.
Preferably, in above-mentioned LED drive circuit, the high-frequency pulse current source is that LLC circuit topologies or LCC circuits are opened up
Flutter.
By foregoing description, a kind of LED drive circuit that the present invention is provided, by set the first synchronous rectifier and
Second synchronous rectifier instead of rectification part diode of the prior art, solve caused by diode is as rectification part
The big problem of on-state loss, and the first drive control circuit and the second drive control circuit are used for the first synchronous rectifier of conducting
With the second synchronous rectifier, electric current is flowed to from source electrode and drain, not by the first synchronous rectifier and the second synchronous rectifier
In body diode, and then loss will not be also produced on body diode.
Meanwhile, DC power supply by the first electric capacity and the first diode for the first drive control circuit is powered, it is and straight
It is connected in the second drive control circuit to power, solves the powerup issue of different drive control circuits.
Brief description of the drawings
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
The accompanying drawing to be used needed for having technology description is briefly described, it should be apparent that, drawings in the following description are only this
Inventive embodiment, for those of ordinary skill in the art, on the premise of not paying creative work, can also basis
The accompanying drawing of offer obtains other accompanying drawings.
Fig. 1 Fig. 1 is a kind of structural representation of LED drive circuit of prior art；
Fig. 2 is a kind of structural representation of LED drive circuit provided in an embodiment of the present invention；
Fig. 3 is the structural representation of another LED drive circuit provided in an embodiment of the present invention；
Fig. 4 is the structural representation of another LED drive circuit provided in an embodiment of the present invention；
Fig. 5 is a kind of structural representation of drive control circuit provided in an embodiment of the present invention；
Fig. 6 is a kind of structural representation of synchronous rectifier provided in an embodiment of the present invention；
Fig. 7 is the structural representation of another LED drive circuit provided in an embodiment of the present invention；
Fig. 8 is the structural representation of another LED drive circuit provided in an embodiment of the present invention.
Specific embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete
Site preparation is described, it is clear that described embodiment is only a part of embodiment of the invention, rather than whole embodiments.It is based on
Embodiment in the present invention, it is every other that those of ordinary skill in the art are obtained under the premise of creative work is not made
Embodiment, belongs to the scope of protection of the invention.
It can be seen from background technology, with reference to Fig. 1, Fig. 1 is a kind of structural representation of LED drive circuit of prior art.
In the prior art, secondary side rectification circuit is to use diode as rectifying device, but due to the conduction voltage drop of diode
It is very high, in the case where output current is larger, cause the on-state loss of diode very big, and then make the effect of circuit in Switching Power Supply
Rate is very low.
Solve the problems, such as that on-state loss is big as rectifying device by introducing synchronous rectifier, but synchronous rectifier
Need of work drive control circuit, and drive control circuit due to the difference of reference edge causes that same direct current supply can not be used
Power supply is powered.
So, how providing a kind of on-state loss that can solve can solve all drive control circuit powerup issues again greatly
Drive circuit, is those skilled in the art's problem demanding prompt solution.
In order to solve the above problems, the invention provides a kind of LED drive circuit, the LED drive circuit includes：High frequency
Pulse current source, isolating transformer and secondary side rectification circuit；
Wherein, the isolating transformer includes：First winding and the second winding；And the high-frequency pulse current source with it is described
First winding is connected；
The secondary side rectification circuit includes：First load circuit and the second load circuit of alternation；Described first is negative
Carrying loop includes the first synchronous rectifier, and second load circuit includes the second synchronous rectifier；First synchronous rectification
Pipe and the second synchronous rectifier alternate conduction；The secondary side rectification circuit is also included for driving first synchronous rectification
First drive control circuit of pipe, the second drive control circuit for driving second synchronous rectifier, the first electric capacity and
First diode；
The source electrode of first synchronous rectifier is connected with the first end of second winding, is loaded back as described first
The input on road；The drain electrode of first synchronous rectifier is output plus terminal；The output end of first load circuit is connected to
Second end of second winding；
The input of second load circuit connects the second end of second winding, second synchronous rectifier
The first end of drain electrode connection second winding, as the output end of second load circuit；Second synchronous rectifier
Source electrode for output ground terminal；
The reference edge of the first drive control circuit connects the source electrode of first synchronous rectifier；
The anode of first diode connects the DC power supply, the negative electrode connection first of first diode
The feeder ear of drive control circuit；One end of first electric capacity connects the feeder ear of the first drive control circuit, described
The other end of the first electric capacity connects the reference edge of the first drive control circuit, and first electric capacity is used to be driven for described first
Dynamic control circuit is powered；
The reference edge of the second drive control circuit connects the source electrode of second synchronous rectifier；Described second drives
The feeder ear connection DC power supply of circuit is controlled, the earth terminal of the DC power supply is second drive control electricity
The reference edge on road, and when second synchronous rectifier is turned on, the DC power supply is by first diode
First electric capacity charges.
Wherein, the output plus terminal of the LED drive circuit connects the positive pole of LED load, and output ground terminal GND connections LED bears
The negative pole of load.
It should be noted that the reference edge of the DC power supply in the application is the output ground terminal of LED drive circuit；Together
When, the DC power supply can be outside the dc source, or LED drive circuit of generation in LED drive circuit
The dc source of input, for DC power supply, the application is not limited.
It should be noted that " input " of the load circuit in the application, refers to electric current inflow in load circuit
One end, accordingly, " output end " of the load circuit refers to one end of electric current outflow in load circuit.
By foregoing description, a kind of LED drive circuit that the present invention is provided, by set the first synchronous rectifier and
Second synchronous rectifier instead of rectification part diode of the prior art, solve caused by diode is as rectification part
The big problem of on-state loss, and the first drive control circuit and the second drive control circuit are used for the first synchronous rectifier of conducting
With the second synchronous rectifier, electric current is flowed to from source electrode and drain, not by the first synchronous rectifier and the second synchronous rectifier
In body diode, and then loss will not be also produced on body diode.
Meanwhile, DC power supply by the first electric capacity and the first diode for the first drive control circuit is powered, it is and straight
It is connected in the second drive control circuit to power, solves the powerup issue of different drive control circuits.
In order to preferably be illustrated to the embodiment of the present invention, below in conjunction with the accompanying drawings, the embodiment that the present invention is provided is entered
Row is specific to be illustrated.
With reference to Fig. 2, Fig. 2 is a kind of structural representation of LED drive circuit provided in an embodiment of the present invention.
The LED drive circuit includes：High-frequency pulse current source 11, isolating transformer T and secondary side rectification circuit；
The isolating transformer T includes：First winding S1 and the second winding S2；And the high-frequency pulse current source 11 and institute
State the first winding S1 connections；
The high-frequency pulse current source 11 is that various circuit topologies such as LLC or LCC are realized, and is an alternating current source, but
In the present invention and it is not construed as limiting.
The secondary side rectification circuit includes：First load circuit and the second load circuit of alternation；Described first is negative
Carrying loop includes the first synchronous rectifier Q1, and second load circuit includes the second synchronous rectifier Q2；Described first is synchronous
Rectifying tube Q1 and the second synchronous rectifier Q2 alternate conductions；The secondary side rectification circuit is also included for driving described first
The first drive control circuit 13 of synchronous rectifier Q1, the second drive control electricity for driving the second synchronous rectifier Q2
Road 14, the first electric capacity C1 and the first diode D1；
Wherein, the reference edge of the source electrode VS of the first synchronous rectifier Q1 and the first drive control circuit 13
GND1, as the input H1-1 of first load circuit；The drain electrode VD of the first synchronous rectifier Q1 is output plus terminal；
The output end H1-2 of first load circuit is connected to the second end S2-1 of the second winding S2；
The input H2-1 of second load circuit connects the second end S2-2 of the second winding S2, and described second is same
The drain electrode VD of step rectifying tube Q2 connects the first end S2-1 of the second winding S2, used as the output end of second load circuit
H2-2；The source electrode VS of the second synchronous rectifier Q2 is output ground terminal GND；
The reference edge GND1 of the first drive control circuit 13 connects the source electrode VS of the first synchronous rectifier Q1；
The anode of the first diode D1 connects the feeder ear VCC of the DC power supply 12, the one or two pole
The negative electrode of pipe D1 connects the feeder ear VCC1 of the first drive control circuit 13；One end connection described first of the first electric capacity C1
The other end of the feeder ear VCC1, the first electric capacity C1 of drive control circuit 13 connects the first drive control circuit 13
Reference edge GND1, the first electric capacity C1 for the first drive control circuit 13 for powering；
The reference edge GND2 of the second drive control circuit 14 connects the source electrode VS of the second synchronous rectifier Q2；Institute
State the feeder ear VCC of the feeder ear VCC2 connection DC power supplies 12 of the second drive control circuit 14, the direct current supply electricity
The earth terminal in source 12 is the reference edge GND2 of the second drive control circuit 14, and when the second synchronous rectifier Q2 conductings
When, the DC power supply 12 is by the first diode D1 for the first electric capacity C1 charges；
The drive end of the first drive control circuit 13 is connected with the grid VG of the first synchronous rectifier Q1；It is described
The drive end of the second drive control circuit 14 is connected with the grid VG of the second synchronous rectifier Q2；That is, described
One synchronous rectifier Q1 is required to corresponding drive control circuit and is driven with the work of the second synchronous rectifier Q2；
Wherein, the isolating transformer T also includes：Tertiary winding S3, the auxiliary source circuit 121 and the tertiary winding
S3 is connected, for obtaining energy from the tertiary winding S3.
Wherein, the output plus terminal of the LED drive circuit connects the positive pole of LED load, and output ground terminal GND connections LED bears
The negative pole of load.
As shown in Fig. 2 because the source electrode VS of the first synchronous rectifier Q1 is not the output of the LED drive circuit
Ground terminal GND, so the reference point of the drive signal of the first synchronous rectifier Q1 is nor the output of the LED drive circuit
Ground terminal GND, but the source electrode VS of the first synchronous rectifier Q1, then earth terminal is auxiliary with what the output ground terminal GND was connected
Helping source circuit 121 can not power for the first drive control circuit 13.
In order to solve the drive control circuit powerup issue of synchronous rectifier, namely two synchronous rectifiers of alternate conduction
Not problem altogether, the application utilize " when the second synchronous rectifier Q2 is turned on, source electrode VS and the output ground of the first synchronous rectifier Q1
Voltage very little between the GND of end, is the conduction voltage drop of the second synchronous rectifier Q2 " this characteristic, devise the first diode D1
With the first electric capacity C1.When the second synchronous rectifier Q2 is turned on, the first diode D1 is the straight of output ground terminal GND by reference to end
Stream power supply 12, is that the first electric capacity C1 charges, and the first electric capacity C1 is stored enough energy；When the second synchronous rectifier Q2 is closed
When disconnected, the first synchronous rectifier Q1 is turned on, the first diode D1 cut-offs, the first electric capacity C1 is supplied for the first drive control circuit 13
Electricity.
Concrete operating principle is as follows：
When the second end S2-2 of the second winding S2 is for just, first end S2-1 is second load circuit when bearing：
S2-2→H2-1→Cout→Q2→H2-2→S2-1；Now, because the second synchronous rectifier Q2 is turned on, so described the
The current potential of one electric capacity C1 one end is equal with the current potential of the output ground terminal GND of the LED drive circuit (to ignore the second synchronous rectifier
The conduction voltage drop of Q2), therefore the DC power supply 12 charged by the first diode D1 to the first electric capacity C1,
The first electric capacity C1 energy storage.
When the second end S2-2 of the second winding S2 is negative, first end S2-1 is timing, first load circuit：
S2-1→H1-1→Q1→Cout→H1-2→S2-2；Now, because the second synchronous rectifier Q2 is closed, the second winding S2
First end S2-1 current potential for Vo (Vo for LED drive circuit output voltage, i.e. voltage on Cout), so the first electric capacity
The current potential of the anode (VCC1) of C1 is Vo+Vc1 (Vc1 is the voltage of the storage on the first electric capacity C1)；Because the LED drives electricity
The output voltage Vo on road usually above the DC power supply 12 supply voltage Vcc, therefore the first diode D1 negative electrodes
Voltage is more than the voltage of the first diode D1 anodes, and the first diode D1 reversely ends, and the first electric capacity C1 is described
First drive control circuit 13 is powered, so that the normal output drive signal of the first drive control circuit 13.
It should be noted that the Cout is expressed as load, and first load circuit and second load circuit
Including but not limited to above device and node.
It follows that by by the feeder ear VCC1 of the first drive control circuit 13 and the one of the first electric capacity C1
End connection, the reference edge GND1 of the first drive control circuit 13 is connected with the other end of the first electric capacity C1, Jin Ershi
The purpose that the first electric capacity C1 is the power supply of the first drive control circuit 13 is showed.
By foregoing description, the LED drive circuit instead of by using synchronous rectifier as rectification part
Diode, solves the problems, such as that on-state loss is big caused by diode is as rectification part, and solve all drive controls
The powerup issue of circuit.
Optionally, the DC power supply 12 is the auxiliary source circuit 121 of the LED drive circuit.
Because the earth terminal of the auxiliary source circuit 121 is connected with the output ground terminal GND of the LED drive circuit, such as Fig. 3
Shown, the output ground terminal GND of the LED drive circuit is the source electrode VS of the second synchronous rectifier Q2, same by described second
The source electrode VS of step rectifying tube Q2 is connected with the output ground terminal GND of the LED drive circuit, and by the second drive control circuit
14 reference edge GND2 is connected with the output ground terminal GND of the LED drive circuit, then the second drive control circuit 14
Power supply source can be just the auxiliary source circuit 121, therefore by the feeder ear VCC2 of the second drive control circuit 14 with
The output end VCC connections of the auxiliary source circuit 121, for obtaining power supply.It should be noted that the auxiliary source circuit
121 can also power for other circuit units in LED drive circuit simultaneously, such as loop control unit is powered.
Based on above-described embodiment, with reference to Fig. 3, Fig. 3 is the structure of another LED drive circuit provided in an embodiment of the present invention
Schematic diagram.Wherein, second load circuit includes：Second electric capacity C2；
One end of the second electric capacity C2 is the input of second load circuit, with the second winding S2 second
End S2-2 connections；The other end of the second electric capacity C2 is connected with the drain electrode VD of the first synchronous rectifier Q1, and as institute
State the output plus terminal of LED drive circuit；
First load circuit includes：3rd electric capacity C3；
One end of the 3rd electric capacity C3 is the output end of first load circuit, with the second winding S2 second
End S2-2 connections；The reference edge GND2 of the other end of the 3rd electric capacity C3 and the second drive control circuit 14 respectively with institute
The source electrode VS connections of the second synchronous rectifier Q2 are stated, and as the output ground terminal GND of the LED drive circuit.
Now, the secondary side rectification circuit includes：First synchronous rectifier Q1, the second synchronous rectifier Q2, first drive
Control circuit 13, the second drive control circuit 14, the first electric capacity C1, the first diode D1, the second electric capacity C2 and the 3rd electric capacity C3,
The secondary side rectification circuit is voltage-multiplied synchronizing rectifier circuit.
Based on above-described embodiment, with reference to Fig. 4, Fig. 4 is the structure of another LED drive circuit provided in an embodiment of the present invention
Schematic diagram.Wherein, second load circuit includes：3rd synchronous rectifier Q3；First load circuit includes：4th is same
Step rectifying tube Q4；
In first load circuit, the drain electrode of the 4th synchronous rectifier Q4 is the output of first load circuit
End, connects the second end of second winding, and the source electrode of the 4th synchronous rectifier Q4 connects the output ground terminal；
In second load circuit, the source electrode Q3 of the 3rd synchronous rectifier is the input of second load circuit
End, connects the second end of second winding, and the drain electrode of the 3rd synchronous rectifier connects the output plus terminal；
The secondary side rectification circuit also includes the 4th drive control circuit for driving the 4th synchronous rectifier Q4
42nd, for driving the 3rd drive control circuit 41, the second diode D2 and the 4th electric capacity C4 of the 3rd synchronous rectifier Q3；
Wherein, the first synchronous rectifier Q1 and the 4th synchronous rectifier Q4 is synchronously turned on, the second synchronous rectifier Q2
Synchronously turned on the 3rd synchronous rectifier Q3；
Wherein, the drain electrode VD of the 3rd synchronous rectifier Q3 is connected with the drain electrode VD of the first synchronous rectifier Q1,
And as the output plus terminal of the LED drive circuit；
Source electrode VS, the reference edge GND4 of the 4th drive control circuit 42 of the 4th synchronous rectifier Q4 and described
Source electrode VSs of the reference edge GND2 of the second drive control circuit 14 respectively with the second synchronous rectifier Q2 is connected, and as institute
State the output ground terminal GND of LED drive circuit；
It is the source electrode VS of the 3rd synchronous rectifier Q3, the reference edge GND3 of the 3rd drive control circuit 41, described
The drain electrode VD of one end of the 4th electric capacity C4 and the 4th synchronous rectifier Q4 respectively with the second end S2- of the second winding S2
2 connections；
The negative electrode of the feeder ear VCC3 of the 3rd drive control circuit 41 and the second diode D2 respectively with it is described
The other end connection of the 4th electric capacity C4, the 4th electric capacity C4 is used to be powered for the 3rd drive control circuit 41；Described
The feeder ear VCC4 of the anode of two diode D2 and the 4th drive control circuit 42 respectively with the auxiliary source circuit 121
Output end VCC is connected；
The earth terminal of the auxiliary source circuit 121 and the second drive control circuit 14 and the 4th drive control electricity
The reference edge on road 42 is identical all for the output negative terminal GND of LED drive circuit, therefore the auxiliary source circuit 121 can be directly used for
It is that the second drive control circuit 14 and the 4th drive control circuit 42 are powered, and as the 4th synchronous rectifier Q4
During conducting, the auxiliary source circuit 121 is by the second diode D2 for the 4th electric capacity C4 charges.
Now, the secondary side rectification circuit includes：First synchronous rectifier Q1, the second synchronous rectifier Q2, first drive
Control circuit 13, the second drive control circuit 14, the first electric capacity C1, the first diode D1, the 3rd synchronous rectifier Q3, the 3rd drive
Dynamic control circuit 41, the second diode D2, the 4th electric capacity C4, the 4th synchronous rectifier Q4 and the 4th drive control circuit 42, institute
Secondary side rectification circuit is stated for full bridge rectifier.
As shown in figure 4, because the source electrode VS of the 3rd synchronous rectifier Q3 is not the output of the LED drive circuit
Ground terminal GND, so the reference point of the drive signal of the 3rd synchronous rectifier Q3 is nor the output of the LED drive circuit
Ground terminal GND, but the source electrode VS of the 3rd synchronous rectifier Q3, then earth terminal is auxiliary with what the output ground terminal GND was connected
Helping source circuit 121 can not power for the 3rd drive control circuit 41, therefore, the present invention first passes through auxiliary source circuit 121
It is the 4th electric capacity C4 energy storage by the second diode D2；During work, then it is the 3rd drive control electricity by the 4th electric capacity C4
Road 41 powers；Concrete operating principle is as follows：
When the first end S2-1 of the second winding S2 is for just, the second end S2-2 for it is negative when, it is the second winding S2, described
First synchronous rectifier Q1, the load C out and the 4th synchronous rectifier Q4 constitute loop；Now, first electric capacity
C1 powers for the first drive control circuit 13, and due to the 4th synchronous rectifier Q4 conductings, so the 4th electricity
The current potential of appearance C4 one end is equal with the current potential of the output ground terminal GND of the LED drive circuit (to ignore the 4th synchronous rectifier Q4's
Conduction voltage drop), therefore the auxiliary source circuit 121 charged by the second diode D2 to the 4th electric capacity C4, it is described
4th electric capacity C4 energy storage.
When the first end S2-1 of the second winding S2 is negative, the second end S2-2 is timing, the second winding S2, described
3rd synchronous rectifier Q3, the load C out and the second synchronous rectifier Q2 constitute loop；Now, due to the described 4th
Synchronous rectifier Q4 is closed, the 3rd synchronous rectifier Q3 conducting, thus the current potential of described 4th electric capacity C4 one end with it is described
The current potential of the output plus terminal of LED drive circuit is equal, therefore the current potential of the anode of the 4th electric capacity C4 is cloudy the second diode
The current potential of pole is that (Vo is the voltage on Cout for the output voltage of LED drive circuit to Vc4+Vo, and Vc4 is on the 4th electric capacity C4
The voltage of storage), because the voltage Vo of the output plus terminal of the LED drive circuit is defeated usually above the auxiliary source circuit 121
Go out the voltage vcc at end, therefore, the voltage of the voltage more than the second diode D4 anodes of the second diode D4 negative electrodes, described second
Diode D2 reversely ends, and the 4th electric capacity C4 powers for the 3rd drive control circuit 41, so that the described 3rd drives
The control normal output drive signal of circuit 41.And under this working condition, the auxiliary source circuit 121 passes through described first
Diode D1 charges to the first electric capacity C1, the first electric capacity C1 energy storage.
It follows that by by the feeder ear VCC3 of the 3rd drive control circuit 41 and the one of the 4th electric capacity C4
End connection, the reference edge GND3 of the 3rd drive control circuit 41 is connected with the other end of the 4th electric capacity C4, Jin Ershi
The purpose that the 4th electric capacity C4 is the power supply of the 3rd drive control circuit 41 is showed.
Further, due to the auxiliary source circuit 121 earth terminal and the LED drive circuit output ground terminal GND
Connection, as shown in figure 4, the output ground terminal GND of the LED drive circuit is the source electrode VS of the 4th synchronous rectifier Q4, will
The source electrode VS of the 4th synchronous rectifier Q4 is connected with the output ground terminal GND of the LED drive circuit, and by the 4 wheel driven
The reference edge GND4 of dynamic control circuit 42 is connected with the output ground terminal GND of the LED drive circuit, then the described 4th drives control
The power supply source of circuit processed 42 can be just the auxiliary source circuit 121, therefore by the confession of the 4th drive control circuit 42
Electric end VCC4 is connected with the output end VCC of the auxiliary source circuit 121, for obtaining power supply.It should be noted that described
Auxiliary source circuit 121 can also be simultaneously that other circuit units in LED drive circuit are powered, such as loop control unit is supplied
Electricity.
By foregoing description, in embodiments of the present invention, the LED drive circuit is by using synchronous rectifier as whole
Stream unit instead of diode, solve the problems, such as that on-state loss is big caused by diode is as rectification part, and solve
The powerup issue of all drive control circuits.
Based on above-described embodiment, with reference to Fig. 5, Fig. 5 is a kind of structure of drive control circuit provided in an embodiment of the present invention
Schematic diagram.Wherein, the first drive control circuit 13 includes：The detection unit 51 of first processing units 52 and first；Described
One detection unit 51 is in parallel with the first synchronous rectifier Q1, the source-drain voltage for detecting the first synchronous rectifier Q1
Vsd, and testing result is sent to the first processing units 52；The first processing units 52 are used for according to the described first inspection
The testing result for surveying unit 51 produces drive signal；And send to the first synchronous rectifier Q1, tool the drive signal
Body is to send to the grid VG of the first synchronous rectifier Q1；
The second drive control circuit 14 includes：Second processing unit and the second detection unit；Second detection is single
It is first in parallel with the second synchronous rectifier Q2, the source-drain voltage Vsd for detecting the second synchronous rectifier Q2, and will inspection
Result is surveyed to send to the second processing unit；The second processing unit is used for according to the inspection of the second synchronous rectifier Q2
Survey result and produce drive signal；And send to the second synchronous rectifier Q2 the drive signal, specifically, sending to institute
State the grid VG of the second synchronous rectifier Q2；
The 3rd drive control circuit 41 includes：3rd processing unit and the 3rd detection unit；3rd detection is single
It is first in parallel with the 3rd synchronous rectifier Q3, the source-drain voltage Vsd for detecting the 3rd synchronous rectifier Q3, and will inspection
Result is surveyed to send to the 3rd processing unit；3rd processing unit is used for according to the inspection of the 3rd synchronous rectifier Q3
Survey result and produce drive signal, and the drive signal is sent to the 3rd synchronous rectifier Q3, specifically, sending to institute
State the grid VG of the 3rd synchronous rectifier Q3；
The 4th drive control circuit 42 includes：Fourth processing unit and the 4th detection unit；4th detection is single
It is first in parallel with the 4th synchronous rectifier Q4, the source-drain voltage Vsd for detecting the 4th synchronous rectifier Q4, and will inspection
Result is surveyed to send to the fourth processing unit；The fourth processing unit is used for according to the inspection of the 4th synchronous rectifier Q4
Survey result and produce drive signal, and the drive signal is sent to the 4th synchronous rectifier Q4, specifically, sending to institute
State the grid VG of the 4th synchronous rectifier Q3.
Illustrated by taking the first synchronous rectifier Q1 as an example below, as shown in figure 5, when first detection unit 51 is detected
Source-drain voltage Vsd to the first synchronous rectifier Q1 is forward conduction voltage (the i.e. pole of body two of the first synchronous rectifier Q1
Pipe A forward conductions) when, the first processing units 52 produce first to turn on drive signal, make the first synchronous rectifier Q1
Conducting, when the source-drain voltage Vsd forward voltage drops that first detection unit 51 detects the first synchronous rectifier Q2 are zero
(i.e. no electric current flows through the first synchronous rectifier Q1) or the source-drain voltage Vsd are that (i.e. described first is same for reverse pressure drop
The drain electrode VD voltage ratio source electrode VS voltages of step rectifying tube Q1 are high) when, the shut-off of the generation of the first processing units 52 first drives letter
Number.
Because after the first synchronous rectifier Q1 is turned on, the electric current I in circuit passes through first synchronous rectifier
The conducting resistance of Q1 not by body diode A, therefore will not produce damage by source electrode VS flow direction drain electrode VD on body diode A
Consumption.It should be noted that the conducting resistance does not embody in Figure 5.
Because electric current I can be by conducting resistance Rdson, then the loss Qr=I produced by conducting resistance2* Rdson, if
Electric current I passes through body diode A, the loss Qd=I*Vd produced by body diode A.But due to the first synchronous rectifier Q1
Conducting resistance Rdson resistance it is minimum, and the Vd of body diode A is typically fixed and 0.7V.Therefore, Qr is far smaller than Qd, then
Illustrate to make Q1 for rectifying device can improve circuit efficiency using first synchronous rectifier.
Similarly, when the source-drain voltage Vsd that second detection unit detects the second synchronous rectifier Q2 is forward direction
During conducting voltage, the second processing unit generation second turns on drive signal；Described in being detected when second detection unit
The source-drain voltage Vsd forward voltage drops of the second synchronous rectifier Q2 are zero or during for reverse pressure drop, the second processing unit generation
Second shut-off drive signal；
When the source-drain voltage Vsd that the 3rd detection unit detects the 3rd synchronous rectifier Q3 is forward conduction electricity
During pressure, the 3rd processing unit generation the 3rd turns on drive signal；When the 3rd detection unit, to detect the described 3rd same
The source-drain voltage Vsd forward voltage drops of step rectifying tube Q3 are zero or during for reverse pressure drop, and the 3rd processing unit generation the 3rd is closed
Disconnected drive signal；
When the source-drain voltage Vsd that the 4th detection unit detects the 4th synchronous rectifier Q4 is forward conduction electricity
During pressure, the fourth processing unit generation the 4th turns on drive signal；When the 4th detection unit, to detect the described 4th same
The source-drain voltage Vsd forward voltage drops of step rectifying tube Q4 are zero or during for reverse pressure drop, and the fourth processing unit generation the 4th is closed
Disconnected drive signal.
Optionally, in embodiments of the present invention, with reference to Fig. 6, Fig. 6 is a kind of synchronous rectifier provided in an embodiment of the present invention
Structural representation.The first synchronous rectifier Q1 is integrated in the first synchronous rectifier with the first drive control circuit 13
In TQ1, i.e., described first synchronous rectifier TQ1 is integrated in institute with the first processing units 52 and first detection unit 51
In stating the first synchronous rectifier TQ1；Wherein, the source electrode VS of the first synchronous rectifier Q1 and the first drive control circuit
13 reference edge GND1 connections.
The source S of the first synchronous rectifier TQ1 is the source electrode VS of the first synchronous rectifier Q1；Described first
The drain D of synchronous rectifier TQ1 is the drain electrode VD of the first synchronous rectifier Q1, the first synchronous rectifier TQ1's
Feeder ear VCC1 is the feeder ear VCC1 of the first drive control circuit 13.
That is, the first synchronous rectifier Q1 with the first drive control circuit 13 as an integrated electricity
Road, defines the integrated circuit for the first synchronous rectifier TQ1, and the first synchronous rectifier TQ1 includes：Source S, leakage
Pole D and feeder ear VCC1, referred to as three end synchronous rectifiers.
Similarly, the second synchronous rectifier Q2 is integrated in the second synchronous rectifier with the second drive control circuit 14
In TQ2, i.e., described second synchronous rectifier Q2 is integrated in described with the second processing unit and second detection unit
In two synchronous rectifier TQ2；Wherein, the source electrode VS of the second synchronous rectifier Q2 and the second drive control circuit 14
Reference edge GND2 is connected.
The source S of the second synchronous rectifier TQ2 is the source electrode VS of the second synchronous rectifier Q2；Described second
The drain D of synchronous rectifier TQ2 is the drain electrode VD of the second synchronous rectifier Q2, the second synchronous rectifier TQ2's
Feeder ear VCC2 is the feeder ear VCC2 of the second drive control circuit 14.
That is, the second synchronous rectifier Q2 with the second drive control circuit 14 as an integrated electricity
Road, defines the integrated circuit for the second synchronous rectifier TQ2, and the second synchronous rectifier TQ2 includes：Source S, leakage
Pole D and feeder ear VCC2, referred to as three end synchronous rectifiers.
The 3rd synchronous rectifier Q3 is integrated in the 3rd synchronous rectifier TQ3 with the 3rd drive control circuit 41
In, i.e., it is same that described 3rd synchronous rectifier Q3 is integrated in the described 3rd with the 3rd processing unit and the 3rd detection unit
In step rectifier TQ3；Wherein, the reference of the source electrode VS of the 3rd synchronous rectifier Q3 and the 3rd drive control circuit 41
End GND3 connections.
The source S of the 3rd synchronous rectifier TQ3 is the source electrode VS of the 3rd synchronous rectifier Q3；Described 3rd
The drain D of synchronous rectifier TQ3 is the drain electrode VD of the 3rd synchronous rectifier Q3, the 3rd synchronous rectifier TQ3's
Feeder ear VCC3 is the feeder ear VCC3 of the 3rd drive control circuit 41.
That is, the 3rd synchronous rectifier Q3 with the 3rd drive control circuit 41 as an integrated electricity
Road, defines the integrated circuit for the 3rd synchronous rectifier TQ3, and the 3rd synchronous rectifier TQ3 includes：Source S, leakage
Pole D and feeder ear VCC3, referred to as three end synchronous rectifiers.
The 4th synchronous rectifier Q4 is integrated in the 4th synchronous rectifier TQ4 with the 4th drive control circuit 42
In, i.e., it is same that described 4th synchronous rectifier Q4 is integrated in the described 4th with the fourth processing unit and the 4th detection unit
In step rectifier TQ4；Wherein, the reference of the source electrode VS of the 4th synchronous rectifier Q4 and the 4th drive control circuit 42
End GND4 connections.
The source S of the 4th synchronous rectifier TQ4 is the source electrode VS of the 4th synchronous rectifier Q4；Described 4th
The drain D of synchronous rectifier TQ4 is the drain electrode VD of the 4th synchronous rectifier Q4, the 4th synchronous rectifier TQ4's
Feeder ear VCC4 is the feeder ear VCC4 of the 4th drive control circuit 42.
That is, the 4th synchronous rectifier Q4 with the 4th drive control circuit 42 as an integrated electricity
Road, defines the integrated circuit for the 4th synchronous rectifier TQ4, and the 4th synchronous rectifier TQ4 includes：Source S, leakage
Pole D and feeder ear VCC4, referred to as three end synchronous rectifiers.
With reference to Fig. 7, Fig. 7 is the structural representation of another LED drive circuit provided in an embodiment of the present invention.Described first
The source S of synchronous rectifier TQ1 is connected with one end of the first electric capacity C1；The feeder ear of the first synchronous rectifier TQ1
VCC1 is connected with the other end of the first electric capacity C1, for obtaining power supply；The first electric capacity C1 is same with described first
One end that the feeder ear VCC1 of step rectifier TQ1 is connected is connected to the output end of auxiliary source circuit 121 by the first diode D1
VCC, and the anode of first diode connects the output end VCC of the auxiliary source circuit 121, negative electrode connection described first
The feeder ear VCC1 of synchronous rectifier TQ1.
The source S of the second synchronous rectifier TQ2 is connected with the output ground terminal GND of the LED drive circuit, and described
The feeder ear VCC2 of two synchronous rectifier TQ2 is connected with the output end VCC of the auxiliary source circuit 121, the auxiliary source circuit
121 are used to be powered for the second synchronous rectifier TQ2.
With reference to Fig. 8, Fig. 8 is the structural representation of another LED drive circuit provided in an embodiment of the present invention, the described 3rd
The source S of synchronous rectifier TQ3 is connected with one end of the 4th electric capacity C4；The feeder ear of the 3rd synchronous rectifier TQ3
VCC3 is connected with the other end of the 4th electric capacity C4, for obtaining power supply；The 4th electric capacity C4 is same with the described 3rd
One end that the feeder ear VCC3 of step rectifier TQ3 is connected is connected to the output end of auxiliary source circuit 121 by the second diode D2
VCC, and the anode of second diode connects the output end VCC of the auxiliary source circuit 121, negative electrode connection the described 3rd
The feeder ear VCC3 of synchronous rectifier TQ3.
The source S of the 4th synchronous rectifier TQ4 is connected with the output ground terminal GND of the LED drive circuit, and described
The feeder ear VCC4 of four synchronous rectifier TQ4 is connected with the output end VCC of the auxiliary source circuit 121, the auxiliary source circuit
121 are used to be powered for the 4th synchronous rectifier TQ4.
It should be noted that " being ... that .. powers " mentioned in the application, the first electric capacity is the first driving control as described
Circuit " power supply " processed, or first electric capacity is powered for first synchronous rectifier, or the 4th electric capacity is the described 3rd
Drive control circuit " power supply ", or the 4th electric capacity is powered for the 3rd synchronous rectifier, or auxiliary source circuit as described
For the second drive control circuit is powered, etc., refer to：For it provides direct current, to aid in the power supply of its work.
A kind of LED drive circuit provided by foregoing description, the present invention, instead of by setting synchronous rectifier
Rectification part diode of the prior art, solves the problems, such as that on-state loss is big caused by diode is as rectification part, and
And be used to turn on corresponding synchronous rectifier by corresponding drive control circuit, electric current is flowed to from source electrode and drain, and
Not by the body diode in synchronous rectifier, and then loss will not be also produced on body diode.
Meanwhile, being changed by the energy of the first electric capacity and the first diode makes the first electric capacity be supplied into the first drive control circuit
Electricity, being changed by the energy of the 4th electric capacity and the second diode makes the 4th electric capacity be powered into the 3rd drive control circuit, auxiliary source
Circuit is that the second drive control circuit and the 4th drive control circuit are powered, and the power supply for solving different drive control circuits is asked
Topic.
The foregoing description of the disclosed embodiments, enables professional and technical personnel in the field to realize or uses the present invention.
Various modifications to these embodiments will be apparent for those skilled in the art, as defined herein
General Principle can be realized in other embodiments without departing from the spirit or scope of the present invention.Therefore, the present invention
The embodiments shown herein is not intended to be limited to, and is to fit to and principles disclosed herein and features of novelty phase one
The scope most wide for causing.
Claims (10)
1. a kind of LED drive circuit, it is characterised in that including：High-frequency pulse current source, isolating transformer, secondary side rectification circuit；
Wherein, the isolating transformer includes：First winding and the second winding；The high-frequency pulse current source with described first around
Group connection；
The secondary side rectification circuit includes：First load circuit and the second load circuit of alternation；Described first loads back
Road includes the first synchronous rectifier, and second load circuit includes the second synchronous rectifier；First synchronous rectifier and
The second synchronous rectifier alternate conduction；The secondary side rectification circuit is also included for driving first synchronous rectifier
First drive control circuit, the second drive control circuit, the first electric capacity and first for driving second synchronous rectifier
Diode；
The source electrode of first synchronous rectifier is connected with the first end of second winding, used as first load circuit
Input；The drain electrode of first synchronous rectifier is output plus terminal；The output end of first load circuit is connected to described
Second end of the second winding；
The input of second load circuit connects the second end of second winding, the drain electrode of second synchronous rectifier
The first end of second winding is connected, as the output end of second load circuit；The source of second synchronous rectifier
Extremely export ground terminal；
The reference edge of the first drive control circuit connects the source electrode of first synchronous rectifier；
The reference edge of the second drive control circuit connects the source electrode of second synchronous rectifier；Second drive control
The feeder ear connection DC power supply of circuit, the earth terminal of the DC power supply is the second drive control circuit
Reference edge；
The anode of first diode connects the DC power supply, and the negative electrode connection first of first diode drives
Control the feeder ear of circuit；One end of first electric capacity connects the feeder ear of the first drive control circuit, described first
The other end of electric capacity connects the reference edge of the first drive control circuit.
2. LED drive circuit according to claim 1, it is characterised in that the first drive control circuit includes：First
Processing unit and the first detection unit；First detection unit is in parallel with first synchronous rectifier, described for detecting
The source-drain voltage of the first synchronous rectifier, and testing result is sent to the first processing units；
The first processing units are used to produce drive signal according to the testing result；And send to institute the drive signal
State the grid of the first synchronous rectifier；
The second drive control circuit includes：Second processing unit and the second detection unit；
Second detection unit is in parallel with second synchronous rectifier, the source and drain for detecting second synchronous rectifier
Voltage, and testing result is sent to the second processing unit；
The second processing unit is used to produce drive signal according to the testing result；And send to institute the drive signal
State the grid of the second synchronous rectifier.
3. LED drive circuit according to claim 2, it is characterised in that when first detection unit detect it is described
When the source-drain voltage of the first synchronous rectifier is forward conduction voltage, the conducting of first processing units generation first drives letter
Number；It is zero or reversely to press when the source-drain voltage forward voltage drop that first detection unit detects first synchronous rectifier
During drop, the first processing units generation first turns off drive signal；
It is described when the source-drain voltage that second detection unit detects second synchronous rectifier is forward conduction voltage
Second processing unit generation second turns on drive signal；When second detection unit detects second synchronous rectifier
Source-drain voltage forward voltage drop is zero or during for reverse pressure drop, and the second processing unit generation second turns off drive signal.
4. LED drive circuit according to claim 3, it is characterised in that first load circuit also includes the 3rd electricity
Hold, second load circuit also includes the second electric capacity；
In first load circuit, one end of the 3rd electric capacity is the output end of first load circuit, and connection is described
Second end of the second winding；The other end of the 3rd electric capacity connects the output ground terminal；
In second load circuit, one end of second electric capacity is the input of second load circuit, and connection is described
Second end of the second winding；The other end of second electric capacity connects the output plus terminal.
5. LED drive circuit according to claim 3, it is characterised in that first load circuit also includes that the 4th is same
Step rectifying tube, second load circuit also includes the 3rd synchronous rectifier；
The secondary side rectification circuit is also included for driving the 4th drive control circuit of the 4th synchronous rectifier, for driving
Move the 3rd drive control circuit, the second diode and the 4th electric capacity of the 3rd synchronous rectifier；Wherein, described first is synchronous
The synchronously conducting of rectifying tube and the 4th synchronous rectifier, second synchronous rectifier and the 3rd synchronous rectifier synchronization
Conducting；
In first load circuit, the drain electrode of the 4th synchronous rectifier is the output end of first load circuit, even
The second end of second winding is connect, the source electrode of the 4th synchronous rectifier connects the output ground terminal；
In second load circuit, the source electrode of the 3rd synchronous rectifier is the input of second load circuit, even
The second end of second winding is connect, the drain electrode of the 3rd synchronous rectifier connects the output plus terminal；
The reference edge of the 3rd drive control circuit connects the source electrode of the 3rd synchronous rectifier；3rd drive control
The output end of circuit is connected with the grid of the 3rd synchronous rectifier；The anode of second diode connects the direct current and supplies
Power supply, the negative electrode of second diode connects the feeder ear of the 3rd drive control circuit；The one of 4th electric capacity
The feeder ear of end connection the 3rd drive control circuit；The other end of the 4th electric capacity connects the 3rd drive control electricity
The reference edge on road；
The reference edge of the 4th drive control circuit connects the source electrode of the 4th synchronous rectifier；4th drive control
The output end of circuit is connected with the grid of the 4th synchronous rectifier；The feeder ear connection institute of the 4th drive control circuit
State DC power supply.
6. LED drive circuit according to claim 5, it is characterised in that the 3rd drive control circuit includes：3rd
Processing unit and the 3rd detection unit；
3rd detection unit is in parallel with the 3rd synchronous rectifier, the source and drain for detecting the 3rd synchronous rectifier
Voltage, and testing result is sent to the 3rd processing unit；
3rd processing unit is used to produce drive signal according to the testing result, and the drive signal is sent to institute
State the grid of the 3rd synchronous rectifier；
The 4th drive control circuit includes：Fourth processing unit and the 4th detection unit；
4th detection unit is in parallel with the 4th synchronous rectifier, the source and drain for detecting the 4th synchronous rectifier
Voltage, and testing result is sent to the fourth processing unit；
The fourth processing unit is used to produce drive signal according to the testing result, and the drive signal is sent to institute
State the grid of the 4th synchronous rectifier；
Wherein, when the source-drain voltage that the 3rd detection unit detects the 3rd synchronous rectifier is forward conduction voltage
When, the 3rd processing unit generation the 3rd turns on drive signal；When the 3rd detection unit detects the described 3rd synchronously
The source-drain voltage forward voltage drop of rectifying tube is zero or during for reverse pressure drop, and the shut-off of the 3rd processing unit generation the 3rd drives letter
Number；
It is described when the source-drain voltage that the 4th detection unit detects the 4th synchronous rectifier is forward conduction voltage
Fourth processing unit generation the 4th turns on drive signal；When the 4th detection unit detects the 4th synchronous rectifier
Source-drain voltage forward voltage drop is zero or during for reverse pressure drop, and the fourth processing unit generation the 4th turns off drive signal.
7. LED drive circuit according to claim 1, it is characterised in that first synchronous rectifier and first drives
Control circuit is integrated in the first synchronous rectifier；
First synchronous rectifier includes：Source electrode, drain electrode and feeder ear；The source electrode of first synchronous rectifier is described
The source electrode of the first synchronous rectifier；The drain electrode of first synchronous rectifier is the drain electrode of first synchronous rectifier, institute
The feeder ear for stating the first synchronous rectifier is the feeder ear of the first drive control circuit；
Or second synchronous rectifier is integrated in the second synchronous rectifier with the second drive control circuit；
Second synchronous rectifier includes：Source electrode, drain electrode and feeder ear；The source electrode of second synchronous rectifier is described
The source electrode of the second synchronous rectifier；The drain electrode of second synchronous rectifier is the drain electrode of second synchronous rectifier, institute
The feeder ear for stating the second synchronous rectifier is the feeder ear of the second drive control circuit.
8. LED drive circuit according to claim 5, it is characterised in that the 3rd synchronous rectifier and the described 3rd
Drive control circuit is integrated in the 3rd synchronous rectifier；
3rd synchronous rectifier includes：Source electrode, drain electrode and feeder ear；The source electrode of the 3rd synchronous rectifier is described
The source electrode of the 3rd synchronous rectifier；The drain electrode of the 3rd synchronous rectifier is the drain electrode of the 3rd synchronous rectifier, institute
The feeder ear for stating the 3rd synchronous rectifier is the feeder ear of the 3rd drive control circuit；
Or the 4th synchronous rectifier is integrated in the 4th synchronous rectifier with the 4th drive control circuit；
4th synchronous rectifier includes：Source electrode, drain electrode and feeder ear；The source electrode of the 4th synchronous rectifier is described
The source electrode of the 4th synchronous rectifier；The drain electrode of the 4th synchronous rectifier is the drain electrode of the 4th synchronous rectifier, institute
The feeder ear for stating the 4th synchronous rectifier is the feeder ear of the 4th drive control circuit.
9. the LED drive circuit according to claim any one of 1-9, it is characterised in that the DC power supply is institute
The auxiliary source circuit of LED drive circuit is stated, the isolating transformer also includes the tertiary winding, the input of the auxiliary source circuit
It is connected with the tertiary winding.
10. LED drive circuit according to claim 9, it is characterised in that the high-frequency pulse current source is LLC circuits
Topology or LCC circuit topologies.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2009142001A (en) * | 2007-12-04 | 2009-06-25 | Yokogawa Electric Corp | Synchronous rectification driving circuit |
| US20100244707A1 (en) * | 2007-12-07 | 2010-09-30 | Koninklijke Philips Electronics N.V. | Led lamp power management system and method |
| CN102412709A (en) * | 2010-09-17 | 2012-04-11 | 东芝照明技术株式会社 | Switching power supply device and adjustable power supply system including the same |
| CN106208714A (en) * | 2016-08-08 | 2016-12-07 | 杭州士兰微电子股份有限公司 | Synchronous rectifying switching power source and control method |
| CN206759768U (en) * | 2017-03-01 | 2017-12-15 | 浙江英飞特光电有限公司 | A kind of LED drive circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1985427A (en) * | 2004-09-30 | 2007-06-20 | 三垦电气株式会社 | DC power supply apparatus |
| JP2009142001A (en) * | 2007-12-04 | 2009-06-25 | Yokogawa Electric Corp | Synchronous rectification driving circuit |
| US20100244707A1 (en) * | 2007-12-07 | 2010-09-30 | Koninklijke Philips Electronics N.V. | Led lamp power management system and method |
| CN102412709A (en) * | 2010-09-17 | 2012-04-11 | 东芝照明技术株式会社 | Switching power supply device and adjustable power supply system including the same |
| CN106208714A (en) * | 2016-08-08 | 2016-12-07 | 杭州士兰微电子股份有限公司 | Synchronous rectifying switching power source and control method |
| CN206759768U (en) * | 2017-03-01 | 2017-12-15 | 浙江英飞特光电有限公司 | A kind of LED drive circuit |
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| CN106787854B (en) | 2023-06-13 |
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